Dynamic three-dimensional structures of a metal-organic framework captured with femtosecond serial crystallography

Crystalline systems consisting of small-molecule building blocks have emerged as promising materials with diverse applications. It is of great importance to characterize not only their static structures but also the conversion of their structures in response to external stimuli. Femtosecond time-resolved crystallography has the potential to probe the real-time dynamics of structural transitions, but, thus far, this has not been realized for chemical reactions in non-biological crystals. In this study, we applied time-resolved serial femtosecond crystallography (TR-SFX), a powerful technique for visualizing protein structural dynamics, to a metal-organic framework, consisting of Fe porphyrins and hexazirconium nodes, and elucidated its structural dynamics. The time-resolved electron density maps derived from the TR-SFX data unveil trifurcating structural pathways: coherent oscillatory movements of Zr and Fe atoms, a transient structure with the Fe porphyrins and Zr6 nodes undergoing doming and disordering movements, respectively, and a vibrationally hot structure with isotropic structural disorder. These findings demonstrate the feasibility of using TR-SFX to study chemical systems.

Length and Charge of the N-terminus Regulate the Lifetime of the Signaling State of Photoactive Yellow Protein

Photoactive yellow protein (PYP) is one of the most extensively studied photoreceptors. Nevertheless, the role of the N-terminus in the photocycle and structural transitions is still elusive. Here, we attached additional amino acids to the N-terminus of PYP and investigated the effect of the length and charge of additional N-terminal residues using circular dichroism, two-dimensional nuclear magnetic resonance (2D-NMR), transient absorption (TA), and transient grating (TG) spectroscopic techniques. TA experiments showed that, except for negatively charged residues (5D-PYP), additional N-terminal residues of PYP generally enable faster dark recovery from the putative signaling state (pB2) to the ground state (pG). TG data showed that although the degree of structural changes can be controlled by adjusting specific amino acid residues in the extended N-terminus of N-terminal extended PYPs (NE-PYPs), the dark recovery times of wt-PYP and NE-PYPs, except for 5D-PYP, are independent of the structural differences between pG and pB2 states. These results demonstrate that the recovery time and the degree of structural change can be regulated by controlling the length and sequence of N-terminal residues of PYP. The findings in this study emphasize the need for careful attention to the remaining amino acid residues when designing recombinant proteins for genetic engineering purposes.

Visualizing Heterogeneous Protein Conformations with Multi-Tilt Nanoparticle-Aided Cryo-Electron Microscopy Sampling

Obtaining the heterogeneous conformation of small proteins is important for understanding their biological role, but it is still challenging. Here, we developed a multi-tilt nanoparticle-aided cryo-electron microscopy sampling (MT-NACS) technique that enables the observation of heterogeneous conformations of small proteins and applied it to calmodulin. By imaging the proteins labeled by two gold nanoparticles at multiple tilt angles and analyzing the projected positions of the nanoparticles, the distributions of 3D interparticle distances were obtained. From the measured distance distributions, the conformational changes associated with Ca²⁺ binding and salt concentration were determined. MT-NACS was also used to track the structural change accompanied by the interaction between amyloid-beta and calmodulin, which has never been observed experimentally. This work offers an alternative platform for studying the functional flexibility of small proteins.

Sample-minimizing co-flow cell for time-resolved pump-probe X-ray solution scattering

A fundamental problem in biological sciences is understanding how macromolecular machines work and how the structural changes of a molecule are connected to its function. Time-resolved techniques are vital in this regard and essential for understanding the structural dynamics of biomolecules. Time-resolved small- and wide-angle X-ray solution scattering has the capability to provide a multitude of information about the kinetics and global structural changes of molecules under their physiological conditions. However, standard protocols for such time-resolved measurements often require significant amounts of sample, which frequently render time-resolved measurements impossible. A cytometry-type sheath co-flow cell, developed at the BioCARS 14-ID beamline at the Advanced Photon Source, USA, allows time-resolved pump-probe X-ray solution scattering measurements to be conducted with sample consumption reduced by more than ten times compared with standard sample cells and protocols. The comparative capabilities of the standard and co-flow experimental setups were demonstrated by studying time-resolved signals in photoactive yellow protein.

Ultrafast coherent motion and helix rearrangement of homodimeric hemoglobin visualized with femtosecond X-ray solution scattering

Ultrafast motion of molecules, particularly the coherent motion, has been intensively investigated as a key factor guiding the reaction pathways. Recently, X-ray free-electron lasers (XFELs) have been utilized to elucidate the ultrafast motion of molecules. However, the studies on proteins using XFELs have been typically limited to the crystalline phase, and proteins in solution have rarely been investigated. Here we applied femtosecond time-resolved X-ray solution scattering (fs-TRXSS) and a structure refinement method to visualize the ultrafast motion of a protein. We succeeded in revealing detailed ultrafast structural changes of homodimeric hemoglobin involving the coherent motion. In addition to the motion of the protein itself, the time-dependent change of electron density of the hydration shell was tracked. Besides, the analysis on the fs-TRXSS data of myoglobin allows for observing the effect of the oligomeric state on the ultrafast coherent motion.

Femtosecond time-resolved X-ray solution scattering (fs-TRXSS) measurements provide information on the structural dynamics of proteins in solution. Here, the authors present a structure refinement method for the analysis of fs-TRXSS data and use it to characterise the ultrafast structural changes of homodimeric haemoglobin.

Effect of the abolition of intersubunit salt bridges on allosteric protein structural dynamics

A salt bridge, one of the representative structural factors established by non-covalent interactions, plays a crucial role in stabilizing the structure and regulating the protein function, but its role in dynamic processes has been elusive. Here, to scrutinize the structural and functional roles of the salt bridge in the process of performing the protein function, we investigated the effects of salt bridges on the allosteric structural transition of homodimeric hemoglobin (HbI) by applying time-resolved X-ray solution scattering (TRXSS) to the K30D mutant, in which the interfacial salt bridges of the wild type (WT) are abolished. The TRXSS data of K30D are consistent with the kinetic model that requires one monomer intermediate in addition to three structurally distinct dimer intermediates (I₁, I₂, and I₃) observed in WT and other mutants. The kinetic and structural analyses show that K30D has an accelerated biphasic transition from I₂ to I₃ by more than nine times compared to WT and lacks significant structural changes in the transition from R-like I₂ to T-like I₃ observed in WT, unveiling that the loss of the salt bridges interrupts the R–T allosteric transition of HbI. Besides, the correlation between the bimolecular CO recombination rates in K30D, WT, and other mutants reveals that the bimolecular CO recombination is abnormally decelerated in K30D, indicating that the salt bridges also affect the cooperative ligand binding in HbI. These comparisons of the structural dynamics and kinetics of K30D and WT show that the interfacial salt bridges not only assist the physical connection of two subunits but also play a critical role in the global structural signal transduction of one subunit to the other subunit via a series of well-organized structural transitions.

The structural and functional roles of salt bridges in the allosteric structural transition of homodimeric hemoglobin are investigated by time-resolved X-ray solution scattering.

Distinctive patterns of pulmonary function change according to baseline lung volume and diffusing capacity

SETTING: Multicentre retrospective study in South Korea.OBJECTIVE: To longitudinally evaluate changes in lung volume and diffusing capacity for carbon monoxide (DLCO) with forced expiratory volume in 1 sec (FEV₁).DESIGN: A total of 155 patients with chronic obstructive pulmonary disease (COPD), whose pulmonary function parameters were measured annually for 5 years, were selected from a prospective cohort in South Korea. A random coefficients model was used to estimate mean annual FEV₁, lung volume parameter and DLCO change rates.RESULTS: Patients were classified into four groups based on baseline DLCO and residual volume/total lung capacity (RV/TLC) measurements. The annual FEV₁ decline rate was greater in patients with low DLCO than in those with normal DLCO, with the greatest decline occurring in patients with low DLCO and normal RV/TLC. RV and RV/TLC declined in patients with high RV/TLC, whereas these increased in patients with normal RV/TLC. DLCO decreased longitudinally in all four groups, with the greatest decline occurring in patients with normal DLCO and normal RV/TLC.CONCLUSIONS: Different subgroups of patients with COPD exhibited distinctive pulmonary function change patterns. Baseline DLCO and RV/TLC may be used as physiological markers to predict long-term changes in pulmonary function.

