TAK-242 improves sepsis-associated acute kidney injury in rats by inhibiting the TLR4/NF-κB signaling pathway

OBJECTIVE

This study was designed to observe the effect of toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB) pathway activity on sepsis-associated acute kidney injury (SA-AKI), thereby providing new considerations for the prevention and treatment of SA-AKI.

METHODS

The rats were divided into Sham, cecal ligation and puncture (CLP), CLP + vehicle, and CLP + TAK-242 groups. Except the Sham group, a model of CLP-induced sepsis was established in other groups. After 24 h, the indicators related to kidney injury in blood samples were detected. The pathological changes in the kidneys were observed by hematoxylin-eosin staining, and tubular damage was scored. Oxidative stress-related factors, mitochondrial dysfunction-related indicators in each group were measured; the levels of inflammatory factors in serum and kidney tissue of rats were examined. Finally, the expression of proteins related to the TLR4/NF-κB signaling pathway was observed by western blot.

RESULTS

Compared with the CLP + vehicle and CLP + TAK-242 groups, the CLP + TAK-242 group reduced blood urea nitrogen (BUN), creatinine (Cr), cystatin-C (Cys-C), reactive oxygen species (ROS), malondialdehyde (MDA), and inflammatory factors levels (p < 0.01), as well as increased superoxide dismutase (SOD) activity of CLP rats (p < 0.01). Additionally, TAK-242 treatment improved the condition of CLP rats that had glomerular and tubular injuries and mitochondrial disorders (p < 0.01). Further mechanism research revealed that TAK-242 can inhibit the TLR4/NF-κB signaling pathway activated by CLP (p < 0.01). Above indicators after TAK-242 treatment were close to those of the Sham group.

CONCLUSION

TAK-242 can improve oxidative stress, mitochondrial dysfunction, and inflammatory response by inhibiting the activity of TLR4/NF-κB signaling pathway, thereby preventing rats from SA-AKI.

ANXA3 interference inactivates ERK/ELK1 pathway to mitigate inflammation and apoptosis in sepsis-associated acute lung injury

Acute lung injury (ALI) is a prevailing and deadly complication of sepsis coupled with increasing incidence and fatality rate. Annexin A3 (ANXA3) has been unraveled to be upregulated during sepsis. This study purposed to assess the role and the mechanism of ANXA3 in sepsis-induced ALI. After the construction of mouse model of sepsis, the pathological changes of mice lung tissues were estimated by H&E staining. ANXA3 expression in mice lung tissues and serum was examined. The degree of pulmonary edema and the levels of inflammatory factors in bronchoalveolar lavage fluid (BALF) were analyzed. In lipopolysaccharide (LPS)-induced mouse ALI model in vitro, CCK-8 assay measured cell viability and flow cytometry analysis detected cell apoptosis. Besides, ELISA assay detected the release of inflammatory cytokines. Western blot analyzed the expression of proteins associated with inflammation, apoptosis and extracellular-signal-regulated kinase (ERK)/ETS-like gene 1 (ELK1) signaling. Results revealed that ANXA3 was overexpressed in the lung tissues and serum of septic mice. Following the knockdown of ANXA3, sepsis-induced lung injury was alleviated, manifested as reduced lung edema, decreased inflammatory cell infiltration and inhibited cell apoptosis. Additionally, ANXA3 silence blocked ERK/ELK1 signaling both in sepsis mouse models and in vitro model of ALI induced by lipopolysaccharide (LPS). Moreover, the inhibitory effects of ANXA3 silencing on ERK/ELK1 signaling activation, the viability damage, inflammation and apoptosis in LPS-induced mouse ALI model in vitro were partially reversed by ERK activator. Collectively, depletion of ANXA3 exerted suppressive effects on the inflammation and apoptosis in sepsis-induced ALI through blocking ERK/ELK1 signaling.

Platelet-derived extracellular vesicles promote endothelial dysfunction in sepsis by enhancing neutrophil extracellular traps

BACKGROUND

The role of platelet-derived extracellular vesicles (PEVs) in the development of sepsis was investigated in this study.

METHODS

After collection of blood samples from sepsis patients and normal volunteers, the extracellular vesicles (EVs) were separated, followed by the isolation of PEVs from the blood of rats. Next, a sepsis rat model was constructed by cecal ligation and puncture (CLP), and rats received tail vein injection of PEVs to explore the role of PEVs in sepsis. Subsequently, nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM) were adopted to determine the diameter of EVs and observe the morphology of PEVs, respectively; flow cytometry to detect the percentage of CD41-and CD61-positive EVs in isolated EVs; and ELISA to assess neutrophil extracellular trap (NET) formation, endothelial function injury-related markers in clinical samples or rat blood and serum inflammatory factor level.

RESULTS

Compared with normal volunteers, the percentage of CD41- and CD61-positive EVs and the number of EVs were significantly elevated in sepsis patients. Moreover, sepsis patients also presented notably increased histone H3, myeloperoxidase (MPO), angiopoietin-2 and endocan levels in the blood, and such increase was positively correlated with the number of EVs. Also, animal experiments demonstrated that PEVs significantly promoted NET formation, mainly manifested as up-regulation of histone H3, high mobility group protein B1 (HMGB1), and MPO; promoted endothelial dysfunction (up-regulation of angiopoietin-2, endocan, and syndecan-1); and stimulated inflammatory response (up-regulation of interleukin (IL) -1β, IL-6, tumor necrosis factor (TNF)-α, and monocyte chemoattractant protein (MCP) -1) in the blood of sepsis rats.

