Molecular genetic and clinical characteristics of MEF2D-BCL9 fusion gene-positive acute B-cell lymphoblastic leukemia / 白血病·淋巴瘤

Objective:To investigate the molecular genetic and clinical characteristics of MEF2D-BCL9 fusion gene-positive acute B-cell lymphoblastic leukemia (B-ALL), and to provide the reference for the diagnosis and treatment of the disease.Methods:The medical record and experimental examination data of a 18-year-old female MEF2D-BCL9 fusion gene-positive B-ALL patient were retrospectively analyzed. The clinical manifestations and biological characteristics of MEF2D-BCL9 fusion gene-positive B-ALL were summarized.Results:This 18-year-old female patient was treated in a local hospital in December 2018 and was diagnosed as B-ALL. She achieved complete remission after chemotherapy and recurred at 6 months after the initial onset, and then she was admitted to Hebei Yanda Ludaopei Hospital in the 9 months after the initial onset.MEF2D-BCL9 fusion gene was detected through RNA-sequencing (RNA-seq) and verified by using polymerase chain reaction and Sanger sequencing. Bone marrow cell morphology was similar to mature B cells with vacuoles but without characteristic chromosome karyotype abnormalities. The patient achieved remission after VLD regimen chemotherapy, chimeric antigen receptor T-cell (CAR-T) therapy and bridged to allogeneic hematopoietic stem cell transplantation (allo-HSCT). She has maintained complete remission for 2 years at the last follow-up in February 2022.Conclusions:MEF2D-BCL9 fusion gene-positive B-ALL is characterized with high risk, early relapse and poor prognosis. These patients may benefit from CAR-T and allo-HSCT. It further emphasizes the importance of taking MEF2D-BCL9 fusion gene into the detection or identification by using RNA-seq, particularly for those newly diagnosed B-ALL patients in children and adolescents with specific bone marrow morphology.

Changes of CD4+CD25+ regulatory T cells and related regulatory factors in acute renal allograft rejection in rats / 中华肾脏病杂志

Objective To observe the level of CD4+CD25+ regulatory T cells (CD4+CD25+ Treg cells) with positive fork head transcription factor 3 (Foxp3) and changes of T-box transcription factor TBX1 (TBX1) and myocyte specific enhancer 2D (MEF2D) expression in peripheral blood of rats with acute rejection after renal transplantation,and to investigate its regulatory mechanisms by combined with renal function,plasma interleukin-10 (IL-10),interferon-γ (IFN-γ) and renal histopathological changes.Methods Rat renal transplantation model was established and divided into two groups:acute rejection group (AR group) and non-acute rejection group (non-AR group).Their renal function including serum creatinine (Scr) and blood urea nitrogen (BUN) in plasma was measured.The renal histopathology was observed by HE staining.Levels of IL-10 and IFN-γ in plasma were detected by ELISA.The proportion of CD4+CD25+ Treg cells was measured by flow cytometry.The mRNA expressions of Foxp3,TBX1 and MEF2D in CD4+CD4+Treg cells were detected by real-time PCR,and their protein expressions were tested by Western blotting.Results Compared with these in the non-AR group,the levels of BUN,Scr and IFN-γ significantly increased in AR group (all P ＜ 0.05),while IL-10 decreased (P ＜ 0.05).Renal histopathology in the acute rejection group showed glomerular hypertrophy and mesangial cell proliferation,capillary proliferation and neutrophil infiltration;renal interstitial edema and tubular necrosis,accompanied by lymphocytes,plasma cells and neutrophils infiltration.Compared with that in the non-AR group,the percentage of CD4+CD25+ Treg cells in peripheral blood was notably lowered in AR group (4.50％±0.50％ vs 5.74％±1.96％,P ＜ 0.05).The mRNA and protein expressions of Foxp3 and MEF2D were lower in AR group than those in non-AR group,while the expressions of TBX1 was elevated (all P ＜ 0.05).Conclusions In rats with acute renal allograft rejection,the percentage of CD4+CD25+ Treg cells and expressions of Foxp3,MEF2D and IL-10 decrease,while the expressions of TBX1 and IFN-γ enhance.These participate in the development of acute rejection after renal transplantation,and aggravate the renal damage.

