Acrylamide monomers in universal adhesives.

OBJECTIVES: The mono-functional monomer 2-hydroxyethyl methacrylate (HEMA) is often added to universal adhesives (UAs) to improve surface wetting and prevent phase separation. Nevertheless, HEMA promotes water sorption and hydrolysis at adhesive interfaces, hereby affecting long-term bonding to dentin. This study investigated if two acrylamide monomers could replace HEMA in an UA formulation applied in etch-and-rinse (2E&R) and self-etch (1SE) bonding mode. METHODS: Four experimental UAs were bonded to bur-cut dentin. In addition to 12 wt% 10-MDP, 25 wt% Bis-GMA and 10 wt% TEGDMA as common monomer composition, 20 %wt ethanol and 15 %wt water as solvent, and 3 wt% polymerization-related additives, the four formulations solely differed for either the acrylamide cross-linker monomer 'FAM-201' as TEGDMA alternative and HEMA replacement, the hydroxyethyl acrylamide monomer 'HEAA' as HEMA alternative, HEMA ('HEMA+'), or extra TEGDMA in a HEMA-free control ('HEMA-'), all added in a 15 wt% concentration. The split-tooth study design involved application in 2E&R mode on one tooth half versus 1SE mode on the corresponding half. Micro-tensile bond strength of half of the micro-specimens was measured upon 1-week distilled water storage ('immediate' 1w µTBS), with the other half measured after additional 6-month storage ('aged' 6 m µTBS). Statistics involved linear mixed-effects (LME) modelling (p < .05). Additionally, interfacial TEM characterization, thin-film (TF) XRD surface analysis, LogP determination, and a cytotoxicity assay were carried out. RESULTS: FAM-201 revealed significantly higher µTBS than HEMA+ at 1w and 6 m when applied both in E&R and SE bonding modes. HEAA's µTBS was significantly lower than that of HEMA+ at 1w when applied in SE mode. TF-XRD and TEM revealed similar chemical and ultrastructural interfacial characterization, including stable 10-MDP_Ca salt nano-layering. FAM-201 was least cytotoxic and presented with an intermediary LogP, while HEAA presented with the highest LogP, indicating high hydrophilicity and water-sorption sensitivity. SIGNIFICANCE: The acrylamide co-monomer FAM-201 could replace HEMA in an UA formulation, while HEAA not.

Nano-Layering Adds Strength to the Adhesive Interface.

X-ray diffraction (XRD) surface analysis and ultrastructural interfacial characterization using transmission electron microscopy (TEM) confirmed that the functional monomer 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) self-assembles into nano-layers at adhesive-tooth interfaces. Self-assembled nano-layering is thought to contribute to the durability of bonding to tooth dentin, although this has not been proven yet. In order to disclose this potential bond-durability contribution of nano-layering, we observed the 3-dimensional (3D) spreading of nano-layering by a series of focused-ion-beam (FIB) milled cross sections by scanning electron microscopy (FIB-SEM) and examined the mechanical properties of self-assembled nano-layering using scanning probe microscopy (SPM). A commercial 10-MDP-containing 3-step self-etch adhesive partially demineralized dentin up to submicron depth, forming a submicron hydroxyapatite-rich hybrid layer. TEM chemically and ultrastructurally confirmed the formation of interfacial nano-layering. FIB-SEM 3D reconstructions disclosed a 3D network of self-assembled nano-layering extending from the hybrid layer up to within the adjacent adhesive-resin layer. SPM revealed that nano-layering within the adhesive-resin layer possessed a higher elastic modulus than that of the surrounding adhesive resin, hereby suggesting that nano-layering contributes to the mechanical strength of adhesives like filler particles do. Nano-layering's 3D expanded structure is expected to strengthen the surrounding resin, as well to better interconnect the adhesive-resin layer to the hybrid layer. In conclusion, this exploratory study demonstrated that nano-layering constitutes a strong phase at the adhesive interface, which may contribute to the clinical longevity of the 10-MDP-based bond to dentin.

Touch-Cure Polymerization at the Composite Cement-Dentin Interface.

