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1.
Zhonghua Yi Xue Za Zhi ; 103(40): 3211-3218, 2023 Oct 31.
Artigo em Zh | MEDLINE | ID: mdl-37879876

RESUMO

The abdominal wall can be treated as a whole physiological and functional entity which is composed of multiple anatomical structures and planes. Surgical approaches and technical details that required are diverse in different area. Indeed, the abdominal wall is confined by several anatomical boundaries which make these surgical planes separated. If one could dissect these boundaries, then separated spaces could be connected, establishing an ample retromuscular/preperitoneal space to accommodate the mesh of ventral hernia repair. The concept of totally visceral sac separation (TVS) is achieved. The TVS concept is a summary of diverse ventral hernia repair techniques. Since its initiation and spread, this technique has been widely accepted and implemented by domestic surgeons due to its outstanding performance. This treatise will review the relevant anatomy as well assurgical tricks by the authors that aid in performing TVS. Some of the details are more tricky and harder to understand, thus this in-depth description of the technique.


Assuntos
Parede Abdominal , Hérnia Ventral , Laparoscopia , Humanos , Telas Cirúrgicas , Hérnia Ventral/cirurgia , Endoscopia , Parede Abdominal/cirurgia , Herniorrafia/métodos , Laparoscopia/métodos
2.
J Chem Phys ; 152(24): 244704, 2020 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-32610998

RESUMO

The development of two-dimensional (2D) magnetic materials with half-metallic characteristics is of great interest because of their promising applications in spintronic devices with high circuit integration density and low energy consumption. Here, by using density functional theory calculations, ab initio molecular dynamics, and Monte Carlo simulation, we study the stability, electronic structure, and magnetic properties of a OsI3 monolayer, of which crystalline bulk is predicted to be a van der Waals layered ferromagnetic (FM) semiconductor. Our results reveal that the OsI3 monolayer can be easily exfoliated from the bulk phase with small cleavage energy and is energetically and thermodynamically stable at room temperature. Intrinsic half-metallicity with a wide bandgap and FM ordering with an estimated TC = 35 K are found for the OsI3 monolayer. Specifically, the FM ordering can be maintained under external biaxial strain from -2% to 5%. The in-plane magnetocrystalline anisotropy energy of the 2D OsI3 monolayer reaches up to 3.89 meV/OsI3, which is an order larger than that of most magnetic 2D materials such as the representative monolayer CrI3. The excellent magnetic features of the OsI3 monolayer therefore render it a promising 2D candidate for spintronic applications.

3.
Ecotoxicol Environ Saf ; 190: 110128, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31891838

RESUMO

Over the last few decades, the threat posed to biodiversity and ecosystem function by atmospheric nitrogen (N) deposition has been increasingly recognized. The disturbed nutrient balance and species composition of plants induced by higher N deposition can impact the biodiversity of the organisms that consume the plants. In this research, we implemented several experiments to estimate the effects of increased N deposition on the growth, survival, and nutrients of the dominant epiphytic lichens in the subtropical mountains in Central China to assess the lichen food amount and nutritional quality for two endangered primates endemic to China. Our results indicated that the thallus growth and propagule survival of the lichens were significantly decreased when nitrogen addition changed from 6.25 to 50.0 kg N·ha-1·y-1; it was also shown that lichen biomass could be decreased by 11.2%-70.2% when the deposition addition exceeded 6.25 kg N·ha-1·y-1. Further, our study revealed that increased nitrogen deposition also reduced the nutritional quality of the lichens via reducing the soluble protein and soluble sugar levels and increasing the fiber content, which would substantially affect the diet selection of the plants consumers in the region, particularly the populations of the two lichen-eating endangered primate species, Rhinopithecus roxellana and R. bieti. Our experimental study suggested that the nitrogen pollution derived from anthropogenic activities could cause cascading effects for the whole forest ecosystem of Central China; thus, more studies about nitrogen deposition in this region are required.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Líquens/química , Nitrogênio/análise , Animais , Atmosfera , Biodiversidade , Biomassa , China , Ecossistema , Poluição Ambiental , Abastecimento de Alimentos , Florestas , Líquens/metabolismo , Nitrogênio/metabolismo , Primatas
4.
Beijing Da Xue Xue Bao Yi Xue Ban ; 50(4): 651-656, 2018 Aug 18.
Artigo em Zh | MEDLINE | ID: mdl-30122766

