Flexural behavior of functionally graded polymeric composite beams

The bending test is one of the most important tests that demonstrates the advantages of functional gradient (FGM) materials, thanks to the stress gradient across the specimen depth. In this research, the flexural response of functionally graded polymeric composite material (FGM) is investigated both experimentally and numerically. Fabricated by a hand lay-up manufacturing technique, the unidirectional glass fiber reinforced epoxy composite composed of ten layers is used in the present investigation. A 3-D finite element simulation is used to predict the flexural strength based on Hashin’s failure criterion. To produce ten layers of FGM beams with different patterns, the fiber volume fraction ( Vf%) ranges from 10% to 50%. A comparison between FGM beams and conventional composite beams having the same average Vf% is made. The experimental results show that the failure of the FGM beams under three points bending loading (3PB) test is initiated from the tensioned layers, and spread to the upper layer. The spreading is followed by delamination accompanied by shear failures. Finally, the FGM beams fail due to crushing in the compression zone. Furthermore, the delamination failure between the layers has a major effect on the rapidity of the final failure of the FGM beams. The present numerical results show that the gradient pattern of FGM beams is a critical parameter for improving their flexural behavior. Otherwise, Vf% of the outer layers of the FGM beams, i.e. Vf% = 30, 40, or 50%, is responsible for improving their flexural strength.

Mechanical and Bond Behavior of an Advanced Quranic Metal-Matrix Composite Material (QMMC)

The holy Quran, from more than 1400 years, told us that Zul-karnain had made a metallic composite material between iron and copper [1,2] as follows:

“Bring me sheets of iron” — until, when he had leveled [them] between the two mountain walls, he said, “Blow [with bellows],” until when he had made it [like] fire, he said, “Bring me, that I may pour over it molten copper * So Gog and Magog were unable to pass over it, nor were they able [to effect] in it any penetration.”: Translation of verses 96 and 97 in Surah Al-Kahf (18), The holy Quran [3].

According to the above story, the matrix is copper, while reinforcement is iron of this metal matrix composite. The present paper is going to investigate the Metal-Matrix Composite Material (MMC) suggested by Zul-karnain at different manufacturing conditions by using the experimental method. The effect of reinforcement temperature on the integrity of such MMC is one of the main goals of the present work. The mechanical behavior of the present QMMC is also examined in the present research as preliminary study. Furthermore, the finite element method is used to predicate the debonding force of MMC based on Virtual-Crack-Closing-Technique (VCCT).

The effects of EPA, DHA, and aspirin ingestion on plasma lysophospholipids and autotaxin

Lysophophatidylcholine (LPC) and lysophosphatidic acid (LPA) are potent lysolipid mediators increasingly linked with atherosclerosis and inflammation. A current model proposing that plasma LPA is produced when LPC is hydrolyzed by the enzyme autotaxin has not been rigorously investigated in human subjects. We conducted a clinical trial of eicosapentaenoic acid/docosahexaenoic acid (EPA/DHA) and aspirin ingestion in normal volunteers. Fasting blood samples were drawn at baseline and after 4-week supplementation with EPA/DHA (3.4 g/d) with and without aspirin (650 mg). Plasma LPC and LPA species and autotaxin activity were measured. EPA-LPC and DHA-LPC concentrations increased significantly with EPA/DHA supplementation whereas EPA- and DHA-LPA did not. Autotaxin activity was unaffected by any treatment, and aspirin had no effect on any endpoint. Taken together, our data demonstrate that plasma LPC, but not LPA, species can be dynamically regulated by dietary supplementation, and argue against a simple model of LPA generation via LPC hydrolysis.

Nanoparticle-targeted delivery of nonanticoagulant heparin and doxorubicin in doxorubicin-resistant breast cancer

e11599

Background: In comparison to low molecular weight heparin (LMWH), non-anticoagulant heparin (NACH), originally developed in our laboratory, has minimal effects on hemostasis. Encapsulation of chemotherapeutic agents and NACH in biodegradable nanoparticles has tremendous potential in improving survival among the breast cancer patients. Furthermore, custom-made nanoparticles with a targeted moiety on the surface would enable us to increase the efficacy and decrease the adverse effects of doxorubicin. Methods: PLGA-PEG nanoparticles co-encapsulating NACH and doxorubicin were synthesized by double emulsion solvent evaporation method. The in vitro efficacy of these nanoparticles was examined in MCF-7 doxorubicin resistant (MCF-7R) cells using MTT cell viability assay. Confocal microscopy was used to examine the uptake of αvβ3 antibody conjugated nanoparticles in human dermal microvascular endothelial cells (HDMEC), which are known to over express αvβ3 integrins. Results: Size measurement by DLS revealed that these nanoparticles co-encapsulating doxorubicin and heparins to be 200–300 nm in size. Data from the MTT assays in MCF-7R cells showed synergy between NACH and doxorubicin when encapsulated in PLGA-PEG nanoparticles. Confocal imaging in HDMEC cells indicates that these nanoparticles have the potential to be used for site specific delivery to the tumor neovascularization. In vivo data in nude mice xenograft (MCF-7R) are shown in the table below (doses of doxorubicin and NACH injected subcutaneously were 0.625 mg/kg and 2.5 mg/kg body weight, respectively). Significant decrease in tumor weight was observed in the mice xenograft, when treated with αvβ3 conjugated nanoparticles co-encapsulating doxorubcin or to greater extent doxorubicin and NACH compares to its non encapsulated counterparts. Conclusions: These data indicated distinct improvement in the anti-tumor efficacy using αvβ3site directed delivery doxorubicin and NACH encapsulted in PLGA-PEG nanoparticles.

