3D visualization reveals the cooling rate dependent crystallization near a wall in dense microgel systems.

Controlled crystallization, melting and vitrification are important fundamental processes in nature and technology. However, the microscopic details of these fundamental phenomena still lack understanding, in particular how the cooling rate and presence of a wall influence the crystal nucleation and glass formation. Thermoresponsive microgels provide the possibility to study phase transitions at the single-particle level, owing to the ability to tune the particle size with temperature. In this study, we employ composite microgels consisting of a hard core and a crosslinked poly(N-isopropyl acrylamide-co-methacrylic acid) shell to study the crystallization of dense suspensions of soft colloids near a wall using confocal microscopy. We investigate the effect of the cooling rate on the fluid-to-solid transition close to the sample wall. The structures formed during cooling range from glassy in the case of a rapid temperature quench to crystalline when a slow cooling rate is used. Detailed analysis of the final structure reveals that the cooling rate also sets the degree of alignment of the crystal domains with the wall as a result of a balance between homogeneous and heterogeneous crystal nucleation. The results presented here yield valuable insight into the microscopic details of temperature-controlled crystallization near a wall. This understanding will help pave the way towards optimal crystallization conditions for microgel applications.

Phase stability of colloidal mixtures of spheres and rods.

We determined the phase boundaries of aqueous mixtures containing colloidal rod-like fd-viruses and polystyrene spheres using diffusing-wave spectroscopy and compared the results with free volume theory predictions. Excluded volume interactions in mixtures of colloidal rods and spheres lead to mediated depletion interactions. The strength and range of this attractive interaction depend on the concentrations of the particles, the length L and diameter D of the rods, and the radius R of the spheres. At strong enough attraction, this depletion interaction leads to phase separation. We experimentally determined the rod and sphere concentrations where these phase transitions occur by systematically varying the size ratios L/R and D/R and the aspect ratio L/D. This was done by using spheres with different radii and modifying the effective diameter of the rods through either the ionic strength of the buffer or anchoring a polymeric brush to the surface of the rods. The observed phase transitions were from a binary fluid to a colloidal gas/liquid phase coexistence that occurred already at very low concentrations due to the depletion efficiency of highly anisotropic rods. The experimentally measured phase transitions were compared to phase boundaries obtained using free volume theory (FVT), a well established theory for calculating the phase behavior of colloidal particles mixed with depletants. We find good correspondence between the experimental phase transitions and the theoretical FVT model where the excluded volume of the rod-like depletants was explicitly accounted for in both the reservoir and the system.

Phase behavior of binary hard-sphere mixtures: Free volume theory including reservoir hard-core interactions.

Comprehensive calculations were performed to predict the phase behavior of large spherical colloids mixed with small spherical colloids that act as a depletant. To this end, the free volume theory (FVT) of Lekkerkerker et al. [Europhys. Lett. 20, 559 (1992)] is used as a basis and is extended to explicitly include the hard-sphere character of colloidal depletants into the expression for the free volume fraction. Taking the excluded volume of the depletants into account in both the system and the reservoir provides a relation between the depletant concentration in the reservoir and that in the system that accurately matches with computer simulation results of Dijkstra et al. [Phys. Rev. E 59, 5744 (1999)]. Moreover, the phase diagrams for highly asymmetric mixtures with size ratios q ≲ 0.2 obtained by using this new approach corroborate simulation results significantly better than earlier FVT applications to binary hard-sphere mixtures. The phase diagram of a binary hard-sphere mixture with a size ratio of q = 0.4, where a binary interstitial solid solution is formed at high densities, is investigated using a numerical free volume approach. At this size ratio, the obtained phase diagram is qualitatively different from previous FVT approaches for hard-sphere and penetrable depletants but again compares well with simulation predictions.

Nanocrystalline silver dressings as an efficient anti-MRSA barrier: a new solution to an increasing problem.