RESUMO

OBJECTIVE: To analyze the conventional application of using comprehensive hemostatic methods during the perioperative period, and the effect of autologous blood transfusion (ABT) device compared with non-negative pressure drainage on preventing blood loss and allogenic blood transfusion after primary total knee arthroplasty (TKA). METHODS: A total of 131 patients (131 knees) with severe knee osteoarthritis who underwent unilateral primary TKA by the same surgeon in Peking University Third Hospital from June 2014 to June 2015 were enrolled in this study. The patients were divided into ABT group (64 patients) and control group (67 patients). ABT devices were used for drainage and blood transfusion in the ABT group while the control group used the non-negative pressure drainage only. The results of the drainage fluid volume, the decrease of hemoglobin, the total blood loss, the hidden blood loss and blood transfusion after TKA were compared between the two groups. RESULTS: The drainage fluid volume in ABT group was significantly higher than that in control group [515 mL (80-1 610 mL) vs. 260 mL (40-670 mL), P<0.001]. The autologous blood transfusion in ABT group was 245 mL (60-1 070 mL). There were no significant differences between the two groups in the value of hemoglobin decrease 1 day after surgery (P=0.340) and 3 days after surgery (P=0.524). There were no significant differences in the total blood loss (P=0.101) and the hidden blood loss (P=0.062) between the two groups either. There were 9 patients in the 131 patients who received allogeneic blood transfusion, of whom 5 in the ABT group (5/64, the blood transfusion rate was 7.8%) and 4 in the control group (4/67, the blood transfusion rate was 6.0%), and no significant differences in the blood transfusion rate between the two groups (P=0.943). CONCLUSION: With the conventional application of using comprehensive hemostatic methods during perioperative period, the ABT device did not show the effective result of controlling postoperative blood loss and failed to reduce the rate of allogeneic blood transfusion in patients with unilateral primary TKA. However, the ABT device could increase the drainage fluid volume and improve the patient's hospitalization expenses. Therefore, there is no need for routine application of ABT device in unilateral primary TKA.


Assuntos
Artroplastia do Joelho , Perda Sanguínea Cirúrgica , Transfusão de Sangue Autóloga , Transfusão de Sangue , Perda Sanguínea Cirúrgica/prevenção & controle , Transfusão de Sangue Autóloga/instrumentação , Hemostáticos , Humanos
5.
Zhonghua Yi Xue Za Zhi ; 98(36): 2933-2936, 2018 Sep 25.
Artigo em Zh | MEDLINE | ID: mdl-30293353

RESUMO

Objective: Investigating a novel approach to treat a midline ventral hernia--totally endoscopic sublay repair (TES). The procedure will be described in detail and the safety and efficacy evaluated. Methods: During July and December 2017, eleven consecutive cases of primary and secondary epigastric midline ventral hernias were repaired using the TES procedure. A large mesh should be placed in the retrorectus position using this minimally invasive procedure. The indications for this procedure include umbilical, epigastric and incisional hernia equal in length to the rectus diastasis. Results: All operations were successful without open conversion. The mean operation time was 120 mins(80-205 min), postoperative pain was mild and the mean VAS was 2.5 on first postoperative day. The average postoperative stay in hospital was 3.3 days (2-5 days). 2 cases experienced postoperative seroma but without adverse effect on the final outcome and no recurrences during the follow-up period of 1 to 6 months. Conclusions: TES procedure is safe, practical and minimally invasive requiring no specific device and highly reproducible. Besides there is no need for expensive anti-adhesion mesh and fixation tacker which make it more cost effective. TES is a good technique for the surgical treatment of midline ventral hernia.