Ceramic restorations are often adhesively luted onto the tooth prep. The so-called touch-cure concept was developed to yield optimum polymerization of composite cement at the restoration-cement-tooth interface for immediate bond stabilization. Although this touch cure is theorized to initiate polymerization at the interface when the accelerator in the primer makes contact with the cement, this process has not yet been proven. This study aimed to elucidate the mechanism of touch cure by measuring the degree of conversion (DC) of composite cement applied with or without an accelerator-containing tooth primer (TP) versus an accelerator-free primer using real-time Fourier-transform infrared spectroscopy (RT-FTIR) and attenuated total reflection (ATR)-FTIR. Interfacial bond strength was measured in shear mode, the accelerator composition confirmed by X-ray fluorescence analysis (XRF), and the interfacial interaction of TP and composite cement with dentin investigated by X-ray diffraction (XRD), focused-ion-beam scanning electron microscopy (FIB-SEM) with 3-dimensional interface reconstruction, and transmission electron microscopy (TEM). RT/ATR-FTIR revealed the significantly highest DC when the composite cement was applied with the accelerator-containing primer. XRF disclosed a vanadium compound as a novel chemical accelerator within TP, instead of a classic chemical curing initiator system, to set off touch cure as soon the cement contacts the previously applied primer. Although the TP contains the acidic functional monomer 10-MDP for adhesion to tooth tissue, touch cure using the accelerator-containing TP combined the fastest/highest DC with the highest bond strength. FIB-SEM and TEM confirmed the tight interfacial interaction at dentin with submicron hybridization along with stable 10-MDP also Ca-salt nanolayering.

Etching Efficacy of Self-Etching Functional Monomers.

Besides chemically interacting with hard tooth tissue, acidic functional monomers of self-etch adhesives should etch the prepared tooth surface to dissolve the smear layer and to provide surface micro-retention. Although the etching efficacy of functional monomers is commonly determined in terms of pH, the pH of adhesives cannot accurately be measured. Better is to measure the hydroxyapatite (HAp)-dissolving capacity, also considering that functional monomers may form monomer-Ca salts. Here, the etching efficacy of 6 functional monomers (GPDM, phenyl-P, MTEGP, 4-META, 6-MHP and 10-MDP) was investigated. Solutions containing 15 wt% monomer, 45 wt% ethanol, and 40 wt% water were prepared. Initially, we observed enamel surfaces exposed to monomer solution by scanning electron microscopy (SEM). X-ray diffraction (XRD) was employed to detect monomer-Ca salt formation. Phenyl-P exhibited a strong etching effect, while 10-MDP-treated enamel showed substance deposition, which was identified by XRD as 10-MDP-Ca salt. To confirm these SEM/XRD findings, we determined the etching efficacy of functional monomers by measuring both the concentration of Ca released from HAp using inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and the amount of monomer-Ca salt formation using 31P magic-angle spinning (MAS) nuclear magnetic resonance (NMR). ICP-AES revealed that the highest Ca concentration was produced by phenyl-P and the lowest Ca concentration, almost equally, by 4-META and 10-MDP. Only 10-MDP formed 10-MDP-Ca salts, indicating that 10-MDP released more Ca from HAp than was measured by ICP-AES. Part of the released Ca was consumed to form 10-MDP-Ca salts. It is concluded that the repeatedly reported higher bonding effectiveness of 10-MDP-based adhesives must not only be attributed to the more intense chemical bonding of 10-MDP but also to its higher etching potential, a combination the other functional monomers investigated lack.

Structural and Chemical Analysis of the Zirconia-Veneering Ceramic Interface.

