Assembly of a fibronectin matrix by adherent platelets stimulated by lysophosphatidic acid and other agonists.

Lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) are agonists of the endothelial differentiation gene (Edg) family of G-protein-coupled receptors. LPA and S1P are generated by platelet activation during blood coagulation. Both lipids induce assembly of exogenous fibronectin (FN) by fibroblasts. This study examined whether LPA and S1P stimulate binding and assembly of fluoresceinated FN (FITC-FN) by adherent platelets. LPA enhanced deposition of FITC-FN into linear arrays overlying platelet surfaces and on edges of platelets adherent to FN or vitronectin (VN). Deposition was greater when platelets were adherent to FN than to VN and was elicited by platelet agonists with the following order of potency: thrombin > LPA = ADP (adenosine diphosphate) > S1P. The linear pattern of FITC-FN deposition was different from the more diffuse pattern of Alexa-fibrinogen (Alexa-FGN) binding to adherent platelets. FITC-FN was deposited by adherent platelets that had dense arrays of cytoskeletal actin when stained with rhodamine-phalloidin. The 70-kd N-terminal fragment of FN or L8 monoclonal antibody to a self-association domain of FN abolished deposition of FITC-FN but had no effect on binding of Alexa-FGN. Conversely, integrilin did not attenuate deposition of FITC-FN but abolished binding of Alexa-FGN. RGDS (Arg-Gly-Asp-Ser) or antibodies to alpha5beta1 or alphaIIbbeta3 integrins caused a partial decrease in LPA-induced deposition of FITC-FN. Correlative electron microscopy with anti-FITC coupled to gold beads revealed linear arrays on platelet surfaces associated with less than 20-nm-diameter filaments. These observations demonstrate that LPA, thrombin, ADP, and S1P induce adherent platelets to bind and assemble FN and suggest that platelets may contribute to early deposition of FN matrix after vascular injury.     

Chinese hamster ovary cell adhesion to human platelet thrombospondin is dependent on cell surface heparan sulfate proteoglycan.

Thrombospondin is a 420-kD platelet alpha-granule glycoprotein that binds specifically to heparin. We examined adhesion to thrombospondin of CHO K1 cells and three mutant CHO lines with varying deficiencies in glycosaminoglycan (GAG) synthesis. In an experiment in which the parent line (K1) had 78% adherence to thrombospondin adsorbed to tissue culture plastic, CHO S745 cells, with less than 6% normal GAG synthesis had 11% adherence. CHO S677 cells, with decreased heparan sulfate proteoglycan but increased chondroitin sulfate proteoglycan, had 42% adherence. CHO S803 cells, with decreased heparan sulfate proteoglycan and normal chondroitin sulfate proteoglycan, had 31% adherence. Heparin inhibited K1 cell adhesion to thrombospondin, but not fibronectin, in a concentration-dependent manner. Dermatan sulfate but not chondroitin sulfate was also inhibitory. There was markedly decreased K1 cell adhesion to a thrombospondin core fragment that lacked the heparin binding NH2-terminal domain. Purified heparin binding domain, although poorly adhesive when adsorbed to substratum, inhibited cell adhesion to intact thrombospondin. Adhesion was better for all cell lines tested, including three human tumor cell lines, when thrombospondin was adsorbed at pH 4.0 compared with pH 7.4. When adsorption of thrombospondin was done at pH 7.4, cell adhesion was better when thrombospondin was adsorbed in the presence of greater than or equal to 0.6 mM calcium, compared to 0.1 mM calcium or EDTA. These findings suggest that thrombospondin can adsorb to plastic with varying degrees of exposure of a cell adhesion domain. We conclude that the thrombospondin cell adhesion receptor on CHO cells is a heparan sulfate proteoglycan, and that cell adhesion to thrombospondin depends on conformation of adsorbed thrombospondin.     

Self-reported pelvic inflammatory disease in the United States, 1988

OBJECTIVE.--To assess any changes in the characteristics of women with self-reported pelvic inflammatory disease (PID) between 1982 and 1988 and to evaluate the role of additional behavioral factors. In 1982, PID was a frequent problem among American women of reproductive age, occurring in one in seven. It was also more common among older (greater than or equal to 30 years) than younger women, more common among blacks than among whites, and more common among formerly married women than among those currently married. DESIGN.--We analyzed data on self-reported PID from the cycle IV National Survey of Family Growth, conducted in 1988. SAMPLE.--The survey was conducted with a multistage probability sample of 8450 women. RESULTS.--The findings from 1982 were all replicated. Additional variables available in 1988 show that PID is more common among women with multiple (two or more) sexual partners (10% to 22%) compared with those with only one lifetime partner (7%) and among women who report a history of sexually transmitted disease (STD) (26%) compared with those with no STD history (10%). Controlling for other variables, age, race, vaginal douching, age at first intercourse, STD history, and number of lifetime partners emerged as independent predictors of self-reported PID among American women of reproductive age. CONCLUSION.--PID is still a widely prevalent condition among American women, PID is associated with a variety of risk factors for STD. Prevention of lower genital tract infection is crucial to avoiding PID and its sequelae.     

