NG2 proteoglycan and the actin-binding protein fascin define separate populations of actin-containing filopodia and lamellipodia during cell spreading and migration

The transmembrane proteoglycan NG2 is able to interact both with components of the extracellular matrix and with the actin cytoskeleton. An examination of the distribution of NG2 during cell spreading suggests that NG2 can associate with two distinct types of actin-containing cytoskeletal structures, depending on the nature of the stimulus derived from the substratum. On fibronectin-coated dishes, cell surface NG2 associates exclusively with stress fibers developing within the cell. On poly-L-lysine-coated dishes, cell surface NG2 is associated with radial processes extending from the cell periphery. Spreading on fibronectin/poly-L-lysine mixtures, as well as on matrix components such as laminin, tenascin, and type VI collagen, produces cells with mosaic characteristics, i.e., NG2 is associated with both types of structures. NG2-positive radial processes are distinct from a second population of radial structures that contain fascin. NG2-positive extensions appear to be individual self-contained units (filopodia), whereas fascin is associated with actin ribs within sheets of membrane (lamellipodia). NG2- and fascin-positive structures are often localized to opposite poles of spreading cells, suggesting a possible role for the two classes of cellular extensions in the establishment of cell polarity during morphogenesis or migration. Time lapse imaging confirms the presence of lamellipodia on the leading edges of migrating cells, while numerous filopodia are present on trailing edges.     

Evaluation of the completion of influenza vaccination

OBJECTIVE: To find the reasons which determine failures to comply with anti-flu vaccinations, so that these can be corrected and the coverage of this preventive action be increased. DESIGN: Observational crossover study, done by means of a telephone survey of people over 65. A questionnaire with closed questions, composed after a pilot study and validated by Cronbach's alpha. SETTING: Primary Care Centre (PCC). PATIENTS: We calculated a population sample for qualitative variables (_ = 0.05; p = 0.60; e = 0.05) of 294 people over 65, chosen from the PCC records, by means of random sampling (K = 4) stratified for age and discounting the telephone selection bias. MEASUREMENTS AND RESULTS: The proportion of vaccinated patients (60.9%) obtained in our study did not significantly differ from that in the general population. The percentage of patients included in the programme for the first time was 14%. Level of satisfaction among those vaccinated was 89.4%, with 8.9% of problems detected being light. Main causes of non-vaccination were: thinking that they didn't need it (63.5%), ignorance of the campaign (35.7%), fear of the reaction (24.3%), forgetting (10.4%). The main form of access to the campaign information was from the PCC, both through individuals and posters. Lack of information was statistically significant (p < 0.00001) as a determinant of non-vaccination, without other factors (age, sex, associated pathologies...) explaining these differences. CONCLUSIONS: Individualised and on-going health education by the PCC is fundamental. This would enable the identification of the group not vaccinated due to their express refusal and the recovery of non-vaccinated patients.     

HLA-DR mismatching correlates with early cardiac allograft rejection, incidence, and graft survival when high-confidence-level serological DR typing is used

To determine if cardiac allograft outcome is improved among patients with fewer HLA-DR mismatches with their donors, we studied 132 recipients of a primary cardiac allograft who were transplanted between December 1985 and December 1991. These recipients and their donors all had high-confidence-level serological HLA-DR typing, previously shown to correlate highly with DNA DR typing. Patients were divided in two groups based on the HLA-DR mismatch with their donors. Group I consisted of 78 patients with 1 or zero DR mismatch and group II of 54 patients with 2 DR mismatches. Allograft outcome measurements included incidence of moderate rejection, incidence of allograft vasculopathy at 12 months, cardiac function measured as left ventricular ejection fraction (LVEF) and cardiac index (CI), and actuarial graft survival up to 7 years. Groups I and group II were not different with regard to recipient age, donor age, ischemia time, pulmonary vascular resistance, sex, or PRA greater than 0%. Group II had a higher incidence of moderate rejection on the first-week biopsy (47% vs. 25%, P = 0.019), and during the first month (84% vs. 58%, P = 0.006), but no difference was found in frequency of rejection from months 2 to 12. LVEF was not different in the groups at any point. CI was better in group I at 12 months (2.76 vs. 2.5, P = 0.03). No statistically significant difference was found in incidence of allograft vasculopathy (17% vs. 26%, P = 0.204). Actual graft survival at 1 year was better for group I (91% vs. 74%, P = 0.008), and actuarial graft survival at 6 years also favored group I (76% vs. 56%, P = 0.04). Using high-confidence-level serological HLA-DR typing assignments we demonstrated that HLA-DR mismatching correlates highly with cardiac allograft outcome. Implications are that heart transplant survival could be improved if prospective matching were feasible and prioritized or if immunosuppression were tailored to the HLA-DR match.     