The interfacial interaction of veneering ceramic with zirconia is still not fully understood. This study aimed to characterize morphologically and chemically the zirconia-veneering ceramic interface. Three zirconia-veneering conditions were investigated: 1) zirconia-veneering ceramic fired on sandblasted zirconia, 2) zirconia-veneering ceramic on as-sintered zirconia, and 3) alumina-veneering ceramic (lower coefficient of thermal expansion [CTE]) on as-sintered zirconia. Polished cross-sectioned ceramic-veneered zirconia specimens were examined using field emission gun scanning electron microscopy (Feg-SEM). In addition, argon-ion thinned zirconia-veneering ceramic interface cross sections were examined using scanning transmission electron microscopy (STEM)-energy dispersive X-ray spectrometry (EDS) at high resolution. Finally, the zirconia-veneering ceramic interface was quantitatively analyzed for tetragonal-to-monoclinic phase transformation and residual stress using micro-Raman spectroscopy (µRaman). Feg-SEM revealed tight interfaces for all 3 veneering conditions. High-resolution transmission electron microscopy (HRTEM) disclosed an approximately 1.0-µm transformed zone at sandblasted zirconia, in which distinct zirconia grains were no longer observable. Straight grain boundaries and angular grain corners were detected up to the interface of zirconia- and alumina-veneering ceramic with as-sintered zirconia. EDS mapping disclosed within the zirconia-veneering ceramic a few nanometers thick calcium/aluminum-rich layer, touching the as-sintered zirconia base, with an equally thick silicon-rich/aluminum-poor layer on top. µRaman revealed t-ZrO2-to-m-ZrO2 phase transformation and residual compressive stress at the sandblasted zirconia surface. The difference in CTE between zirconia- and the alumina-veneering ceramic resulted in residual tensile stress within the zirconia immediately adjacent to its interface with the veneering ceramic. The rather minor chemical elemental shifts recorded in the veneering ceramic did not suffice to draw definitive conclusions regarding potential chemical interaction of the veneering ceramic with zirconia. Sandblasting damaged the zirconia surface and induced phase transformation that also resulted in residual compressive stress. Difference in CTE of zirconia versus that of the veneering ceramic resulted in an unfavorable residual tensile stress at the zirconia-veneering ceramic interface.

Osteocalcin-immunoreactive neurons in the vagal and glossopharyngeal sensory ganglia of the rat.

Immunohistochemistry for osteocalcin (OC) was performed on the rat vagal and glossopharyngeal sensory ganglia. OC-immunoreactive (IR) neurons were detected in the jugular (10%), petrosal (11%) and nodose ganglia (6%). The cell size analysis demonstrated that OC-IR neurons were predominantly small to medium-sized in the jugular ganglion (mean+/-S.D.=356.3+/-192.2 microm(2), range=86.5-831.5 microm(2)). On the other hand, such neurons were medium-sized to large in the petrosal (mean+/-S.D.=725.6+/-280.7 microm(2), range=124.7-1540.4 microm(2)) and nodose ganglia (mean+/-S.D.=857.5+/-330.2 microm(2), range=367.1-1608.0 microm(2)). In the circumvallate papilla, OC-IR nerve fibers were located in the vicinity of taste buds. Some taste bud cells were also immunoreactive for the calcium-binding protein (CaBP). In the carotid body, however, OC-IR nerve fibers could not be detected. Retrograde tracing with fluorogold revealed that OC-IR nerve fibers in the circumvallate papilla mainly originated from the petrosal ganglion. These findings may suggest that OC-IR petrosal neurons have chemoreceptive function in the tongue.

Age and magnetic effects on ectopic bone formation induced by purified bone morphogenetic protein.

A mixture of heparin-Sepharose-purified bovine bone morphogenetic protein (BMP) and type I atellocollagen was implanted in the subcutaneous tissues of 4-week, 10-month and 18-month-old rats. The implants were removed at 7, 14 and 21 days after implantation. The effects of rat age on ectopic bone formation were evaluated on the explants using H&E staining, morphometric analysis, alkaline phosphatase (ALP) activity and calcium (Ca) content determination, as well as immunohistochemical staining of type IV collagen present in the basement membrane of blood vessels. On day 14 and 21, bone was observed in 4-week and 10-month-old rats but the amount of bone formed in the later was less than in the former. In 18-month-old rats, bone was first found focally in very limited regions of the explants on day 21 and the amount of bone was much less than in 4-week-old rats. At all periods ALP activity was higher in younger rats. On day 7, there were more blood vessels in the explants of 4-week-old rats than in those of 10- or 18-month-old rats. On day 14 and 21, more blood vessels were found in the central regions of the explants in 4-week-old rats than in the same regions in 10- or 18-month-old rats. The findings in the present study indicated that the rate and quantity of ectopic bone formation were reduced, and that the difference in blood vessel distribution might be related to the reduction in ectopic bone formation in aged rats, and suggest that the difference in blood vessel distribution is related to ectopic bone formation. Magnetism can stimulate ectopic bone formation induced by BMP.