The emergence of multi-drug-resistant strains of bacteria represents a particular challenge in the field of wound management. The aim of the current study was to investigate whether nanocrystalline silver dressings possess the physical properties to act as a barrier to the transmission of methicillin-resistant Staphylococcus aureus (MRSA) in the laboratory setting and in a clinical setting. Initially, MRSA suspension and colony culture experiments were performed showing that nanocrystalline silver dressings act as potent and sustained antimicrobial agents, efficiently inhibiting MRSA penetration. Subsequently, a double-centre clinical trial was initiated using nanocrystalline silver dressings as a cover for 10 MRSA colonized wounds in a total of seven patients. By delineating the MRSA load on the upper side of the dressing and the wound bed each time the dressing was changed (i.e. after 1, 24, 48 and 72 h), nanocrystalline silver dressings were found to provide a complete, or almost complete, barrier to the penetration/spread of MRSA in 95% of readings. In addition, 67% of all wound observations showed a decrease in the MRSA load with an eradication rate of 11%. We believe that nanocrystalline silver dressings may become an important part of local MRSA management, with cost benefits to both patients and the healthcare system.

[Total cervix occlusion--an efficient measure in prolapsed amniotic membranes in extreme prematurity?]. / Der totale Muttermundsverschluss--eine effiziente Massnahme bei prolabierender Fruchtblase im Bereich der extremen Frühgeburtlichkeit?

BACKGROUND: We analysed retrospectively whether the total cervix occlusion implicates efficient the prolongation of pregnancy in patients with bulging fetal membranes during extreme prematurity. PATIENTS AND METHODS: Between 1993 and 1999 nineteen pregnant women (17 singleton and 2 twin pregnancies) with cervical incompetence and bulging membranes at 20 to 27 weeks' gestation (mean 24 weeks) underwent total cervix occlusion (TCO) at the Department of Obstetrics at the Technische Universität of Munich after taking cervical cultures, prophylactic antibiotic treatment, tocolysis and induction of fetal lung maturity (after 33 weeks of gestational age). RESULTS: Eleven of nineteen pregnancies were carried beyond 32 weeks' gestation. 6 of 21 fetuses, included 2 twin pregnancies died. Considering the perinatal mortality the mean prolongation of pregnancy was 9.4 weeks after total cervix occlusion. 9 of 19 pregnant women were delivered beyond 37 weeks of gestational age. CONCLUSION: Taking the small number and the lack of a randomized trial into consideration, these results implicate the total cervix occlusion as an efficient method in cases of bulging membranes during extreme prematurity. Nevertheless a thorough postoperative control and screening of infectious complications are required.

[Initial experiences with primiparous women using a new kind of Epi-no labor trainer]. / Erste klinische Erfahrungen bei Erstgebärenden mit einem neuartigen Geburtstrainer Epi-no.

PURPOSE: The effectiveness of a vaginal dilatator (Epi-no) in avoiding episiotomies and improving the fetal outcome was examined. DATA SOURCES AND METHODS: Fifty pregnant women were included in our prospective study and took part in the prepartal birth training program with Epi-no. Matched-pairs were compared for the rate of episiotomy and perineal tears, neonatal APGAR score, average time of training, duration of labour and analgesia during delivery. RESULTS: We found a significant reduction in the rate of episiotomies in the group of women who participated in the birth training program with Epi-no (EG: 49%) compared to women who did not take part in our training program (NEG: 82%). Also the rate of perineal tears was twice as high in the latter (4% vs. 2%). Moreover, children of women of the EG showed better one-minute-APGAR-scores. In addition to this we found a significant reduction in the average duration of the second stage of labour in the EG (29 min) if compared with the NEG (54 min). Women in the EG had a lower rate of PDA (16% vs. 36%) and needed less analgesics than those in the NEG. Women of the EG who delivered without episiotomy had trained on average two days longer than women who had had an episiotomy. CONCLUSION: Birth training with Epi-no decreases the rate of episiotomies in primiparous significantly.

