Catheter ablation of atrial fibrillation in elderly population

Background Although elderly patients have been included in published series of catheter ablation for atrial fibrillation (AF), clinical benefit and safety remain still less defined in this population. A retrospective analysis of the results of catheter ablation for AF in a large volume center focused on comparison of elderly patients with the rest of the patient cohort was conducted in this study. Methods Consecutive patients who underwent catheter ablation for AF between January 2001 and December 2016 were analysed. A total population of 3197 patients was dichotomized by the age of 70 years (394 elderly vs. 2803 younger subjects). Patients were followed in terms of arrhythmia status and sur?vival for a median period of 18 vs. 21 and 35 vs. 57 months, respectively. Results Elderly patients were more frequently females (49% vs. 29%, P < 0.0001), had a history of hypertension (79% vs. 57%, P < 0.0001), diabetes (16% vs. 11%, P < 0.01), stroke (9% vs. 6%, P < 0.01), coronary/peripheral artery disease (14% vs. 8%, P < 0.0001), and CHA2DS2-VASc score (3.1 ± 1.3 vs. 1.5 ± 1.2 s, P < 0.0001). Major complications were more frequent in elderly (5.3% vs. 3.2%, P = 0.03); however, this difference was driven by vascular complications (3.6% vs. 1.9%, P = 0.04). There were comparable rates of cerebrovascular (0.3 vs. 0.3%) or nonvascular complications (1.8 vs. 1.2%). Good arrhythmia control was inferior in elderly patients as compared with the rest of the cohort, both without and with antiarrhythmic drugs: 44.2% vs. 58.2% (P < 0.0001) and 78.2 vs. 83.2% (P < 0.01), respectively. Poor arrhythmia control was associated with relative risk of all-cause mortality of 2.7 (95% CI: 1.1–6.4) in elderly patients and 1.4 (95% CI: 0.9–2.0) in younger subjects. Conclusions Catheter abla?tion for AF in elderly patients is safe although somewhat less effective. Good arrhythmia control is associated with better survival, especially in elderly patients.     

Comparison of in-hospital outcomes between octogenarians and nonagenarians undergoing transcatheter aortic valve replacement: a propensity matched analysis

Background Aortic valve stenosis (AS) is very common in the elderly patients above 80 years. Transcatheter aortic valve replacement (TAVR) in such patients is being increasingly performed. This study sought to assess in-hospital outcome differences between octogenarians and nonagenarians and predictors of mortality in nonagenarians undergoing TAVR with severe AS. Method The study population was derived from the National Inpatient Sample (NIS) for the years 2012–2014 using ICD-9 CM procedure codes 35.05 and 35.06 for TAVR. Hospitalizations below 80 years of age were excluded. After performing propensity score matching (1: 2), in-hospital outcomes were compared in matched cohorts. Then, multivariate model was developed to analyze predictors of in-hospital mortality in nonagenarians. Results There were 11,630 hospitalizations in the octogenarian and 5815 hospitalizations in the nonagenarian group. Primary outcome of in-hospital mortality (6% vs. 4.1%, P ≤ 0.001) was higher in nonagenarians compared to octogenarians. Secondary outcomes including stroke (3.4% vs. 2.8%, P ≤ 0.001), renal failure (18.9% vs. 17.3%, P ≤ 0.001), blood transfusion (35% vs. 32.6%, P ≤ 0.001), vascular complications (4.5% vs. 3.5%, P ≤ 0.001), and pacemaker implantation (27.8% vs. 24.8%, P ≤ 0.001) were higher in nonagenarians. There was no difference in their length of stay. Median cost (70,374$ vs. 65,381$, P ≤ 0.001) was slightly higher with nonagenarian. Conclusions Although in-hospital mortality is slightly higher in nonagenarians, it is acceptable. This difference in mortality is at least partly explained by higher complications in nonagenarians. Efforts should be made to decrease the complications which can further narrow the difference in in-hospital mortality between the groups.     