[The indications for postoperative adjuvant therapy in node-negative breast cancer patients].

A clinicopathological study on prognosis has been carried out in 233 breast cancer patients with more than twenty inspected nodes and without lymph node metastasis. Multivariate analysis of clinicopathological findings in node-negative breast cancers showed that the best combination of clinical features predicting prognosis were age, menstruation status, tumor location and tumor diameter; and from 11 pathological features, three factors (histological type, histological grade and the grade of tumor infiltrating lymphocytes) were selected under condition of p<0.05. With solid-tubular carcinoma, histological grade III and negative tumor infiltrating lymphocytes as the 3 poor prognostic factors, node-negative breast cancers were classified. The recurrence rates of subgroups with the number of 3, 2, 1 and 0 were 28%, 16%, 7% and 0%, respectively. We conclude that the grade of tumor infiltrating lymphocytes is especially significant as the prognostic factor in node-negative breast cancers, and that postoperative adjuvant chemoendocrine therapy must be performed for patients with node-negative breast cancer with more than two poor prognostic pathological factors.

Novel fluoro-carbon functional monomer for dental bonding.

Among several functional monomers, 10-methacryloxydecyl dihydrogen phosphate (10-MDP) bonded most effectively to hydroxyapatite (HAp). However, more hydrolysis-resistant functional monomers are needed to improve bond durability. Here, we investigated the adhesive potential of the novel fluoro-carbon functional monomer 6-methacryloxy-2,2,3,3,4,4,5,5-octafluorohexyl dihydrogen phosphate (MF8P; Kuraray Noritake Dental Inc., Tokyo, Japan) by studying its molecular interaction with powder HAp using solid-state nuclear magnetic resonance ((1)H MAS NMR) and with dentin using x-ray diffraction (XRD) and by characterizing its interface ultrastructure at dentin using transmission electron microscopy (TEM). We further determined the dissolution rate of the MF8P_Ca salt, the hydrophobicity of MF8P, and the bond strength of an experimental MF8P-based adhesive to dentin. NMR confirmed chemical adsorption of MF8P onto HAp. XRD and TEM revealed MF8P_Ca salt formation and nano-layering at dentin. The MF8P_Ca salt was as stable as that of 10-MDP; MF8P was as hydrophobic as 10-MDP; a significantly higher bond strength was recorded for MF8P than for 10-MDP. In conclusion, MF8P chemically bonded to HAp. Despite its shorter size, MF8P possesses characteristics similar to those of 10-MDP, most likely to be associated with the strong chemical bond between fluorine and carbon. Since favorable bond strength to dentin was recorded, MF8P can be considered a good candidate functional monomer for bonding.

Analyses of shape of eyes and structure of optic nerves in eyes with tilted disc syndrome by swept-source optical coherence tomography and three-dimensional magnetic resonance imaging.

PURPOSE: To evaluate the deeper structures of the optic nerve and to analyze the shape of eyes with tilted disc syndrome (TDS) by swept-source optical coherence tomography (OCT) and three-dimensional magnetic resonance imaging (3D MRI). METHODS: The medical records of 54 eyes of 36 patients with TDS were reviewed. The patients with TDS and high myopia were analyzed separately from those without high myopia. All the eyes were examined with a swept-source OCT, and 22 of the eyes were examined by 3D MRI. RESULTS: A total of 38 eyes of 29 patients were highly myopic and 16 eyes of 15 patients were not highly myopic. The representative OCT findings of the optic disc were: a sloping of the lamina cribrosa posteriorly from the upper part to the lower part, a protrusion of the upper edge of Bruch's membrane, and choroid. The distance and the depth of the most protruded point from the fovea were significantly greater in the eyes with non-highly myopic TDS than those with highly myopic TDS. In the 3D MRI, the lower part of the posterior segment was protruded outward, and the optic nerves attached at the upper nasal edge of the protrusion. CONCLUSIONS: The abnormalities detected by swept-source OCT and 3D MRI analyses indicate the possibility that the essential pathology of TDS is a deformity of the inferior globe below the optic nerve, and the positional relation between the fovea and the inferior protrusion determines the degree of myopia.