[Table: see text]

No significant financial relationships to disclose.

Effects of novel heparin-derived compounds on tumor uptake of chemotherapeutics and chemoresponse

2537

Thrombotic complications are the second most common cause of mortality in cancer patients and fibrin deposition in the tumor microenvironment might play a key role in tumor progression and inference with tumor chemotherapeutic uptake. Treatments that target these processes may result in improved uptake of chemotherapeutic agents and subsequent inhibition of tumor growth and metastasis. Tissue Factor (TF) is frequently associated with aggressive behavior and poor outcome in tumors. We have previously demonstrated potent anti-tumor efficacy for various mechanisms that interfere with TF/VIIa. The purpose of this study was to investigate the effects of low molecular weight heparins (LMWH) and sulfated non-anticoagulant LMWH (S-NACH) on tumor chemotherapeutic uptake. Studies: (1) Nude mice xenograft A549 human lung carcinoma: LMWH or S-NACH at 10 mg/kg S.C. daily effectively limited tumor growth. (2) LCC6 human lung tumor xenograft model: Paclitaxel alone or in combination with Tinzaparin or S-NACH on tumor re-growth after discontinuation of treatment: Paclitaxel + S-NACH treatment showed significant (P<0.01) tumor growth suppression and improved survival when compared to Paclitaxel. (3) Biodistribution studies: animals were injected with LMWH S.C. daily for 5 days (10 mg/kg) then injected i.v. with [124-I]-Paclitaxel. LMWH increased [124-I]-Paclitaxel uptake into LCC6 tumors with tumor: muscle ratios several fold greater than that of [124-I]-Paclitaxel alone at 24 hrs post injection. This is a highly significant result in the light of the fact that the FDA criterion for a clinically meaningful effect is a 15% increase in uptake. (4) HPLC studies of tumor uptake of Doxorubicin (DOX in mice treated with 10 mg/kg of LMWH or S-NACH for 10 days followed by Doxorubicin (2.5 mg/kg). Both LMWH and S-NACH significantly (P<0.01) increased the uptake of chemotherapeutic agent DOX in MCF7 DOX resistant tumors by 1.5–2 folds but not in heart or lung tissues, confirming the findings obtained with another agent [124-I]-Paclitaxel. Conclusions: LMWH or S-NACH increased chemotherapeutics uptake and hence chemoresponse. Protocols utilizing adjuvant or neo-adjuvant therapy with LMWH or S-NACH could lead to increase tumor chemo responsiveness and overcoming tumor chemo resistance.

No significant financial relationships to disclose.

Evaluation of Sympathetic Blockade after Intrathecal and Epidural Lidocaine in Rats by Laser Doppler Perfusion Imaging

The widespread use of neuraxial anaesthesia increases the need for animal models to evaluate therapeutic prospects, mechanisms and risks of this technique. As a methodological prerequisite, we characterised the sympathetic blockade after different modes of neuraxial anaesthesia with regard to segments supplying the splanchnic region. Under haemodynamic monitoring, lidocaine 2% or saline were infused via intrathecal (10 microl), lumbar epidural (10 and 30 microl) or thoracic epidural (10 and 30 microl) catheters. Segmental spread of neuraxially infused local anaesthetic was assessed using methylene blue. Mean arterial blood pressure decreased more severely after neuraxial lidocaine in thoracic epidural (10 and 30 microl) compared to high-volume (30 microl anaesthesia animals. Determination of the sympathetic blockade by means of laser Doppler perfusion imaging was restricted to the paws due to a higher density of subcutaneous blood vessels as compared to the abdominal wall (mean +/- SD: 3.93 +/- 0.06 vs. 1.35 +/- 0.05/384 mm(2), p < 0.05). Only high-volume (30 microl) lumbar and thoracic epidural anaesthesia (10 and 30 microl) increased skin perfusion in both hind and front paws. This extensive sympathetic blockade was demonstrated to include splanchnic segments using thermography. Segmental spread of methylene blue did not closely correspond to laser Doppler findings and should be interpreted as minimum rather than exact epidural spread of local anaesthetic.