A Scoring System for Prediction of Cervical Lymph Node Metastasis in Patients with Head and Neck Squamous Cell Carcinoma

BACKGROUND AND PURPOSE

An accurate and comprehensive assessment of lymph node metastasis in patients with head and neck squamous cell cancer is crucial in daily practice. This study constructed a predictive model with a risk scoring system based on CT characteristics of lymph nodes and tumors for patients with head and neck squamous cell carcinoma to stratify the risk of lymph node metastasis.

MATERIALS AND METHODS

Data included 476 cervical lymph nodes from 191 patients with head and neck squamous cell carcinoma from a historical cohort. We analyzed preoperative CT images of lymph nodes, including diameter, ratio of long-to-short axis diameter, necrosis, conglomeration, infiltration to adjacent soft tissue, laterality and T-stage of the primary tumor. The reference standard comprised pathologic results. Multivariable logistic regression analysis was performed to develop the risk scoring system. Internal validation was performed with 1000-iteration bootstrapping.

RESULTS

Shortest axial diameter, ratio of long-to-short axis diameter, necrosis, and T-stage were used to develop a 9-point risk scoring system. The risk of malignancy ranged from 7.3% to 99.8%, which was positively associated with increased scores. Areas under the curve of the risk scoring systems were 0.886 (95% CI, 0.881-0.920) and 0.879 (95% CI, 0.845-0.914) in internal validation. The Hosmer-Lemeshow goodness-of-fit test indicated that the risk scoring system was well-calibrated (P = .160).

CONCLUSIONS

We developed a comprehensive and simple risk scoring system using CT characteristics in patients with head and neck squamous cell carcinoma to stratify the risk of lymph node metastasis. It could facilitate decision-making in daily practice.

Chromophore-Removal-Induced Conformational Change in Photoactive Yellow Protein Determined through Spectroscopic and X-ray Solution Scattering Studies

Photoactive yellow protein (PYP) induces negative phototaxis in Halorhodospira halophila via photoactivation triggered by light-mediated chromophore isomerization. Chromophore isomerization proceeds via a volume-conserving isomerization mechanism due to the hydrogen-bond network and steric constraints inside the protein, and causes significant conformational changes accompanied by N-terminal protrusion. However, it is unclear how the structural change of the chromophore affects the remote N-terminal domain. To understand photocycle-related structural changes, we investigated the structural aspect of chromophore removal in PYP because it possesses a disrupted hydrogen-bond network similar to that in photocycle intermediates. A comparison of the structural aspects with those observed in the photocycle would give a clue related to the structural change mechanism in the photocycle_. Chromophore removal effects were assessed via UV-vis spectroscopy, circular dichroism, and X-ray solution scattering. Molecular shape reconstruction and an experiment-restrained rigid-body molecular dynamics simulation based on the scattering data were performed to determine protein shape, size, and conformational changes upon PYP bleaching. Data show that chromophore removal disrupted the holo-PYP structure, resulting in a small N-terminal protrusion, but the extent of conformational changes was markedly less than those in the photocycle. This indicates that disruption of the hydrogen-bond network alone in bleached PYP does not induce the large conformational change observed in the photocycle, which thus must result from the organized structural transition around the chromophore triggered by chromophore photoisomerization along with disruption of the hydrogen-bond network between the chromophore and the PYP core.

Photocycle of Photoactive Yellow Protein in Cell-Mimetic Environments: Molecular Volume Changes and Kinetics

Using various spectroscopic techniques such as UV-visible spectroscopy, circular dichroism spectroscopy, NMR spectroscopy, small-angle X-ray scattering, transient grating, and transient absorption techniques, we investigated how cell-mimetic environments made by crowding influence the photocycle of photoactive yellow protein (PYP) in terms of the molecular volume change and kinetics. Upon addition of molecular crowding agents, the ratio of the diffusion coefficient of the blue-shifted intermediate (pB) to that of the ground species (pG) significantly changes from 0.92 and approaches 1.0. This result indicates that the molecular volume change accompanied by the photocycle of PYP in molecularly crowded environments is much smaller than that which occurs in vitro and that the pB intermediate under crowded environments favors a compact conformation due to the excluded volume effect. The kinetics of the photocycle of PYP in cell-mimetic environments is greatly decelerated by the dehydration, owing to the interaction between the protein and small crowding agents, but is barely affected by the excluded volume effect. The results lead to the inference that the signaling transducer of PYP may not necessarily utilize the conformational change of PYP to sense the signaling state.

Comparison of Strain in GaN-Based Blue Light-Emitting Diode Grown on Silicon(111) and Sapphire Substrates

We compare the strain states and device performances of GaN-based blue light-emitting diodes (LEDs) grown on Si(111) and sapphire substrates. The strain characteristics are investigated using micro-Raman spectroscopy and high-resolution transmission electron microscopy. These analyses reveal that GaN layer grown on Si has a residual tensile strain in contrast to a compressive strain for GaN on sapphire, and quantum wells (QWs) on GaN/Si experience reduced lattice mismatch than those of GaN/sapphire. When external quantum efficiencies of LED on sapphire and Si substrates are compared, the LED on Si shows better efficiency droop characteristics and this is attributed to a decrease in piezo-electric field strength in InGaN/GaN layers owing to reduced lattice mismatch.

Reconstruction algorithm for nasal basal cell carcinoma with skin involvement only: analysis of 221 cases repaired by minor surgery

BACKGROUND

Basal cell carcinoma (BCC) often occurs on the nose. Reconstruction of the nose should yield excellent aesthetic and functional outcomes.

AIM

We propose a technical algorithm for the reconstruction of surgical defects, based on our analysis of 221 cases of nasal BCC with skin involvement only, which could be repaired by minor surgery.

METHODS

The aesthetic and functional outcomes for various reconstruction techniques were analysed according to defect location and size. A reconstruction algorithm was proposed with the aim of obtaining the best surgical results.

RESULTS

Defect location and size were key considerations. Primary closure was the first option for small defects (< 10 mm), with scores of 3.4 for objective aesthetic outcome (OAO), 3.2 for subjective aesthetic outcome (SAO) and 3.3 for subjective functional outcome (SFO). The first option for medium defects (1-20 mm) was the island pedicle flap, with scores of 3.5 for OAO, 3.2 for SAO and 3.7 for SFO. The first option for large defects (> 20 mm) was the transposition flap for the upper nose (scores of 2.0 for OAO and SAO and 3.0 for SFO) and the interpolation flap for the lower nose (2.8 for OAO and 2.9 for SAO and SFO).

CONCLUSIONS

We have proposed an algorithm to select the optimal technique for repairing nasal BCC surgical defects according to their size and location.

Structural Studies of Potassium Transport Protein KtrA Regulator of Conductance of K+ (RCK) C Domain in Complex with Cyclic Diadenosine Monophosphate (c-di-AMP)

Although it was only recently identified as a second messenger, c-di-AMP was found to have fundamental importance in numerous bacterial functions such as ion transport. The potassium transporter protein, KtrA, was identified as a c-di-AMP receptor. However, the co-crystallization of c-di-AMP with the protein has not been studied. Here, we determined the crystal structure of the KtrA RCK_C domain in complex with c-di-AMP. The c-di-AMP nucleotide, which adopts a U-shaped conformation, is bound at the dimer interface of RCK_C close to helices α3 and α4. c-di-AMP interacts with KtrA RCK_C mainly by forming hydrogen bonds and hydrophobic interactions. c-di-AMP binding induces the contraction of the dimer, bringing the two monomers of KtrA RCK_C into close proximity. The KtrA RCK_C was able to interact with only c-di-AMP, but not with c-di-GMP, 3',3-cGAMP, ATP, and ADP. The structure of the KtrA RCK_C domain and c-di-AMP complex would expand our understanding about the mechanism of inactivation in Ktr transporters governed by c-di-AMP.

