The influence of glancing angle deposited nano-rough platinum surfaces on the adsorption of fibrinogen and the proliferation of primary human fibroblasts

We have used the glancing angle deposition (GLAD) method as a simple and fast method to generate nano-rough surfaces for protein adsorption experiments and cell assays. The surface roughness and the detailed geometrical surface morphology of the thin films were characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). As the GLAD deposition angle approaches grazing incidence, sharp and whisker-like columnar protrusions are formed. Smaller and less sharp surface features appear for the thin films synthesized at higher deposition angles. By changing the GLAD deposition angle together with the total amount of mass deposited per area on the respective surfaces, the size of the surface features can be varied on the nanoscale. Using the GLAD topographies as model surfaces, we have investigated the influence of the nano-roughness on fibrinogen adsorption and on the proliferation of primary human fibroblasts. It is found that fibrinogen, an important blood protein, preferentially adheres on the whisker-like nano-rough substrates in comparison to a flat surface. Furthermore, the proliferation of the human fibroblasts is significantly reduced on the nano-rough substrates. These results demonstrate that the GLAD technique can be used to fabricate nano-rough surface morphologies that significantly influence both protein and cellular adhesion to surfaces and are therefore well suited for biological assays.

Increased performance of secondary clarifiers using dynamic distribution of minimum return sludge rates

Most wastewater treatment plants have several secondary clarifiers or even more sets of clarifiers including several secondary clarifiers, and in practice it is a well known problem that equal distribution of the load to the single clarifier (or set of clarifiers) is very difficult-not to say impossible-to obtain. If the problem is neglected, quite a big percentage of the total clarifier capacity-measured as the max. allowed hydraulic load-can be lost. Further, return sludge rates are seldom controlled by any other means than as a (typically too high) percentage of the inlet to the wastewater treatment plant-giving a varying and too low suspended solids concentration in the return sludge, which again can lead to an unnecessary use of polymer in the pre-dewatering of the surplus sludge taken from the return sludge. A control of the return sludge rate divided into two parts - control of the total return sludge flow and control of how the total flow shall be distributed between the secondary clarifiers - is able to solve the mentioned problems. Finally, as shall be demonstrated on full scale wastewater treatment plants, a considerable increase of the hydraulic capacity of the treatment plants can be obtained.

GPR30 does not mediate estrogenic responses in reproductive organs in mice

The G protein-coupled receptor Gpr30 (Gper) was recently claimed to bind to estradiol and to activate cytoplasmic signal transduction pathways in response to estradiol. However, there are conflicting data regarding the role of Gpr30 as an estrogen receptor (ER): several laboratories were unable to demonstrate estradiol binding to GPR30 or estradiol-activated signal transduction in Gpr30-expressing cells. To clarify the potential role of Gpr30 as an ER, we generated Gpr30-deficient mice. Although Gpr30 was expressed in all reproductive organs, histopathological analysis did not reveal any abnormalities in these organs in Gpr30-deficient mice. Mutant male and female mice were as fertile as their wild-type littermates, indicating normal function of the hypothalamic-pituitary-gonadal axis. Moreover, we analyzed estrogenic responses in two major estradiol target organs, the uterus and the mammary gland. For that purpose, we examined different readout paradigms such as morphological measures, cellular proliferation, and target gene expression. Our data demonstrate that in vivo Gpr30 is dispensable for the mediation of estradiol effects in reproductive organs. These results are in clear contrast to the phenotype of mice lacking the classic ER alpha (Esr1) or aromatase (Cyp19a1). We conclude that the perception of Gpr30 (based on homology related to peptide receptors) as an ER might be premature and has to be reconsidered.

ELISA for complexes of urokinase-type and tissue-type plasminogen activators with their type-1 inhibitor (uPA-PAI-1 and tPA-PAI-1)