Painful inflammation-induced increase in mu-opioid receptor binding and G-protein coupling in primary afferent neurons

Opioids mediate their analgesic effects by activating mu-opioid receptors (MOR) not only within the central nervous system but also on peripheral sensory neurons. The peripheral analgesic effects of opioids are best described under inflammatory conditions (e.g., arthritis). The present study investigated the effects of inflammation on MOR binding and G-protein coupling of full versus partial MOR agonists in dorsal root ganglia (DRG) of primary afferent neurons. Our results show that Freund's complete adjuvant (FCA) unilateral hindpaw inflammation induces a significant up-regulation of MOR binding sites (25 to 47 fmol/mg of protein) on DRG membranes without affecting the affinity of either full or partial MOR agonists. In our immunohistochemical studies, the number of MOR-immunoreactive neurons consistently increased. This increase was mostly caused by small-diameter nociceptive DRG neurons. The full agonist DAMGO induced MOR G-protein coupling in DRG of animals without FCA inflammation (EC50 = 56 nM; relative Emax = 100%). FCA inflammation resulted in significant increases in DAMGO-induced MOR G-protein coupling (EC50 = 29 nM; relative Emax = 145%). The partial agonist buprenorphine hydrochloride (BUP) showed no detectable G-protein coupling in DRG of animals without FCA inflammation; however, partial agonist activity of BUP-induced MOR G-protein coupling was detectable in animals with FCA inflammation (EC50 = 1.6 nM; relative Emax = 82%). In behavioral studies, administration of BUP produced significant antinociception only in inflamed but not in noninflamed paws. These findings show that inflammation causes changes in MOR binding and G-protein coupling in primary afferent neurons. They further underscore the important differences in clinical studies testing peripherally active opioids in inflammatory painful conditions.

Circulating soluble tumor necrosis factor receptor as a marker for diagnosis of pulmonary embolus

The purpose of this clinical study was to determine the relationship between plasma soluble tumor necrosis factor receptor (T.N.F.R.) and pulmonary embolism. The histological evidence of the interaction between leukocytes and the venous wall of a thrombosed vein, as well as the over-production of TNF in plasma prompted us to assay a more stable polypeptide, namely TNF receptor, as potential markers for pulmonary embolism. Five mL of plasma were obtained from twenty patients, ranging in the age from 24 to 74 years, who had been diagnosed as having pulmonary embolism through pulmonary angiography, and 20 healthy volunteers in the same age group. The samples were then studied by enzyme-link immunosorbent assay (ELISA) for measurement of soluble TNF receptor. Patients with pulmonary embolism maintained a higher serum concentration of soluble TNF receptors. It appears that plasma measurement of soluble TNF receptor could be used as a clinical test for diagnosis of pulmonary embolism.

High levels of oestrogen receptor-alpha in tumorigenesis: inhibition of cell growth and angiogenic factors

We previously found that the stable overexpression of oestrogen receptor-alpha in the human endothelial cell line ECV304* inhibits its growth in vitro, and that this inhibition is possibly mediated through a down-regulation of the vasoactive agents endothelin-1 and vascular endothelial growth factor. Here we show an in vivo growth-inhibitory effect of oestrogen receptor-alpha overexpression in tumours initiated in nude mice from the same clone of ECV304. In addition, we show that this growth inhibition is accompanied by an alphavbeta3-mediated inhibition of cell migration in vitro, and a down-regulation of the integrin alphavbeta3, vascular endothelial growth factor and vascularization in vivo. The levels of vascular endothelial growth factor and integrin alphavbeta3, through their effect on cell growth and migration, contribute to the process of angiogenesis and to the pathogenesis of atherosclerosis and cancer. The results shown here demonstrate that a higher level of oestrogen receptor-alpha in the cell, through its effect on certain angiogenic factors, may play a role in the control of angiogenesis.

Analgesic and antiinflammatory effects of two novel kappa-opioid peptides

BACKGROUND

This study investigates two new kappa-agonist tetrapeptides, FE 200665 and FE 200666, with high peripheral selectivity as a result of poor central nervous system penetration.

METHODS

Four days after administration of Freund adjuvant into the hind paw of male Wistar rats, antinociceptive effects of intraplantar and subcutaneous injection of FE 200665 and FE 200666 were measured by paw pressure algesiometry and compared with the kappa-agonist U-69,593. Peripheral and kappa-receptor selectivity was assessed by the antagonists naloxone methiodide (NLXM) and nor-binaltorphimine, respectively. Antiinflammatory effects were evaluated by paw volume plethysmometry and histologic score.