Self-assembled Nano-layering at the Adhesive interface.

According to the 'Adhesion-Decalcification' concept, specific functional monomers within dental adhesives can ionically interact with hydroxyapatite (HAp). Such ionic bonding has been demonstrated for 10-methacryloyloxydecyl dihydrogen phosphate (MDP) to manifest in the form of self-assembled 'nano-layering'. However, it remained to be explored if such nano-layering also occurs on tooth tissue when commercial MDP-containing adhesives (Clearfil SE Bond, Kuraray; Scotchbond Universal, 3M ESPE) were applied following common clinical application protocols. We therefore characterized adhesive-dentin interfaces chemically, using x-ray diffraction (XRD) and energy-dispersive x-ray spectroscopy (EDS), and ultrastructurally, using (scanning) transmission electron microscopy (TEM/STEM). Both adhesives revealed nano-layering at the adhesive interface, not only within the hybrid layer but also, particularly for Clearfil SE Bond (Kuraray), extending into the adhesive layer. Since such self-assembled nano-layering of two 10-MDP molecules, joined by stable MDP-Ca salt formation, must make the adhesive interface more resistant to biodegradation, it may well explain the documented favorable clinical longevity of bonds produced by 10-MDP-based adhesives.

HEMA inhibits interfacial nano-layering of the functional monomer MDP.

Previous research showed that the functional monomer 10-methacryloxydecyl dihydrogen phosphate (MDP) ionically bonds to hydroxyapatite (HAp) and forms a nano-layered structure at the interface with HAp-based substrates. Such hydrophobic nano-layering is considered to contribute to the long-term durability of the bond to tooth tissue. However, dental adhesives are complex mixtures usually containing different monomers. This study investigated the effect of the monomer 2-hydroxyethylmethacrylate (HEMA) on the chemical interaction of MDP with HAp by x-ray diffraction (XRD), nuclear magnetic resonance (NMR), and quartz crystal microbalance (QCM). We examined the chemical interaction of 5 experimental MDP solutions with increasing concentrations of HEMA. XRD revealed that addition of HEMA inhibits nano-layering at the interface, while NMR confirmed that MDP remained adsorbed onto the HAp surface. QCM confirmed this adsorption of MDP to HAp, as well as revealed that the demineralization rate of HAp by MDP was reduced by HEMA. It was concluded that even though the adsorption of MDP to HAp was not hindered, addition of HEMA inhibited interfacial nano-layering. Potential consequences with regard to bond durability necessitate further research.

Self-etch monomer-calcium salt deposition on dentin.

Previous research, in which the bonding effectiveness of the 3 self-etch monomers HAEPA, EAEPA, and MAEPA was determined, showed that MAEPA was most effective. In this study, the molecular interactions of these monomers with hydroxyapatite and dentin were investigated by combining x-ray diffraction, infrared spectroscopy, and scanning electron microscopy. We tested the null hypothesis that the bonding performance of these monomers does not correlate to the formation of monomer-calcium salts and to hydrolytic stability of these monomer-calcium complexes. Monomer/ethanol/water solutions were prepared and applied to synthetic hydroxyapatite and dentin. While HAEPA and EAEPA dissolved dentin considerably and deposited unstable calcium-phosphate salts (DCPD), MAEPA formed hydrolysis-resistant monomer-calcium salts that remained attached to the dentin surface even after being washed. The chemical stability of the monomer-Ca salts was thought to contribute in particular to the bond durability, but this study shows that the formation of stable monomer-calcium salts also enhances the 'immediate' bonding performance of self-etch adhesives.