CONCLUSION

PEVs aggravate endothelial function injury and inflammatory response in sepsis by promoting NET formation.

UHPLC-MS/MS -based Untargeted Lipidomics Analysis of Septic Patients

BACKGROUND

Lipids take part in many pathophysiological processes of sepsis, thus, the variation of lipid composition may have clue on the severity and pathogen to sepsis. The objective of our study is to expand the profile of lipid compositions and screen potential biomarkers in intensive care unit (ICU) patients with sepsis.

METHODS

Patients admitted to the ICU clearly diagnosed with celiac sepsis were included in this prospective study. Age-matched healthy participants from the Physical Examination Center were used as the control group. Blood samples were obtained from patients within the first 12 h of admission. We analysed different components of the lipid metabolism between the sepsis patients and controls and described characteristic features during sepsis.

RESULTS

Thirty patients with celiac sepsis and 30 sex- and age-matched healthy controls were enrolled in this study. The lipid metabolic signature was obviously different between the sepsis patients and healthy controls and was mostly downregulated in sepsis patients. We identified 65 lipid species. Sixty-four lipid molecules were found to be significantly downregulated in sepsis patients, and only the level of one phosphatidylethanolamine (PE) molecule, PE (34:2) was higher in the sepsis patients with sepsis group comparing with the control group. The analysis of metabolic pathway illustrated the different lipid molecules were closely related to PC、LPC、and PE.

CONCLUSION

Sepsis contributes to impaired expression of most lipids, which mainly result in the disorder of glycerolipid metabolic pathway, including PC、LPC、and PE.

Impaired function of skeletal stem cells derived from growth plates in ovariectomized mice

INTRODUCTION

Mouse skeletal stem cells (mSSCs, CD45^-Ter119^-Tie2^-CD51⁺Thy^-6C3^-CD105^-CD200⁺population) are identified in growth plates (GP) and play important roles in bone regeneration. However, the role of mSSCs in osteoporosis remains unclear.

MATERIALS AND METHODS

The GP were stained by HE staining, and the mSSC lineage was analyzed by flow cytometry at postnatal of 14 days and 30 days in wild-type mice. The mice (8 weeks) were either sham operated or ovariectomy (OVX) and then sacrificed at 2, 4 and 8 w. The GP were stained by Movat staining, and mSSC lineage was analyzed. Then, mSSCs were sorted by fluorescence-activated cell sorting (FACS); the clonal ability, chondrogenic differentiation and osteogenic differentiation were evaluated, and the changed genes were analyzed by RNA-seq.

RESULTS

The percentage of mSSCs were decreased with the narrow GP. Heights of GP were decreased significantly in 8w-ovx mice compared with 8w-sham mice. We found the percentage of mSSCs were decreased in mice at 2w after ovx, but the cell numbers were not changed. Further, the percentage and cell numbers of mSSCs were not changed at 4w and 8w after ovx. Importantly, the clonal ability, chondrogenic differentiation and osteogenic differentiation of mSSCs were impaired at 8w after ovx. We found 114 genes were down-regulated in mSSCs, including skeletal developmental genes such as Col10a1, Col2a1, Mef2c, Sparc, Matn1, Scube2 and Dlx5. On the contrary, 526 genes were up-regulated, including pro-inflammatory genes such as Csf1, Nfkbla, Nfatc2, Nfkb1 and Nfkb2.

CONCLUSION

Function of mSSCs was impaired by up-regulating pro-inflammatory genes in ovx-induced osteoporosis.

[Nontargeted lipidomic analysis of sera from sepsis patients based on ultra-high performance liquid chromatography-mass spectrometry/mass spectrometry]

OBJECTIVE

To analyze the changes of serum lipidomics in patients with sepsis and healthy controls, search for the differences of lipid metabolites, and reveal the changes of lipidomics in the process of sepsis.

METHODS

A prospective observational study was conducted. From September 2019 to April 2020, morning blood samples of upper extremity superficial veins were collected from 30 patients with definite sepsis diagnosed in intensive care unit (ICU) of Shanxi Bethune Hospital and 30 age-matched healthy subjects during the same period. Serum lipid metabolites were analyzed by ultra-high performance liquid chromatography-mass spectrometry/mass spectrometry (UPLC-MS/MS), and the quality control samples were analyzed by base peak spectroscopy (BPC) and verified experimental repetition. Student t-test and fold change (FC) were used for screening significant differences in lipid metabolites and determining their expression changes. Principal component analysis (PCA) and orthogonal projectionto latent structure discriminant analysis (OPLS-DA) were used to determine the entire allocation of experimental groups apiece, access the quality of being near to the true value of model, and screen the differential lipid metabolites with variable importance of projection (VIP). Finally, Metabo Analyst platform database was used to analyze lipid molecular metabolic pathways.

RESULTS

BPC results showed that the experimental repeatability was good and the experimental data was reliable. The main parameter model interpretation rate of PCA model R²X = 0.511, indicating that the model was reliable. The main parameter model interpretation rate of OPLS-DA model R²Y = 0.954, Q² = 0.913, indicating that the model was stable and reliable. With FC > 2.0 or FC < 0.5, P < 0.05, a total of 72 differential lipid metabolites were obtained based on VIP > 1. Based on Metabo Analyst 5.0, 24 distinguishable lipid metabolites were identified including 8 phosphatidylethanolamine (PE), 7 lysophosphatidylcholine (LPC), 6 phosphatidylcholine (PC), 2 lysophosphatidylethanolamine (LPE) and 1 phosphatidylserine (PS). Compared with healthy volunteers, the lipid molecules expression proved down-regulated in most sepsis patients, including PC, LPC, LPE, and some PE, while some PE and PS were up-regulated, which was mainly related to the PE (18:0p/20:4), PC (16:0/16:0) and LPC (18:1) metabolic pathways in glycerophospholipids.