Assuntos
Hérnia Ventral , Telas Cirúrgicas , Endoscopia , Humanos , Duração da Cirurgia , Complicações Pós-Operatórias
6.
Beijing Da Xue Xue Bao Yi Xue Ban ; 48(2): 351-5, 2016 Apr 18.
Artigo em Zh | MEDLINE | ID: mdl-27080295

RESUMO

OBJECTIVE: To evaluate the efficiency of the tibial coronal alignment after total knee arthroplasty with the extramedullary cutting system guided by the tibial tubercle and anterior tibial tendon, and to discuss the potential risk factors for the postoperative malalignment. METHODS: A retrospective study of 212 primary unilateral TKA surgeries (in 188 patients) in our hospital between June to December in 2014 had been analysed. All the cases were performed by one surgical group. An extramedullary tibial cutting guide system had been used, with a landmark of one third inner-medial tibial tubercle as a proximal anatomy reference, and anterior tibial tendon as a distal marker. The mechanical axis of lower extremity in full-length X-ray was measured before surgery, and the tibial prosthetic coronal alignment was checked two weeks postoperation, evaluating the accuracy of this extramedullary cutting system guided by our method. RESULTS: Since good alignment was defined as an angle within 3 degrees of the perpendicular to the mechanical axis, the tibial component positions were acceptable in 191 knees (90.1%), five knees were in valgus postoperative, and sixteen knees were in varus. There were seventeen(8.7%) in 179 knees with a preoperative varus presented malalignment after surgery, and four in 12 preoperative valgus kneess howed malalignment also, no statistical difference was found by Chi-square test(χ(2)=2.778,P=0.096), which cannot define the relationship between the varus or valgus deformity preoperation and the malalignmentposition in tibial prosthesis after surgery. Twenty-two knees suffered a severe preoperative deformity as a varus or valgus angle larger than 20 degrees with absolute value of mechanical axis before surgery and tibial prosthetic coronal alignment were 21.95 °(20.00°,26.90°)and 1.85°(0.10°, 7.10°), showed a significant difference (Z=2.11,P=0.035) compared with the data [10.65°(0.50°,19.80°)in preoperative mechanical axis and 1.10°(0.00°,4.60°)in the tibial prosthetic coronal alignment]of 190 knees who presented a mild deformity before surgery(less than 20 degrees), the result indicated the severe preoperative deformity might be a potential mal-alignment risk factor within this cutting system in TKA surgery. CONCLUSION: The tibial coronal alignment after total knee arthroplasty could achieve good results with extramedullary cutting guide, by using one third inner-medial tibial tubercle and anterior tibial tendon as a proximal and distal anatomy marker. Postoperative varus might occur in this system, and tibial prosthetic malalignment appeared more often in the patients who suffered a severe deformity before surgery.


Assuntos
Artroplastia do Joelho , Mau Alinhamento Ósseo/diagnóstico , Articulação do Joelho/cirurgia , Tíbia/cirurgia , Povo Asiático , Humanos , Articulação do Joelho/diagnóstico por imagem , Prótese do Joelho , Extremidade Inferior/diagnóstico por imagem , Período Pós-Operatório , Estudos Retrospectivos , Fatores de Risco , Tendões , Tíbia/diagnóstico por imagem
7.
Heredity (Edinb) ; 114(2): 133-42, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25370210

RESUMO

Relatedness between individuals is central to ecological genetics. Multiple methods are available to quantify relatedness from molecular data, including method-of-moment and maximum-likelihood estimators. We describe a maximum-likelihood estimator for autopolyploids, and quantify its statistical performance under a range of biologically relevant conditions. The statistical performances of five additional polyploid estimators of relatedness were also quantified under identical conditions. When comparing truncated estimators, the maximum-likelihood estimator exhibited lower root mean square error under some conditions and was more biased for non-relatives, especially when the number of alleles per loci was low. However, even under these conditions, this bias was reduced to be statistically insignificant with more robust genetic sampling. We also considered ambiguity in polyploid heterozygote genotyping and developed a weighting methodology for candidate genotypes. The statistical performances of three polyploid estimators under both ideal and actual conditions (including inbreeding and double reduction) were compared. The software package POLYRELATEDNESS is available to perform this estimation and supports a maximum ploidy of eight.