Augmentation of anti-influenza virus hemagglutinin antibody production by Peyer's patch cells with Bifidobacterium breve YIT4064.

Bifidobacterium breve YIT4064 was tested an an adjuvant for oral influenza vaccine by the murine Peyer's patch cell culture method. The organism augmented production of anti-influenza virus hemagglutinin immunoglobulin A antibody by Peyer's patch cells in response to addition of hemagglutinin. These antibodies may be disseminated to the respiratory mucosal tissue and prevent influenza virus infection.

Ribulose-peptide in human semen: I. Isolation.

A substance apparently related to a compound consisting of phospho-peptide and ribulose-peptide in the yolk of chick embryos was isolated from acid soluble fractions of human semen by means of Dowex 1 (OH) form column chromatography. The treated precipitate of human semen was examined with an analytical ultracentrifuge by means of synthetic boundary cells and found to be a single component. The sedimentation coefficient was 0.80. The sugar component in the precipitate was identified as ribulose by paper chromatography, color reaction, absorption spectrum of the reaction product in the orcinol, and enzymatic analysis. Amino acids detected in the acid hydrolysate of the precipitate were lysine, histidine, arginine, aspartic acid, threonine, serine, glutamic acid, proline, glycine, alanine, valine, isoleucine, and leucine. From the above, this substance was determined to be a ribulose-peptide.

Thrombolysis of canine femoral artery thrombus by a novel modified tissue-type plasminogen activator (E6010).

The thrombolytic activity of a novel modified tissue-type plasminogen activator (t-PA) (E6010) was examined in a canine model with copper coil-induced femoral artery thrombus. This model, in which thrombolytic activity can be easily and directly quantified by determining changes in thrombus weight, should be useful for comparing the activities of various thrombolytic agents. Using this model, the present study showed that the thrombolytic activity of bolus intravenous injection of E6010 was identical to that of continuous intravenous infusion of recombinant t-PA at the same dose. This thrombolytic activity can be explained by changes in blood concentrations of the administered thrombolytic agents. On the other hand, administration of the thrombolytic agents dose-dependently caused significant changes in the levels of hemostatic and fibrinolytic factors. These changes were not so marked with administration of E6010, and therefore we concluded that E6010 is unlikely to cause bleeding complications after administration.

[Effects of E3123 on pancreatic injury in the isolated, perfused rat pancreas and in a pancreatic slice].

We studied the effect of E3123 on pancreatic injury induced in the isolated, perfused pancreas or in a pancreatic slice. Exposure of the isolated, perfused rat pancreas to trypsin-taurocholate or phospholipase A2 caused the leakage of pancreatic enzyme (lipase) into the perfusate. In trypsin-taurocholate-induced pancreatic injury, E3123 and nafamostat mesilate suppressed the leakage of lipase at concentrations of 0.1-1 microM and 1-10 microM, respectively. In phospholipase A2 induced pancreatic injury, E3123 at 10 microM significantly suppressed the enzyme leakage, and nafamostat mesilate had a weak suppressive effect. Exposure of a rat pancreatic slice to phospholipase A2 also caused the leakage of pancreatic enzyme, while the inhibition of enzyme leakage by E3123 was similar to that observed in the isolated, perfused pancreas; nafamostat mesilate was not effective. This finding suggests the possible involvement of a unique mechanism of action in the protection against pancreatic injury by E3123. Therefore, we studied the effect of E3123 on hemolysis by osmotic shock using rat red blood cells. E3123 demonstrated a potent protective effect against the hemolysis, suggesting that a membrane-stabilizing action may contribute to the protection E3123 affords against pancreatic injury.

Comparison of ticlopidine and cilostazol for the prevention of restenosis after percutaneous transluminal coronary angioplasty.