Activation and complexation of protein C and cleavage and decrease of protein S in plasma of patients with intravascular coagulation

Activated protein C (APC) is inhibited by two major plasma inhibitors (PCIs). To find evidence for in vivo complexation of APC, immunoblotting studies were performed on plasmas of 85 patients with suspected disseminated intravascular coagulation (DIC). Samples from 62 of these patients contained 5% to 35% of protein C antigen in APC:inhibitor complexes, indicating that protein C activation and inhibition had occurred. In 24 normal plasmas, no detectable APC:PCI complexes were observed (less than 5%). Patients with higher levels of complexes had more abnormal coagulation test data for DIC. The major band of APC complexes detected by anti-protein C antibodies did not react with antibodies to the heparin-dependent protein C inhibitor (PCI- 1) previously described. Rather, APC was complexed with another recently described plasma protein C inhibitor, PCI-2. Immunoblotting studies for protein S, the cofactor for APC, revealed that the majority of the DIC patient plasmas contained a higher than normal proportion of protein S in cleaved form, suggesting that protein S may have been proteolytically inactivated. Protein S total antigen levels were also found to be low in DIC patients, excluding those with malignancy. These studies support the hypothesis that the protein C pathway is activated during DIC.     

Contraceptive use at first premarital intercourse: United States, 1965-1988

The proportion of U.S. women who used a contraceptive method at their first premarital intercourse rose from 47 percent in 1975-1979 to 65 percent in 1983-1988. Overall, and among non-Hispanic white women, this change resulted entirely from an increase in the use of condoms by their partners. The proportion of whites who used a condom at first premarital intercourse, for example, increased from 24 percent to 45 percent. Among blacks, condom use at first intercourse increased from 24 percent to 32 percent during that period, and pill use rose from 15 percent to 23 percent. Among all women, the method most often used at first intercourse during every period in the study was the condom, followed by the pill and withdrawal. The proportion of women using a method at first premarital intercourse varies strikingly according to individual characteristics. Among the various demographic subgroups, the proportion who use a method varies from 32 percent of Hispanic women to 68 percent of Jewish women. Whites are more likely to use a method than are blacks, and fundamentalist Prostestants are less likely to use a method than are other Protestants or Catholics. The proportion using a method is higher among women whose mothers completed high school than among those whose mothers did not. In addition, the proportion rises with age at first intercourse. Multiple logistic regression showed that the independent effects of Hispanic origin, Jewish or fundamentalist Protestant religious affiliation and the education of a woman's mother are large and significant.(ABSTRACT TRUNCATED AT 250 WORDS)     

Localization of realistic cortical activity in MEG using current multipoles

We present a novel approach to MEG source estimation based on a regularized first-order multipole solution. The Gaussian regularizing prior is obtained by calculation of the sample mean and covariance matrix for the equivalent moments of realistic simulated cortical activity. We compare the regularized multipole localization framework to the classical dipole and general multipole source estimation methods by evaluating the ability of all three solutions to localize the centroids of physiologically plausible patches of activity simulated on the surface of a human cerebral cortex. The results, obtained with a realistic sensor configuration, a spherical head model, and given in terms of field and localization error, depict the performance of the dipolar and multipolar models as a function of variable source surface area (50-500 mm(2)), noise conditions (20, 10, and 5 dB SNR), source orientation (0-90 degrees ), and source depth (3-11 cm). We show that as the sources increase in size, they become less accurately modeled as current dipoles. The regularized multipole systematically outperforms the single dipole model, increasingly so as the spatial extent of the sources increases. In addition, our simulations demonstrate that as the orientation of the sources becomes more radial, dipole localization accuracy decreases substantially, while the performance of the regularized multipole model is far less sensitive to orientation and even succeeds in localizing quasi-radial source configurations. Furthermore, our results show that the multipole model is able to localize superficial sources with higher accuracy than the current dipole. These results indicate that the regularized multipole solution may be an attractive alternative to current-dipole-based source estimation methods in MEG.     

Witnessed embolization of a right atrial mass during transesophageal echocardiography: implications regarding the safety of esophageal intubation.

A patient with chronic lung disease and a right atrial density that was difficult to distinguish on a transthoracic echocardiogram underwent transesophageal echocardiography (TEE) that demonstrated two mobile masses attached to the anterior right atrial wall. During the TEE procedure, the patient experienced coughing and retching due to the esophageal intubation, and the embolization of one of the right atrial masses was observed. This case is the first to document this mechanism of pulmonary embolism (a mechanism that was suspected in two prior reports), and it questions the safety of procedures that induce retching and coughing in patients with mobile right atrial masses.     

On the identity of vitronectin and S-protein: immunological crossreactivity and functional studies

Vitronectin (serum spreading factor), a major serum cell adhesion molecule, was compared with S-protein, the inhibitor of the C5-9 membrane attack complex. Data from the literature indicate that S-protein and vitronectin are alpha globulins with the same aminoterminal residues, amino acid compositions, and concentrations in normal plasma (150 to 250 micrograms/mL). Both proteins have been reported to interact with the thrombin-antithrombin complex. The cDNA sequences of vitronectin and S-protein were recently determined and found to be almost identical. In the present studies, rabbit-anti-S-protein and a monoclonal antibody to vitronectin both recognized 65,000- and 75,000-molecular weight (mol wt) polypeptides when plasma or serum proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transferred to nitrocellulose paper. The 65,000 and 75,000-mol wt polypeptides bound more avidly from serum than plasma to monoclonal anti-vitronectin or heparin coupled to agarose. The presence or absence of the polypeptides constituted a major difference between the heparin-binding proteins of serum and plasma. When complement-activated serum and unactivated serum were separated by gel filtration, vitronectin coeluted with C9 in high-mol-wt fractions of activated serum but not unactivated serum. Purified S-protein was recognized by the monoclonal antibody to vitronectin and promoted spreading of human skin fibroblasts. Both vitronectin and S-protein were degraded by thrombin. On the basis of immunological and functional, as well as biochemical, properties, therefore, S-protein and vitronectin are the same.