Assuntos
Funções Verossimilhança , Modelos Genéticos , Poliploidia , Genótipo , Heterozigoto , Endogamia , Padrões de Herança , Modelos Estatísticos , Software
8.
Cytotherapy ; 10(1): 90-7, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18202978

RESUMO

BACKGROUND: C3H10T1/2 cells, from a mouse embryonic fibroblast cell line, were used to investigate the improvement of alginate-based microencapsulated cells for cellular therapy. METHODS: Purified sodium alginate (PSA) and non-purified sodium alginate (SA) were used to prepare alginate-based microcapsules, and their biocompatibility and membrane strength were then compared for the purposes of analyzing the advantages of purifying SA. In addition, poly-l-lysine (PLL) was replaced by chitosan for alginate-chitosan microcapsule preparation. The process of optimization and chemical modification of alginate-chitosan microcapsules using polyethylene glycol was also reviewed. RESULTS: The results showed improved biocompatibility and membrane strength of PSA-based microcapsules. Under optimal conditions, mesenchymal stromal cell (MSC)-loaded alginate-chitosan microcapsules with good morphology could be obtained using PSA and chitosans of medium molecular weight (1.0-2.5 x 10(5)). A chitosan solution of 0.1% (w/v) and a reaction time of 7 min between alginate and chitosan were determined as optimal preparation parameters. DISCUSSION: It could be concluded that the chemical modification of alginate-based microcapsules can improve their biocompatibility.


Assuntos
Alginatos/química , Materiais Biocompatíveis/química , Cápsulas/química , Transplante de Células-Tronco/métodos , Animais , Materiais Biocompatíveis/farmacologia , Técnicas de Cultura de Células , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Quitosana/química , Células-Tronco Embrionárias/química , Células-Tronco Embrionárias/citologia , Fibroblastos/citologia , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Membranas Artificiais , Camundongos , Polietilenoglicóis/química
9.
Amino Acids ; 33(3): 537-41, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17048123

RESUMO

Optically pure (S)-3-p-hydroxyphenyllactic acid derivatives are important intermediates of peroxisome proliferator-activated receptor alpha/gamma dual agonists and heteropeptides. Many efforts have been made for synthesis of those intermediates, but there exist some flaws yet. We observed that dielectric constants of organic solvents drastically affected diazotization of O-benzyl-L-tyrosine. Optically pure (S)-3-p-benzyloxyphenyllactic acid was obtained by simple recrystallization when DMF or DMSO of higher dielectric constant was used as a co-solvent in diazotization of O-benzyl-L-tyrosine. It was easily turned into various optically pure (S)-3-p-hydroxyphenyllactic acid derivatives.


Assuntos
Fenilpropionatos , Conformação Molecular , Fenilpropionatos/síntese química , Fenilpropionatos/química , Solventes
10.
Chemosphere ; 68(1): 10-6, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17292453

RESUMO

Water, suspended solid (SS) and sediment samples were collected from nine water courses in Tianjin, China and analyzed for dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDXs, including o,p'-,p,p'-DDT, DDD and DDE). The average DDX concentrations in water, SS and sediment were 59+/-30 ng l(-1), 2690+/-1940 ng g(-1)dry wt. and 340+/-930 ng g(-1)dry wt., respectively. Due to the termination of the extensive agricultural application and industrial manufacture, DDXs in river sediment decreased by one order of magnitude since 1970's and low DDT fractions in these sediments were observed. Still, DDXs in the sediments near the outlets of the major manufacturers remained relatively high attributed to the historic input. DDXs in sediment were also positively correlated with organic matter content. Spatial distributions of DDXs in SS and water was different from that in sediment. For SS, a negative correlation between DDX concentration and SS content indicated a dilution effect in many rivers. Dissolved organic carbon content was the major factor affecting DDX concentrations in water phase. Wastewater discharged from dicofol manufacturers and likely illegal agricultural application were the primary reasons causing high DDT (DDE+DDD) ratios in SS and water.