RESULTS

Similar to intraplantar U-69,593, intraplantar FE 200665 (3-100 microg) and FE 200666 (1-30 microg) resulted in significant and dose-related increases of paw pressure thresholds. Higher doses of FE 200665 (0.2-20 mg) and FE 200666 (0.06-6 mg) were required by subcutaneous route to produce similar antinociceptive responses, supporting a peripheral site of action. nor-Binaltorphimine dose-dependently antagonized this effect, implying kappa-opioid selectivity. Analgesic effects of subcutaneous FE 200665 and FE 200666 were abolished by intraplantar nor-binaltorphimine, and both subcutaneous and intraplantar effects were dose-dependently antagonized by subcutaneous NLXM, further demonstrating a peripheral site of action. One to 6 days after Freund adjuvant inoculation, single and repeated intraplantar injections of FE 200665, FE 200666, and U-69,593 significantly reduced paw volume and histologic scores. Both changes were reversed by intraplantar nor-binaltorphimine and subcutaneous NLXM.

CONCLUSION

FE 200665 is a peripherally selective kappa-agonist with potent analgesic and antiinflammatory properties that may lead to improved analgesic-antiinflammatory therapy compared with centrally acting opioids or standard nonsteroidal antiinflammatory drugs.

Effects in humans of intravenously administered endotoxin on soluble cell-adhesion molecule and inflammatory markers: a model of human diseases

1. Endotoxin, a component of the cell wall of Gram-negative bacteria, could be a predisposing mediator of many pathological disorders. The present study was undertaken to determine the effects and time-course of acute endotoxin challenge on inflammatory and cell-adhesion molecule markers shedding in the plasma as potential surrogates. 2. Six normal male subjects per group (age range 21-35 years) were injected with 4 ng/kg, i.v., reference standard Escherichia coli (0113:h10:k) endotoxin or physiological saline. 3. Plasma inflammatory markers (tumour necrosis factor (TNF)-alpha, interleukin (IL)-6 and TNF-receptor I (RI)) and cell-adhesion molecule markers (soluble L-selectin, soluble P-selectin, soluble vascular cell adhesion molecule (VCAM)-1) were determined using sensitive and specific ELISA. 4. Tumour necrosis factor-alpha increased from a basal level of 2.8 pg/mL to approximately 800 pg/mL at 90 min after endotoxin. Similarly, IL-6 peaked 2-3 h after endotoxin injection, with a rapid decline by 6-8 h, and levels returned to basal values by 24 h. 5. In contrast, TNF-RI peaked at 2 h (increasing from basal levels of 900-3300 pg/mL) with a much slower decline and without return to basal levels at 24 h (1400 pg/mL). 6. Endotoxin resulted in a rapid rise in soluble L-selectin within 1 h, which increased from a basal of 150-425 ng/mL. This rapid rise in soluble L-selectin was sustained for up to 2.5 h and then rapidly declined to basal levels by 3.5 h. 7. In contrast, plasma soluble P-selectin levels showed a delayed and progressive increase up to 8 h (increasing from a basal level of 50-95 ng/mL), with a partial decline at 24 h (80 ng/mL). 8. Similarly, soluble VCAM-1 levels showed a progressive rise up to 24 h (increasing from basal values of 600-1000 ng/mL). 9. This acute human model of endotoxin exposure demonstrated an upregulation of inflammatory stimuli leading to a short-term hyperactivation of leucocytes and a more sustained activation of platelets and endothelium. 10. This model provides a non-invasive method for studying the complex effects of endotoxin-like pathogens on different cellular events using soluble plasma surrogate markers.

Dexamethasone and stress-induced analgesia

Analgesia induced in rats by cold-water swim stress and measured by the tail-flick and hot-plate methods was significantly antagonized after IP pretreatment for 3 days with 8 mg/kg dexamethasone. The analgesia developed by the cold-water swim stressor was also attenuated by 1 mg/kg naloxone. These results suggest that the corticosteroids may have a role in modulating stress-induced analgesia and that the adrenal-pituitary axis modulates the endogenous opiate system. These conclusions are based on recent reports that indicate the release of the opiate-like peptide beta-endorphin and adrenocorticotropin (ACTH) from the pituitary are increased by acute stress and inhibited by administration of the synthetic glucocorticoid dexamethasone.