我国山丘疫区和平原疫区利什曼原虫分离株基因组DNA基因型分析

目的：分析我国山丘和平原疫区利什曼原虫分离株基因组DNA（nDNA）的多态性。方法：对基因组DNA进行内切酶酶切、Southern杂交、染色体定位。探针采用地高辛标记。结果：采用gp63探针，显示杜氏利什曼原虫（Leishmaniadonovani，L．d．）江苏人株和L．d．Jeddah nDNA之间有相似的染色体杂交带，L．d．四川人株和L．infantum nDNA之间有相似的染色体杂交带；采用β－tubulin探针，显示L．d．江苏人株与L．d．Jeddah nDNA之间有两条相似的染色体杂交带，L．d．四川犬株与L．d．甘肃犬株nDNA之间有三条相似的染色体杂交带、与L．d．汶川人株nDNA之间有两条相似的染色体杂交带。结论：提示平原疫区的江苏人株与L. d. J eddah 之间存在同源性, 山丘疫区的L. d. 四川人株与L. infantum 之间存在同源性, L. d. 四川犬株与L. d. 甘肃犬株之间存在同源性、与L. d. 汶川人株之间既存在同源性又存在差异, 山丘疫区与平原疫区分离株之间存在异源性。     

细胞因子体外扩增脐血CD^＋34细胞移植SCID鼠人类免疫功能的 …

ObjectiveTo explore the hematopoietic function of cytokine-expanding CD⁺₃₄ cells from umbilical cord blood in vitro.MethodCord blood cells expanded with FLT3(FMS-like tyrosine kinase 3)-ligand and thrombopoietin were transplanted in SCID(severe combined immune-deficient)mice. Human mature cell surface markers were detected with flow cytometry and used as indicator of succeeding transplantation.ResultAfter 2 and 3 weeks culture,the number of CD⁺₃₄ cells increased approximately 10 and 37 folds. After transplantation with 6.6×10⁴ to 6.9×10⁵ CD⁺₃₄ cells,respectively the percentage of human CD⁺₄₅ cells in the bone marrow of all 10 SCID mice is 0.2%～4.0%. The percentage of human CD⁺₃ cells in the peripheral blood and spleen of 6 SCID mice is 0.1%～2.3%. The percentage of human CD⁺₁₉ cells in the peripheral blood and spleen of 3 SCID mice are 0.3%～1.3%.ConclusionCD⁺₃₄ cells expanded with FLT3-ligand and thrombopoietin are potential engraft used for reconstitution of both hematopoietic and immunologic function of SCID mice.     

Growth hormone-releasing hormone and gonadotropin-releasing hormone stimulate nitric oxide production in 17beta-estradiol-primed rat anterior pituitary cells

It was reported that neuronal nitric oxide synthase (nNOS) was expressed only in gonadotrophs and folliculo-stellate cells in the anterior lobe of the pituitary gland. However, recent studies have demonstrated the occurrence of nNOS in the somatotrophs and lactotrophs. In the present study, we investigated effects of growth hormone-releasing hormone (GHRH), gonadotropin-releasing hormone (GnRH), and 17β-estradiol on nitric oxide (NO) release in cultured rat anterior pituitary cells in vitro. The NO ₂ ⁻ level in the incubation medium of the rat anterior pituitary cells was dependent on the cell density. Pretreatment with 10 μM 17β-estradiol resulted in an increase in medium NO ₂ ⁻ level. GHRH and GnRH failed to change medium NO ₂ ⁻ levels, but they elicited increases in medium NO ₂ ⁻ levels in estrogen-treated cells. The GHRH-induced increase in NO ₂ ⁻ level was inhibited by Nχ-nitro-l-arginine methyl ester, a NOS inhibitor. These findings suggest that GnRH and GHRH could activate nNOS in the gonadotrophs and the somatotrophs, respectively.     