Glucose metabolism of breast cancer assessed by 18F-FDG PET: histologic and immunohistochemical tissue analysis.

UNLABELLED: Breast cancer is characterized by elevated glucose consumption resulting in increased uptake of 18F-FDG. However, tracer uptake varies considerably among tumors imaged with PET. This study compared histologic and immunohistochemical tissue analysis of breast carcinomas with preoperative FDG uptake assessed by PET to identify tumor characteristics that define the degree of tracer accumulation. METHODS: FDG uptake in breast tumors was quantified by calculating standardized uptake values (SUVs) corrected for partial-volume effect and normalized to blood glucose level at the time of tracer injection. The histologic sections of 50 invasive and 6 noninvasive breast carcinomas were analyzed for histologic type, microscopic tumor growth pattern, percentage of tumor cells, presence of inflammatory cells, density of blood vessels, histopathologic grading, tumor cell proliferation (mitotic rate and antibody binding of MIB-1), expression of estrogen and progesterone receptors, and expression of the glucose transporter protein Glut-1. RESULTS: A positive correlation was found between FDG uptake and histologic tumor type (ductal vs. lobular; P = 0.003), microscopic tumor growth pattern (nodular vs. diffuse; P = 0.007), and tumor cell proliferation (MIB-1; P = 0.009). Tumors with diffuse growth patterns had significantly lower SUVs compared with clearly defined tumors. A weak relationship was found between FDG uptake and the percentage of tumor cells (P = 0.06). Lower densities of blood vessels corresponded to higher FDG uptakes (P = 0.08). However, even significant correlations showed poor correlation coefficients. No relationship was found between FDG uptake and the following: tumor size; axillary lymph node status; percentage of necrotic, fibrotic, and cystic compounds; presence of inflammatory cells; steroid receptor status; and expression of Glut-1. CONCLUSION: Histologic and immunohistochemical tissue analysis was unable to sufficiently explain the variation of FDG uptake in breast cancer. The degree of metabolic changes after malignant transformation is most likely explained by a complex interaction between cellular energy demand and tumoral microenvironment. Therefore, FDG PET imaging may not be used to estimate tumor biologic behavior of breast cancer such as differentiation, histopathologic grading, cell proliferation, or axillary lymph node status.

Breast imaging with positron emission tomography and fluorine-18 fluorodeoxyglucose: use and limitations.

PURPOSE: To evaluate the diagnostic value of positron emission tomography (PET) using fluorine-18 fluorodeoxyglucose (FDG) for the diagnosis of primary breast cancer. PATIENTS AND METHODS: Preoperatively, 144 patients with masses suggestive of breast cancer underwent PET imaging of the breast. To identify breast cancer by increased metabolic activity, parametric FDG-PET images were analyzed for increased tracer uptake applying conventional image reading (CIR) and sensitive image reading (SIR). One hundred eighty-five breast tumors were evaluated by histology, revealing 132 breast carcinomas and 53 benign masses. RESULTS: Breast carcinomas were identified with an overall sensitivity of 64.4% (CIR) and 80.3% (SIR). The increase in sensitivity (SIR) resulted in a noticeable decrease in specificity, from 94.3% (CIR) to 75.5% (SIR). At stage pT1, only 30 (68.2%) of 44 breast carcinomas were detected, compared with 57 (91.9%) of 62 at stage pT2. A higher percentage of invasive lobular carcinomas were false-negative (65.2%) compared with invasive ductal carcinomas (23.7%). Nevertheless, positive PET scans provided a high positive-predictive value (96.6%) for breast cancer. CONCLUSION: Partial volume effects and varying metabolic activity (dependent on tumor type) seem to represent the most significant limitations for the routine diagnostic application of PET. The number of invasive procedures is therefore unlikely to be significantly reduced by PET imaging in patients presenting with abnormal mammography. However, the high positive-predictive value, resulting from the increased metabolic activity of malignant tissue, may be used with carefully selected subsets of patients as well as to determine the extent of disease or to assess therapy response.