Assuntos
DDT/análise , Poluição Química da Água/análise , China , DDT/metabolismo , Diclorodifenil Dicloroetileno/análise , Diclorodifenildicloroetano/análise , Sedimentos Geológicos/química , Rios , Microextração em Fase Sólida , Fatores de Tempo
11.
J Anim Sci ; 95(10): 4239-4250, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29108073

RESUMO

Long noncoding RNA (lncRNA) has been increasingly implicated in the regulation of muscle development. Large White pigs have a higher muscle growth rate than do Mashen pigs. In the present study, the lncRNA expression profiles in skeletal muscle of these 2 pig breeds were compared at 1, 90, and 180 d of age using RNA sequencing. We obtained 2,718 million clean reads and identified a total of 5,153 novel lncRNA. We found 1,407 differentially expressed lncRNA that showed consistent expression patterns between the 2 breeds at all the 3 sampling points. Ten lncRNA were randomly selected, and their expression was validated using Real-time Quantitative PCR. In summary, this study identifies a number of lncRNA that correlate with muscle growth. The regulation and function of these lncRNA in muscle growth and development need to be further explored.


Assuntos
Desenvolvimento Muscular/genética , RNA Longo não Codificante/genética , Suínos/genética , Animais , Sequência de Bases , Perfilação da Expressão Gênica/veterinária , Masculino , Músculo Esquelético/crescimento & desenvolvimento , Distribuição Aleatória , Análise de Sequência de RNA/veterinária , Suínos/crescimento & desenvolvimento
12.
Environ Pollut ; 142(3): 567-75, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16360248

RESUMO

A previously published data set of HCH isomer concentrations in topsoil samples from Tianjin, China, was subjected to geospatial analysis. Semivariograms were calculated and modeled using geostatistical techniques. Parameters of semivariogram models were analyzed and compared for four HCH isomers. Two-dimensional ordinary block kriging was applied to HCH isomers data set for mapping purposes. Dot maps and gray-scaled raster maps of HCH concentrations were presented based on kriging results. The appropriateness of the kriging procedure for mapping purposes was evaluated based on the kriging errors and kriging variances. It was found that ordinary block kriging can be applied to interpolate HCH concentrations in Tianjin topsoil with acceptable accuracy for mapping purposes.


Assuntos
Monitoramento Ambiental/métodos , Hexaclorocicloexano/análise , Resíduos de Praguicidas/análise , Poluentes do Solo/análise , China , Coleta de Dados/métodos , Interpretação Estatística de Dados , Monitoramento Ambiental/instrumentação
13.
Environ Pollut ; 139(1): 183-93, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16087280

RESUMO

A level IV fugacity model was used to simulate the dynamic changes of gamma-hexachlorocyclohexane (gamma-HCH) concentrations in environmental media in Tianjin, China. A similar model (level III) was previously used and validated under steady state conditions; this paper explores its dynamic behavior. Application of the level IV fugacity model has been validated using independently observed gamma-HCH concentrations in various media during the early 1980s and during 2001. Sensitivity analysis was conducted using coefficient-of-variation normalized sensitivity coefficients. The model was also subject to uncertainty analysis using Monte Carlo simulation. It was found that concentrations of gamma-HCH reached within 95% of their steady-state levels in all media after less than 15 years. Around one order-of-magnitude decreases in gamma-HCH concentrations in various media occurred between 1993 and 2001. We project that gamma-HCH concentrations will decrease another 1.7-1.9 orders of magnitude to reach 1.1 (0.9-1.2) x 10(-14), 2.7 (2.5-3.0) x 10(-10), 1.2 (1.1-1.3) x 10(-7), and 6.1 (5.4-6.8) x 10(-8) mol/m(3), in air, water, soil, and sediment, respectively, by 2020. The sensitivities and true uncertainty of the model are discussed.