CONCLUSIONS

There are significant differences in lipid metabolites between the sera of sepsis patients and healthy volunteers. PE (18:0p/20:4), PC (16:0/16:0) and LPC (18:1) may be new targets for sepsis prediction and intervention.

[Management of major complications in surgical treatment of mandibular osteoradionecrosis by using vascularized free flaps]

Objective: To retrospectively analyze of the prevention and management of major complications in surgical treatment of osteoradionecrosis (ORN) of the mandible by using vascularized free flaps and to provide a reference for improving clinical treatments. Methods: All cases diagnosed as mandibular ORN and received surgical treatment in the Department of Oral and Maxillofacial Surgery, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University from August 2014 to March 2019 were included. The patients' clinical data, mainly including general information, primary tumor, interval time between radiotherapy and osteoradionecrosis, surgical methods and postoperative complications, were collected. The data of surgical methods and postoperative complications of these patients were compared with the similar data of patients with malignant tumor surgically treated by using vascularized free flaps during the same period. Results: The postoperative follow-up data of 104 patients with mandibular ORN, who underwent surgery in our hospital, were collected. In the control group, surgeries of vascularized free flap transfer were performed in 430 patients with malignant tumor. Among the 34 ORN cases (34/104, 32.7%) of segmental resection with vascularized free flap transfer, there were 13 cases (13/34, 38.2%) of postoperative local infection in maxillofacial area, 6 cases (17.6%) of pulmonary infection, 2 cases (5.9%) of venous thrombosis, 3 cases (8.8%) of anastomotic artery rupture and 5 cases (14.7%) of vascular crisis. One case died of depression and misanthropy. Meanwhile, among 430 patients with malignant tumor who underwent surgeries of vascular free flap reconstruction, 25 cases (5.8%) had postoperative local infection and 29 cases (6.7%) had pulmonary infection. Vascular crisis occurred in 12 cases (2.8%) and anastomotic artery rupture in 1 case (0.2%). No venous thrombosis and misanthropy occurred. The incidence of postoperative complications in mandibular ORN was much higher than that of vascularized free flap transfer surgeries in malignant tumor cases (P<0.05). Conclusions: Compared with patients with malignant tumors undergoing vascularized free flap transfer surgeries, patients with mandibular ORN undergoing same surgeries are more likely to have postoperative complications. This study may help clinicians to fully understand the local, general and psychological conditions during the perioperative period of ORN patients.

Early Signal of Emerging Nuclear Collectivity in Neutron-Rich ^{129}Sb

Radioactive ^{129}Sb, which can be treated as a proton plus semimagic ^{128}Sn core within the particle-core coupling scheme, was studied by Coulomb excitation. Reduced electric quadrupole transition probabilities, B(E2), for the 2^{+}⊗πg_{7/2} multiplet members and candidate πd_{5/2} state were measured. The results indicate that the total electric quadrupole strength of ^{129}Sb is a factor of 1.39(11) larger than the ^{128}Sn core, which is in stark contrast to the expectations of the empirically successful particle-core coupling scheme. Shell-model calculations performed with two different sets of nucleon-nucleon interactions suggest that this enhanced collectivity is due to constructive quadrupole coherence in the wave functions stemming from the proton-neutron residual interactions, where adding one nucleon to a core near a double-shell closure can have a pronounced effect. The enhanced electric quadrupole strength is an early signal of the emerging nuclear collectivity that becomes dominant away from the shell closure.

Constraint of the astrophysical ^{26g}Al(p,γ)^{27}Si destruction rate at stellar temperatures

The Galactic 1.809-MeV γ-ray signature from the β decay of ^{26g}Al is a dominant target of γ-ray astronomy, of which a significant component is understood to originate from massive stars. The ^{26g}Al(p,γ)^{27}Si reaction is a major destruction pathway for ^{26g}Al at stellar temperatures, but the reaction rate is poorly constrained due to uncertainties in the strengths of low-lying resonances in ^{27}Si. The ^{26g}Al(d,p)^{27}Al reaction has been employed in inverse kinematics to determine the spectroscopic factors, and hence resonance strengths, of proton resonances in ^{27}Si via mirror symmetry. The strength of the 127-keV resonance is found to be a factor of 4 higher than the previously adopted upper limit, and the upper limit for the 68-keV resonance has been reduced by an order of magnitude, considerably constraining the ^{26g}Al destruction rate at stellar temperatures.