Targeting Myocyte-specific Enhancer Factor 2D Contributes to the Suppression of Cardiac Hypertrophic Growth by MiR-92b-3p in Cardiomyocytes / 中山大学学报(医学科学版)

[Objective]To investigate the role and the potential target of miR-92b-3p in angiotensin Ⅱ(Ang-Ⅱ)-induced mouse cardiac hypertrophy.[Methods]Ang-Ⅱ-induced cardiac hypertrophy models were established in adult C57BL/6 mice. AgomiR-92b-3p,the cholesterol-modified miR-92b-3p mimic,was delivered to increase the level of miR-92b-3p in mouse myocar?dium via tail vein injection. In the present study,three groups of mice were used in the animal experiment as follows,the agomiR-negative control(agomiR-NC)+saline group,the agomiR-NC+Ang-Ⅱgroup and the agomiR-92b-3p+Ang-Ⅱgroup. A cell model of cardiac hypertrophy was also established in Ang-Ⅱ-induced neonatal mouse cardiomyocytes in this study Luciferase activity was assayed after transfection using a luciferase reporter assay system. The expression of Myocyte-specific enhancer factor 2D( MEF2D) and hypertrophy-related genes atrial natriuretic peptide (ANP),cardiac muscle α-actin (ACTA1) and β-myosin heavy chain (MHC)at mRNA and protein levels in Ang-Ⅱ-induced hypertrophic myocardium and cardiomyocytes were detected by qRT-PCR and Western blot,respectively.[Results]The expression of ANP,ACTA1,β-MHC were markedly increased in Ang-Ⅱ-induced hypertrophic myocardium and cardiomyocytes. Dual luciferase reporter assay revealed that MEF2D is a potential target gene of miR-92b-3p. And miR-92b-3p can reduce the expression of MEF2D at the post-transcriptional level. Functionally,miR-92b-3p mimic, consistent with MEF2D siRNA,inhibited cell size increase and protein expression of ANP,ACTA1 andβ-MHC in Ang-II-treated mouse cardiomyocytes.[Conclusions]MEF2D is a novel target of miR-92b-3p,a target gene of miR-92b-3,which mediates the ef?fect of miR-92b-3p on attenuating cardiomyocyte hypertrophy.

Comparison among 3 kinds of culture substrates of odontogenic induced pluripotent stem cells / 重庆医学

Objective To comparatively study the characteristics of 3 kinds of culture substrates of human odontogenic induced pluripotent stem cells(iPSCs).Methods The human odontogenic iPSCs were cultured by 3 kinds of substrates:mouse embryonic fibroblasts(MEF),matrigel and recombinant human vitronectin(VTN-N).The iPSCs growth situation was compared among three groups.Results The preparation time of these 3 kinds of substrates was 14,3,1 hlespectively,and,the difference was statistically significant (P＜0.05).The iPSCs reprogramming time was (30± 1.6),(26 ± 2.1),(27 ± 1.4) d,lespectively,wht that in the MEF group significantly higer than in other two groups (P＜0.05).The reprogramming efficiencies were 0.3 ％ ± 0.03 ％,0.56 ％ ± 0.08 ％,0.7 ％ ± 0.02 ％ respectively (P＜ 0.05).Three kinds of substrate could better support iPSCs growth and make them to maintain un-differentiation status.Conclusion with no heterologous animal components,and the adrantaga of simple pleparation,oonfrollable standard and shorter gramming time is easy to prepare,the standard is controllable and the reprogramming time is shorter,which is an ideal substrate for supporting iPSCs growth.