An ELISA has been developed for the assessment of complexes between the urokinase-type (uPA) and the tissue-type plasminogen (tPA) activators with their inhibitor type-1 (PAI-1) in cell-culture medium and cytosolic extracts of breast tumours. The "4-stage/2-site" ELISA involves 2 polyclonal antibodies in the pre-analyte stage 2 and in the post-analyte stage. For the specific measurement of the uPA-PAI-1 complex, 2 assay formats may be employed, uPA/PAI-1 and PAI-1/uPA. This offers an attractive facility for quality-assessment studies of this kind of assays. Analogously, the tPA-PAI-1 complex was assessed using the formats tPA/PAI-1 and PAI-1/tPA. Only complexes are able to evoke a signal in their appropriate assay formats. The free component, however, which responds to the capture antibody, could interfere with the binding of the complex molecule, reducing the OD signal. Increasing the coating Ab concentration diminishes the signal-suppressing effect of the free component. In 15 cell-culture supernatants, uPA and PAI-1 concentrations were measured as well as the uPA of PAI-1 complex in different dilutions in 2 assay formats. The differences between the values of complex measured in the 2 assay formats could be accounted for by the free uPA and PAI-1 concentrations. At dilution 1:10, the measured values obtained in the 2 separate formats differed substantially (correlation coefficient r = 0.641). At dilution 1:20, the differences were already smaller between the values (agreement 0.945). At dilution 1:30, close agreement between the corresponding values was observed (r = 0.971). Extrapolation to infinite dilution of the results obtained resulted in an even closer estimation of the complex concentration. Comparable results have been observed when tPA, PAI-1 and tPA-PAI-1 values were measured in tumour biopsy extracts.

Effects of m-chlorophenylpiperazine on regional brain glucose utilization: a positron emission tomographic comparison of alcoholic and control subjects

m-Chlorophenylpiperazine (mCPP) is a mixed serotonin agonist/antagonist used extensively in psychiatric research. Alcoholics show blunted neuroendocrine responses to mCPP, and in some settings mCPP can induce craving for alcohol, particularly among early onset alcoholics. We used 2-[18F]-2-deoxy-D-glucose positron emission tomography to examine the effects of intravenously administered mCPP (0.08 mg/kg) on brain glucose utilization in a group of 18 male alcoholics and 12 healthy male control subjects. Differences between two sequential scans (the first followed placebo and the second followed mCPP) were evaluated statistically with a Gaussian random field-based method. Among healthy volunteers mCPP significantly increased brain glucose metabolism in the right medial and posterior orbital gyrus, the cerebellar hemispheres bilaterally, the left nucleus accumbens, the head of the caudate nucleus bilaterally, the anterior and medial-dorsal nuclei of the thalamus bilaterally, the middle frontal gyrus, the left insular cortex, the left middle temporal gyrus, and the posterior cingulate gyrus. Among alcoholic subjects mCPP significantly increased brain glucose metabolism in larger areas of the cerebellum and posterior cingulate than it did in healthy volunteers, but compared with the healthy volunteers, alcoholics showed a smaller area of mCPP-induced activation in the thalamus, almost no activation in the orbital cortices, and no activation at all in the head of the caudate nucleus or the middle frontal gyrus. These results suggest that a serotoninergic challenge activates basal ganglia circuits involving orbital and prefrontal cortices among healthy volunteers but that the response of these circuits is blunted among alcoholics.

Epithelial glycoprotein-330 mediates endocytosis of plasminogen activator-plasminogen activator inhibitor type-1 complexes

Epithelial glycoprotein 330 (gp330) is structurally similar to the multifunctional alpha 2-macroglobulin receptor/low density lipoprotein receptor-related protein (alpha 2MR/LRP), gp330 and alpha 2MR/LRP bind Ca2+ with high affinity, and both receptors bind and mediate endocytosis of alpha 2MR-associated protein (RAP). In the present report, we describe that affinity-purified gp330 from rabbit renal cortex binds plasminogen activator inhibitor type-1 (PAI-1) complexed with urokinase-type plasminogen activator (uPA). alpha 2M-methylamine, which binds with high affinity to alpha 2MR/LRP, did not bind to gp330. The apparent Kd for binding of uPA.PAI-1 complexes was about 0.8 nM at 4 degrees C. The binding was calcium-dependent and inhibited by recombinant RAP (rRAP) and tissue type plasminogen activator-PAI-1 complexes. Thin sections of rabbit renal proximal tubules bound 125I-labeled uPA.PAI-1 and rRAP in the apical part of proximal tubules corresponding to the localization of gp330. The binding of 125I-uPA.PAI-1 complexes in tubules was abolished by excess unlabeled rRAP, and a rRAP-inhibitable endocytosis and degradation of labeled uPA.PAI-1 complexes was demonstrated by perfusion of isolated rabbit proximal tubules. The results establish an endocytotic function of gp330 and suggest that gp330 is an important component of the fibrinolytic system in gp330-containing epithelial as found in, for example, kidney and lung.