The objective evaluation of the severity of psoriatic scales with desquamation collecting tapes and image analysis

BACKGROUND

Assessment of psoriatic scales is important to determine the severity of psoriasis. However, there are very limited numbers of objective, quantitative and observer-independent tools for measuring the severity of psoriasis.

OBJECTIVE

To determine whether the bioengineering parameters of the psoriatic scale can be used to assess the severity of psoriasis instead of the psoriatic severity index of scales (PSIs) score.

METHODS

Thirty-four patients with psoriasis were included. A representative lesion from each patient was selected and bioengineering parameters were measured using the Corneofix(®). Simultaneously, the severity of the scales was assessed by the PSIs score using clinical photographs of the lesions. In addition, skin color and elasticity parameters were also measured using the Colorimeter(®), the Mexameter(®) and the Cutometer(®).

RESULTS

Statistical differences in the scale parameters were observed between the PSIs 2 and 3 scores. Among the scale parameters, the percent area and area in μm(2) were negatively correlated with the PSIs score. In addition, the Colorimeter(®) a, b parameters and the Cutometer(®) R9 parameters were significantly correlated with the PSIs score.

CONCLUSIONS

The results of this study showed that the severity of psoriatic scales could be measured objectively using the Corneofix(®).

Remifentanil protects myocardium through activation of anti-apoptotic pathways of survival in ischemia-reperfused rat heart

Remifentanil is a commonly used opioid in anesthesia with cardioprotective effect in ischemia-reperfused (I/R) heart. We evaluated the influence of remifentanil on myocardial infarct size and expressions of proteins involved in apoptosis in I/R rat heart following various time protocols of remifentanil administration. Artificially ventilated anesthetized Sprague-Dawley rats were subjected to a 30 min of left anterior descending coronary artery occlusion followed by 2 h of reperfusion. Rats were randomly assigned to one of five groups; Sham, I/R only, remifentanil preconditioning, postconditioning and continuous infusion group. Myocardial infarct size, the phosphorylation of ERK1/2, Bcl2, Bax and cytochrome c and the expression of genes influencing Ca2+ homeostasis were assessed. In remifentanil-administered rat hearts, regardless of the timing and duration of administration, infarct size was consistently reduced compared to I/R only rats. Remifentanil improved expression of ERK1/2 and anti-apoptotic protein Bcl2, and expression of sarcoplasmic reticulum genes which were significantly reduced in the I/R rats only. Remifentanil reduced expression of pro-apoptotic protein, Bax and cytochrome c. These suggested that remifentanil produced cardioprotective effect by preserving the expression of proteins involved in anti-apoptotic pathways, and the expression of sarcoplasmic reticulum genes in I/R rat heart, regardless of the timing of administration.

Reactive oxygen species in rats with chronic post-ischemia pain

BACKGROUND

An emerging theme in the study of the pathophysiology of persistent pain is the role of reactive oxygen species (ROS). In the present study, we examined the hypothesis that the exogenous supply of antioxidant drugs during peri-reperfusion would attenuate pain induced by ischemia/reperfusion (IR) injury. We investigated the analgesic effects of three antioxidants administered during peri-reperfusion using an animal model of complex regional pain syndrome-type I consisting of chronic post-ischemia pain (CPIP) of the hind paw.

METHODS

Application of a tight-fitting tourniquet for a period of 3 h produced CPIP in male Sprague-Dawley rats. Low-dose allopurinol (4 mg/kg), high-dose allopurinol (40 mg/kg), superoxide dismutase (SOD, 4000 U/kg), N-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg), or SOD (4000 U/kg)+L-NAME (10 mg/kg) was administered intraperitoneally just after tourniquet application and at 1 and 2 days after reperfusion for 3 days. The effects of antioxidants in rats were investigated using mechanical and cold stimuli. Each group consisted of seven rats.

RESULTS

Allopurinol caused significant alleviation in mechanical and cold allodynia for a period of 4 weeks in rats with CPIP. Both SOD and L-NAME, which were used to investigate the roles of superoxide (O2(-)) and nitric oxide (NO) in pain, also attenuated neuropathic-like pain symptoms in rats for 4 weeks.

CONCLUSIONS

Our findings suggest that O2(-) and NO mediate IR injury-induced chronic pain, and that ROS scavengers administered during the peri-reperfusion period have long-term analgesic effects.

Caspase-3 activation as a key factor for HBx-transformed cell death

OBJECTIVES

Nuclear factor-kappa B (NF-kappaB) activation has been associated with the tumorigenic growth of hepatitis B virus X protein (HBx)-transformed cells. This study was aimed to find a key target for treatment of HBx-mediated cancers.

MATERIALS AND METHODS

NF-kappaB activation, endoplasmic reticulum-stress (ER-stress), caspase-3 activation, and cell proliferation were evaluated after Chang/HBx cells permanently expressing HBx viral protein were treated with inhibitors of NF-kappaB, proteasome and DNA topoisomerase.

RESULTS

Inhibition of NF-kappaB transcriptional activity by transient transfection with mutant plasmids encoding Akt1 and glycogen synthase kinase-3beta (GSK-3beta), or by treatment with chemical inhibitors, wortmannin and LY294002, showed little effect on the survival of Chang/HBx cells. Furthermore, IkappaBalpha (S32/36A) mutant plasmid or other NF-kappaB inhibitors, 1-pyrrolidinecarbonidithioic acid and sulphasalazine, were also shown to have little effect on the cell proliferation. By contrast, proteasome inhibitor-1 (Pro1) and MG132 enhanced the HBx-induced ER-stress response and the subsequent activation of caspase-12, -9 and -3 and reduced cell proliferation. Camptothecin (CPT), however, triggered activation of caspase-3 without induction of caspase-12, and reduced cell proliferation. In addition, CPT-induced cell death was reversed by pre-treatment with z-DEVD, a caspase-3-specific inhibitor.

CONCLUSIONS

Detailed exploitation of the regulators of caspase-3 activation could open the gate for finding an efficient target for development of anticancer therapeutics against HBx-transformed hepatocellular carcinoma.

Identification of Lps2 as a key transducer of MyD88-independent TIR signalling

In humans, ten Toll-like receptor (TLR) paralogues sense molecular components of microbes, initiating the production of cytokine mediators that create the inflammatory response. Using N-ethyl-N-nitrosourea, we induced a germline mutation called Lps2, which abolishes cytokine responses to double-stranded RNA and severely impairs responses to the endotoxin lipopolysaccharide (LPS), indicating that TLR3 and TLR4 might share a specific, proximal transducer. Here we identify the Lps2 mutation: a distal frameshift error in a Toll/interleukin-1 receptor/resistance (TIR) adaptor protein known as Trif or Ticam-1. Trif(Lps2) homozygotes are markedly resistant to the toxic effects of LPS, and are hypersusceptible to mouse cytomegalovirus, failing to produce type I interferons when infected. Compound homozygosity for mutations at Trif and MyD88 (a cytoplasmic TIR-domain-containing adaptor protein) loci ablates all responses to LPS, indicating that only two signalling pathways emanate from the LPS receptor. However, a Trif-independent cell population is detectable when Trif(Lps2) mutant macrophages are stimulated with LPS. This reveals that an alternative MyD88-dependent 'adaptor X' pathway is present in some, but not all, macrophages, and implies afferent immune specialization.