Seasonal variation and source apportionment of organic tracers in PM10 in Chengdu, China

Organic compound tracers including n-alkanes, triterpane, sterane, polycyclic aromatic hydrocarbons (PAHs) and dicarboxylic acids of airborne particulate matter (PM10) were characterized for samples collected at five sites from July 2010 to March 2011 using GC/MS. Spatial and temporal variations of these organic tracers in PM10 were studied, and their sources were then identified respectively. Average daily concentrations of PM10 varied in different seasons with the trend of PM10 in winter (0.133 mg/m(3)) > autumn (0.120 mg/m(3)) > spring (0.103 mg/m(3)) > summer (0.098 mg/m(3)). Daily concentrations of n-alkanes (C11-C36) ranged from 12.11 to 163.58 ng/m(3) with a mean of 61.99 ng/m(3). The C max and CPI index of n-alkanes indicated that vehicle emissions were the major source in winter, while the contributions of high plant wax emissions became significant in other seasons. It was discovered that the main sources of triterpenoid and steranes were gasoline and diesel engine emissions. Concentrations of ∑15PAHs in PM10 also varied (12.25-58.56 ng/m(3)) in different seasons, and chrysene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(ghi) perylene and fluoranthene were the dominant components. In the four seasons, the concentration of ∑15PAHs was relatively higher at the northern site because of traffic congestion. The main source of airborne PAHs was traffic emissions and coal combustion. Average daily concentrations of dicarboxylic acids (C4-C10) in PM10 ranged from 12.11 to 163.58 ng/m(3), of which azeleic acid was the major compound (0.49-52.04 ng/m(3), average 14.93 ng/m(3)), followed by succinic acid (0.56-19.08 ng/m(3), average 6.84 ng/m(3)). The ratio of C6/C9 showed that the major source in winter was biological, while the contributions of emissions from anthropogenic activities were much higher in summer.

Double-magic nature of 132Sn and 208Pb through lifetime and cross-section measurements

Single-neutron states in (133)Sn and (209)Pb, which are analogous to single-electron states outside of closed atomic shells in alkali metals, were populated by the ((9)Be, (8)Be) one-neutron transfer reaction in inverse kinematics using particle-γ coincidence spectroscopy. In addition, the s(1/2) single-neutron hole-state candidate in (131)Sn was populated by ((9)Be, (10)Be). Doubly closed-shell (132)Sn (radioactive) and (208)Pb (stable) beams were used at sub-Coulomb barrier energies of 3 MeV per nucleon. Level energies, γ-ray transitions, absolute cross sections, spectroscopic factors, asymptotic normalization coefficients, and excited-state lifetimes are reported and compared with shell-model expectations. The results include a new transition and precise level energy for the 3p(1/2) candidate in (133)Sn, new absolute cross sections for the 1h(9/2) candidate in (133)Sn and 3s(1/2) candidate in (131)Sn, and new lifetimes for excited states in (133)Sn and (209)Pb. This is the first report on excited-state lifetimes of (133)Sn, which allow for a unique test of the nuclear shell model and (132)Sn double-shell closure.

Neutron single particle structure in 131Sn and direct neutron capture cross sections

Recent calculations suggest that the rate of neutron capture by (130)Sn has a significant impact on late-time nucleosynthesis in the r process. Direct capture into low-lying bound states is expected to be significant in neutron capture near the N=82 closed shell, so r-process reaction rates may be strongly impacted by the properties of neutron single particle states in this region. In order to investigate these properties, the (d,p) reaction has been studied in inverse kinematics using a 630 MeV beam of (130)Sn (4.8 MeV/u) and a (CD(2))(n) target. An array of Si strip detectors, including the Silicon Detector Array and an early implementation of the Oak Ridge Rutgers University Barrel Array, was used to detect reaction products. Results for the (130)Sn(d, p)(131)Sn reaction are found to be very similar to those from the previously reported (132)Sn(d, p)(133)Sn reaction. Direct-semidirect (n,γ) cross section calculations, based for the first time on experimental data, are presented. The uncertainties in these cross sections are thus reduced by orders of magnitude from previous estimates.

Halo nucleus 11Be: a spectroscopic study via neutron transfer

The best examples of halo nuclei, exotic systems with a diffuse nuclear cloud surrounding a tightly bound core, are found in the light, neutron-rich region, where the halo neutrons experience only weak binding and a weak, or no, potential barrier. Modern direct-reaction measurement techniques provide powerful probes of the structure of exotic nuclei. Despite more than four decades of these studies on the benchmark one-neutron halo nucleus 11Be, the spectroscopic factors for the two bound states remain poorly constrained. In the present work, the 10Be(d,​p) reaction has been used in inverse kinematics at four beam energies to study the structure of 11Be. The spectroscopic factors extracted using the adiabatic model were found to be consistent across the four measurements and were largely insensitive to the optical potential used. The extracted spectroscopic factor for a neutron in an nℓj=2s(1/2) state coupled to the ground state of 10Be is 0.71(5). For the first excited state at 0.32 MeV, a spectroscopic factor of 0.62(4) is found for the halo neutron in a 1p(1/2) state.

Near-barrier fusion of Sn + Ni and Te + Ni systems: examining the correlation between nucleon transfer and fusion enhancement

The fusion excitation functions for radioactive (132)Sn + (58)Ni and stable (130)Te + (58,64)Ni were measured at energies near the Coulomb barrier. The coupling of transfer channels in heavy-ion fusion was examined through a comparison of Sn + Ni and Te + Ni systems, which have large variations in the number of positive Q-value nucleon transfer channels. In contrast with previous experimental comparisons, where increased sub-barrier fusion cross sections were observed in systems with positive Q-value neutron transfer channels, the reduced excitation functions were equivalent for the different Sn + Ni and Te + Ni systems. The present results suggest a dramatically different influence of positive Q-value transfer channels on the fusion process for the Sn + Ni and Te + Ni systems.