Mechanism of CCCP-induced non-canonical autophagy / 中国生化药物杂志

Objective To identify the factors those regulate CCCP-induced non-canonical autophagy.Methods Different cells expressing GFP-LC3 were treated with or without CCCP (30μM) for 6 h.Fluorescent images were taken and cell lysates were analyzed by western blot assay.Real-time PCR was used to measure the mRNA levels of LC3B.FIP200-KO MEF cells were cultured and treated by 30 μM CCCP with or without water channel inhibitors, for 6 h.Cell lysates were analyzed by Western blot assay.Results CCCP could not induced autophagy in Atg5-KO MEF cells.CCCP could induce non-canonical autophagy in ULK1-KO MEF, FIP200-KO MEF, and Beclin1-KD U251.CCCP treatment in FIP200-KO MEF cells had no effect on the expression level of LC3B mRNA.We also found two distinct aquaporin water channel inhibitors could inhibit the generation of LC3 which was induced by CCCP.Conclusion CCCP induced non-canonical autophagy was Atg5-dependent, but Beclin1-, ULK1-and FIP200-independent.Osmotic imbalance could regulate CCCP-induce non-canonical autophagy.

MEF2C mediates inhibitory effect of microRNA-214 on cardiomyocyte hypertrophy / 中国病理生理杂志

AIM:To investigate the effect of microRNA-214 ( miR-214) on cardiomyocyte hypertrophy and the expression of the potential target genes .METHODS:A cell model of hypertrophy was established based on angiotensin-Ⅱ( Ang-Ⅱ)-induced neonatal mouse ventricular cardiomyocytes ( NMVCs) .Dual luciferase reporter assay was performed to verify the interaction between miR-214 and the 3’ UTR of MEF2C.The expression of MEF2C and hypertrophy-related genes at mRNA and protein levels was determined by RT-qPCR and Western blot , respectively .RESULTS:The expression of ANP, ACTA1,β-MHC and miR-214 was markedly increased in Ang-Ⅱ-induced hypertrophic cardiomyocytes .Dual lu-ciferase reporter assay revealed that miR-214 interacted with the 3’ UTR of MEF2C, and miR-214 was verified to inhibit MEF2C expression at the transcriptional level .The protein expression of MEF2C was markedly increased in the hypertro-phic cardiomyocytes .Moreover, miR-214 mimic, in parallel to MEF2C siRNA, inhibited the expression of hypertrophy-re-lated genes in Ang-Ⅱ-induced NMVCs.CONCLUSION:MEF2C is a target gene of miR-214, which mediates the effect of miR-214 on attenuating cardiomyocyte hypertrophy .

Diseño mecánico de un exoesqueleto para rehabilitación de miembro superior / Mechanical design of an exoskeleton for upper limb rehabilitation

El ritmo de vida actual, tanto sociocultural como tecnológico, ha desembocado en un aumento de enfermedades y padecimientos que afectan las capacidades físico-motrices de los individuos. Esto ha originado el desarrollo de prototipos para auxiliar al paciente a recuperar la movilidad y la fortaleza de las extremidades superiores afectadas. El presente trabajo aborda el diseño de una estructura mecánica de un exoesqueleto con 4 grados de libertad para miembro superior. La cual tiene como principales atributos la capacidad de ajustarse a la antropometría del paciente mexicano (longitud del brazo, extensión del antebrazo, condiciones geométricas de la espalda y altura del paciente). Se aplicó el método BLITZ QFD para obtener el diseño conceptual óptimo y establecer adecuadamente las condiciones de carga de servicio. Por lo que, se definieron 5 casos de estudio cuasi-estáticos e implantaron condiciones para rehabilitación de los pacientes. Asimismo, mediante el Método de Elemento Finito (MEF) se analizaron los esfuerzos y deformaciones a los que la estructura está sometida durante la aplicación de los agentes externos de servicio. Los resultados presentados en éste trabajo exhiben una nueva propuesta para la rehabilitación de pacientes con problemas de movilidad en miembro superior. Donde el equipo propuesto permite la rehabilitación del miembro superior apoyado en 4 grados de libertad (tres grados de libertad en el hombro y uno en el codo), el cual es adecuado para realizar terapias activas y pasivas. Asimismo, es un dispositivo que está al alcance de un mayor porcentaje de la población por su bajo costo y fácil desarrollo en la fabricación.