Formoterol,a new long-acting selectiveβ 2-agonist,decreases airway responsiveness in children with asthma

We compared the protective effect and duration of action of inhaled formoterol with salbutamol and placebo in 16 asthmatic children in a double-blind, cross-over study. All had an FEV₁ ≥ 70% predicted normal and a provocative concentration of methacholine (MCh) required to decrease their FEV₁ by 20% (PC₂₀) ≤ 4 mg/ml. On each study day, FEV₁ was within 10% and PC₂₀ within one doubling-dose of the initial visit. Patients received either placebo, salbutamol 200μg, formoterol 12μg, or formoterol 24μg by metered-dose inhaler. FEV₁ and PC₂₀ were measured repeatedly over 12 h. After salbutamol, peak FEV₁ was 120% of baseline at 30 min and returned to baseline in 3 h. After formoterol (12 or 24μg) peak FEV₁ was 118% at 3 h and remained above baseline for at least 12 h. Protection from MCh by both doses of formoterol was significantly better than by salbutamol. Protection from formoterol 12 and 24μg at 12 h was equivalent to that from salbutamol at 3 h. The PC₂₀ of four children 48 h after formoterol 24μg was more than twice their baseline PC₂₀. Formoterol by inhalation is potent and long-acting and provides significantly better antiasthma protection than salbutamol.     

Real-world comparison of non-vitamin K antagonist oral anticoagulants and warfarin in Asian octogenarian patients with atrial fibrillation

Background The efficacy and safety of non-vitamin K antagonist oral anticoagulants (NOACs) and warfarin in Asian octogenarian atrial fibrillation (AF) patients have not been established in a real-world setting. We aimed to evaluate the efficacy and safety of NOACs and warfarin in Korean octogenarian patients. Methods A total of 293 consecutive patients aged ≥ 80 years with non-valvular AF who had taken either NOACs (148 cases, 50.5%) or warfarin (145 cases, 49.5%) were retrospectively reviewed. The efficacy outcome was the composite of stroke or systemic embolism. The safety outcome was major bleeding. Results The follow-up duration was 375 patient-years (172 patient-years with NOACs and 203 patient-years with warfarin). Patients on NOACs were slightly older (P = 0.006) and had slightly higher HAS-BLED scores (P = 0.034). The efficacy of both anticoagulants was high (1.16% for NOACs vs. 2.98% for warfarin per 100 patient-years, P = 0.46). The safety outcome was relatively high in both NOACs and warfarin groups (8.96% vs. 12.46%, P = 0.29). The efficacy and safety outcomes tended to decrease non-significantly in low dose NOACs than in common dose NOACs or warfarin (0.85% vs. 1.84% vs. 2.98% in efficacy outcome, P = 0.69; and 6.97% vs. 13.29% vs. 12.46% in safety outcome, P = 0.34). Conclusions NOACs were highly effective for prevention of stroke or systemic embolism in Asian octogenarian AF patients. However, major bleeding occurred excessively high in both anticoagulant groups. Further study is required on the optimal anticoagulant regimen in octogenarian population.     

Prolonged treatment with oral and inhaled tulobuterol does not induce airways tachyphlaxis

β ₂-agonists have been shown to induceβ ₂-adrenoceptor down-regulation in vivo and in vitro. Whether this has any functional relevance remains unclear. Tulobuterol is a new syntheticβ ₂-agonist with potent and prolonged bronchodilator activity when given by oral and inhaled routes. The effect of tulobuterol aerosol (400μg q.i.d.) and tulobuterol tablets (2 mg b.i.d.) was studied in patients with chronic asthma and reversible airways obstruction in two separate trials. Tulobuterol produced significant bronchodilatation after the first and final dose over a 6-h period and the effects were comparable. The bronchodilator activity of tulobuterol given by inhalation and oral routes was not attenuated after 6 months of continuous treatment. There was significant improvement in symptom score and lung function measurements. Side effects, predominantly tremors, were observed at the start of treatment with tablet formulation but the incidence and severity of tremors decreased after 6 months. The changes in BP and pulse rate were not clinically significant. These results confirm the potent bronchodilator activity of tulobuterol and the lack of tachyphylaxis after prolonged treatment.     