Improved gene expression using low molecular weight peptides produced from protamine sulfate

DNA condensation plays a key role in non-viral gene delivery by affecting gene transfection, nuclear targeting, and eventual gene expression efficiency. Theoretically, a DNA condenser with the appropriate DNA condensation ability but without affecting DNA dissociation from DNA condensates inside the cytoplasm should be a perfect carrier for gene delivery. Protamine is a natural DNA condensation agent and has been widely used in gene delivery. In this work, protamine was selectively digested enzymatically to produce low molecular weight protamine fragments (LMWPs) of various lengths and amino acid compositions. The DNA condensation ability and gene transfection efficiency of these LMWP peptides were tested. Compared to protamine, all the LMWP peptides showed lower DNA binding strength. However, some LMWP peptides demonstrated excellent DNA condensation ability and could form very compact DNA condensates with small particle size (approximately 100 nm). More interestingly, LMWP peptide-mediated in vitro gene delivery showed prolonged (up to 12 days) gene expression. Results from this study suggest that designing DNA condensers with appropriate and tunable DNA binding strengths and condensation abilities would be an effective means to improve gene expression and thus gene therapy efficiency. Since LMWP peptides have low immunogenicity, they would be safer than protamine for use in gene therapies.

Enhanced fusion-evaporation cross sections in neutron-rich 132Sn on 64Ni

Evaporation residue cross sections have been measured with neutron-rich radioactive 132Sn beams on 64Ni in the vicinity of the Coulomb barrier. The average beam intensity was 2 x 10(4) particles per second and the smallest cross section measured was less than 5 mb. Large sub-barrier fusion enhancement was observed. Coupled-channel calculations taking into account inelastic excitation significantly underpredict the measured cross sections below the barrier. The presence of several neutron transfer channels with large positive Q values suggests that multinucleon transfer may play an important role in enhancing the fusion of 132Sn and 64Ni.

A less toxic heparin antagonist--low molecular weight protamine

A new thirteen amino acid peptide, named low molecular weight protamine (LMWP), was obtained through the enzymatic digestion of native protamine. Both in vitro and in vivo results showed that LMWP fully maintained the heparin neutralization function of protamine but had much lower immunogenicity and antigenicity. Unlike protamine, neither LMWP nor LMWP/heparin complexes caused significant blood platelet aggregation in rats. These results suggest that LMWP can be used as a substitute for protamine for developing a new generation of nontoxic heparin antagonists.

ATTEMPTS: a heparin/protamine-based delivery system for enzyme drugs

A prodrug delivery system termed "Antibody Targeted, Triggered, Electrically Modified Prodrug-Type Strategy (ATTEMPTS)" has been developed to permit the antibody-directed administration of inactive enzyme drug including tissue-type plasminogen activator (tPA), and allow a subsequent triggered release of the active tPA at the target site. Cation-modified tPA (mtPA) was attached to a heparin-antifibrin complex via ionic interaction, and the active tPA can subsequently be released by the addition of protamine, a competitive heparin inhibitor. Anti-fibrin IgG was conjugated to heparin via an end-point attachment to form the heparin-antifibrin complex which provides the targeting efficiency of the final heparin/mtPA complex. Cation modification was performed by either chemical conjugation by linking (Arg)7Cys to tPA with N-succinimidy-3-(2-pyridyldithio) propionate or by recombinant DNA methods. Results show that the modification process did not significantly alter the specific activity of tPA with regard to plasminogen activation, fibrin-binding ability, and response toward fibrinogen. The complexes of both modified tPA-heparin did not yield any intrinsic catalytic activity owing to the blockage of the active site of tPA by the attached heparin. On the other hand, heparin-induced inhibition of modified tPA activity was reversed by adding protamine, which is similar to that of a prodrug delivery system. These results suggest that heparin/protamine-based enzyme delivery systems may be a useful tool to improve current enzyme therapeutic status, as well as thrombolytic therapy, by both regulating the release of active enzyme and aborting the associated systemic toxic effect. Currently, modification of enzyme drugs has been optimized by recombinant DNA technology assisted by computer simulation. In addition, the original strategy has been revised to obtain enhanced therapeutic efficacy.

ATTEMPTS: a heparin/protamine-based prodrug approach for delivery of thrombolytic drugs

The aim of this study is to develop a heparin/protamine-based prodrug system for the controlled delivery of enzyme such as tissue-type plasminogen activator (tPA). This approach, termed antibody targeted, triggered, electrically modified prodrug-type strategy (ATTEMPTS), would permit antibody-directed administration of inactive tPA, and allow a subsequent triggered release of the active tPA at the target site. Cation-modified tPA (mtPA) was attached to a heparin--antifibrin complex via ionic interaction. The active tPA can be subsequently released by the addition of protamine, a competitive heparin inhibitor. Anti-fibrin IgG was conjugated to heparin via an end-point attachment to form the heparin--antifibrin--complex which provides the targeting efficiency of the final heparin--mtPA complex. Cation-modification was performed either by chemical conjugation by linking (Arg)(7)Cys to tPA with N-succinimidy-3-(2-pyridyldithio) propionate or by recombinant DNA method. Results show that the chemical modification process did not significantly alter specific activity of tPA with regard to plasminogen activation, fibrin-binding ability, and response toward fibrinogen. Expressed modified tPA (EmtPA) produced by recombinant DNA methods retained the same catalytic activity of the parent tPA, as well as a dynamic catalytic behavior depending upon the presence of heparin and protamine. Both types of modified tPA, especially the mtPA demonstrated a significantly higher affinity toward heparin or heparin--antifibrin complex than native tPA. In addition, the complexes of mtPA--heparin did not yield any intrinsic clot lysis activity owing to the blockage of the active site of tPA by attached heparin. On the other hand, heparin-induced inhibition of both mtPA and EmtPA activity was reversed by adding protamine, as confirmed by chromogenic and in vitro clot lysis assays. These results suggested that a heparin/protamine-based tPA delivery system may be a useful tool to improve current thrombolytic therapeutic status, by both precisely regulating the release of active tPA and aborting the associated bleeding risk. Alternatively, this ATTEMPTS approach could also be used to deliver enzyme drugs while diminishing their associated toxic effects.