The pace of modern life, both socio-cultural and technologically, has led to an increase of diseases and conditions that affect the physical-motor capabilities of persons. This increase has originated the development of prototypes to help patients to regain mobility and strength of the affected upper limb. This work, deals with the mechanical structure design of an exoskeleton with 4 degrees freedom for upper limb. Which has the capacity to adjust to the Mexican patient anthropometry (arm length, forearm extension, geometry conditions of the back and the patient's height) BLITZ QFD method was applied to establish the conceptual design and loading service conditions on the structure. So, 5 quasi-static cases of study were defined and conditions for patient rehabilitation were subjected. Also by applying the finite element method the structure was analyzed due to service loading. The results presented in this work, show a new method for patient rehabilitation with mobility deficiencies in the upper limb. The proposed new design allows the rehabilitation of the upper limb under 4 degrees of freedom (tree degrees of freedom at shoulder and one at the elbow), which is perfect to perform active and passive therapy. Additionally, it is an equipment of low cost, which can be affordable to almost all the country population.

Detection of the Efflux-Mediated Erythromycin Resistance Transposon in Streptococcus pneumoniae

BACKGROUND: The present analysis focuses on phenotypic and genotypic characterizations of efflux-mediated erythromycin resistance in Streptococcus pneumoniae due to an increase in macrolide resistance in S. pneumoniae worldwide. METHODS: We investigated the prevalence of efflux-mediated erythromycin resistance and its relevant genetic elements from 186 specimens of S. pneumonia isolated from clinical and normal flora from Tehran, Iran. The presence of erythromycin resistance genes was tested by PCR with two sets of primers, specific for erm(B) and mef(A/E), and their genetic elements with tetM, xis, and int genes. Isolates were typed with the BOX PCR method and tested for resistance to six antibiotics. RESULTS: Antibiotic susceptibility tests revealed that 100% and 47% isolates were resistant to tetracycline and erythromycin, respectively. The erythromycin and clindamycin double-disc diffusion test for macrolide-lincosamide-streptograminB (MLSB) resistance phenotype showed 74 (84%) isolates with the constitutive MLSB phenotype and the remaining with the M phenotype. BOX PCR demonstrated the presence of 7 types in pneumococci with the M phenotype. Fourteen (16%) isolates with the M phenotype harbored mef(A/E), tetM, xis, and int genes. CONCLUSIONS: The present results suggest dissemination of polyclonal groups of S. pneumoniae with the M phenotype carrying resistance genes attributed to transposon 2009.

Development of a new coating substrate for human embryonic stem cell culture / 中国实验动物学报

Objective To reduce the animal component contamination for human embryonic stem cells ( hESCs ) and to simplify hESCs culture process , we develop a new coating substrate which can support the hESCs growth without dif -ferentiation, and is easy to store and use. Methods Mouse embryonic fibroblasts(MEF)were fixed on the surface of plate by methanol.hESCs were cultured on this new substrate and were passaged every 5 to 6 days.After 10 passages, we checked the cell morphology , alkaline phosphatase expression , embryonic specific markers and the differentiation ability in vitro.Results After 10 passages , the hESCs grew well on this new substrate and maintained the typical hESCs morpholo -gy.Alkaline phosphatase staining was positive .Immunofluorescence staining showed that the expressions of Oct 4, SSEA4, Tra-1-60 were positive .The cells formed embryoid body in vitro .Conclusions This methanol-fixed MEF substrate can support the growth of undifferentiated hESCs .The coating material can be produced in large scale and stored for a long time.It provides a new and relatively easy way to amplify hESCs .

Genotyping of erythromycin resistant group C & G streptococci isolated in Chennai, south India.