Estrogen receptor-alpha in the inhibition of cancer growth and angiogenesis

A high level of estrogen receptor-alpha (ER-alpha) is believed to be favorable in the prognosis and treatment of certain female cancers. ER-alpha expression in the ER-negative breast cancer cell lines inhibits their proliferation and invasive, metastatic potential in vitro. We stably overexpressed the ER-alpha in the human endometrial cancer cell line Ishikawa and showed that, unlike estradiol, high levels of ER-alpha significantly inhibit the growth of tumors xenografted from the Ishikawa cells. Subsequent to ER-alpha overexpression, in vivo down-regulation of vascular endothelial growth factor was observed in tumor xenografts. In addition, these tumors showed an inhibition of vascularization and of the angiogenic agent, integrin alphavbeta3. Involvement of a switch in the angiogenic pathways during tumorigenesis has been a recent focus of interest. Our results indicate that a high level of ER-alpha may be beneficial in the control of female cancers because of its inhibitory effect on such angiogenic pathways.

The activation state of alphavbeta 3 regulates platelet and lymphocyte adhesion to intact and thrombin-cleaved osteopontin

Cleavage of osteopontin by thrombin has been reported to enhance cell adhesion. We asked whether thrombin could regulate the alpha(v)beta(3)-mediated adhesion of platelets and B lymphocytes to this substrate. Although there was no difference in the extent or the avidity of thrombin- and ADP-stimulated platelet adhesion to intact or thrombin-cleaved human osteopontin, both the extent and avidity of phorbol ester-stimulated B cell adhesion to thrombin-cleaved osteopontin was significantly increased. Thus, these data suggest that the ability of alpha(v)beta(3) to recognize osteopontin can be differentially regulated in a cell-specific manner. To localize the alpha(v)beta(3) binding site on osteopontin, we measured cell adhesion to the two thrombin cleavage products of osteopontin and to a series of nested RGD-containing osteopontin peptides cross-linked to albumin. Whereas ADP-stimulated platelets adhered to the amino-terminal but not the carboxyl-terminal osteopontin fragment and to the osteopontin peptide RGDSVVYGLR, phorbol ester-stimulated B cells did not adhere to this peptide, although they did so in the presence of 1 mm Mn(2+). Thus, our data confirm that thrombin cleavage enhances the accessibility of the binding motif for alpha(v)beta(3) on osteopontin, but this enhancement is also a function of the activation state of alpha(v)beta(3). Moreover, they indicate that the sequence RGDSVVYGLR contains sufficient information to specify activation-dependent alpha(v)beta(3)-mediated platelet and lymphocyte adhesion.

Effects of the novel alphav integrin antagonist SM256 and cis-platinum on growth of murine squamous cell carcinoma PAM LY8

Increased density of proliferating and migrating tumor cells and neovascular endothelial cells has been associated with tumor progression and poor prognosis in patients with squamous cell carcinoma (SCC). Tumor and neovascular endothelial cells in squamous cell carcinoma have been reported to express integrin heterodimers containing the alphav subunit, which binds to vitronectin and other extracellular matrix proteins that contain the amino acid recognition sequence Arg-Gly-Asp (RGD). In the present study, we examined the effect of the novel non-peptide alphav integrin antagonist SM256 on growth of SCC line PAM LY8 in BALB/c SCID mice, and determined whether SM256 has direct inhibitory effects on growth of murine endothelial and PAM LY8 SCC cells in vitro. SM256 inhibits cell adhesion of murine cells expressing alphavbeta3 and alphavbeta5 integrins in vitro with an IC50 of 35 nM and 30 nM, respectively. Growth of Pam LY8 tumors in vivo was inhibited with 14-day continuous administration of SM256 by subcutaneous osmotic diffusion pump, during which a mean serum concentration of 56 nM was detected. While both murine aortic endothelial cells and PAM LY8 were found to express alphav integrins by fluorescence cytofluorometry, SM256 at 50 nM in MTT assay completely inhibited growth of endothelial cells, but had no significant direct effect on growth of PAM LY8 cells. We compared the effect on growth of PAM LY8 of SM256 infusion versus single agent or combination chemotherapy with a maximally tolerated dose of cis-platinum, which is used as a standard chemotherapy for SCC. When treatment was initiated at either 7 or 21 days following establishment of tumor, 14-day infusion of SM256 had an inhibitory effect on growth that was similar to that obtained with single dose cis-platinum, but no additive effect of concurrent therapy with SM256 and cis-platinum was observed. These results demonstrate the activity and feasibility of use of alphav antagonists such as SM256 for therapy of SCC.