Decay of a Resonance in 18Ne by the Simultaneous Emission of Two Protons

Radioactive ion beams of 17F were used to study several resonance states in 18Ne. Clear evidence for simultaneous two-proton emission from the 6.15 MeV state (Jpi = 1(-)) in 18Ne has been observed with the reaction 17F+1H. Because of limited angular coverage, the data did not differentiate between the two possible mechanisms of simultaneous decay, diproton (2He) emission or direct three-body decay. The two-proton partial width was found to be 21+/-3 eV assuming 2He emission and 57+/-6 eV assuming three-body decay. The total width of the 1(-) state was measured to be 50+/-5 keV. Several additional resonances that decay by single proton emission were also studied.

Titration study of MUSE (Medicated Urethral System for Erection) in erectile dysfunction

PURPOSE

We assessed the erectile responses and adverse reactions to prostaglandin E1 delivered via the medicated urethral system for erection (MUSE) in a titration study to determine optimal dose.

METHODS

Sixty-four patients with erectile dysfunction underwent in-office testing with MUSE to determine erectile response. Following thorough instructions, patients were taught how to use MUSE themselves. The titration study started with a dose of 125 micrograms, and increased to 250 micrograms, 500 micrograms, and finally 1,000 micrograms. In patients who had an erectile response, erection scoring, color duplex Doppler study, blood pressure monitoring, recording of subjective complaints, and repeated laboratory examinations were performed to evaluate the positive and adverse effects of MUSE.

RESULTS

Forty-three of the 64 patients achieved a maximal erection with MUSE, as shown by systolic peak flow velocities in the deep penile arteries of greater than 27 cm/s on Doppler ultrasonography. One patient was unsatisfied with his erectile response and dropped out of the study. Of the 42 patients who completed the study, most (35) were satisfied with the response achieved at the higher doses of 500 micrograms and 1,000 micrograms. A modified soft rubber band was needed to achieve a satisfactory erectile response in 18 patients. Only four patients experienced serious urethral burning during MUSE application.

CONCLUSIONS

MUSE was effective and safe in most patients with erectile dysfunction in this study. For patients not satisfied with the extent of penile rigidity achieved with MUSE, the use of a modified soft rubber band for erectile assistance, as well as a program for improved patient education, may help to achieve a better erectile response and facilitate compliance with treatment regimens at home.

A prodrug approach for delivery of t-PA: construction of the cationic t-PA prodrug by a recombinant method and preliminary in vitro evaluation of the construct

Previously, we reported a novel prodrug approach, that could lead to targeted thrombolysis without the risk of bleeding. The approach consists of a protein conjugate made of two components: a fibrin targeting antibody (Ab) linked to an anionic heparin, and a plasminogen activator (PA) derivatized with cationic species. These two components are linked by means of an electrostatic interaction. Because the cationic species are small, the modified PA would retain its thrombolytic activity. However, this activity would be inhibited after binding to the counterpart due to the blockage of the PA active site by the appended macromolecules. Because protamine is a clinical antagonist to heparin, it can be used in humans to dissociate the modified PA from its counterpart. Thus, the approach would permit the administration of a fibrin targeting but inactive thrombolytic drug (thereby alleviating the bleeding risk by avoiding systemic generation of plasmin), and subsequently a triggered release of the active drug to the fibrin deposit. In our previous work, we demonstrated the feasibility of the approach by producing a positively charged PA by means of chemical conjugation of a cationic CRRRRRRR peptide with urokinase. In this study, we further extended our work and produced a similar cationic t-PA by means of a recombinant DNA approach; i.e., by fusion of a poly(Arg)7 peptide to the kringle-1 domain of t-PA. Results obtained from the restriction enzyme analysis and the Western blot yielded full identification of this recombinant protein. This recombinant poly(Arg)7-modified-t-PA protein conjugate (termed "rmt-PA" hereafter) completely retained the fibrinolytic activity of the original recombinant, unmodified t-PA (termed "rt-PA" hereafter), as measured by the chromogenic assay and fibrin agar lysis assay. The prodrug and triggered release features of the proposed approach were confirmed by partial inhibition of the plasminogen activating activity of this protein by heparin, and the partial reversal of such inhibition by protamine.

Biomedical application of immobilized enzymes

Reports on chemical immobilization of proteins and enzymes first appeared in the 1960s. Since then, immobilized proteins and enzymes have been widely used in the processing of variety of products and increasingly used in the field of medicine. Here, we present a review of recent developments in immobilized enzyme use in medicine. Generally speaking, the use of immobilized enzyme in medicine can be divided into two major categories: biosensors and bioreactors. A brief overview of the evolution of the biosensor and bioreactor technology, of currently existing applications of immobilized enzymes, of problems that researchers encountered, and of possible future developments will be presented.

A novel approach for delivery of enzyme drugs: preliminary demonstration of feasibility and utility in vitro

A novel heparin/protamine-based approach for delivery of enzyme drugs without associated toxic effects has been proposed. This approach would allow an enzyme drug to be administered in an inactive (i.e. pro-drug) form and then released at the target site in an active form using protamine as the triggering agent. The pro-drug and the triggered release features of this approach would permit the enzyme drug to act specifically and only on its target substrates while sparing normal substrates, thereby alleviating unwanted toxic effects. The in vitro feasibility of the approach has been successfully demonstrated using trypsin as the model protease drug. In addition, the utility of the approach has also been demonstrated by applying the system in delivering streptokinase, one of the most widely used clinical drugs in thrombolytic therapy. This approach may open up the possibility of developing a wide range of new catalytic drugs that are initially thought to be impossible for therapeutic use due to their potent toxic effects.