Background & objectives: Increasing resistance to erythromycin has been observed worldwide in group C and group G streptococci (GCS/GGS). The information available from India is scanty. The aim of the study was to identify erythromycin resistant GCS/GGS isolates in Chennai, south India, and to compare erythromycin resistant genotypes with emm types. Methods: One hundred and thirty one GCS/GGS isolates were tested for erythromycin resistance by disc diffusion and agar dilution methods. Erythromycin resistance genotypes [erm(A), erm(B) and mef(A)] were determined by a multiplex PCR. emm types of erythromycin resistant GCS/GGS isolates was also assessed using emm gene sequencing method. Results: Sixteen of the 131 isolates (12.21%) were resistant to erythromycin. Majority of the isolates were GGS (15/16). Eight of the 16 (50%) were S. dysgalactiae subsps. equisimilis. Twelve isolates (75%) were MLSB phenotype and four (25%) were M phenotype. Of the 12 isolates which exhibited MLSB resistance, seven showed cMLSB phenotype and were positive for erm(B) gene. The remaining five were iMLSB phenotype of which three were positive for erm(A) gene and two for erm(B) gene. erm(A) was common among carriers whereas erm(B) was common among clinical isolates. Interpretation & conclusions: MLSB was the predominant phenotype and erm(B) was the common genotype in the present study. The emm type stC1400.0 was frequently associated with erythromycin resistant GCS/GGS in our study.

Molecular cloning and in silico analysis of the duck (Anas platyrhynchos) MEF2A gene cDNA and its expression profile in muscle tissues during fetal development

The role of myogenic enhancer transcription factor 2a (MEF2A) in avian muscle during fetal development is unknown. In this work, we cloned the duck MEF2A cDNA sequence (GenBank accession no. HM460752) and examined its developmental expression profiles in cardiac muscle, non-vascular smooth muscle and skeletal muscle. Duck MEF2A cDNA comprised 1479 bp encoding 492 amino acid residues. In silico analysis showed that MEF2A contained MADS (MCM1, AGAMOUS, DEFICIENS and SRF -serum response factor), MEF2 and mitogen-activated protein kinase (MAPK) transcription domains with high homology to related proteins in other species. Modified sites in these domains were conserved among species and several variants were found. Quantitative PCR showed that MEF2A was expressed in all three muscles at each developmental stage examined, with the expression in smooth muscle being higher than in the other muscles. These results indicate that the conserved domains of duck MEF2A, including the MADS and MEF2 domains, are important for MEF2A transcription factor function. The expression of MEF2A in duck smooth muscle and cardiac muscle suggests that MEF2A plays a role in these two tissues.

Differential Expression of PKD2-Associated Genes in Autosomal Dominant Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by formation of multiple fluid-filled cysts that expand over time and destroy renal architecture. The proteins encoded by the PKD1 and PKD2 genes, mutations in which account for nearly all cases of ADPKD, may help guard against cystogenesis. Previously developed mouse models of PKD1 and PKD2 demonstrated an embryonic lethal phenotype and massive cyst formation in the kidney, indicating that PKD1 and PKD2 probably play important roles during normal renal tubular development. However, their precise role in development and the cellular mechanisms of cyst formation induced by PKD1 and PKD2 mutations are not fully understood. To address this question, we presently created Pkd2 knockout and PKD2 transgenic mouse embryo fibroblasts. We used a mouse oligonucleotide microarray to identify messenger RNAs whose expression was altered by the overexpression of the PKD2 or knockout of the Pkd2. The majority of identified mutations was involved in critical biological processes, such as metabolism, transcription, cell adhesion, cell cycle, and signal transduction. Herein, we confirmed differential expressions of several genes including aquaporin-1, according to different PKD2 expression levels in ADPKD mouse models, through microarray analysis. These data may be helpful in PKD2-related mechanisms of ADPKD pathogenesis.