Blood partition and protein binding of a new neuroprotective agent for ischemia-reperfusion damage, KR-31378

The blood partition of KR-31378 between plasma and blood cells and the factors influencing the binding of the drug to 4% human serum albumin (HSA) using an equilibrium dialysis technique were evaluated. KR-31378 reached an equilibrium rapidly between plasma and blood cells of rabbit blood. The equilibrium plasma/blood cells concentration ratios were independent of initial rabbit blood concentrations of KR-31378, 1, 10 and 50 microg/ml; the values were in the range of 1.42-2.33. It took approximately 12-h incubation to reach an equilibrium between plasma and isotonic Søresen phosphate buffer of pH 7.4 containing 3% dextran ('the buffer'). The binding of KR-31378 to 4% HSA was dependent on HSA concentrations (the binding values were 25.3 and 32.0% for HSA concentrations of 2 and 5%, respectively), incubation temperature (the binding values were 48.8, 29.0 and 25.8% for 4, 22 and 37 degrees C, respectively), pHs of isotonic Sørensen phosphate buffer containing 3% dextran (the binding values were 17.7, 20.6, 22.8, 25.6 and 29.5% for buffer pHs of 5.8, 6.4, 7.0, 7.4 and 8.0, respectively) and alpha-1-acid glycoprotein (AAG) concentrations (the binding values were 25.6, 29.9, 34.4 and 50.3% for AAG concentrations of 0, 0.08, 0.16 and 0.32%, respectively).

The relationship between body mass index and the prevalence of obesity-related diseases based on the 1995 National Health Interview Survey in Korea

This study estimated the body mass index (BMI) distribution of Koreans and examined the relationship between BMI and obesity-related diseases, in particular hypertension and diabetes mellitus. We also attempted to provide primary data to determine suitable BMI cut-off points for obesity in Korea. The 1995 National Health Interview Study (NHIS) data were used to estimate BMI and the prevalence of hypertension and diabetes mellitus. A random sample of 5750 Koreans (15-69 years of age) were investigated. BMI was calculated by self-reported weights and heights. The diagnoses of hypertension and diabetes mellitus were obtained from self-reported conditions specified in response to consultations with physicians. The mean BMI was 22.6+/-2.6 kg m(-2) for males and 21.7+/-4.8 kg m(-2) for females. The prevalence of hypertension and diabetes mellitus increased with BMI. The odds ratios of the third quartile of BMI (21.9-23.8 kg m(-2)) for hypertension and diabetes mellitus compared with the first quartile were 6.04 and 3.22, respectively. The odds ratio of the fourth quartile (>23.8 kg m(-2)) of BMI was not significantly different from that of the third quartile. The risk of hypertension and diabetes mellitus increased at the third quartile of BMI (21.9-23.8 kg m(-2)), this quartile being much lower than both the current World Health Organization (WHO) BMI cut-off point of overweight of 25.0 kg m(-2), and the 90th percentile proposed in the Monica project, BMI 26.4 kg m(-2). This finding was notable considering the fact that both hypertension and diabetes mellitus occur in Koreans with lower BMIs than whites. Further studies are necessary to identify the BMI cut-off point for obesity in Korea.

Pan-caspase inhibitor zVAD enhances cell death in RAW246.7 macrophages

Even though the pan-caspase inhibitor zVAD has been widely used as an anti-apoptotic agent, inefficient prevention or even enhancement of cell death has been reported in certain cells. To further investigate its effects on cell death, three different cell types were exposed to various apoptotic stimuli in the presence or absence of zVAD. In Jurkat cells, zVAD protected against cell death induced by tumor necrosis factor (TNF), sodium nitroprusside (SNP) and etoposide, whereas in L929 cells cell death was increased. In RAW246.7 macrophages, zVAD showed similar effects as in L929 cells. However, unlike L929 cells, in which the cell death by TNF is known to be necrosis, RAW246.7 cells manifested features of apoptosis such as chromatin condensation and nuclear fragmentation. Induction of cell death by zVAD in lipopolysaccharide (LPS)-activated RAW246.7 cells also showed the same features as those observed in SNP- and etoposide-treated cells. Initiation of an apoptotic process by zVAD not only disputes the sole role of caspases in apoptosis but also suggests an anti-apoptotic function of certain caspase(s). Death of LPS-activated macrophages may be controlled by an anti-apoptotic caspase.

Characterization of the selectivity and mechanism of cytochrome P450 inhibition by dimethyl-4,4'-dimethoxy-5,6,5',6'-dimethylenedioxybiphenyl-2,2'-dicarboxylate

In vitro studies with human liver microsomes and cytochrome P450 (P450) prototype substrates were performed to characterize the selectivity and mechanism of inhibition of P450 by dimethyl-4,4'-dimethoxy-5,6,5',6'-dimethylenedioxybiphenyl-2,2'-dicarboxylate (DDB). DDB was found to be a strong inhibitor of testosterone 6beta-hydroxylation activity (CYP3A4) with a K(i) value of 0.27 +/- 0.21 microM. At higher concentrations, DDB marginally inhibited caffeine N(3)-demethylation (CYP1A2), diclofenac 4'-hydroxylation (CYP2C9), and dextromethorphan O-demethylation (CYP2D6) activities, but this compound had no effect on CYP2A6-, CYP2C19-, and CYP2E1-mediated reactions. Spectral analysis indicated that the formation of metabolite-P450 complex having absorbance at 456 nm was concentration-dependent; 5 to 33% of the total P450 was complexed in rat and human liver microsomes after a 5-min incubation with DDB. In addition, microsomal incubations with DDB in the presence of NADPH resulted in a loss of spectral P450 content, which was restored after adding K(3)Fe(CN)(6). This complex formation resulted in a time-dependent loss of CYP3A-catalyzed marker activity (testosterone 6beta-hydroxylation) in human liver microsomes. The inhibition was only partially restored upon dialysis. These results collectively suggest that formation of a metabolite-CYP3A complex with DDB was responsible for the CYP3A-selective time-dependent loss of catalytic function of CYP3A.

Nucleotide sequence of envelope protein of Japanese encephalitis virus SA14-14-2 adapted to vero cells

Live attenuated Japanese encephalitis (JE) virus SA(14)-14-2 produced in primary dog kidney cells (PDK) was adapted to Vero cells. In an effort to gain insight into the molecular basis of the biological characteristics of the SA14-14-2(Vero) strain, the 1500 nucleotide sequence encoding the envelope (E) gene which possesses major neutralizing epitopes was determined and compared with the sequences of two other attenuated JE virus strains, SA14-14-2(PHK) and SA14-14-2(PDK). The amino acid sequence of the C-terminal region (a.a. 280-500) was found to be identical for all three strains, while the N-terminal region (a.a. 1-279) shows sequence variation. The distribution of mutations in the N-terminal region was nearly the same among the three attenuated strains, suggesting that the N-terminal sequences might be related with virus-host cell specificity. However, it was found that Lys and Val (a.a. 138 and 176, respectively), known to be responsible for attenuation, are still conserved in SA(14)-14-2(Vero). Animal testing showed that SA(14)-14-2(Vero) has an attenuation phenotype similar to that of the parent SA(14)-14-2(PDK) strain in mice.

A novel anti-ischemic ATP-sensitive potassium channel (K(ATP)) opener without vasorelaxation: N-(6-aminobenzopyranyl)-N'-benzyl-N' '-cyanoguanidine analogue

This paper describes the design, synthesis, and biological evaluation of a novel anti-ischemic compound, (2S,3S,4R)-N-(6-amino-3,4-dihydro-2-dimethoxymethyl-3-hydroxy-2-methyl-2H-benzopyranyl)-N'-benzyl-N"-cyanoguanidine (33), and the structure-activity relationships leading to the discovery of this compound. Compound 33 significantly reduced the myocardial infarct zone to area at risk (IZ/AAR) in the ischemic myocardium rat model with high cardioselectivity. Since the cardioprotective effect of compound 33 is reversed by ATP-sensitive potassium channel (K(ATP)) blockers, its anti-ischemic effect appears to be at least mediated by K(ATP) opening. In addition, compound 33 shows good protective activity on neuronal cells against oxidative stress, and therefore it is suggested that compound 33 may have therapeutic potential both in cardio- and in neuroprotection.