A non-transmembrane form of Jagged-1 regulates the formation of matrix-dependent chord-like structures

Jagged-Notch interactions regulate a transmembrane ligand-receptor signaling pathway involved in the regulation of cell fate determination as well as myoblast and endothelial cell differentiation. To further examine the role of the transmembrane ligand, Jagged-1, in the regulation of cell differentiation, we stably transfected NIH 3T3 cells with a truncated form of Jagged(J)-1, which results in the secretion of a soluble(s) form of the protein. Comparison of gene expression by serial analysis demonstrated that among the 227 transcripts differentially regulated in the sJ-1 transfectants, the expression of the pro-alpha-2(I) collagen transcript and pro-alpha-1(I) collagen translation product was predominantly repressed in sJ-1 transfectants. When plated on extracellular matrices, sJ-1 transfectants formed prominent chord-like structures on type I collagen but not on fibrin, fibronectin, or vitronectin. While the sJ-1 transfectants exhibited growth kinetics similar to control cells and were unable to grow in soft agar, the cells were less sensitive to contact inhibition of growth in vitro and sJ-1 allografts formed tissue masses in nude mice after a prolonged latency period and exhibited an abundance of host-derived microvascular endothelial cells. These data suggest that J-1 may be able to modulate, in a matrix-dependent manner, the organization of cell to cell interactions including its ability to promote the development of chord-like structures.

Diagnosis of pulmonary embolism by use of urinary TNF alpha and its soluble TNF receptor I

The purpose of this clinical study was to determine the concentration of soluble tumor necrosis factor in urine of patients with pulmonary embolism (PE), verses voluntary control individuals. Sixteen patients (ages 24 to 74 years) with diagnosis of PE, documented by ventilation perfusion scan or pulmonary angiogram, were the subjects of this study. Ten cc of urine was obtained from each patient and subjected to a solid-phase enzyme-linked immunosorbent assay thus determining the soluble tumor necrosis factor (TNF) receptor I (R I) and TNF alpha levels in these samples. In this pilot study of PE cases, a statistically significant elevation in urinary levels of TNF alpha and soluble TNF R I was demonstrated in PE patients. The average urinary soluble TNF R I in normal subjects was 1,029 pg/mL and in PE patients the average TNF R I was 3,734.4 pg/mL. The clinical diagnosis of PE is a challenging problem for the physician. Late diagnosis and delayed management of this condition could be associated with massive PE. Although pulmonary angiography is the gold standard for diagnosis of PE, it requires expensive equipment, trained radiologists, and the patient could be at risk of sensitivity to contrast agents.

Stable over-expression of estrogen receptor-alpha in ECV304 cells inhibits proliferation and levels of secreted endothelin-1 and vascular endothelial growth factor

Studies with mammalian vascular cells have suggested growth inhibitory effects of estrogen on the vascular wall. To investigate the involvement of estrogen receptor-alpha (ER) in the control of endothelial cell proliferation, we have stably transfected human estrogen receptor-alpha cDNA into the endothelial cell line ECV304. The clone ECV-ER, thus obtained, over-expresses estrogen receptor to a level approximately 10-fold higher than the parent cell line. Effects of this over-expression were studied on the cell growth rate, and on the levels of secreted endothelin-1 and vascular endothelial growth factor (VEGF). Similar to the previously reported data in other cell types, we found the transfection of ER in ECV304 cells to be inhibitory to their growth. Our ER-over-expressing clone of ECV304 also showed an inhibition of secreted endothelin-1 and VEGF levels. Moreover, the growth inhibition of this ER-over-expressing clone was reversed by the addition of endothelin-1 or VEGF to the medium. In view of the growth-stimulatory effect of endothelin-1 and VEGF on vascular cells, our results indicate that estrogen receptor-alpha may bring about its growth inhibition partly by suppressing endothelin-1 and/or VEGF production in ECV304 cells.

Expression of proinflammatory and proangiogenic cytokines in patients with head and neck cancer

Altered immune, inflammatory, and angiogenesis responses are observed in patients with head and neck squamous cell carcinoma (HNSCC), and many of these responses have been linked with aggressive malignant behavior and a decrease in prognosis. In this study, we examined the hypothesis that HNSCC cells produce cytokines that regulate immune, inflammatory, and angiogenesis responses. We identified important regulatory cytokines in supernatants of well-defined and freshly cultured HNSCC cell lines by ELISA and determined whether these cytokines are detected in tumor cell lines and tissue specimens by immunohistochemistry. The serum concentration of the cytokines and cytokine-dependent acute phase inflammatory responses (i.e., fibrinogen, C-reactive protein, and erythrocyte sedimentation rate) from patients with HNSCC was determined, and the potential relationship of serum cytokine levels to tumor volume was analyzed. Cytokines interleukin (IL)-1alpha, IL-6, IL-8, granulocyte-macrophage colony-stimulating factor (GM-CSF), vascular endothelial growth factor (VEGF), and basic fibroblast growth factor were detected in similar concentration ranges in the supernatants of a panel of established University of Michigan squamous cell carcinoma (UM-SCC) cell lines and supernatants of freshly isolated primary HNSCC cultures. Evidence for the expression of IL-1alpha, IL-6, IL-8, granulocyte-macrophage colony-stimulating factor, and VEGF in HNSCC cells within tumor specimens in situ was obtained by immunohistochemistry. In a prospective comparison of the cytokine level and cytokine-inducible acute-phase proteins in serum, we report that cytokines IL-6, IL-8, and VEGF were detected at higher concentrations in the serum of patients with HNSCC compared with patients with laryngeal papilloma or age-matched control subjects (at P < 0.05). The serum concentrations of IL-8 and VEGF were found to be weakly correlated with large primary tumor volume (R2 = 0.2 and 0.4, respectively). Elevated IL-1- and IL-6-inducible acute-phase responses were also detected in cancer patients but not in patients with papilloma or control subjects (at P < 0.05). We therefore conclude that cytokines important in proinflammatory and proangiogenic responses are detectable in cell lines, tissue specimens, and serum from patients with HNSCC. These cytokines may increase the pathogenicity of HNSCC and prove useful as biomarkers or targets for therapy.