A novel heparin/protamine-based pro-drug type delivery system for protease drugs

Previously we proposed a heparin/protamine-based system for delivery of protease drugs such as tissue-specific plasminogen activator (tPA). To demonstrate the feasibility of this approach as well as its pro-drug and triggered release features, positively charged peptides [(Arg)(7)Cys] were successfully linked to tissue-specific plasminogen activator (tPA) using the crosslinking agent N-succinimidyl-3-(2-pyridyldithio)- propionate. This cation-modified tPA showed much stronger heparin affinity than the parent tPA. The complex formed by mtPA and heparin was stable in human plasma, and the activity of mtPA in such a complex was inhibited by the appended heparin. Similarly, the activity of mtPA could also be inhibited by a heparin-antifibrin IgG conjugate in which heparin was linked, via endpoint attachment, to the sugar moieties in the F(c) region of anti-fibrin IgG. Aside from this pro-drug feature exhibited by the binding of the macromolecule heparin to mtPA, results from chromogenic and in vitro clot lysis assay demonstrated that the heparin-induced inhibition of the mtPA activity could be easily reversed by the addition of an adequate amount of protamine. These findings suggest the applicability of the heparin/protamine delivery system to abort the potential bleeding risks associated with clinical use of tPA. In addition to the chemical conjugation method, modified tPA could also be produced by the recombinant DNA method. The expressed modified tPA (EmtPA) thus prepared retained the full catalytic activity of the parent tPA, and this activity could also be inhibited by heparin, and the heparin-induced inhibition could be reversed following the addition of protamine.

The potential mechanism for the effect of heparin on tissue plasminogen activator-mediated plasminogen activation

The effects and possible role of heparin on tissue plasminogen activator-mediated plasminogen activation was thoroughly investigated. Direct analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated that heparin increased the conversion of plasminogen to plasmin. Experiments by fluorescence quenching suggested that the stimulation of tissue plasminogen activator activity probably was due to a direct binding of heparin to tissue plasminogen activator, causing a conformational change of tissue plasminogen activator and rendering it more accessible to plasminogen interaction. The absence of additive stimulation effects on tissue plasminogen activator-mediated plasminogen activation when both heparin and fibrinogen were present also implied that both compounds interacted with tissue plasminogen activator via the same domain; it appeared to be most likely via the kringle-2 domain in tissue plasminogen activator based on studies using epsilon-aminocaproic acid as an inhibitor. Unlike heparin-induced stimulation of antithrombin-thrombin interaction, the heparin-induced stimulation of tissue plasminogen activator did not seem to follow a template model. Only in the presence of a high plasminogen or a low tissue plasminogen activator concentration, massive stimulation of tissue plasminogen activator activity was observed via a pseudotemplate model. The results suggest that precautions concerning high heparin dose should be given during its conjunctive clinical use with tissue plasminogen activator in thrombolytic therapy to reduce the risk of hemorrhage.

Inhibition of nitric oxide synthesis in primary cultured mouse hepatocytes by alpha-lipoic acid

Recent work shows that septic or endotoxic shock is associated with lipopolysaccharide and cytokine mixture-induced nitric oxide (NO) synthesis in liver. Here we found that DL-alpha-lipoic acid inhibited but other thiol-containing antioxidants such as glutathione and N-acetylcysteine enhanced lipopolysaccharide and cytokine mixture (referred as LPS/CM)-induced NO synthesis in hepatocytes. The inhibitory action of alpha-lipoic acid on hepatocyte NO synthesis was as potent as that of NG-monomethyl-L-arginine without obvious cytotoxicity. Deletion by diethylmaleate or inhibition by buthionine sulfoximine of intracellular glutathione caused a significant decrease in hepatocyte NO synthesis, implying that increased intracellular reduced glutathione levels could not be the reason for alpha-lipoic acid inhibited NO synthesis. alpha-Lipoic acid inhibition of NO synthesis seems to be from alpha-lipoic acid improved carbohydrate metabolism in hepatocytes. Since alpha-lipoic acid is an essential compound existing naturally in physiological systems, it may serve as both a research and therapeutic agent for sepsis.

Not only the nature of peptide but also the characteristics of cell membrane determine the antimicrobial mechanism of a peptide

The mechanisms of antimicrobial actions of magainin 2, buforin II and poly L-lysine against various Escherichia coli strains were studied. Poly L-lysine inhibited BL21, AD 434 and GroE+/DnaK+ growth without lysing the cell. Magainin 2 had a pore-forming activity on BL 21 and AD 434 membrane but could not inhibit the GroE+/DnaK+ growth in a nutrient-rich medium. Buforin II, which killed BL21 and AD 434 without cell membrane damage, lysed GroE+/DnaK+ to death. Once they were introduced into the cell by electroporation, all three peptides were able to inhibit cell growth at concentrations of 10 times lower than their MICs. These results indicate that the nature of the peptide and also the characteristics of the cell membrane determine the antimicrobial actions of a peptide.