Association of non-synonymous variants in WIPF3 and LIPA genes with ab-dominal aortic aneurysm: an autopsy study

Background Abdominal aortic aneurysm (AAA) is a multifactorial disease with strong genetic components. Various genetic loci have been associated with clinical AAA, but few studies have investigated pathological AAA, an intermediate phenotype of the disease. Methods We examined 2263 consecutive autopsies of older Japanese subjects from a study on geriatric diseases in Japanese individuals (The JG-SNP study). The presence of AAA was determined with a pathological diagnosis during autopsy. Single nucleotide variants (SNVs) associated with AAA were determined with an Illumina HumanExome Beadchip array. Logistic regression analyses were performed to determine genetic associations. Age, gender, and other risk factors of AAA were analyzed as covariates. Results 118 subjects with AAA and 2145 subjects without AAA were analyzed in a case-control setting. No variants reached significance after applying the Bonferroni correction (P < 2.05×10^?6). The strongest associations were found with rs3750092 (p.E321G, OR: 0.36, 95% CI: 0.24–0.56, P = 6.09 ? 10^?6), a variant in the WAS/WASL interacting protein family 3 (WIPF3), and with rs1051338 (p.T16P, OR: 2.50, 95% CI: 1.70–3.66, P = 2.79 ? 10^?6) and rs2246942 (intronic, OR: 2.32, 95% CI: 1.58–3.41, P = 1.61 ? 10^?5), variants in the lysosomal acid lipase A (LIPA). LIPA is essential for macrophage cholesterol metabolism. Immunohistological analyses of WIPF3 protein in AAA samples from three subjects revealed that WIPF3 was expressed in macrophages of atheromatous plaques. Conclusions This study suggests that WIPF3 and LIPA, both of which are expressed in the macrophages are involved in pathological AAA. These results should be regarded as hypothesis-generating; thus, replication study is warranted.     

Predictors and in-hospital prognosis of recurrent acute myocardial infarction

Objective To investigate the contributing factors and in-hospital prognosis of patients with or without recurrent acute myocardial infarction (AMI). Methods A total of 1686 consecutive AMI patients admitted to Peking University People’s Hospital from January 2010 to December 2015 were recruited. Their clinical characteristics were retrospectively compared between patients with or without a recurrent AMI. Then multivariable logistic regression was used to estimate the predictors of recurrent myocardial infarction. Results Recurrent AMI patients were older (69.3 ± 11.5 vs. 64.7 ± 12.8 years, P < 0.001) and had a higher prevalence of diabetes mellitus (DM) (52.2% vs. 35.0%, P < 0.001) compared with incident AMI patients, they also had worse heart function at admission, more severe coronary disease and lower reperfusion therapy. Age (OR = 1.03, 95% CI: 1.02–1.05; P < 0.001), DM (OR = 1.86, 95% CI: 1.37–2.52; P < 0.001) and reperfusion therapy (OR = 0.74; 95% CI: 0.52–0.89; P < 0.001) were independent risk factors for recurrent AMI. Recurrent AMI patients had a higher in-hospital death rate (12.1% vs. 7.8%, P = 0.039) than incident AMI patients. Conclusions Recurrent AMI patients presented with more severe coronary artery conditions. Age, DM and reperfusion therapy were independent risk factors for recurrent AMI, and recurrent AMI was related with a high risk of in-hospital death.     

Regulation of cell adhesion

Cell function usually requires an accurate control of attachment to and detachment from many other cells or biological surfaces. This is usually achieved by a combination of multiple cell processes the relative importance of which may be difficult to assess. The aim of this review is to discuss the role of different mechanisms used to control adhesion on the basis of selected examples and recently developed methodologies allowing quantitative study of cell adhesion. It is concluded that cells control adhesion by modifying (i) adhesion receptor expression, as a consequence of exocytosis, endocytosis, or proteolytic mechanisms, (ii) adhesion receptor intrinsic activity, through a variety of conformational changes, (iii) receptor organisation in cell membranes, as a consequence of topographical distribution and clustering, lateral mobility, and strength of anchoring to the cytoskeleton, and (iv) general processes unrelated to a specific receptors, such as glycocalyx changes or modification of cell shape or surface mechanical properties.     