Rapid synthesis of RGD mimetics with isoxazoline scaffolds on solid phase: identification of alphavbeta3 antagonists lead compounds

Isoxazoline containing RGD mimetics were rapidly synthesized on a solid phase to optimize linkers, regioisomers of isoxazoline scaffolds, and exosite binding groups to yield lead alphavbeta3 antagonists.

Synthesis and antiplatelet effects of an isoxazole series of glycoprotein IIb/IIIa antagonists

Despite the excellent in vitro potency of a series of benzamide glycoprotein IIb/IIIa antagonists, which have been reported previously, poor in vivo potency in the inhibition of platelet aggregation was observed when the most potent inhibitor XU057 was dosed intravenously to dogs. In this communication, we report that replacement of the benzamide in XU057 with an isoxazolecarboxamide resulted in significant improvement in in vivo potency. More importantly, the analogue XU065 showed an excellent oral antiplatelet effect in dogs.

Diagnosis of deep venous thrombosis by use of soluble necrosis factor receptor

The purpose of this clinical study was to find a relationship between soluble tumor necrosis factor (TNF) receptor, deep venous thrombosis (DVT), and pulmonary emboli (PE). Clinical diagnosis of deep venous thrombosis and pulmonary emboli is a major dilemma for the clinician. Most existing tests are technician dependent, are expensive, or require sophisticated equipment. Advances in molecular biology will permit investigation of the value of TNF receptor as a test for screening, diagnosis, and evolution of DVT and PE. Forty patients with diagnosis of DVT, documented by real-time ultrasound imaging, were the subject of this clinical study. Five cc of plasma from each patient was studied by enzyme-linked immunosorbent assay (Elisa) for measurement of soluble TNF receptor. Significantly increased concentration of plasma-soluble TNF receptor was present in patients with DVT as opposed to normal individuals. There was a close relationship between plasma concentration of soluble TNF receptor and evaluation of the disease. In this preliminary clinical study, it appears that plasma measurement of soluble TNF receptor could be used as a clinical test for diagnosis of DVT and PE.

Design, synthesis, and in vitro activities of benzamide-core glycoprotein IIb/IIIa antagonists: 2,3-diaminopropionic acid derivatives as surrogates of aspartic acid

In an effort to discover novel nonpeptide glycoprotein IIb/IIIa (GPIIb/IIIa, alpha IIb/beta 3) inhibitors, we investigated RGD mimetics featuring a 3-substituted benzoic acid as the core, benzamidine as the basic moiety, and a series of beta- and alpha-substituted beta-alanine derivatives as aspartic acid surrogates. It was found that the use of beta-methyl beta-alanine slightly improved the anti-aggregant potency in human platelet-rich plasma over the unsubstituted beta-alanine compound, while beta-substitution with a trifluoromethyl group resulted in considerable loss in activity. Significant enhancement (up to 100-fold) in potency was obtained when the beta-alanine was replaced with N2-substituted 1-2,3-diaminopropionic acid derivatives. Among the three types of alpha-substituents (carbamate, amide, and sulfonamide) investigated, no apparent preference was observed with respect to in vitro potency. However, alkyl groups were more favorable than arylalkyl groups (Cbz) in the carbamate analogues. We also investigated piperidine, piperazine, and N-formamidinopiperidine as replacements for the benzamidine moiety. The former two replacements led to a drop in potency while the latter replacement resulted in maintenance of activity as compared with the corresponding benzamidine analogue.