Antimicrobial susceptibility of Streptococcus pneumoniae and genotypic characterization of erythromycin-resistant strains in Porto Alegre, Brazil

The antimicrobial susceptibility of 64 strains of S. pneumoniae obtained from three hospitals in Porto Alegre, Brazil, isolated between 2004 and 2005, was determined, using the agar-dilution method. The prevalence of resistant (intermediate and full resistance) strains to trimethoprim/sulphamethoxazole, penicillin, tetracycline, erythromycin, chloramphenicol, and ceftriaxone were 68 percent, 28 percent, 18 percent, 15 percent, 3 percent, and 1 percent, respectively. All strains were susceptible to vancomycin. Among 18 penicillin-resistant strains, 7 were resistant to at least two other antimicrobial drugs. All erythromycin-resistant strains, except one, contained the erm(B) and/or mef(A/E) genes, with a predominance of the former. The resistance rate to penicillin and erythromycin in Porto Alegre remained stable. The combination of trimethoprim/ sulphamethoxazole should not be recommended to treat pneumococcal infections, because of the high rate of resistant strains.

Prevalence of mef and ermB genes in invasive pediatric erythromycin-resistant Streptococcus pneumoniae isolates from Argentina / Prevalencia de los genes mef y ermB en aislamientos invasivos de Streptococcus pneumoniae resistentes a eritromicina recuperados de pacientes pediátricos en Argentina

During the period 1993-2001, a total of 1,499 pneumococci isolates were recovered through the Argentinean surveillance of Streptococcus pneumoniae causing invasive disease in children under 6 years of age, 3.5% of which were erythromycin resistant. Among the 50 erythromycin-resistant strains available, 58% (n=29) harbored mefA/E genes (15 mefA, 30%; and 14 mefE, 28%), 34% (n=17) ermB, and 6% (n=3) both mefA/E plus ermB genes, while one isolate was negative for all the acquired genes studied. The England14-9 (42%), Poland6B-20 (20%) and Spain9v-3 (16%) clones were responsible for the emergence of pneumococcal macrolide resistance in pediatric population from Argentina.

En el marco del programa de vigilancia regional SIREVA, se analizaron 1499 aislamientos de Streptococcus pneumoniae causantes de enfermedad invasiva en menores de 6 años, recuperados entre 1993 y 2001. Se detectó un 3,5% de resistencia a eritromicina. De los 50 aislamientos resistentes a eritromicina que pudieron ser estudiados, el 58% (n=29) tenían los genes mefA/E (15 mefA, 30% y 14 mefE, 28%), el 34% (n=17) el gen ermB y el 6% (n=3) la combinación de genes mefA/E y ermB. Sólo un aislamiento fue negativo para todos los genes analizados. Los clones internacionales England14-9, Poland6B-20 y Spain9v-3 representaron el 78% del total de aislamientos resistentes (42, 20 y 16%, respectivamente) y se consideraron los responsables de la emergencia de la resistencia a macrólidos entre los neumococos que afectan a la población pediátrica de Argentina.

Myocyte-specific enhancer binding factor 2C (MEF2C) expression in the dentate gyrus during development and after pilocarpine-induced status epilepticus: a preliminary report / Realce miócito específico ligado a expressão do fator 2C (MEF2C) no giro denteado durante o desenvolvimento e após uso de pilocarpina induzindo status epilepticus: estudo preliminar

OBJECTIVE: As axon outgrowth and dentate granule cell neurogenesis are hallmarks of hippocampal development and are also the two morphologic changes in the structure of the dentate gyrus after status epilepticus (SE), we hypothesized that molecules involved in normal development may also play a role during epileptogenesis. METHOD: Using in situ hybridization, we have characterized mRNA expression of myocyte-specific enhancer binding factor 2C (MEF2C) in the dentate gyrus during development (P0, P3, P7, P14 and P28) and at multiple time points following pilocarpine-induced SE (3, 7, 14, 28 days after SE). RESULTS: It was demonstrated that MEF2C is up-regulated during development (P0, P3, P7, P14 and P28) and in the adult rat dentate gyrus following SE (3, 7, 14, 28 days after SE). CONCLUSIONS: The molecules controlling cell-fate decisions in the developing dentate gyrus are also operative during epileptogenesis.