Apoptosis by pan-caspase inhibitors in lipopolysaccharide-activated macrophages

Although apoptosis has been observed in macrophages during the course of infections, the mechanism of apoptosis in activated macrophages is not fully understood. This study shows that pan-caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (ZVAD) or t-butyloxycarbonyl-Asp-fluoromethylketone (Boc-D) caused the death of lipopolysaccharide (LPS)-activated macrophages and RAW 264.7 cells with apoptotic features. The apoptosis was also observed in lipoprotein-treated bacteria but not in CpG oligonucleotide- or flagellin-treated macrophages, indicating a difference of cellular responses downstream of different Toll-like receptors. Consistent with the induction of cell death by pan-caspase inhibitors, no activation of known caspases was detected in LPS-ZVAD-treated cells, suggesting an involvement of unknown proapoptotic caspases in the cell death. ZVAD inhibited the activation of extracellular signal-regulated kinase (ERK) and p38 but not of nuclear factor (NF)-kappa B induced by LPS, suggesting that the ZVAD-sensitive molecule lies upstream of the ERK and p38 pathways but downstream of the divergent site of NF-kappa B and mitogen-activated protein kinases. Our results demonstrate that apoptosis of macrophages induced by LPS+ZVAD is independent from the known proapoptotic caspases and suggest that activity of an unidentified ZVAD-sensitive molecule(s) is involved in the survival of LPS-activated macrophages.

Monitoring of electrokinetic removal of heavy metals in tailing-soils using sequential extraction analysis

This research focused on the monitoring of the electrokinetic removal of heavy metals from tailing-soils, and emphasizes the dependency of removal efficiencies upon their physico-chemical states, as demonstrated by the different extraction methods adopted, which included aqua regia and sequential extraction. The tailing-soils examined contained high concentrations of target metal contaminants (Cd=179mgkg(-1), Cu=207mgkg(-1), Pb=5175mgkg(-1), and Zn=7600mgkg(-1)). The removal efficiencies of the different metals were significantly influenced by their speciations, mobilities and affinities (adsorption capacities) in the soil matrix. The removal efficiencies of mobile and weakly bound fractions, such as the exchangeable fraction were more than 90% by electrokinetic treatment, but strongly bound fractions, such as the organically bound species and residual fraction were not significantly removed (less than 30% removal efficiencies). In accordance with the general sequence of mobilities of heavy metals in soils, the removal efficiencies of more mobile heavy metals (Cd, Cu, and Zn) were higher than that of less mobile heavy metal (Pb).

A purified inactivated Japanese encephalitis virus vaccine made in Vero cells

A second generation, purified, inactivated vaccine (PIV) against Japanese encephalitis (JE) virus was produced and tested in mice where it was found to be highly immunogenic and protective. The JE-PIV was made from an attenuated strain of JE virus propagated in certified Vero cells, purified, and inactivated with formalin. Its manufacture followed current GMP guidelines for the production of biologicals. The manufacturing process was efficient in generating a high yield of virus, essentially free of contaminating host cell proteins and nucleic acids. The PIV was formulated with aluminum hydroxide and administered to mice by subcutaneous inoculation. Vaccinated animals developed high-titered JE virus neutralizing antibodies in a dose dependent fashion after two injections. The vaccine protected mice against morbidity and mortality after challenge with live, virulent, JE virus. Compared with the existing licensed mouse brain-derived vaccine, JE-Vax, the Vero cell-derived JE-PIV was more immunogenic and as effective as preventing encephalitis in mice. The JE-PIV is currently being tested for safety and immunogenicity in volunteers.

Profiling of protein kinases in the neoplastic transformation of human ovarian surface epithelium

OBJECTIVE

The aim of this study was to study the pattern of protein kinase expression in a culture model of epithelial ovarian carcinogenesis.

METHODS

Cultures of normal human ovarian surface epithelium (OSE), OSE from women with BRCA1 mutations, a cell culture model of preneoplastic (SV40 T-antigen-immortalized, nontumorigenic) and neoplastic (SV40-E-cadherin transfected, tumorigenic) OSE, and three ovarian cancer cell lines were used to represent OSE phenotypes of different genetic backgrounds and at different, progressive stages of neoplastic transformation. The protein kinase network signaling was studied by Western blotting, simultaneously using multiple antibodies for specific protein kinases.

RESULTS

High levels of cGMP-dependent protein kinase were found in normal and preneoplastic OSE, but were absent in neoplastic OSE. In contrast, expression of MEK6 was detected exclusively in neoplastic OSE. The expressions of casein kinase II (CK2), p38 mitogen-activated protein kinase (MAPK), cyclin-dependent kinase, and the phosphatidylinositol 3-kinase (PI3K) effectors Akt2 and p70 S6 kinase (S6K) were several-fold higher in neoplastic OSE than in normal OSE, whereas the expressions of the MAPKs extracellular signal-regulated kinases ERK1 and -2 were unchanged. Importantly, constitutive phosphorylation of Akt2 and p70 S6K, as found in neoplastic OSE, was also observed in overtly normal OSE from women with predisposing BRCA1 gene mutations.

CONCLUSIONS

These data demonstrate that different repertoires of downstream signaling proteins, particularly those of the MEK6-p38 MAPK-CK2 pathway and the PI3K pathway, are correlated with phenotypic manifestations of a cell culture model of OSE at progressive stages in the development of ovarian cancer. Changes in PI3K effectors are already found in overtly normal OSE from women with BRCA1 mutations.

Metaxin is required for tumor necrosis factor-induced cell death

We used retrovirus insertion-mediated random mutagenesis and tumor necrosis factor (TNF) selection to generate TNF-resistant lines from L929 cells. The metaxin gene, which encodes a protein located on the outer membrane of mitochondria, was identified to be the gene disrupted in one of the resistant lines. The requirement of metaxin in TNF-induced cell death of L929 was confirmed by the restoration of TNF sensitivity after ectopic reconstitution of metaxin expression. Analysis of the cell death induced by other stimuli revealed that metaxin deficiency-mediated death resistance was selective to certain stimuli. Studies using deletion mutants of metaxin showed that mitochondrial association of metaxin is required for the function of metaxin. Over-expression of truncated metaxin lacking the mitochondria anchoring sequence mimicked metaxin deficiency in wild-type cells. Interfering with metaxin prevented TNF-induced necrotic cell death in L929 cells and apoptosis in MCF-7 cells. Our work has thus defined a novel component in the death pathway used by TNF and some other death stimuli.

Phosphorylation of purified recombinant hepatitis B virus-X protein by mitogen-activated protein kinase and protein kinase C in vitro

The recombinant human hepatitis B virus-X protein (rhHBx) has been expressed as inclusion bodies in Escherichia coli and purified. By sequential dialysis of urea, rhHBx was folded into the native structure, which was demonstrated by both the efficacy of its transcriptional activation of the adenovirus major late promoter, fluorescence and circular dichroism (CD) analysis. The increase in CD values at 220 nm and a corresponding blue shift of the intrinsic fluorescence emission confirmed the ability of HBx to refold in lower concentrations of urea to produce the active protein. After purification and renaturation, the rhHBx protein was found to be phosphorylated by protein kinase C (PKC) and mitogen-activated protein kinase (MAPK). In vivo phosphorylation of HBx was also demonstrated. Although PKC and MAPK enhance the HBx phosphorylation in vitro, neither protein kinase A nor caseine kinase II (CKII) phosphorylate HBx protein, though there are possible substrate residues of both kinases in HBx protein. Phosphoamino acid analysis of the total acid hydrolyzed HBx showed that serine residues can be phosphorylated by PKC or MAPK.