Assuntos
Poluentes Ambientais/análise , Hexaclorocicloexano/análise , Inseticidas/análise , Poluentes Atmosféricos/análise , China , Monitoramento Ambiental/métodos , Sedimentos Geológicos , Resíduos Perigosos/análise , Modelos Químicos , Método de Monte Carlo , Reprodutibilidade dos Testes , Poluentes do Solo/análise , Incerteza , Poluentes Químicos da Água/análise
14.
Sci Total Environ ; 345(1-3): 115-26, 2005 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-15919533

RESUMO

Atmospheric dustfall samples from 23 locations in Tianjin, China, were collected and analyzed for 16 polycyclic aromatic hydrocarbons (PAHs) classified by the Environmental Protection Agency as priority pollutants from March 2002 to March 2003. SigmaPAH16 (sum of 16 PAH compounds) concentrations in the dustfall collected during heating season ranged from 2.5 to 85.5 mug/g, while that during the non-heating season varied from 1.0 to 48.2 microg/g dry weight. The dominant components in the heating season included naphthalene, phenanthrene, fluoranthene, and chrysene, while naphthalene, fluorene, phenanthrene, and fluoranthene were dominant during the non-heating season. Compared with the non-heating season, the heating season was characterized by a higher fraction of high-molecular-weight PAHs with four to six rings with exception of the samples from the east industrial area. The east industrial area had more significant correlations between individual PAH compounds, and more discrete triangular components of three-, four-, five- and six-ring PAHs. No significant correlations were observed between the PAHs concentrations and total organic carbon (TOC) in the dustfall samples. The deposition fluxes of sigmaPAH15 (sum of 15 PAHs except naphthalene), sigmaPAH6 (sum of 6 carcinogenic PAHs recommended by IARC) and benzo[a]pyrene (BaP) from atmospheric deposition to the whole area were estimated as 1911, 196, and 53 microg/m2/year, respectively. The deposition rates for PAH compounds in the east industrial area were higher than those in the urban and rural areas. Furthermore, the deposition contribution of PAHs during domestic heating season in winter was not significant relative to the annual inputs.


Assuntos
Poluição do Ar em Ambientes Fechados/análise , Poeira , Monitoramento Ambiental , Habitação/normas , Hidrocarbonetos Policíclicos Aromáticos/análise , China , Calefação/normas
15.
Environ Pollut ; 134(1): 97-111, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15572228

RESUMO

Tianjin urban/industrial complex is highly polluted by some persistent organic pollutants. In this study, the levels of 16 priority polycyclic aromatic hydrocarbons (PAHs) were tested in sediment, water, and suspended particulate matter (SPM) samples in 10 rivers in Tianjin. The total concentration of 16 PAHs varied from 0.787 to 1943 microg/g dry weight in sediment, from 45.81 to 1272 ng/L in water, and from 0.938 to 64.2 microg/g dry weight in SPM. The levels of PAHs in these media are high in comparison with values reported from other river and marine systems. Variability of total concentrations of PAHs in sediment, water, and SPM from nine different rivers is consistent with each other. No obvious trends of total PAHs concentration variations were found between upstream and downstream sediment, water, and SPM samples for most rivers, which indicate local inputs and disturbances along these rivers. The spatial distributions of three-phase PAHs are very similar to each other, and they are also similar to those found in topsoil. However, their chemical profiles are significantly different from that of topsoil. The change of profiles is consistent with the different aqueous transport capability of 16 PAHs. Low molecular weight PAHs predomination suggests a relatively recent local source and coal combustion source of PAHs in the study area.


Assuntos
Monitoramento Ambiental/métodos , Hidrocarbonetos Policíclicos Aromáticos/análise , Rios/química , Poluentes Químicos da Água/análise , China , Resíduos Industriais
16.
Chemosphere ; 60(6): 753-61, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15939453

RESUMO

The dynamic exposures to HCHs of individuals born between the years 1913 and 1993 in Tianjin have been simulated by connecting a fugacity model (IV) with a multimedia exposure model. Ingestion is the most important pathway for human beings to take up HCHs, and concentrations in the human body correlate with body weight changes. Accumulations of HCHs were derived assuming that the degradation in human body behaved linearly. The health risk of exposure to HCHs was measured using cancer risk and loss of life expectancy (LLE), and LLE was modified from its original definition to incorporate a dynamic calculation that takes variances in exposure into account. Monte-Carlo simulations were run to analyze the uncertainties of the model.