Positron emission tomography using [(18)F]Fluorodeoxyglucose for monitoring primary chemotherapy in breast cancer.

PURPOSE: To address the role of positron emission tomography (PET) using [(18)F]fluorodeoxyglucose (FDG) to monitor primary (neoadjuvant) chemotherapy in patients with locally advanced breast cancer. PATIENTS AND METHODS: Quantification of regional FDG uptake of the breast acquired after the first and second courses of chemotherapy was compared with the baseline scan in 22 patients with a total of 24 breast carcinomas. To evaluate the predictive value of PET imaging, histopathologic response after completion of chemotherapy classified as gross residual disease (GRD) or minimal residual disease (MRD) served as the gold standard. RESULTS: Significant differences in tracer uptake between nonresponding tumors (GRD) and responding lesions (MRD) were observed (P <.05) as early as after the first course of chemotherapy. Tracer uptake showed little change in tumors with GRD found later in pathologic analysis but decreased sharply to the background level in most tumors with MRD. After the first course, all responders were correctly identified (sensitivity 100%, specificity 85%) by a standardized uptake value decrease below 55% of the baseline scan. At this threshold, histopathologic response could be predicted with an accuracy of 88% and 91% after the first and second courses of therapy, respectively. CONCLUSION: This study demonstrates that in patients with advanced breast cancer undergoing primary chemotherapy, FDG-PET differentiates responders from nonresponders early in the course of therapy. This may help improve patient management by avoiding ineffective chemotherapy and supporting the decision to continue dose-intensive preoperative chemotherapy in responding patients.

Blocking HER-2/HER-3 function with a dominant negative form of HER-3 in cells stimulated by heregulin and in breast cancer cells with HER-2 gene amplification.

Amplification and overexpression of the HER-2 (neu/ erbB-2) gene in human breast cancer are clearly important events that lead to the transformation of mammary epithelial cells in approximately one-third of breast cancer patients. Heterodimer interactions between HER-2 and HER-3 (erbB-3) are activated by neu differentiation factor/heregulin (HRG), and HER-2/HER-3 heterodimers are constitutively activated in breast cancer cells with HER-2 gene amplification. This indicates that inhibition of HER-2/HER-3 heterodimer function may be an especially effective and unique strategy for blocking the HER-2-mediated transformation of breast cancer cells. Therefore, we constructed a bicistronic retroviral expression vector (pCMV-dn3) containing a dominant negative form of HER-3 in which most of the cytoplasmic domain was removed for introduction into cells. By using a bicistronic retroviral vector in which the antibiotic resistance gene and the gene of interest are driven by a single promoter, we attained 100% coordinate coexpression of antibiotic resistance with the gene of interest in target cell populations. Breast carcinoma cells with HER-2 gene amplification (21 MT-1 cells) and normal mammary epithelial cells without HER-2 gene amplification from the same patient (H16N-2 cells) were infected with pCMV-dn3 and assessed for HER-2/ HER-3 receptor tyrosine phosphorylation, p85PI 3-kinase and SHC protein activation, growth factor-dependent and -independent proliferation, and transformed growth in culture. Dominant negative HER-3 inhibited the HRG-induced activation of HER-2/HER-3 and signaling in H16N-2 and 21 MT-1 cells as well as the constitutive activation of HER-2/HER-3 and signaling in 21 MT-1 cells. Responses to exogenous HRG were strongly inhibited by dominant negative HER-3. In contrast, the proliferation of cells stimulated by epidermal growth factor was not apparently affected by dominant negative HER-3. The growth factor-independent proliferation and transformed growth of 21 MT-1 cells were also strongly inhibited by dominant negative HER-3 in anchorage-dependent and independent growth assays in culture. Furthermore, the HRG-induced or growth factor-independent proliferation of 21 MT-1 cells was inhibited by dominant negative HER-3, whereas the epidermal growth factor-induced proliferation of these cells was not: this indicates that dominant negative HER-3 preferentially inhibits proliferation induced by HER-2/HER-3.