Conversion of Glu-plasminogen to Lys-plasminogen is necessary for optimal stimulation of plasminogen activation on the endothelial cell surface

When Glu-plasminogen is bound to cells, plasmin (Pm) formation by plasminogen (Pg) activators is markedly enhanced compared with the reaction in solution. It is not known whether the direct activation of Glu-Pg by Pg activators is promoted on the cell surface or whether plasminolytic conversion of Glu-Pg to the more readily activated Lys-Pg is necessary for enhanced Pm formation on the cell surface. To distinguish between these potential mechanisms, we tested whether Pm formation on the cell surface could be stimulated in the absence of conversion of Glu-Pg to Lys-Pg. Rates of activation of Glu-Pg, Lys-Pg, and a mutant Glu-Pg, [D646E]Glu-Pg, by either tissue Pg activator (t-PA) or urokinase (u-PA) were compared when these Pg forms were either bound to human umbilical vein endothelial cells (HUVEC) or in solution. ([D646E]Glu-Pg can be cleaved at the Arg(561)-Val(562) bond by Pg activators but does not possess Pm activity subsequent to this cleavage because of the mutation of Asp(646) of the serine protease catalytic triad.) Glu-Pg activation by t-PA was enhanced on HUVEC compared with the solution phase by 13-fold. In contrast, much less enhancement of Pg activation was observed with [D646E]Glu-Pg ( approximately 2-fold). Although the extent of activation of Lys-Pg on cells was similar to that of Glu-Pg, the cells afforded minimal enhancement of Lys-Pg activation compared with the solution phase (1.3-fold). Similar results were obtained when u-PA was used as activator. When Glu-Pg was bound to the cell in the presence of either t-PA or u-PA, conversion to Lys-Pg was observed, but conversion of ([D646E]Glu-Pg to ([D646E]Lys-Pg was not detected, consistent with the conversion of Glu-Pg to Lys-Pg being necessary for optimal enhancement of Pg activation on cell surfaces. Furthermore, we found that conversion of [D646E]Glu-Pg to [D646E]Lys-Pg by exogenous Pm was markedly enhanced ( approximately 20-fold) on the HUVEC surface, suggesting that the stimulation of the conversion of Glu-Pg to Lys-Pg is a key mechanism by which cells enhance Pg activation.

Pulmonary vascular effects of propofol at baseline, during elevated vasomotor tone, and in response to sympathetic alpha- and beta-adrenoreceptor activation

BACKGROUND

This in vivo study had two primary objectives. The first goal was to determine whether the pulmonary vascular effects of propofol depend on the preexisting level of vasomotor tone, and the second was to investigate the effects of propofol on the pulmonary vascular responses to sympathetic alpha- and beta-adrenoreceptor activation.

METHODS

Thirty-one mongrel dogs were chronically instrumented to measure the left pulmonary vascular pressure-flow (LPQ) relation. Left lung autotransplantation (LLA) was also performed in eight additional dogs to induce a long-term increase in pulmonary vascular resistance. LPQ plots were measured on separate days in the conscious state and during propofol anesthesia. LPQ plots were measured at baseline and when vasomotor tone was acutely increased with the alpha agonist, phenylephrine, or the thromboxane mimetic, U46619. In separate experiments, cumulative dose-response curves to alpha- (phenylephrine) and beta- (isoproterenol) adrenoreceptor agonists were generated in conscious and propofol-anesthetized dogs.

RESULTS

Compared with the conscious state, propofol had no effect on the baseline LPQ relation in normal or post-LLA dogs. However, propofol caused pulmonary vasoconstriction (P < 0.05) when vasomotor tone was acutely increased with either phenylephrine or U46619 in normal or post-LLA dogs. The pulmonary vasoconstrictor response to alpha-adrenoreceptor activation was potentiated (P < 0.05) during propofol anesthesia, whereas the pulmonary vasodilator response to beta-adrenoreceptor activation was not altered.

CONCLUSION

These results indicate that the pulmonary vascular response to propofol anesthesia is tone-dependent. During sympathetic activation, propofol may favor alpha-adrenoreceptor-mediated vasoconstriction over beta-adrenoreceptor-mediated vasodilation.

Dose-dependent pharmacokinetics of a new reversible proton pump inhibitor, DBM-819, after intravenous and oral administration to rats: hepatic first-pass effect

The dose-dependent pharmacokinetic parameters of DBM-819 were evaluated after intravenous (5, 10 and 20 mg/kg) and oral (10, 20 and 50 mg/kg) administrations of the drug to rats. The hepatic first-pass effect was also measured after intravenous and intraportal administrations of the drug, 10 mg/kg, to rats. After intravenous administration, the dose-normalized (based on 5 mg/kg) area under the plasma concentration-time curve from time zero to time infinity, AUC, at 20 mg/kg (27.0 and 45.8 microg min/ml) was significantly greater than that at 5 mg/kg due to saturable metabolism. After oral administration, the dose-normalized (based on 10 mg/kg) AUC(0-12 h) at 50 mg/kg (25.1, 18.3 and 49.2 microg min/ml) was significantly greater than those at 10 and 20 mg/kg again due to saturable metabolism. After oral administration of DBM-819, 10 mg/kg, 2.86% of oral dose was not absorbed and the extent of absolute oral bioavailability (F) was estimated to be 46.7%. After intraportal administration of DBM-819, 10 mg/kg, the AUC was 51.9% of intravenous administration, suggesting that approximately 48.1% was eliminated by liver (hepatic first-pass effect). The considerable hepatic first-pass effect of DBM-819 was also supported by significantly greater AUC of M3 (3.70 and 6.86 microg min/ml), a metabolite of DBM-819, after intraportal administration. The AUCs of DBM-819 were not significantly different (comparable) between intraportal and oral administrations of the drug, 10 mg/kg, suggesting that gastrointestinal first-pass effect of DBM-819 was almost negligible in rats. At 10 mg/kg oral dose of DBM-819, the hepatic first-pass effect was approximately 48.1%, F was approximately 46.7 and 2.86% was not absorbed from gastrointestinal tract in rats.

Vitamin E improves microsomal phospholipase A2 activity and the arachidonic acid cascade in kidney of diabetic rats

The purpose of the present study was to investigate the effects of vitamin E on microsomal phospholipase A2 activity and the arachidonic acid cascade in the kidneys of streptozotocin (STZ)-induced diabetic rats. Sprague-Dawley male rats weighing 100 +/- 10 g were randomly assigned to one normal and three STZ-induced diabetic groups. The diabetic groups were fed a vitamin E-free diet (the DM-0E group), 40 mg vitamin E/kg diet (the DM-40E group) or a 400 mg vitamin E/kg diet (the DM-400E group). The kidney vitamin E concentrations were 59 and 49% lower in the DM-0E and DM-40E groups, respectively, than in the normal group. The kidney thiobarbituric acid reactive substance concentrations in the DM-0E, DM-40E and DM-400E groups were 119, 84 and 33% greater, respectively, than that in the normal group. The concentration in the DM-400E group was 39% lower than that in the DM-0E group. The phospholipase A2 (PLA2) activity in the kidney microsomes of the DM-0E-40E and DM-400E groups were 88, 58 and 35% greater, respectively, than that in the normal group. The activity in the DM-400E group was 28% lower than that in the DM-0E group and 16% lower than that in the DM-40E group. The differences in the phospholipids in the kidney microsomes included reductions in the phosphatidylcholine and phosphatidylethanolamine compositions. Phosphatidylethanolamine hydrolysis in the kidney microsomes of the DM-0E and DM-40E groups were 84 and 64%, which did not differ from the DM-400E group. The formation of thromboxane A2 (TXA2) in the kidney microsomes was 137 and 70% greater in the DM-0E and DM-40E groups, respectively, than in the normal group. TXA2 formation did not differ between the DM-400E and normal groups. The formation of prostacyclin in the kidney microsomes was 60 and 44% lower in the DM-0E and DM-40E groups, respectively, than in the normal group, whereas the DM-400E group did not differ from that in the normal group. The ratio of prostacyclin to TXA2 was 82 and 65% lower than normal in the DM-0E and DM-40E groups, respectively. Kidney function appears to be improved by vitamin E supplementation due to its antithrombus action, which in turn controls the arachidonic acid cascade system.

High-performance liquid chromatographic analysis of a new neuroprotective agent for ischemia-reperfusion damage, KR-31378

A high-performance liquid chromatographic method was developed for the determination of a neuroprotective agent for ischemia-reperfusion damage, KR-31378, in human plasma and urine and in rat tissue homogenates. The method involved deproteinization of the the biological samples with 0.5 volumes of saturated Ba(OH)2, 0.5 volumes of 0.04 M ZnSO4 and 1 volume of acetonitrile. A 80-microl aliqout of the supernatant was injected onto a reversed-phase C18 column. The mobile phase, 50 mM triethylamine acetate : acetonitrile : tetrahydrofuran (65:30:5, v/v/v), was run at a flow rate of 1.0 ml/min. The column effluent was mornitored by a ultraviolet detector set at 310 nm. The retention time of KR-31378 was approximately 6.5 min. The detection limits of KR-31378 in human plasma and urine and rat tissue homogenates were 0.2, 0.5 and 0.5 microg/ml, respectively. The coefficients of variation (within-day and between-day) were below 13.6% for human plasma and urine and rat homogenates. No interferences from endogenous substances were found.