Structure of cell–cell adhesion mediated by the Down syndrome cell adhesion molecule

The Down syndrome cell adhesion molecule (DSCAM) belongs to the immunoglobulin superfamily (IgSF) and plays important roles in neural development. It has a large ectodomain, including 10 Ig-like domains and 6 fibronectin III (FnIII) domains. Previous data have shown that DSCAM can mediate cell adhesion by forming homophilic dimers between cells and contributes to self-avoidance of neurites or neuronal tiling, which is important for neural network formation. However, the organization and assembly of DSCAM at cell adhesion interfaces has not been fully understood. Here we combine electron microscopy and other biophysical methods to characterize the structure of the DSCAM-mediated cell adhesion and generate three-dimensional views of the adhesion interfaces of DSCAM by electron tomography. The results show that mouse DSCAM forms a regular pattern at the adhesion interfaces. The Ig-like domains contribute to both trans homophilic interactions and cis assembly of the pattern, and the FnIII domains are crucial for the cis pattern formation as well as the interaction with the cell membrane. By contrast, no obvious assembly pattern is observed at the adhesion interfaces mediated by mouse DSCAML1 or Drosophila DSCAMs, suggesting the different structural roles and mechanisms of DSCAMs in mediating cell adhesion and neural network formation.

The Down syndrome cell adhesion molecule (DSCAM) was initially identified by isolating genes responsible for the phenotypes of Down syndrome (1), a genetic disease featured with cognitive and learning deficits (2). The DSCAM gene locates at the Down syndrome critical region (DSCR) on human chromosome 21 and is broadly expressed in nervous system (1, 3, 4), and its expression increases in patients with Down syndrome and in mouse models (3, 5, 6). Therefore, DSCAM has been hypothesized as a candidate gene associated with neurodevelopmental disorders and its dysregulation may lead to cognitive impairment and intellectual disability in Down syndrome (7), but the mechanism for the association between DSCAM and Down syndrome is still poorly understood.In invertebrates, Drosophila DSCAM1 (dDSCAM1) undergoes extensive alternative splicing by generating 38,016 isoforms with distinct recognition specificity (8–10), which is crucial for isoneuronal avoidance (11, 12). Loss of function or overexpression of dDSCAM1 in mutant flies causes defects or disorders in dendrite arborization (13, 14), axon guidance (15, 16), axon branching (17, 18), and synaptic targeting (11, 19, 20). Drosophila DSCAM2 (dDSCAM2) and DSCAM4 (dDSCAM4) also function in neural network formation by directing dendritic targeting but without the massive isoform diversity (21), and dDSCAM2 can mediate axonal tiling as well (22). Aplysia DSCAM (aDSCAM) is involved in transsynaptic protein localization (23).In vertebrates, two paralogous DSCAM genes, DSCAM and DSCAML1 (DSCAM-LIKE1) were identified (1, 24) and both of them could promote isoneuronal and homotypic self-avoidance (25, 26). In mouse, neurons expressing DSCAM (mDSCAM) or DSCAML1 (mDSCAML1) mutants may lose their mosaic pattern and neurite arborization (26, 27). Although the mechanism of mDSCAM-mediated self-avoidance remains unclear, it has been suggested that mDSCAM may function by masking the adhesion mediated by certain cadherin superfamily members (28). In addition, mDSCAM may also regulate neurite outgrowth (29, 30), promote cell death (31, 