Combined transvaginal B-mode and color Doppler sonography for differential diagnosis of ovarian tumors: results of a multivariate logistic regression analysis.

OBJECTIVE: Transvaginal sonography is limited in its ability to assess early stage cancers of the ovary as well as in distinguishing benign processes. As a method for characterization of tumor vascularization, color-coded Doppler sonography may be able to improve the diagnostic accuracy of B-mode sonography. METHODS: Preoperative transvaginal B-mode and Doppler sonography was performed in 63 patients with unclear adnexal lesions prior to operation. Using multiple logistic regression, the independent variables of each procedure were selected and combined to yield a diagnostic flow chart. The diagnostic accuracy of this decision matrix was tested on 257 patients with unclear adnexal tumors. RESULTS: In the 63 adnexal tumors investigated, the diagnostic impact of isolated sonomorphological assessment with evidence of a "solid area" was 78%. Using Doppler sonography, the best discrimination was achieved by displaying the vascular distribution ("central vascularization"). Combining these independent significant variables of the two procedures raised the diagnostic accuracy to 90% (sensitivity 86%, specificity 93%). The validity achieved by this combination was confirmed by the independent application of this method to the 257 adnexal tumors with unclear malignancy status (diagnostic accuracy 93%, sensitivity 92%, specificity 94%). CONCLUSIONS: The combination of sonography and Doppler sonography achieves high and reproducible diagnostic accuracy in preoperative malignancy status assessment of adnexal tumors. The additional use of Doppler sonography can thus provide significant aid both for differential diagnostics of adnexal lesions and for the choice of surgical route in the case of an existing indication for operative therapy.

Localization of fibroblast growth factor-2 (basic FGF) and FGF receptor-1 in adult human kidney.

BACKGROUND: The expression pattern of fibroblast growth factor-2 (FGF-2; basic FGF), a pleiotrophic growth factor, as well as one of its receptors (FGFR1), in the kidney is highly controversial. METHODS: Using an approach that combines multiple antibodies for immunohistochemistry and correlative in situ hybridization, we assessed the intrarenal expression of both FGF-2 and FGFR1 in 13 specimens of adult kidney removed during tumor nephrectomy. RESULTS: The FGF-2 expression pattern in the kidneys as detected by immunohistochemistry was variable and depended on the antibody used. The most consistent expression of FGF-2 protein was demonstrated in glomerular parietal epithelial cells, tubular cells (mainly of the distal nephron), as well as arterial endothelial cells. These locations also corresponded to areas of FGF-2 mRNA expression. Additionally, by immunohistochemistry, FGF-2 protein was detected in arterial smooth muscle cells and occasional podocytes. The expression of FGFR1 protein and mRNA was most consistently present in tubular cells of the distal nephron and in vascular smooth muscle cells. In situ hybridization, but not immunohistochemistry, also suggested FGFR1 expression in cells that could not be precisely identified within the glomerular tuft as well as some interstitial cells. CONCLUSION: These data suggest potential autocrine and paracrine pathways within the FGF-2 system, particularly within the vascular walls and in the distal nephron, and thereby provide information for further mechanistic understanding of the role of the FGF-2 system in human renal disease.

Detection of multiple fibronectin isoforms in fetal fibroblast monolayer culture: a novel method for the qualitative and quantitative detection of multiple antigens.