PET imaging of opiate receptor binding in human epilepsy using [18F]cyclofoxy

We used [18F]cyclofoxy (CF), a potent opiate antagonist with affinity for mu and kappa receptors, and the Scanditronix PC1024-7B PET scanner to study 14 patients with complex partial seizures (CPS), and 14 normal controls. Epileptic foci were localized by prolonged EEG-video monitoring. EEG was recorded continuously during each scan. Immediately before CF administration, [15O]labeled water was used to measure cerebral blood flow, and showed hypoperfusion ipsilateral to the EEG focus. Blood samples (corrected for radiolabeled metabolites) and tissue time-activity data were acquired over 90 min following bolus CF injection. Anatomic regions were outlined directly on the PET images. A kinetic model was used to derive the total volume of distribution (Vt) in each brain region. Specific binding (Vs) was determined by substracting non-specific binding (Vt) measured in a receptor-poor brain region (occipital cortex). Regions with high Vs included mesial temporal lobes, thalamus, basal ganglia, and frontal cortex. Individual patients appeared to have higher binding in temporal lobe ipsilateral to the EEG focus, but there was no asymmetry for the patients as a group in mean Vt or Vs in anterior mesial, posterior mesial, anterior lateral, posterior lateral temporal cortex, thalamus, basal ganglia, or, for Vt, in regions of low specific binding: occipital lobe, parietal lobe, cerebellum.

Urokinase-plasminogen activator, a new and independent prognostic marker in breast cancer

Urokinase plasminogen activator (UK-PA) is a serine protease implicated in cancer invasion and metastasis. In this investigation, patients with breast cancers containing high levels of UK-PA antigen had significantly higher risk of early disease recurrence and shorter overall survival than did patients with low levels of the protein. In univariate analysis, UK-PA was a more powerful discriminator for disease-free interval than axillary node status, tumor size, or estradiol receptor. For overall survival, UK-PA as a prognostic marker, was of similar magnitude to axillary node status but stronger than that of tumor size or estradiol receptor. In multivariate analysis, for both disease-free interval and survival, UK-PA was an independent risk factor, being independent of tumor size, axillary node status, and estradiol receptor. UK-PA appears to be a new and independent prognostic marker in breast cancer.

Forskolin down-regulates type-1 plasminogen activator inhibitor and tissue-type plasminogen activator and their mRNAs in human fibrosarcoma cells

We have studied the effect of the adenylate cyclase-stimulating agent forskolin on expression of components of the plasminogen activation system in the human fibrosarcoma cell line HT-1080. By enzyme-linked immunosorbent assays, forskolin was found to cause a 2 to 4-fold decrease in intracellular and culture medium levels of type-1 inhibitor of plasminogen activators (PAI-1) and tissue-type plasminogen activator (t-PA). This was true for cells not treated with other agents and for cells, in which the PAI-1 and t-PA levels had been increased 5 to 10-fold by treatment with dexamethasone. This down-regulation could be traced back to corresponding decreases in the cellular levels of PAI-1 and t-PA mRNAs. Of the two PAI-1 mRNAs, the 2.4 kb species was 5-fold decreased by forskolin in cells treated with dexamethasone, while the 3.4 kb transcript was unaffected; in cells not treated with dexamethasone, forskolin affected the two PAI-1 transcripts in parallel. These studies show that in addition to the many inducers of PAI-1, PAI-1 gene expression is also subject to negative modulation by cyclic AMP. They also show that t-PA gene expression, in contrast to the induction by cyclic AMP observed in many other cell lines, may also be subject to negative regulation by cyclic AMP. Thus, hormonal agents acting with cyclic AMP as a second messenger may be involved in down-regulating PAI-1 and t-PA expression in vivo.

Accessibility of receptor-bound urokinase to type-1 plasminogen activator inhibitor

Urokinase plasminogen activator (uPA) interacts with a surface receptor and with specific inhibitors, such as plasminogen activator inhibitor type 1 (PAI-1). These interactions are mediated by two functionally independent domains of the molecule: the catalytic domain (at the carboxyl terminus) and the growth factor domain (at the amino terminus). We have now investigated whether PAI-1 can bind and inhibit receptor-bound uPA. Binding of 125I-labeled ATF (amino-terminal fragment of uPA) to human U937 monocyte-like cells can be competed for by uPA-PAI-1 complexes, but not by PAI-1 alone. Performed 125I-labeled uPA-PAI-1 complexes can bind to uPA receptor with the same binding specificity as uPA. PAI-1 also binds to, and inhibits the activity of, receptor-bound uPA in U937 cells, as shown in U937 cells by a caseinolytic plaque assay. Plasminogen activator activity of these cells is dependent on exogenous uPA, is competed for by receptor-binding diisopropyl fluorophosphate-treated uPA, and is inhibited by the addition of PAI-1. In conclusion, in U937 cells the binding to the receptor does not shield uPA from the action of PAI-1. The possibility that in adherent cells a different localization of PAI-1 and uPA leads to protection of uPA from PAI-1 is to be considered.