OBJETIVO: Como o crescimento axonal e a neurogênese do giro denteado são características intrínsecas do hipocampo durante o processo de desenvolvimento, e também são duas alterações morfológicas na estrutura do giro denteado após o status epilepticus (SE), nós hipotetizamos que as moléculas envolvidas no processo normal do desenvolvimento hipocampal também podem participar do processo de epileptogênese. MÉTODO: Utilizando hibridização in situ, caracterizamos a expressão do RNAm do fator de transcrição myocyte-specific enhancer binding factor 2C (MEF2C) no giro denteado durante o desenvolvimento (P0, P3, P7, P14 e P28) e em diferentes períodos após o SE (3, 7, 14, 28 dias após SE). RESULTADOS: Foi demonstrado um aumento da expressão de MEF2C no giro denteado durante o desenvolvimento e no giro denteado de animais adultos após o SE. CONCLUSÃO: As moléculas que controlam o destino celular durante o processo de desenvolvimento também estão operativas durante o processo de epileptogênese.

MODELACIÓN POR ELEMENTOS FINITOS EN UN MODELO DE ANEURISMA

En un modelo con características geométricas y un comportamiento mecánico de la pared arterial generalizado para aneurismas periféricos, se realiza una modelación por elementos finitos (MEF) del efecto de la presión arterial y del espesor de la pared arterial en el saco de un aneurisma. Se analizan los esfuerzos de Von Misses, los esfuerzos tensores transversales y el desplazamiento en el saco del aneurisma. Se encuentra que el lugar más propenso a la ruptura para esta geometría de aneurismas es la región circundante a la arteria eferente y opuesta al flujo aferente. Se propone un proceso para realizar MEF en cualquier geometría de aneurisma y condiciones de presión, para analizar el riesgo y el lugar más probable de la ruptura.

Considering a model with generalized geometry and mechanical properties of the arterial wall for the peripheral vasculature aneurisms, a finite element modeling (FEM) is developed for analyzing the effects of arterial blood pressure and the arterial wall thickness in the aneurismal sac. The von Misses stresses, the transversal tensor stresses and the displacement in the aneurismal sac wall are analyzed. The possible site of rupture for this aneurism geometry is found surrounding the efferent artery and opposed to the flow inlet. A method for applying FEM to any aneurism geometry and blood pressure conditions is proposed for analyzing the risk of rupture and possible rupture site.

Antimicrobial Susceptibility Patterns and Macrolide Resistance Genes of beta-Hemolytic Viridans Group Streptococci in a Tertiary Korean Hospital

The aim of this study was to investigate antimicrobial susceptibilities and macrolide resistance mechanisms of beta-hemolytic viridans group streptococci (VGS) in a tertiary Korean hospital. Minimum inhibitory concentrations (MICs) of seven antimicrobials were determined for 103 beta-hemolytic VGS isolated from various specimens. The macrolide resistance mechanisms of erythromycin-resistant isolates were studied by the double disk test and polymerase chain reaction (PCR). The overall resistance rates of beta-hemolytic VGS were found to be 47.5% to tetracycline, 3.9% to chloramphenicol, 9.7% to erythromycin, and 6.8% to clindamycin, whereas all isolates were susceptible to penicillin G, ceftriaxone, and vancomycin. Among ten erythromycin-resistant isolates, six isolates expressed a constitutive MLSB (cMLSB) phenotype, and each of the two isolates expressed the M phenotype, and the inducible MLSB (iMLSB) phenotype. The resistance rates to erythromycin and clindamycin of beta-hemolytic VGS seemed to be lower than those of non-beta-hemolytic VGS in our hospital, although cMLSB phenotype carrying erm(B) was dominant in beta-hemolytic VGS.