Assuntos
Poluentes Ambientais/análise , Contaminação de Alimentos , Hexaclorocicloexano/análise , Inseticidas/análise , Resíduos de Praguicidas/análise , Fatores Etários , Peso Corporal , China , Produtos Agrícolas , Monitoramento Ambiental , Humanos , Isomerismo , Carne , Modelos Teóricos , Método de Monte Carlo , Medição de Risco , Alimentos Marinhos , Incerteza , Verduras
17.
Int J Biochem Cell Biol ; 32(6): 677-86, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10785364

RESUMO

During recent years, it has become increasingly clear that the ubiquitin-proteasome proteolytic pathway regulates intracellular protein degradation in various physiological and pathophysiological conditions. Substrates specifically degraded by the proteasome are important tools to assess the involvement of the proteasome in cellular proteolysis. It was recently proposed that the membrane permeable substrate methoxysuccinyl-phenylalanine-leucine-phenylalanine-7-amido-4- trifluoromethyl coumarin (FLF) is degraded specifically by the proteasome. The role of other proteolytic pathways in the degradation of FLF, however, is not fully understood. In the present study, we tested the role of different proteolytic pathways in the degradation of FLF in cultured myotubes and HepG2 cells by treating the cells with inhibitors of lysosomal, calpain and proteasome activity. In addition, we tested the hypothesis that insulin blocks proteasome-dependent degradation of FLF in myotubes and HepG2 cells. Results suggest that degradation of FLF in both myotubes and HepG2 cells is regulated by proteasome and calpain activity but not by lysosomal activity. Insulin inhibited proteasome-dependent but not calpain-dependent degradation of FLF in both myotubes and HepG2 cells. The results are important because they suggest that FLF degradation does not specifically reflect proteasome activity.


Assuntos
Calpaína/metabolismo , Cumarínicos/metabolismo , Cisteína Endopeptidases/metabolismo , Complexos Multienzimáticos/metabolismo , Oligopeptídeos/metabolismo , Animais , Cálcio/metabolismo , Linhagem Celular , Inibidores de Cisteína Proteinase/farmacologia , Humanos , Insulina/metabolismo , Insulina/farmacologia , Lactonas/farmacologia , Lisossomos/metabolismo , Masculino , Complexo de Endopeptidases do Proteassoma , Ratos , Ratos Sprague-Dawley , Células Tumorais Cultivadas
18.
Endocrinology ; 141(8): 2743-51, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10919258

RESUMO

We examined the effect of insulin-like growth factor I (IGF-I), administered in vivo, on protein turnover rates and gene expression of the ubiquitin-proteasome proteolytic pathway in skeletal muscle of septic rats. Sepsis was induced by cecal ligation and puncture. Other rats were sham-operated. Miniosmotic pumps were implanted sc, and groups of rats received IGF-I (7 mg/kg x 24 h) or saline. Protein synthesis and breakdown rates were determined in incubated extensor digitorum longus muscles. Messenger RNA levels for ubiquitin and the ubiquitin-conjugating enzyme E2(14k) were determined by Northern blot analysis. Sepsis resulted in an approximately 30% reduction of muscle protein synthesis, and this effect of sepsis was blunted in rats treated with IGF-I. In contrast, IGF-I did not prevent the sepsis-induced increase in total and myofibrillar muscle protein breakdown. Ubiquitin and E2(14k) messenger RNA levels were increased several fold in muscle from septic rats, and this effect of sepsis was abolished in IGF-I treated rats. The results suggest that administration of IGF-I may improve sepsis-induced muscle cachexia by stimulating protein synthesis. However, because muscles were resistant to IGF-I, with regard to regulation of protein breakdown, the use of IGF-I to treat muscle cachexia during sepsis remains unclear. An additional important implication of the present study is that changes in messenger RNA levels for ubiquitin and the ubiquitin-conjugating enzyme E2(14k) do not always reflect changes in muscle protein breakdown rates.