Analyzing the expression of multiple distinct antigens within a single monolayer culture involves cumbersome immunostaining techniques. We describe a simple and economical procedure for the detection and quantification of multiple antigens within a single monolayer. By generating an immunohistochemical grid which divides a monolayer in a standard tissue culture dish into 20 distinct areas, we were able to detect and quantify four individual fibronectin (FN) isoforms within a single fibroblast monolayer culture. Quantification of each isoform was performed using a modified enzyme-linked immunoassay. In addition, within the same monolayer, each FN isoform was detected using standard immunohistochemical detection with DAB visualization. Using this novel approach to immunohistochemical analysis we determined that within the first 4 days of culture, the quantity of all FN isoforms increases faster than the number of cells. However, upon reaching confluency, the quantity of FN/cell drops dramatically. After reaching confluency, the amount of FN/cell levels off and remains constant within the postconfluent monolayer. Statistical analysis of the quantity of FN/cell indicates that a significant reduction in the amount of FN/cell occurs in the 2 days prior to reaching confluency. The distribution of all the FN isoforms, with the exception of B-FN, was found along the length of the cell body. In contrast, the distribution of B-FN was altered in postconfluent monolayers where it was detected only in distinct locations within the monolayer.

Expression and assembly of the angiogenic marker B-fibronectin by endothelial cells in vitro: regulation by confluency.

Recent studies have demonstrated the association of the rare fibronectin (FN) isoform B-FN with newly formed blood vessels. Although B-FN is a unique angiogenesis marker, it is not clear whether B-FN associated with the neovasculature is expressed by the endothelial cells (EC) or obtained from the microenvironment. Here we report on a study analyzing the expression and assembly of B-FN by bovine microvascular EC (BMEC) in vitro. We determined that BMEC express B-FN and assemble it into fibrils during monolayer culture. Furthermore, in addition to assembling endogenous B-FN, subconfluent BMEC can assemble exogenous B-FN provided by a non-EC source. Upon reaching confluency the assembly and expression of B-FN by BMEC is inhibited and the previously assembled B-FN is eventually eliminated from postconfluent EC monolayers. Indeed, confluent BMEC assemble neither endogenous nor exogenous B-FN, while they continue to assemble other FN isoforms. We conclude that BMEC in vitro express B-FN and assemble B-FN fibrils using endogenous as well as exogenous B-FN. The expression and assembly of B-FN are tightly regulated by confluency. Our observations in vitro are a plausible explanation for the absence of B-FN in established blood vessels in vivo, and the subsequent reappearance of B-FN in angiogenic vessels. Furthermore, since our observations of B-FN assembly in BMEC monolayers correspond to previously published observations in vivo, B-FN may be utilized as an appropriate marker for angiogenic behavior of EC in vitro.

Basic fibroblast growth factor receptors and their prognostic value in human breast cancer.

We performed a saturation binding study with 125I-labeled FGF (fibroblast growth factor)-2 in a nonselected series of 250 human primary breast cancers. Two hundred twenty-five breast cancer biopsies possessed bFGFR (basic FGF receptor). The median dissociation constant was 0.35 nM (range, 0.014-1.9), and the median concentration was 1126 fmol/mg protein (range, 49-7328). FGFR-1 was localized, using a specific monoclonal antibody, in cancerous cells and in epithelial cells in normal breast or in benign tumors. In all of the tissues studied, light stromal cell staining was also observed. Thus, the localization of FGFR-1 in carcinoma cells supports the hypothesis that an important part of FGF-2 binding reflects binding to FGFR-1. bFGFR concentrations were positively correlated to estrogen receptor and progesterone receptor levels. Cox univariate analyses showed that the bFGFR (> or = upper quartile) was associated to longer relapse-free survival [P = 0.004; RR (risk ratio), 0.46] and overall survival (P = 0.001; RR, 0.35); age, estrogen receptor levels, progesterone receptor levels, node involvement, tumor diameter, and histoprognostic grading were prognostic, also. In Cox multivariate analyses, only the bFGFR, age, node involvement, and histoprognostic grading were prognostic factors; the bFGFR was associated with longer relapse-free survival (P = 0.03; RR, 0.4) and overall survival (P = 0.009; RR, 0.3). The present study confirms that FGF could be an important regulator of human breast cancer growth and that patients with a high level of bFGFR had a better prognosis.