P38/caspase-3 mediated MEF2C pathway and its significance in the injuries of hippocampal CA1 region of rats following ischemia/reperfusion / 基础医学与临床

Objective To investigate the level of MEF2C phosphorylation (activation) and protein expression, and to further clarify the possible mechanism following ischemia-reperfusion in hippocampal CA1 region of rat. MethodsBrain ischemia was induced by four-vessel occlusion in SD rats. Protein level was determined by Western blotting. Results MEF2C was significantly activated with a peak at 6 h of reperfusion, but its protein expression decreased in late phase of reperfusion (3～5 d). The elevation of activated (17 ku) and the inactivated forms (32 ku) of caspase-3 proteases were remarkable during 1～5 d of reperfusion. In addition, Ac-DEVD-CHO, a specific inhibitor of caspase-3, up-regulated MEF2C protein level of 3 d reperfusion. SB202190 (an inhibitor of P38), but not ERK5-antisense oligonucleotides, not only inhibited MEF2C activation of 6 h reperfusion but also apparently prevented the increase of caspase-3 activation caused by 3 d reperfusion. Conclusion P38/caspase-3 mediated MEF2C pathway may function in the injuries of hippocampal CA1 region of rats following ischemia/reperfusion.

Cloning and Analyzing The Promoter of PPAR? / 生物化学与生物物理进展

Peroxisome proliferator-activated receptors (PPARs) are a family of nuclear hormone receptors belonging to the steroid receptor superfamily. Three PPAR isoforms, PPAR?, PPAR? (also known as PPAR?) and PPAR? have been found in the mouse. They can activate expression of many genes, including those involved in lipidmetabolism. PPAR? is ubiquitously expressed, but the level of expression differs markedly between different cell types. PPAR? is expressed in skeletal muscle at 10- and 50-fold higher levels compared with PPAR? and PPAR?, respectively. A role for PPAR? in skeletal muscle is to increase the genes expression with relation to oxidative metabolism. In order to determine the molecular mechanisms governing PPAR? gene expression in muscle, a 2 kb 5′ flanking region was cloned and analyzed. The DNA fragment is able to transcribe GFP in COS7 cells. Dual luciferase assay is used to quantify promoter activity. Deletion analysis of the 2 kb PPAR? promoter fragment in COS7 and NIH 3T3 cells shows that the proximal promoter sequence, nt -197 to +120, confers basal transcriptional activity of the mouse PPAR? gene. Computational analysis of putative cis-acting elements located within the ～2.0 kb mouse PPAR? 5′-flanking sequence was performed using the TRANSFAC database and MatInspector software and 4 potential MEF2A binding sites were found. And there is a potential binding site sharing 100% identity with positive element of MEF2A in the proximal promoter (nt -261). Co-transfection experiments of the PPAR? promoter reporter and pMEF2A expression plasmid (pMEF2A) showed that MEF2A significantly enhanced transcription activity of PPAR? promoter in NIH 3T3. Moreover, the enhancive effect depended on the concentration of plasmid pMEF2A transfected into cells. The results suggested that MEF2A may enhance transcription activity of the PPAR promoter in muscle cells.

Problems Associated with Establishment of Human Embryonic Stem Cell

Stem cells are the body's master cells and have the ability to produce all manner of tissues. Embryonic stem(ES) cells, derived from the inner cell mass(ICM) of the mammalian blastocyst, can continuously proliferate in an undifferentiated state and differentiate into a desired cell lineage under certain conditions. These abilities make ES cells an appealing source for cell replacement therapies, the study of developmental biology, and drug/ toxin screening studies. Compared to mouse ES cells, human ES cells have only recently been derived and studied. Although there are many differences in properties between mouse and human ES cells, the study of mouse ES cells has provided important insight into human ES cell research. In this review, I describe the advantages and disadvantages of methods used for human ES cell derivation, the expansion of human ES cells.