Assuntos
Expressão Gênica/efeitos dos fármacos , Fator de Crescimento Insulin-Like I/farmacologia , Ligases/genética , Proteínas Musculares/metabolismo , Sepse/metabolismo , Ubiquitinas/genética , Animais , Northern Blotting , Masculino , Miofibrilas/metabolismo , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Enzimas de Conjugação de Ubiquitina
19.
Clin Exp Metastasis ; 2(3): 205-12, 1984.
Artigo em Inglês | MEDLINE | ID: mdl-6543700

RESUMO

ECA109 human oesophageal carcinoma cells were injected either subcutaneously or intraperitoneally into BALB/CATc 1-nu/nu mice. After 23 weeks tumours were examined histologically and by scanning electron microscopy. Subcutaneous ECA109 tumours were well-delineated without signs of invasion. By contrast, intra-abdominal tumours invaded into the abdominal wall and abdominal organs. This result provides us with another example of site-dependence of invasion in vivo.


Assuntos
Neoplasias Esofágicas/patologia , Animais , Linhagem Celular , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Microscopia Eletrônica de Varredura , Invasividade Neoplásica , Transplante de Neoplasias , Fatores de Tempo
20.
Transplantation ; 64(1): 114-23, 1997 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-9233711

RESUMO

BACKGROUND: Protocols that incorporate donor-specific cell infusions using bone marrow, spleen, or blood transfusion continue to enhance allograft survival and often lead to tolerance in experimental models. Clinical benefits from these modalities have not been as striking, leading to ongoing study in this field. We have explored culture techniques for the in vitro selection and development of cellular effectors capable of enhancing allograft survival. METHODS: Rat bone marrow or spleen cells cultured under a variety of conditions were screened for suppressor function. Bone marrow cells, nonadherent to plastic, cultured for 7 days with granulocyte-macrophage colony-stimulating factor, lipopolysaccharide, and with or without splenocytes were found to contain predominantly myeloid lineage cells and had the ability to suppress phytohemagglutinin or mixed lymphocyte reaction-induced splenocyte proliferation. Standard donor-specific peripheral blood transfusion was compared with cultured donor-specific bone marrow cells, splenocytes, or marrow cells cultured with splenocytes (cocultured) administered intravenously at 1 x 10(7) cells/kg the day before an ACI to Lewis heterotopic heart transplant. Cyclosporine was administered at 10 mg/kg on day -1 and 2.5 mg/kg on days 0-6 relative to transplantation. RESULTS: Mean allograft survival in cyclosporine-treated animals was 8.5 days without and 16.6 days with a donor-specific blood transfusion. Cocultured cells extended allograft survival (39.5 days), whereas bone marrow or splenocytes cultured alone did not. With Percoll gradient separation, two predominant culture subfractions, one with potent suppressor function and another with stimulator function, were identified. Flow cytometric analysis showed mixed populations enriched for macrophages but also including dendritic cells in both subfractions. The suppressive fraction extended allograft survival to 20.8 days and the stimulatory fraction was less effective, yet remixing of both fractions regained the full allograft survival advantage. CONCLUSIONS: In this model, the coculture of bone marrow cells and splenocytes with granulocyte-macrophage colony-stimulating factor and lipopolysaccharide produced functionally divergent subpopulations that synergistically enhanced allograft survival. The development of cellular effectors with enhanced ability to prolong allograft survival using in vitro culture techniques is possible, and provides a new therapeutic option in the use of cell infusion-based therapies.


Assuntos
Células da Medula Óssea , Sobrevivência de Enxerto/fisiologia , Baço/citologia , Animais , Transfusão de Sangue , Divisão Celular/efeitos dos fármacos , Centrifugação com Gradiente de Concentração , Técnicas de Cocultura , Células Dendríticas/citologia , Fator Estimulador de Colônias de Granulócitos e Macrófagos/farmacologia , Lipopolissacarídeos/farmacologia , Macrófagos/citologia , Ratos , Ratos Endogâmicos ACI , Ratos Endogâmicos BN , Ratos Endogâmicos BUF , Ratos Endogâmicos Lew
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