32), and control neuronal delamination (33). Studies have also shown that it could direct lamina-specific synaptic connections in chick (34) and be involved in cell movement in zebrafish (35). In contrast to dDSCAM1, the extensive alternative splicing has not been found for DSCAM in vertebrates, suggesting the different roles in the formation of neuronal circuits.DSCAM belongs to the immunoglobulin superfamily (IgSF) and consists of 10 immunoglobulin-like (Ig-like) domains, 6 type III fibronectin (FnIII) domains, a transmembrane domain, and a cytoplasmic domain (Fig. 1A). The domain arrangements of DSCAMs from invertebrates and vertebrates are quite similar, and the amino acid sequence identities of DSCAM among homologs are 98% between mDSCAM and hDSCAM (human), 59% between mDSCAM and mDSCAML1, and 33% between mDSCAM and dDSCAM1. The crystal structures of the N-terminal Ig-like domains of dDSCAM1 have been solved (36, 37). The eight N-terminal Ig-like domains form a dimer with a double-S–shaped conformation, which is critical for the homophilic cell adhesion (36). However, it is unclear whether the N-terminal Ig-like domains of mDSCAM and mDSCAML1 adopt a similar conformation to dDSCAM1, and the roles of other domains of DSCAM in cell adhesion remain elusive.Open in a separate windowFig. 1.Conformations of the ectodomains of mDSCAM, mDSCAML1, and dDSCAM1. (A) Diagrams of mDSCAM, mDSCAML1, and dDSCAM1 (ovals, Ig-like domains; rounded rectangles, FnIII domains; vertical rectangles, transmembrane domains; rectangles, cytoplasmic domains). (B–D) Negative staining EM images show the particles of mDSCAM-D_1–8, mDSCAM-D_9–16, and mDSCAM-D_1–16, respectively (Top, red arrows). (Scale bar, 50 nm.) The selected particles (Middle; the particles are picked from different images) and their contours (Bottom) are also listed. (Scale bar, 10 nm.) The schematic models of mDSCAM-D_1–8, mDSCAM-D_9–16, and mDSCAM-D_1–16 are shown in the Top Left Insets, respectively. (E–G) Negative staining EM images show the particles of mDSCAML1-D_1–8, mDSCAML1-D_9–16, and mDSCAML1-D_1–16, respectively (Top, red arrows). (Scale bar, 50 nm.) The selected particles (Middle) and their contours (Bottom) are also listed. (Scale bar, 10 nm.) The schematic models of mDSCAML1-D_1–8, mDSCAML1-D_9–16, and mDSCAML1-D_1–16 are shown in the Top Left Insets, respectively. (H–J) Negative staining EM images show the particles of dDSCAM1-D_1–8, dDSCAM1-D_9–16, and dDSCAM1-D_1–16, respectively (Top, red arrows). (Scale bar, 50 nm.) The selected particles (Middle) and their contours (Bottom) are also listed. (Scale bar, 10 nm.) The schematic models of dDSCAM1-D_1–8, dDSCAM1-D_9–16, and dDSCAM1-D_1–16 are shown in the Top Left Insets, respectively.Recently, electron tomography (ET) has become a powerful tool to provide three-dimensional (3D) views of biological samples (38, 39). By combining correlative light and electron microscopy (CLEM), high-pressure freezing and freeze substitution (HPF-FS), ultrathin sectioning and ET, the 3D structure of cellular or tissue samples can be reconstructed at nanometer resolution, revealing the molecular architecture of macromolecules in situ (40–43). Here we characterize the structures of mDSCAM, mDSCAML1, and dDSCAMs by electron microscopy (EM) as well as other biochemical and biophysical methods and reconstruct the 3D views of the mDSCAM-mediated adhesion interface by electron tomography, thereby unveiling the in situ structural model and the potential mechanism of cell adhesion by DSCAM.     

