Ezrin is a cytoplasmic linker molecule between plasma membrane components and the actin-containing cytoskeleton. We studied whether ezrin is associated with intercellular adhesion molecule (ICAM)-1, -2, and -3. In transfected cells, ICAM-1 and ICAM-2 colocalized with ezrin in microvillar projections, whereas an ICAM-1 construct attached to cell membrane via a glycophosphatidylinositol anchor was uniformly distributed on the cell surface. An interaction of ICAM-2 and ezrin was seen by affinity precipitation, microtiter binding assay, coimmunoprecipitation, and surface plasmon resonance methods. The calculated K D value was 3.3 ؋ 10 ؊7 M. Phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P 2 ) induced an interaction of ezrin and ICAM-1 and enhanced the interaction of ezrin and ICAM-2, but ICAM-3 did not bind ezrin even in the presence of PtdIns(4,5)P 2 . PtdIns(4,5)P 2 was shown to bind to cytoplasmic tails of ICAM-1 and ICAM-2, which are the first adhesion proteins demonstrated to interact with PtdIns(4,5)P 2 . The results indicate an interaction of ezrin with ICAM-1 and ICAM-2 and suggest a regulatory role of phosphoinositide signaling pathways in regulation of ICAM-ezrin interaction.
Accelerated atherosclerosis in diabetes has been suggested as being due to an enhanced oxidative modification of LDL. We hypothesized that the titers of autoantibodies against oxidized LDL (oxLDL) may be increased in patients with non-insulin-dependent diabetes mellitus (NIDDM) and that they may contribute to various manifestations of atherosclerosis among such patients. In a 10-year follow-up study of 91 newly diagnosed NIDDM patients and 82 nondiabetic control subjects, autoantibodies against oxLDL (expressed as the ratio of autoantibodies against oxLDL and native LDL) were measured at baseline and after 10 years. Quantitative ultrasonography to examine the intimal-medial thickness of the common carotid artery (a morphological index of arterial wall injury) and carotid bifurcation was performed at the 10-year examination. The relationship of autoantibodies against oxLDL to the occurrence of cardiovascular death, fatal and nonfatal myocardial infarction, stroke, and any cardiovascular event as well as to the intimal-medial thickness of the common carotid artery and carotid bifurcation was evaluated. Associations between these autoantibodies and metabolic variables (fasting glucose, glycosylated hemoglobin, insulin, and serum lipids) in NIDDM patients were also examined. Autoantibodies against oxLDL did not differ between NIDDM and control subjects (NIDDM: baseline, 1.63 and 0.61 to 23.6; 10-year examination, 1.64 and 0.06 to 59.0; control group: baseline, 1.84 and 0.13 to 36.0; 10-year examination, 1.50 and 0.25 to 8.29; median and range, P = .62, baseline; P = .45, 10 year). In both groups, the titers of these autoantibodies measured at baseline and after 10 years significantly correlated with each other (r = .63 for the diabetic and r = .51 for the control group, respectively, P < .001 for each). The frequency of all cardiovascular events was markedly higher in the NIDDM group than in the control group, but autoantibodies against oxLDL had no significant association with any of these events, including cardiovascular mortality. At the 10-year examination the intimal-medial thickness of the common carotid artery (1.24 +/- 0.36 versus 1.06 +/- 0.30 mm, P = .002) and carotid bifurcation (2.11 +/- 0.73 versus 1.77 +/- 0.82 mm, P = .01) were greater in NIDDM patients than in control subjects, but autoantibodies did not show any association with the intimal-medial thicknesses in either the diabetic or control groups. Autoantibodies against oxLDL indicate the presence of oxidatively modified LDL in vivo, but their titers in the serum do not seem to associate with the excess cardiovascular mortality, morbidity, or intimal-medial thickness of the carotid artery.
Antimicrobial agents (antibody and non-antibody) present in human saliva protect oral tissues by a variety of mechanisms, such as prevention of bacterial adhesion, agglutination of micro-organisms, and inhibition of multiplication and metabolism. However, studies in which the concentrations of various salivary antimicrobial agents have been correlated to the presence and severity of oral diseases--of dental caries, in particular--have produced controversial data, and it seems evident, also on the basis of the present study, that no single salivary antimicrobial factor (except flow rate) affects oral health to a significant degree. In the present study, we report the levels of some selected salivary antimicrobial agents in predentate and dentate human infants, with a comparison to the levels found in young adults' saliva. Salivary lysozyme, peroxidase, and hypothiocyanite concentrations were already at the adult level at the time when the primary teeth erupt, whereas immunoglobulin (IgA, IgG, and IgM), lactoferrin, myeloperoxidase, and thiocyanate concentrations were significantly lower in children than in adults. Dentate children had more IgG, thiocyanate, and protein in whole saliva than did predentate children.
We analyzed the flow rate and composition of paraffin-stimulated whole saliva samples from 35 adult diabetic patients and their age- and sex-matched, non-diabetic, clinically healthy controls. All patients had insulin-dependent diabetes (IDDM) with a mean (+/- S.D.) duration of 14.0 +/- 9.1 years. The saliva analysis included the quantitation of total protein, amylase, immunoglobulins (isotypes A, G, and M), and the non-antibody, innate antimicrobial factors (lysozyme, lactoferrin, salivary peroxidase, myeloperoxidase, thiocyanate, and hypothiocyanite). The whole saliva samples from diabetic patients had significantly higher amounts of IgA (p less than 0.001) and IgG (p less than 0.05) than did the controls. No differences between the study groups were observed in flow rate, protein content, amylase activity, or IgM. The levels of innate defense factors were similar in both study groups except for salivary peroxidase, which was higher (p less than 0.02) among diabetics than among controls. Our results indicate that the antimicrobial defense capacity of whole saliva is not impaired in diabetic patients.
Previous studies of the possible associations of salivary antimicrobial agents with dental caries have given controversial results, obviously mainly because almost all studies have been cross-sectional. Our aim was to find out, in a two-year longitudinal follow-up study, the associations among selected salivary non-immune and immune antimicrobial variables, cariogenic bacteria, and caries increment. The study population was comprised of 63 subjects, all of whom had their 13th birthday during the first study year. In addition to a comprehensive dental examination at baseline and after 2 yrs, paraffin-stimulated whole saliva samples were collected in a standardized way at six-month intervals. Saliva samples were analyzed for flow rate, buffer effect, lysozyme, lactoferrin, total peroxidase activity, hypothiocyanite, thiocyanate, agglutination rate, and total and specific anti-S. mutans IgA and IgG, as well as for numbers of total and mutans streptococci, lactobacilli, and total anaerobic bacteria. Cluster analysis and Spearman-Rank correlation coefficients were used to explore possible associations between and among the studied variables. During the two-year period, a statistically significant increase was observed in flow rate, thiocyanate, agglutination rate, anti-S. mutans IgA antibodies, lactobacilli, and total anaerobes, whereas lysozyme, lactoferrin, and total and anti-S. mutans IgG antibodies declined significantly. Based on various analyses, it can be concluded that, at baseline, total IgG and hypothiocyanite had an inverse relationship with subsequent two-year caries increment, anti-S. mutans IgG antibodies increased with caries development, and mutans streptococci and lactobacilli correlated positively with both baseline caries and caries increment. Total anaerobic microflora was consistently more abundant among caries-free individuals. In spite of the above associations, we conclude that none of the single antimicrobial agents as such has sufficiently strong power to have diagnostic significance in vivo with respect to future caries.
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