Prevention of restenosis after percutaneous transluminal coronary angioplasty (PTCA) continues to be a significant problem. Recent controlled studies have demonstrated that cilostazol suppresses restenosis after PTCA. The effects of ticlopidine, another antiplatelet agent, were compared in terms of outcomes of patients randomized for treatment with the two drugs after PTCA. A total of 35 patients (47 lesions) were assigned prospectively and randomly to ticlopidine (17 patients, 24 lesions) and cilostazol (18 patients, 23 lesions) groups. Minimal luminal diameter (MLD) and percentage of stenosis to reference diameter were estimated before PTCA, just after the procedure and after 4 months follow-up. All patients underwent 4 months angiographic follow-up, at the end of which MLD was 2.03+/-0.71 mm in the ticlopidine group and 2.05+/-0.68 mm in the cilostazol group (p = 0.95), and the percentage of stenosis to reference diameter was 31.4+/-16.7% and 30.0+/-17.0%, respectively (p = 0.78). The restenosis rate was 12.5% in the ticlopidine group and 17.4% in the cilostazol group (p = 0.69), relatively low as compared to the 20% to 30% reported in previous studies. Adverse drug reactions during the follow-up period were observed in two of the ticlopidine group and none of the cilostazol group. We conclude that both ticlopidine and cilostazol are effective for the prevention of restenosis after PTCA, however the former may be associated with slight side effects.

[Effects of E-3123, a new protease inhibitor, on several protease activities and on experimental acute pancreatitis].

4-(2-Succinimidoethylthio) phenyl 4-guanidinobenzoate (E-3123) potently inhibited trypsin, plasmin and thrombin with IC50 values of 3.9 x 10(-8) M, 9.5 x 10(-7) M and 1.9 x 10(-6) M, respectively. Experimental acute pancreatitis was induced by injection of a mixture of trypsin and taurocholate into the pancreas in rats and rabbits or by an application of a closed duodenal loop in dogs. Intravenous infusion of E-3123 at 0.03-0.3 mg/kg in rats or at 0.3-3.0 mg/kg in rabbits reduced mortality after the induction of pancreatitis in a dose-dependent manner. Light microscopy of the pancreas in the E-3123-treated rabbits revealed marked decrease in cell necrosis and acinar cell vacuolation. Increase in plasma lipase activities associated with the progression of pancreatitis in rabbits was also reduced by the infusion of E-3123. In dogs with pancreatitis, increases in serum trypsin and lipase activities were significantly reduced by infusion of E-3123 at 1.0 and 3.0 mg/kg. The efficacies of E-3123 in the in vivo experiments were higher than those of nafamostat mesilate. These results show that E-3123 may possess suppressing effects on pathogenesis and development of acute pancreatitis.

Thrombolytic effects of a novel modified tissue plasminogen activator, E6010, on coronary thrombosis in the pig.

This study was conducted to compare the thrombolytic effect of a novel modified tissue plasminogen activator, E6010, with that of recombinant human tissue plasminogen activator (t-PA), administered by single intravenous bolus injection in pigs with occlusive coronary thrombosis. Thrombosis was induced by electrical stimulation of the intimal surface of the left circumflex coronary artery. Coronary blood flow velocity and hemodynamic parameters were observed for 1 hr after complete cessation of coronary flow. Ten minutes after heparin injection (300 U/kg), E6010, t-PA or placebo was intravenously administered as a bolus. E6010 at 0.2 and 0.4 mg/kg caused recanalization of the occluded coronary artery in 1 of 6 and 5 of 5 pigs, respectively. The time to recanalization after 0.4 mg/kg of E6010 was 22 +/- 11 min (mean +/- S.E.M.). t-PA (0.4 mg/kg) caused recanalization in only 1 of 5 pigs. Recanalization did not occur in any of the 6 animals administered placebo. Plasma clearance of E6010 was smaller than that of t-PA (4.9 +/- 0.3 vs. 9.4 +/- 3.8 ml/min/kg). There were no significant differences in plasma levels of fibrinogen, alpha 2-plasmin inhibitor and plasminogen among the placebo, E6010 and t-PA groups. These results suggest that the slower clearance of E6010 from plasma contributes to the effective thrombolytic action of E6010 following single intravenous bolus injection.