Calcium and cellular adhesion mechanism--involvement of intracellular calcium to cell adhesion

Cell to cell and cell to extracellular matrix adhesion play an essential role in embryogenesis, differentiation, morphological development and disease processes. Adhesion processes are affected by two reverse directional signaling: expression of adhesion molecules is regulated by inside-out signaling and the molecules transduce extracellular information into cytoplasm by "outside-in" signaling. Cadherins are a family of Ca(2+)-dependent cell-cell adhesion molecules that are important for the mutual association of vertebrate cells. During cell differentiation, for example, the amount or the nature of the cell-surface cadherins and other adhesion molecules change, affecting many aspects of cell-cell adhesion and cell migration.     

Cooperative inhibitory effects of antisense oligonucleotide of cell adhesion molecules and cimetidine on cancer cell adhesion

AIM: To explore the cooperative effects of antisense oligonucleotide (ASON) of cell adhesion molecules and cimetidine on the expression of E-selectin and ICAM-1 in endothelial cells and their adhesion to tumor cells. METHODS: After treatment of endothelial cells with ASON and/or cimetidine and induction with TNF-α, the protein and mRNA changes of E-selectin and ICAM-1 in endothelial cells were examined by flow cytometry and RT-PCR,respectively. The adhesion rates of endothelial cells to tumor cells were measured by cell adhesion experiment. RESULTS: In comparison with TNF-α inducing group, lipoASON and lipo-ASON/cimetidine could significantly decrease the protein and mRNA levels of E-selectin and ICAM-1 in endothelial cells, and lipo-ASON/cimetidine had most significant inhibitory effect on E-selectin expression (from 36.37&#177;1.56% to 14.23&#177;1.07%, P&lt;0.001). Meanwhile,cimetidine alone could inhibit the expression of E-selectin(36.37&#177;1.56% vs 27.2&#177;1.31%, P&lt;0.001), but not ICAM-1(69.34&#177;2.50% vs68.07&#177;2.10%,P&gt;0.05)and the two kinds ofmRNA, either. Compared with TNF-α inducing group, the rate of adhesion was markedly decreased in lipo-E-selectin ASON and lipo-E-selectin ASON/cimetidine treated groups(P&lt;0.05),and lipo-E-selectin ASON/cimetidine worked better than lipo-E-selectin ASON alone except for HepG2/ECV304 group(P&lt;0.05). However, the decrease of adhesion was not significant in lipo-ICAM-1 ASON and lipo-ICAM-1 ASON/dmetidine treated groups except for HepG2/ECV304 group (P &gt;0.05). CONCLUSION: These data demonstrate that ASON in combination with cimetidine in vitro can significantly reduce the adhesion between endc~thelial cells and hepatic or colorectal cancer cells, which is stronger than ASON or cimetidine alone. This study provides some useful proofs for gene therapy of antiadhesion.     

Memory in receptor-ligand-mediated cell adhesion

Single-molecule biomechanical measurements, such as the force to unfold a protein domain or the lifetime of a receptor-ligand bond, are inherently stochastic, thereby requiring a large number of data for statistical analysis. Sequentially repeated tests are generally used to obtain a data ensemble, implicitly assuming that the test sequence consists of independent and identically distributed (i.i.d.) random variables, i.e., a Bernoulli sequence. We tested this assumption by using data from the micropipette adhesion frequency assay that generates sequences of two random outcomes: adhesion and no adhesion. Analysis of distributions of consecutive adhesion events revealed violation of the i.i.d. assumption, depending on the receptor-ligand systems studied. These include Markov sequences with positive (T cell receptor interacting with antigen peptide bound to a major histocompatibility complex) or negative (homotypic interaction between C-cadherins) feedbacks, where adhesion probability in the next test was increased or decreased, respectively, by adhesion in the immediate past test. These molecular interactions mediate cell adhesion and cell signaling. The ability to "remember" the previous adhesion event may represent a mechanism by which the cell regulates adhesion and signaling.     

Topology of cell adhesion molecules.

The neural cell adhesion molecule (N-CAM) exists in two major forms [ld (large cytoplasmic domain) peptide and sd (small cytoplasmic domain) peptide] that contain transmembrane segments and different cytoplasmic domains and in a third form [ssd (small surface domain) peptide] that lacks transmembrane and cytoplasmic regions. All forms have the same extracellular region of more than 600 amino acid residues, a region also found in a fragment (Fr2) that can be released from cells by proteolysis. The liver cell adhesion molecule (L-CAM) is expressed as a single species that is distinct from N-CAM, but its extracellular region can also be obtained as a proteolytic fragment (Ft1). Examination of the various forms of N-CAM and the Ft1 fragment of L-CAM by electron microscopy of rotary shadowed molecules indicated that they all have rod-shaped structures that contain a hinge region which is apparently flexible. Both the ssd chain and the Fr2 fragment of N-CAM are single rods bent into arms approximately 18 and 10 nm long. The ld and sd chains are longer bent rods that form rosettes comprising two to six branches; detergent treatment disrupts these rosettes into single rods. Specific antibodies that block homophilic N-CAM binding labeled the distal ends of the branches of the ld/sd rosettes and the ends of the longer arm of both the ssd chain and the Fr2 fragment. Antibodies that bind to the sialic acid-rich region of N-CAM bound near the hinge. These data indicate that the N-CAM rosettes are formed by interaction between their transmembrane or cytoplasmic domains and not by interactions involving their homophilic binding sites. The L-CAM Ft1 fragment is also a bent rod with an apparently flexible hinge; like the ssd chain and the Fr2 fragment of N-CAM, it does not form aggregates. The similarities between L-CAM and N-CAM, despite their differences in amino acid sequence, suggest that their general configuration and the presence of a flexible hinge are important elements in assuring effective and specific cell-cell adhesion.     