Efficient purification of mouse anti-FGF receptor IgM monoclonal antibody by magnetic beads.

Affinity chromatography has been widely used for the purification of monoclonal antibodies (MAb). Traditionally, activated agarose beads conjugated with specific antisera have been used as a solid support in chromatographic protein purification. Magnetic beads conjugated with various antibodies have recently become an alternative method for the isolation of diverse proteins, nucleic acids, and cell types. In this study, murine anti-fibroblast growth factor receptor 1 (FGFR1) immunoglobulin M (IgM) was isolated from protein solutions to compare immunoaffinity column chromatography and magnetic bead IgM purification methods. Using immobilized rat anti-mouse IgM MAb, an UltraLink 1-ethyl-3-(3-dimethylaminopropyl)carboiimide (EDC)/diaminodipropylamine (DADPA) immunoaffinity column and polystyrene-coated magnetic beads were used for the purification of mouse IgM from bovine serum albumin/phosphate-buffered saline (BSA/PBS) as well as from crude ascites. Protein quantitation and percent IgM yield were determined by reducing SDS-PAGE electrophoresis followed by silver staining, then IgM and protein contaminants were quantitated using densitometry analysis. IgM anti-FGFR1 binding specificity and immunologic activity were determined by enzyme-linked immunosorbant assay (ELISA). This study demonstrates that magnetic bead isolation of IgM from ascites is more effective than traditional affinity chromatography purification as determined by greater IgM yield, purity, and immunologic activity.

Optimized differential diagnosis of breast lesions by combined B-mode and color Doppler sonography.

To optimize the sensitivity and specificity of gray-scale imaging and color Doppler in breast tumor diagnosis, alone and in combination, 89 women with palpable breast masses were scanned preoperatively and standard parameters were determined in both modes. Parameters significant for differentiation of benign and malignant tumors identified using univariate analysis were combined and weighted using multivariate analysis (multiple logistic regression). Histologically 59 tumors were malignant and 30 benign. Gray-scale sonography alone achieved a sensitivity of 88% and a specificity of 96% using the parameters of wall structure and posterior acoustic attenuation. Color Doppler achieved a sensitivity of 85% and a specificity of 79% using resistance index and pulsatility index as parameters. Combination of both methods yielded an accurate diagnosis in 84/87 patients (sonographic lesion correlates were absent in two cases), equivalent to a sensitivity of 97% and a specificity of 96%. Thus the individual diagnostic performance of gray-scale imaging and color Doppler sonography in palpable breast disease is further enhanced using multiple logistic regression to combine independently significant parameters.

Characterization of a functional angiotensin IV receptor on coronary microvascular endothelial cells.

A new class of angiotensin receptors has recently been identified that exhibits both high specificity and affinity for the hexapeptide (3-8) fragment of angiotensin II, angiotensin IV (AngIV). Here, utilizing radioligand binding, we fully characterize AngIV binding at the AT4 receptor on cultured bovine coronary venular endothelial cells (CVEC), and report that when AngIV and bFGF are presented simultaneously an enhancement of DNA synthesis results that is significantly greater than that produced by bFGF alone. The level of DNA synthesis was determined by the incorporation of [3H]thymidine into quiescent CVEC monolayers following exposure to 10 nM AngIV and 10 ng/ml bFGF for 1, 3, 5, 7, 9, or 11 days. A significant enhancement of DNA synthesis (P < 0.01) was seen following 3, 5, 7, 9 and 11 days exposure. In addition, AngIV does not bind to bFGF or heparin, and conversely, bFGF is unable to compete for AngIV binding which suggests that this synergistic response is mediated by independent receptors for these ligands. Results of this study indicate that microvascular endothelial cells are significantly more responsive to bFGF in the presence of nanomolar concentrations of AngIV.