Structural characterization of the cyanelle peptidoglycan of Cyanophora paradoxa by 252Cf plasma desorption mass spectrometry and fast atom bombardment/tandem mass spectrometry

A strategy for the structural characterization of the four major NaBH4-reduced peptidoglycan monomers derived from muramidase-digested peptidoglycan from the cyanelles of the flagellate Cyanophora paradoxa Korschikoff is described. Initial molecular weight determination of these glycopeptides was performed by positive and negative ion plasma desorption mass spectrometry. Due to the presence of two pairs of disaccharide tripeptide and disaccharide tetrapeptide monomers differing in mass by 112 units, respectively, an as yet unknown peptidoglycan modification either at the carbohydrate or at the peptide moiety was assumed. beta-Elimination of the disaccharide unit from the unreduced peptidoglycan monomers yielded the corresponding (modified) N1-lactyltripeptides and -tetrapeptides, respectively. These peptides, N-terminally blocked with lactic acid, unambiguously showed the modification to be located on the peptide moiety. By positive ion fast atom bombardment/hybrid tandem mass spectrometry of the reduced peptidoglycan monomers as well as of the corresponding deglycosylated monomers (= N1-lactylpeptides) the modification was determined to be linked to the glutamic acid moiety. Based on combined data from plasma desorption mass spectrometry, tandem mass spectrometry, accurate mass measurement and amino acid analysis of the acid hydrolysate after derivatization with o-phthaldialdehyde by high-performance liquid chromatography we could establish the structure of the modification as N-acetylputrescine. Finally, the confirmation of the linkage of the glutamic acid to diaminopimelic acid via the gamma-COOH was based on the presence of a-type peptide backbone fragment ions in the positive ion plasma desorption mass spectra of the modified N1-lactylpeptides.     

企业柔性:基于集成的观点

从集成的思想出发分析了柔性的内涵，认为企业柔性的目标是提高企业在动态环境条件下的整体竞争优势，柔性的基础是在更大范围内的协调优化与有效集成；从系统的角度将企业柔性分为市场柔性，研发柔性，制造柔性与组织柔性四个维度，对每个维度所包括的具体内容进行了分析；建立了企业柔性的概念模型，从整体的角度出发对企业的柔性的形式与作用机制进行了描述。     

金刚石薄膜异质外延的研究进展

主要介绍金刚石薄膜在Si上异质外延的研究状况。综述了外延金刚石薄膜的偏压形核 ,SiC过渡层的影响及一些实验参数对外延薄膜质量的影响等 ,并论述了发展方向     

海水介质中高活性镁合金负极的电化学性能

研制了一种新型镁合金负极材料；用电化学方法测定了镁合金负极在人造海水介质中的电化学性能，用浸泡法测定了材料在人造海水介质中的自腐蚀速度，用扫描电子显微镜观察了镁合金腐蚀后的表面形貌，并与AP65合金和纯镁进行了比较。结果表明，新研制的镁合金在人造海水介质中的开路电位增加，自腐蚀速度降低，稳定工作电位提高，电极表面腐蚀均匀，可开发用于高电性能电池的负极材料。     

The Effect of the Charge Fluctuation of Dust Parti-cles on Ion-acoustic Wave Excited Through Ionization Instability

The effect of the charge fluctuation of dust particles on ion acoustic wave (IAW) excited through ionization instability was investigated. The hydrodynamic equations and linear time-dependent perturbation theory served as the starting point of theory, by which the dispersion relation and growth rate of the IAW were given. By comparing the results with the case of constant dust charges, it was found that the charge fluctuation of dust particles reduces the instability of the wave mode.     

The development of pre- and post-natal veins

There is little information on the metabolic response to ingested fructose in patients with cirrhosis. Glucose kinetics, plasma lipid and blood lactate levels, whole body substrate oxidation rates and energy expenditure were measured following ingestion of 75 g fructose, in 8 cirrhotic patients and 6 controls. Fasting plasma glucose levels and rates of glucose appearance (Ra) and disappearance (Rd) were similar. The basal rate of lipolysis was higher in cirrhotic patients (P < 0.05), but whole body lipid and carbohydrate oxidation rates and energy expenditure were similar. After fructose ingestion, plasma fructose levels were much higher in cirrhotic patients (P < 0.001) and the incremental area under the plasma glucose curve was twice that of controls (P < 0.05). The increase in glucose in patients with cirrhosis was due to an increase in glucose Ra and an initial reduction in glucose Rd. Plasma non-esterified fatty acid levels fell to similar low levels in both groups. Glycerol levels fell in controls (P < 0.05) but not in cirrhotic patients. Blood lactate levels, fasting and after oral fructose, were similar in cirrhotics and controls. The time course of suppression of lipid oxidation and stimulation of carbohydrate oxidation was more closely related to fructose levels than to serum fatty acid levels in both groups. The percent suppression and total quantity of lipid oxidized in 4 h after fructose were not significantly different, but the suppressed lipid oxidation rates and elevated carbohydrate oxidation rates were sustained for longer in the cirrhotics. The data suggest that fructose uptake and metabolism inhibits oxidation of intracellular lipid. There was a smaller increase in energy expenditure after fructose in cirrhotics (P < 0.001), but normal overall storage of fructose; the likely explanation is reduced first pass hepatic fructose uptake in cirrhotics making more fructose available to the periphery for incorporation into muscle glycogen. The energy cost of storing fructose as muscle glycogen is less than that of storing it as liver glycogen. Preferential incorporation of fructose carbon into muscle glycogen, with lower rates of hepatic glycogen and triglyceride synthesis, would therefore result in less energy expenditure after a fructose load in cirrhotics.