Antagonists of alcohol inhibition of cell adhesion

Increasing evidence suggests that alcohols act within specific binding pockets of selective neural proteins; however, antagonists at these sites have not been identified. 1-Alcohols from methanol through 1-butanol inhibit with increasing potency the cell-cell adhesion mediated by the immunoglobulin cell adhesion molecule L1. An abrupt cutoff exists after 1-butanol, with 1-pentanol and higher 1-alcohols showing no effect. Here, we demonstrate surprisingly strict structural requirements for alcohol inhibition of cell-cell adhesion in L1-transfected NIH 3T3 fibroblasts and in NG108-15 neuroblastoma x glioma hybrid cells treated with BMP-7, an inducer of L1 and neural cell adhesion molecule. The target site discriminates the tertiary structure of straight-chain and branched-chain alcohols and appears to comprise both a hydrophobic binding site and an adjacent hydrophilic allosteric site. Modifications to the 2- and 3-carbon positions of 1-butanol increased potency, whereas modifications that restrict movement about the 4-carbon abolished activity. The effects of ethanol and 1-butanol on cell-cell adhesion were antagonized by 1-pentanol (IC(50) = 715 microM) and 1-octanol (IC(50) = 3.6 microM). Antagonism by 1-octanol was complete, reversible, and noncompetitive. 1-Octanol also antagonized ethanol inhibition of BMP-7 morphogenesis in NG108-15 cells. 1-Octanol and related compounds may prove useful in dissecting the role of altered cell adhesion in ethanol-induced injury of the nervous system.     

E-selectin and vascular cell adhesion molecule-1 mediate adult T-cell leukemia cell adhesion to endothelial cells

We studied the adhesion properties of peripheral blood leukemic cells from 10 patients with adult T-cell leukemia (ATL) to endothelial cells to better understand the mechanism of leukemic cell infiltration. ATL cells expressed lymphocyte function-associated antigen-1 (LFA-1), but the expression of very late antigen-4 (VLA-4) and sialyl-Lewisx (SLex) was variable. They did not express sialyl-Lewisa (SLea). Cell adhesion assays, which were performed in nine patients, showed marked adhesion of ATL cells to interleukin [IL]-1-activated human umbilical vein endothelial cells (HUVEC). A monoclonal antibody (MoAb) against E- selectin consistently inhibited ATL cell adhesion, and an MoAb against vascular cell adhesion molecule-1 (VCAM-1) or an MoAb against VLA-4 sometimes diminished it. In contrast, an MoAb against LFA-1 had a minor effect on freshly isolated ATL cell adhesion to HUVEC. The percentage of SLex+ cells in the cell population adherent to IL-1-activated HUVEC was slightly higher than that in unseparated cells. These results, together with the detection of E-selectin expression on the endothelium at ATL skin lesions, indicate that E-selectin-mediated adhesion is the major pathway for the adherence of ATL cells to endothelial cells. In addition, the ligand for E-selectin on ATL cells appears to differ from that on neutrophils.     

Electrostatic interaction influences cell adhesion?

The effect of electrostatic forces on the adhesion of LEP-19 diploid embryonal fibroblasts, Hep-2 laryngeal carcinoma cells, Raji lymphoblastoma cells and Sp 2/0 myeloma cells was examined in vitro. Adhesivity of all tested cell lines was higher on the cationized glass than on untreated or anionized glass. The negatively charged sialic acids on the cell surface play a role in cell adhesion. The participation of electrostatic interaction is independent of the energy metabolism in serum-free conditions.