Mitogenic-factor-dependent regulation of lipopolysaccharide and cytokine mixture-mediated hepatocyte nitric oxide synthesis in vitro

Hepatocellular mitogen (HGF and EGF) inhibited lipopolysaccharide and cytokine mixture (referred as LPS/CM)-induced NO synthesis and cellular injury in hepatocytes. Mitogenic inhibitors such as hydroxyurea and Wortmannin could not reverse EGF or HGF-inhibited NO production, whereas both of them showed some inhibitory effect on hepatocyte NO synthesis. Although activation of protein kinase C (PKC) by phorbol 12-myristate 13-acetate (PMA) had no effect on hepatocyte NO synthesis, deletion of PKC activity by long-term treatment of hepatocytes with PMA abolished LPS/CM-induced NO production. In addition, pretreatment of hepatocytes with HGF and EGF also blocked LPS/CM-induced NO synthesis in the hepatocyte. These results suggest that proliferating signal is not directly involved in mitogen-inhibited NO synthesis in the hepatocyte, and LPS/CM-mediated NO synthesis is associated with the metabolic/redox state of hepatocytes.

Protective effect of linoleic acid on IFN gamma-induced cellular injury in primary culture hepatocytes

We have previously demonstrated that treatment of hepatocytes with IFN gamma results a series of cellular injury processes, including DNA synthesis arrest, membrane breakage and apoptosis. In the present work, we show that IFN gamma suppresses cellular respiration and protein synthesis in hepatocytes, and that cellular respiration suppression is an early event in the IFN gamma-induced cellular injuries. Polyunsaturated fatty acids (PUFAs) increased cellular respiration of hepatocytes, but only linoleic acid showed some protective effect against IFN gamma-induced cellular respiration suppression. Linoleic acid also reduced other IFN gamma-mediated cellular injuries, including membrane breakage and protein synthesis inhibition. Like linoleic acid, fetal bovine serum also inhibited IFN gamma-induced cellular damage. Increased NAD levels were found in both IFN gamma-treated and non-treated hepatocytes following the addition of PUFAs, but clofibrate, a peroxisome proliferator, bromophenacyl bromide (BPB), an inhibitor of phospholipase, nordihydroguaiaretic acid (NDGA), an inhibitor of lipoxygenase, and arachidonic acid, a metabolite of linoleic acid, did not inhibit IFN gamma-induced cellular injury. In addition, the combination of linoleic acid and IFN gamma induced nitric oxide (NO) synthesis in hepatocytes. These results suggest that fatty acid may play an important role in liver homeostasis during chronic inflammatory states and sepsis.

Nitric oxide is not involved in lipopolysaccharide and cytokine mixture-induced cellular injuries in primary cultured hepatocytes

Nitric oxide (NO) from artificial NO donors induces cell death through complete inhibition of mitochondrial respiration of hepatocytes. Treatment of hepatocytes with lipopolysaccharide (LPS) and cytokine mixture (interferon gamma and tumor necrosis factor alpha) not only results in NO production but also causes cellular respiration suppression and cell death in hepatocytes. NG-monomethyl-L-arginine, a specific inhibitor of nitric oxide synthase, inhibits hepatocyte NO synthesis but cannot prevent hepatocytes from LPS and cytokine mixture-induced cellular injuries. Similarly, some metabolic intermediates capable of inhibiting hepatocyte NO synthesis cannot block LPS and cytokine mixture-mediated cellular injuries in hepatocytes. These results imply that lipopolysaccharide and cytokine mixture-induced cellular injuries and NO syntheses are parallel events, NO is not involved in LPS and cytokine mixture-induced cell damage.

Inhibition of lipopolysaccharide and cytokine mixture-mediated hepatocyte nitric oxide synthesis by dimethyl sulfoxide

Treatment and pretreatment of hepatocytes with 2% dimethyl sulfoxide (DMSO) inhibited lipopolysaccharide and cytokine mixture (LPS/CM)-mediated NO synthesis in hepatocytes without any obvious effects on cell viability. DMSO at concentrations of 0.5-4% stimulated DNA replication and increased albumin secretion in LPS/CM-treated hepatocytes. Genisein, a inhibitor of protein tyrosine kinase (PTK), inhibited LPS/CM-mediated NO synthesis in hepatocytes. These results suggest that PTK is critical for hepatocyte NO synthesis, and DMSO-inhibited NO synthesis may be associated with prevention of LPS/CM-induced PTK activation in hepatocytes.

Role of metabolic intermediates in lipopolysaccharide/cytokine-mediated production of nitric oxide in isolated mouse hepatocytes

Induction of nitric oxide synthase by bacterial endotoxin in vivo can be mimicked by treating cultured hepatocytes with a combination of lipopolysaccharide and cytokines (LPS/cytokines), but the role of LPS/cytokine-induced nitric oxide in hepatocyte glucose metabolism is ambiguous. In this study, intermediary metabolite effects on LPS/cytokine-induced hepatocyte nitric oxide synthesis were examined. Pyruvate, lactate, oxaloacetate, and fumarate all showed some inhibitory effects on hepatocyte nitric oxide synthesis. However, these metabolic intermediates could not improve the mitochondrial respiration of LPS/cytokine-treated hepatocytes. Phosphoenolpyruvate carboxykinase activity (or flux) relating factors, glucocorticoids and cAMP, also blocked LPS/cytokine-induced nitric oxide synthesis. Insulin was much less potent than cAMP and glucocorticoids, and phorbol ester did not show any effect on hepatocyte nitric oxide synthesis. These results suggest that LPS/cytokine-induced nitric oxide synthesis is related, at least partly, to phosphoenolpyruvate carboxykinase activity (or flux) in hepatocytes.