Hypersensitivity pneumonitis caused by Fusarium napiforme in a home environment

BACKGROUND

We report a case of hypersensitivity pneumonitis (HP) in a 17-year-old male student caused by Fusarium napiforme found in his home environment.

METHODS

The patient was diagnosed according to history, chest radiograph, spirometry, high-resolution chest CT, and transbronchial lung biopsy. To identify the causative agent, cultured aeromolds were collected by the open-plate method. From the main fungi cultured, fungal antigens were prepared, and immunoblot analysis with the patient's serum and each fungal antigen was performed.

RESULTS

Five fungal species were isolated from the patient's home. Immunoblotting analysis with the patient's serum demonstrated more than 10 IgG-binding fractions to F. napiforme extract only, while little binding was noted with the other fungal antigens.

CONCLUSIONS

We should be aware that HP may be caused by F. napiforme in the home environment.

Flavohemoglobin Hmp affords inducible protection for Escherichia coli respiration, catalyzed by cytochromes bo' or bd, from nitric oxide

Respiration of Escherichia coli catalyzed either by cytochrome bo' or bd is sensitive to micromolar extracellular NO; extensive, transient inhibition of respiration increases as dissolved oxygen tension in the medium decreases. At low oxygen concentrations (25-33 microm), the duration of inhibition of respiration by 9 microm NO is increased by mutation of either oxidase. Respiration of an hmp mutant defective in flavohemoglobin (Hmp) synthesis is extremely NO-sensitive (I(50) about 0.8 microm); conversely, cells pre-grown with sodium nitroprusside or overexpressing plasmid-borne hmp(+) are insensitive to 60 microm NO and have elevated levels of immunologically detectable Hmp. Purified Hmp consumes O(2) at a rate that is instantaneously and extensively (>10-fold) stimulated by NO due to NO oxygenase activity but, in the absence of NO, Hmp does not contribute measurably to cell oxygen consumption. Cyanide binds to Hmp (K(d) 3 microm). Concentrations of KCN (100 microm) that do not significantly inhibit cell respiration markedly suppress the protection of respiration from NO afforded by Hmp and abolish NO oxygenase activity of purified Hmp. The results demonstrate the role of Hmp in protecting respiration from NO stress and are discussed in relation to the energy metabolism of E. coli in natural O(2)-depleted environments.

Dose-dependent pharmacokinetics of a new neuroprotective agent for ischemia-reperfusion damage, KR-31378, in rats

The dose-dependent pharmacokinetic parameters of a new neuroprotective agent for ischemia-reperfusion damage, KR-31378, were evaluated after intravenous and oral administration, 10, 20, and 50 mg/kg, to rats. After intravenous administration of 50 mg/kg, the dose-normalized (10 mg/kg) AUC (994 microg min/mL) was significantly greater than that at 10 (569 microg min/ml) and 20 (660 microg min/mL) mg/kg. This could be due to slower clearance (Cl) with increasing dosage (18.5, 14.6, and 10.2 mL/min/kg for 10, 20, and 50 mg/kg, respectively). The slower Cl with increasing dosage could be due to saturable metabolism of KR-31378 in rats and this could be supported by significantly slower Cl(nr) and significantly greater 24-h urinary excretion of the drug at 50 mg/kg than those at 10 and 20 mg/kg. After oral administration of 50 mg/kg, the dose-normalized (10 mg/kg) AUC (1160 microg min/mL) was significantly greater than that at 10 (572 microg min/mL) and 20 (786 microg min/mL) mg/kg. Note that the AUCs were comparable (not significantly different) between intravenous and oral administration at each dosage, indicating that the absorption from gastrointestinal tract was almost complete and the first-pass (gastric, intestinal, and hepatic) effect was not considerable after oral administration to rats.

KR 31372, a benzopyran derivative, inhibits oxidized LDL-stimulated proliferation and migration of vascular smooth muscle cells

KR 31372 is a benzopyran derivative. Both [3H]thymidine incorporation and migrations (chemotactic and wound-edge) of cultured smooth muscle cells (SMCs) were greatly stimulated by oxidized low-density lipoprotein (LDL). These effects were significantly suppressed by KR 31372 (10(7) - 10(6) M) and PDGF-BB antibody (10(8) - 10(6) M). Preincubation with KR 31372 led to a decrease in the synthesis of PDGF-BB-like immunoreactivity (PDGF-BB-LI) that had been stimulated by oxidized LDL. Otherwise, KR 31372 and probucol strongly inhibited the production of thiobarbituric acid reactive substances (TBARS) caused by the incubation of LDL with Cu2+ ion, and significantly reduced the intracellular oxidative stress when stimulated with H,O2. Taken together, it is suggested that KR 31372 may inhibit the oxidized LDL-stimulated syntheses of DNA and PDGF-BB, and migration of the SMCs, in part, via the antioxidant activity.

Propofol selectively attenuates endothelium-dependent pulmonary vasodilation in chronically instrumented dogs

BACKGROUND

The objective was to investigate the effects of propofol anesthesia on the pulmonary vascular response to endothelium-dependent and -independent vasodilators, compared with the responses measured in the conscious state.

METHODS

Twenty-six conditioned, male, mongrel dogs were instrumented long-term to measure the left pulmonary vascular pressure-flow relation. Pressure-flow plots were measured on separate days in conscious and propofol-anesthetized (5.0 mg/kg plus 0.5 mg. kg-1. min-1 intravenously) dogs at baseline, after preconstriction with the thromboxane mimetic U46619, and during the cumulative intravenous administration of endothelium-dependent (acetylcholine and bradykinin) and -independent (proline-nitric oxide) vasodilators.

RESULTS

Propofol had no effect on the baseline pressure-flow relation compared with the conscious state. A lower (P < 0.05) dose of U46619 was necessary to achieve the same degree of preconstriction during propofol anesthesia. The pulmonary vasodilator responses to bradykinin and proline-nitric oxide were similar in the conscious and propofol-anesthetized states. In contrast, the pulmonary vasodilator response to acetylcholine was markedly attenuated (P < 0.01) during propofol anesthesia. The intralipid vehicle for propofol had no effect on the acetylcholine dose-response relation.

CONCLUSION

These results suggest that propofol causes a specific defect in the signal transduction pathway for acetylcholine-induced pulmonary vasodilation. This defect involves the endothelial and not the vascular smooth muscle component of the response.

Stress-induced activation of protein kinase CK2 by direct interaction with p38 mitogen-activated protein kinase

Protein kinase CK2 has been implicated in the regulation of a wide range of proteins that are important in cell proliferation and differentiation. Here we demonstrate that the stress signaling agents anisomycin, arsenite, and tumor necrosis factor-alpha stimulate the specific enzyme activity of CK2 in the human cervical carcinoma HeLa cells by up to 8-fold, and this could be blocked by the p38 MAP kinase inhibitor SB203580. We show that p38alpha MAP kinase, in a phosphorylation-dependent manner, can directly interact with the alpha and beta subunits of CK2 to activate the holoenzyme through what appears to be an allosteric mechanism. Furthermore, we demonstrate that anisomycin- and tumor necrosis factor-alpha-induced phosphorylation of p53 at Ser-392, which is important for the transcriptional activity of this growth suppressor protein, requires p38 MAP kinase and CK2 activities.