Calcium, calmodulin and protein kinase C dependence of platelet shape change

Platelet shape change (PSC) represents the initial phase of platelet activation and is normally investigated in ethylene diamine tetraacetic acid (EDTA) containing platelet rich plasma (PRP); EDTA is a potent chelator of calcium and therefore reduces ionized calcium to negligible levels. It is therefore assumed that it is a process independent of calcium. To test the hypothesis that PSC may be dependent upon intracellular calcium, we examined the effect of 8-(N,N-Diethylamino) octyl 3,4,5-Trimethoxybenzoate hydrochloride (TMB-8), an inhibitor of intercellular calcium mobilization on PSC. It produced a dose dependent inhibition of PSC. We then examined whether PSC was dependent upon calmodulin and protein kinase C, a calcium dependent enzyme which is cardinal to platelet aggregation. Both calmidazolium, a specific inhibitor of calmodulin, and H-9, a specific inhibitor of protein kinase C, produced dose dependent inhibition of PSC. Finally, we investigated whether GP IIb/IIIa receptor which binds fibrinogen was involved in PSC; DMP 728 [(cyclic [D-2-amino-butyryl-N2-methyl-L-arginyl-glycyl-L-aspartyl-3- (a min o-methyl-benzoic acid], methanesulfonic acid salt] a potent GP IIb/IIIa receptor antagonist was without any effect on PSC. We conclude that PSC is a calcium, calmodulin and protein kinase C dependent process like platelet aggregation but that it does not require extracellular calcium or the participation of platelet GP IIb/IIIa complex.

Decreased enkephalinase activity following postnatal treatment with phenobarbital

The effect of postnatal administration of phenobarbital on enzymes degrading enkephalin was examined. Daily subcutaneous injections (45 mg/kg) of phenobarbital were given to male and female rats from postnatal day 1 to 19. Brains from rats treated with saline and phenobarbital were used to prepare aminopeptidases (high speed supernatant) and enkephalinase A (synaptosomal membrane preparation). Incubation of methionine enkephaline (ME) with aminopeptidases from rat brain liberated tyrosine (T), while incubating with enkephalinase A resulted in the formation of tyrosylglycylglycin (TGG). Separation and quantification of tyrosine, tyrosylglycylglycin and methionine enkephalin was performed using a high performance liquid chromatograph, coupled to electrochemical and ultraviolet detectors in series. The treatment of the rats with phenobarbital resulted in a significant inhibition of enkephalinase A when measured in vitro, using methionine enkephalin as substrate. Preliminary studies with secobarbital show similar results to those obtained with phenobarbital.

Prenatal alcohol exposure alters enkephalin levels, without affecting ethanol preference

Pregnant dams were pair-fed a liquid diet containing 35% ethanol derived calories or isocaloric sucrose during the last two trimesters of pregnancy. No differences were observed in adult ethanol preference between fetal alcohol exposed (FAE) animals and pair-fed controls. However, Met- and Leu-enkephalin levels were significantly elevated in globus pallidus of adult FAE animals. Pituitary levels were unaffected.

Analysis of enkephalins, beta-endorphins and small peptides in their sequences by highly sensitive high-performance liquid chromatography with electrochemical detection: implications in opioid peptide metabolism

Sensitivity in the 10-100 pg range for enkephalins, beta-endorphin, tyrosine (T), 12 tyrosylglycine (T-G) and tyrosylglycylglycine (T-G-G) was attained by using a high-performance liquid chromatographic (HPLC) method with electrochemical detection which is at least 100 times more sensitive than HPLC with UV detection. The chromatographic conditions on a reversed-phase C18 silica column were 50 mM sodium phosphate buffer (pH 2.1) (A) in acetonitrile-methanol (1:1) (B), isocratic mixture, flow-rate 0.6-1 ml/min, UV detection at 205 nm, electrochemical oxidation potential + 1.25 V. The separation of T, T-G and T-G-G was obtained by using 10% B while the separation of the pentapeptide, enkephalins required 40% B. Separation of enkephalins from beta-endorphin was attained at a shorter retention times did not exceed 15 min. This method can be used to determine tissue levels and pharmacodynamics of enkephalins and beta-endorphin. A highly specific measurement of the different enzymes involved in the metabolism of enkephalin has been achieved.

Prolonged intermittent footshock stress decreases Met and Leu enkephalin levels in brain with concomitant decreases in pain threshold

The influence of a 21 day intermittent footshock regimen upon enkephalin levels in brain and adrenals was examined in the rat. Changes in pain sensitivity as well as analgesic and hyperthermic responsiveness to morphine (7.5 mg/kg) were also monitored. Following the stress regimen, Met and Leu enkephalin levels were decreased by 40 to 50% in brain, but were unchanged in adrenals. Post-stress pain thresholds were markedly decreased in stressed animals while the analgesic properties of morphine were enhanced. Core body temperature of stressed animals was significantly raised, but the hyperthermic response to morphine was unchanged.