Interaction of plasminogen activator inhibitor (PAI-1) with vitronectin

Immobilized vitronectin was found to bind both purified plasminogen activator inhibitor type 1 (PAI-1) and the PAI-1 in conditioned culture medium of human sarcoma cells. Similarly, immobilized PAI-1 bound both purified vitronectin and vitronectin from normal human serum. These interactions were demonstrated using both enzyme immunoassay and radioiodinated proteins. Solid-phase vitronectin bound PAI-1 with Kd 1.9 x 10(-7) M, and the reverse interaction gave a Kd 5.5 x 10(-8) M. Evidence was also found for a second type of binding with a Kd below 10(-10) M. The molar ratios of the two proteins in the complex at the saturation levels were approximately one molecule of soluble PAI-1 bound per three molecules of immobilized vitronectin and approximately one molecule of soluble vitronectin being bound per one molecule of immobilized PAI-1. Binding of PAI-1 to vitronectin did not lead to an irreversible loss of the ability of PAI-1 to inhibit urokinase (u-PA) and tissue-type plasminogen activator (t-PA). Active u-PA released vitronectin-bound 125I-labeled PAI-1 radioactivity, suggesting that u-PA interacts with the complex. The Mr 50,000 urokinase cleavage product of PAI-1 also bound to vitronectin, but this bound fragment did not inhibit u-PA. Binding of PAI-1 to vitronectin did not interfere with the ability of vitronectin to promote the adhesion and spreading of cells. These results suggest that the interaction between vitronectin and PAI-1 may serve to confine pericellular u-PA activity to focal contact sites where cells use proteolysis in regional detachment.

Immunoaffinity purification of HTC rat hepatoma cell plasminogen activator-inhibitor-1

Incubation of HTC rat hepatoma cells with the synthetic glucocorticoid dexamethasone rapidly inhibits tissue-type plasminogen activator activity by inducing a specific plasminogen activator-inhibitor (PAI-1). Using immobilized polyclonal antibodies raised against HT-1080 human fibrosarcoma PAI-1, we have purified HTC PAI-1 from serum-free medium conditioned by dexamethasone-treated HTC hepatoma cells and shown it to be antigenically related to human PAI-1. Greater than 100-fold purification with greater than 75% yield was achieved in a single step. The purified PAI-1 migrates on SDS-polyacrylamide gels as a single major band of 49 kDa with a minor band of 46 kDa. Digestion of PAI-1 with endoglycosidase F causes a shift toward faster migrating species which retain inhibitory activity. The purified PAI-1 was stable at pH 2.5, lost 50% of its activity after 15 min at 45 degrees C, and showed marked activation after treatment with SDS or guanidine-HCl. Purified PAI-1 rapidly inhibited and formed complexes with both tissue-type and urokinase-type plasminogen activators. Polyclonal rabbit antirat PAI-1 antibodies were raised which immunoprecipitate both free and complexed PAI-1.

Distinct localizations of urokinase-type plasminogen activator and its type 1 inhibitor under cultured human fibroblasts and sarcoma cells

We studied the immunocytochemical localization of urokinase-type plasminogen activator (u-PA) and the type 1 plasminogen activator inhibitor (PAI-1) in human fibroblasts and sarcoma cells, using both polyclonal and monoclonal antibodies. The u-PA was found to be located at discrete cell-substratum contact sites, and also at areas of cell-cell contacts, whereas PAI-1 was distributed as a homogeneous carpet excluding strialike areas on the substrate under the cells. To confirm the extracellular localization of u-PA and PAI-1, we stained the cells live at 0 degree C before fixation. A double-labeling experiment showed different distribution of u-PA and PAI-1 under the cells, and especially their peripheral parts. The staining pattern of u-PA and PAI-1 resisted treatment with 0.2% saponin followed by mechanical removal of cells, a method previously reported to isolate focal contact membranes of fibroblasts. We further demonstrated the deposition of u-PA to the contact areas of cells obtained by saponin treatment by zymography, and that of PAI-1 by metabolic labeling, reverse zymography, immunoblotting, and immunoprecipitation. Fibronectin was also present in the preparations. The deposition of both PAI-1 and fibronectin by the sarcoma cells was enhanced, after treating the cells with 10(-6) M dexamethasone. The confinement of u-PA to discrete contact sites and the more uniform distribution of PAI-1 on the cell substratum may explain how cells producing large amounts of enzyme inhibitors can produce PA-mediated focal proteolysis.