Cyclic GMP-dependent and -independent regulation of MAP kinases by sodium nitroprusside in isolated cardiomyocytes

Sodium nitroprusside (SNP) elicits various physiological effects, in part through generation of the membrane permeable mediator nitric oxide (NO). In the heart, besides its role in regulating contractility, NO is involved in both protection from and induction of cellular damage. The present study investigated the role of SNP in the regulation of the mitogen-activated protein kinases (MAPKs) in isolated adult rat cardiomyocytes. SNP maximally activated Erk1, Erk2, p38 MAPK and MAPKAPK2 in 5-10 min. The activation of MAPKAPK2 by SNP was blocked by the soluble guanylyl cyclase inhibitor, 1H-[1, 2,4]oxadiazolol[4,3-a]quinoxalin-1-one (ODQ) and the p38 MAPK inhibitor, SB203580. The activation of Erk1 was insensitive to ODQ but completely blocked by the Mek1 inhibitor PD98059. The membrane-permeable homologue of cGMP, 8-Br-cGMP, also activated p38 MAPK (A(0.5) approximately 50 microM) but not Erk1 and Erk2. These results indicate that p38 MAPK and MAPKAPK2 are activated by SNP in cGMP-dependent pathways, while the Erk1 activation by SNP is independent of cGMP levels.

Ischemia induced activation of heat shock protein 27 kinases and casein kinase 2 in the preconditioned rabbit heart

Protein kinase C (PKC), p38 MAP kinase, and mitogen-activated protein kinase-activated kinases 2 and 3 (MAPKAPK2 and MAPKAPK3) have been implicated in ischemic preconditioning (PC) of the heart to reduce damage following a myocardial infarct. This study examined whether extracellular signal-regulated kinase (Erk) 1, p70 ribosomal S6 kinase (p70 S6K), casein kinase 2 (CK2), and other hsp27 kinases are also activated by PC, and if they are required for protection in rabbit hearts. CK2 and hsp27 kinase activities declined during global ischemia in control hearts, whereas PC with 5 min ischemia and 10 min reperfusion increased their activities during global ischemia. Resource Q chromatography resolved two distinct peaks of hsp27 phosphotransferase activities; the first peak (at 0.36 M NaCl) appeared to correspond to the 55-kDa MAPKAPK2. Erk1 activity was elevated in both control and PC hearts after post-ischemic reperfusion, but no change was observed in p70 S6K activity. Infarct size (measured by triphenyltetrazolium staining) in isolated rabbit hearts subjected to 30 min regional ischemia and 2 h reperfusion was 31.0+/-2.6% of the risk zone in controls and was 10.3+/-2.2% in PC hearts (p<0.001). Neither the CK2 inhibitor 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) nor the Mek1/2 inhibitor PD98059 infused during ischemia blocked protection by PC. The activation of CK2 and Erk1 in ischemic preconditioned hearts appear to be epiphenomena and not required for the reduction of infarction from myocardial ischemia.

Ischemic preconditioning activates MAPKAPK2 in the isolated rabbit heart: evidence for involvement of p38 MAPK

Recent studies suggest that p38 mitogen-activated protein kinase (MAPK) may be involved in ischemic preconditioning (PC). To further test this possibility, the regulation of MAPK-activated protein kinase 2 (MAPKAPK2), a kinase immediately downstream from p38 MAPK, and the activity of c-Jun NH(2)-terminal kinase (JNK), a second MAPK, were examined in preconditioned hearts. Isolated, perfused rabbit hearts were subjected to 20 to 30 minutes of global ischemia. Ventricular biopsies before treatment and after 20 minutes of ischemia were homogenized, and the activities of MAPKAPK2 and JNK were evaluated. For the MAPKAPK2 experiments, 7 groups were studied, as follows: control hearts; preconditioned hearts; hearts treated with 500 nmol/L R(-) N(6)-(2-phenylisopropyl) adenosine (PIA), an A(1)-adenosine receptor agonist; preconditioned hearts pretreated with 100 micromol/L 8-(p-sulfophenyl) theophylline (SPT), an adenosine receptor antagonist; preconditioned hearts also treated with SB 203580, a potent inhibitor of p38 MAPK activation; hearts treated with 50 ng/mL anisomycin (a p38 MAPK/JNK activator); and hearts treated with both anisomycin (50 ng/mL) and the tyrosine kinase inhibitor genistein (50 micromol/L). MAPKAPK2 activity was not altered in control hearts after 20 minutes of global ischemia. By contrast, there was a 3.8-fold increase in activity during ischemia in preconditioned hearts. Activation of MAPKAPK2 in preconditioned hearts was blocked by both SPT and SB 203580. MAPKAPK2 activity during ischemia increased 3.5-fold and 3.3-fold in hearts pretreated with PIA or anisomycin, respectively. MAPKAPK2 activation during ischemia in hearts pretreated with anisomycin was blocked by genistein. In separate hearts, anisomycin mimicked the anti-infarct effect of PC, and that protection was abolished by genistein. JNK activity was measured in control and preconditioned hearts. There was a comparable, modest decline in activity during 30 minutes of global ischemia in both groups. As a positive control, a third group of hearts was treated with anisomycin before global ischemia, and in these, JNK activity increased by 290% above baseline. These results confirm that the p38 MAPK/MAPKAPK2 pathway is activated during ischemia only if the heart is in a preconditioned state. These data further support p38 MAPK as an important signaling component in ischemic PC.

Growth hormone-induced alteration in ErbB-2 phosphorylation status in 3T3-F442A fibroblasts

The growth hormone receptor (GHR), a cytokine receptor superfamily member, requires the JAK2 tyrosine kinase for signaling. We now examine functional interactions between growth hormone (GH) and epidermal growth factor (EGF) in 3T3-F442A fibroblasts. Although EGF enhanced ErbB-2 tyrosine phosphorylation, GH, while causing retardation of its migration on SDS-polyacrylamide gel electrophoresis, decreased ErbB-2's tyrosine phosphorylation. GH-induced retardation was reversed by treatment of anti-ErbB-2 precipitates with both alkaline phosphatase and protein phosphatase 2A, suggesting that GH induced serine/threonine phosphorylation of ErbB-2. Both GH-induced shift in ErbB-2 migration and GH-induced MAP kinase activation were unaffected by a protein kinase C inhibitor but were blocked by the mitogen-activated protein kinase/extracellular signal-regulated kinase kinase 1 (MEK1) inhibitor, PD98059. Notably, leukemia inhibitory factor, but not interferon-gamma, also promoted ErbB-2 shift and mitogen-activated protein kinase activation. Cotreatment with EGF and GH versus EGF alone resulted in a 35% decline in acute ErbB-2 tyrosine 1248 autophosphorylation, a marked decline (approximately 50%) in DNA synthesis, and substantially decreased cyclin D1 expression. We conclude that in 3T3-F442A cells, 1) the GH-induced decrease in ErbB-2 tyrosine phosphorylation correlates with MEK1/mitogen-activated protein kinase activity and 2) GH antagonizes EGF-induced DNA synthesis and cyclin D1 expression in a pattern consistent with its alteration in ErbB-2 phosphorylation status.

A catalytically active Jak2 is required for the angiotensin II-dependent activation of Fyn

Recent work with interleukins has shown a convergence of tyrosine phosphorylation signal transduction cascades at the level of the Janus and Src families of tyrosine kinases. Here we demonstrate that activation of the seven-transmembrane AT(1) receptor by angiotensin II induces a physical association between Jak2 and Fyn, in vivo. This association requires the catalytic activity of Jak2 but not Fyn. Deletion studies indicate that the region of Jak2 that binds Fyn is located between amino acids 1 and 240. Studies of the Fyn SH2 and SH3 domains demonstrate that the SH2 domain plays the primary role in Jak2/Fyn association. Not surprisingly, this domain shows a marked preference for tyrosine-phosphorylated Jak2. Surface plasmon resonance estimated the dissociation equilibrium constant (K(d)) of this association to be 2.36 nM. Last, in vivo studies in vascular smooth muscle cells show that, in response to angiotensin II, Jak2 activation is required for Fyn activation and induction of the c-fos gene. The significance of these data is that Jak2, in addition to serving as a critical angiotensin II activated signal transduction kinase, also functions as a docking protein and participates in the activation of Fyn by providing phosphotyrosine residues that bind the SH2 domain of Fyn.