White adipose tissue contributes to UCP1-independent thermogenesis

Beta3-adrenergic receptors (AR) are nearly exclusively expressed in brown and white adipose tissues, and chronic activation of these receptors by selective agonists has profound anti-diabetes and anti-obesity effects. This study examined metabolic responses to acute and chronic beta3-AR activation in wild-type C57Bl/6 mice and congenic mice lacking functional uncoupling protein (UCP)1, the molecular effector of brown adipose tissue (BAT) thermogenesis. Acute activation of beta3-AR doubled metabolic rate in wild-type mice and sharply elevated body temperature and BAT blood flow, as determined by laser Doppler flowmetry. In contrast, beta3-AR activation did not increase BAT blood flow in mice lacking UCP1 (UCP1 KO). Nonetheless, beta3-AR activation significantly increased metabolic rate and body temperature in UCP1 KO mice, demonstrating the presence of UCP1-independent thermogenesis. Daily treatment with the beta3-AR agonist CL-316243 (CL) for 6 days increased basal and CL-induced thermogenesis compared with naive mice. This expansion of basal and CL-induced metabolic rate did not require UCP1 expression. Chronic CL treatment of UCP1 KO mice increased basal and CL-stimulated metabolic rate of epididymal white adipose tissue (EWAT) fourfold but did not alter BAT thermogenesis. After chronic CL treatment, CL-stimulated thermogenesis of EWAT equaled that of interscapular BAT per tissue mass. The elevation of EWAT metabolism was accompanied by mitochondrial biogenesis and the induction of genes involved in lipid oxidation. These observations indicate that chronic beta3-AR activation induces metabolic adaptation in WAT that contributes to beta3-AR-mediated thermogenesis. This adaptation involves lipid oxidation in situ and does not require UCP1 expression.

High-performance liquid chromatographic mass spectrometric method for the determination of ursodeoxycholic acid and its glycine and taurine conjugates in human plasma

A novel sensitive high-performance liquid chromatography-electrospray mass spectrometry method has been developed for the determination of ursodeoxycholic acid (UDCA) and its glycine and taurine conjugates, glycoursodeoxycholic acid (GDCA) and tauroursodeoxycholic acid (TDCA). The procedure involved a solid phase extraction of UDCA, GDCA, TDCA and the internal standard, 23-nordeoxycholic acid from human plasma on a C18 Bond Elut cartridge. Chromatography was performed by isocratic reverse phase separation with methanol/25 mM ammonium acetate (40/60, v/v) containing 0.05% acetic acid on a C18 column with embedded polar functional group. Detection was achieved using an LC-MS/MS system. The standard curve was linear over a working range of 10-3000 ng/ml for all analytes and gave an average correlation coefficient of 0.9992 or better during validation. The absolute recovery for UDCA, GDCA, TDCA and the internal standard was 87.3, 83.7, 79.5 and 95.8%, respectively. This method is simple, sensitive and suitable for pharmacokinetics, bioequivalence or clinical studies.

Anti-proliferative effects induced by anti-CD4 human/murine chimeric antibody and murine anti-CD4 monoclonal antibody

The effects of chimeric anti-CD4 human/murine chimeric antibody and murine anti-CD4 monoclonal antibody (McAb) on the proliferation induced by anti-CD3 McAb, phytohemagglutinin (PHA), IL-2, and allogeneic cells were studied. The results showed that chimeric anti-CD4 antibody and murine anti-CD4 McAb could inhibit the proliferation induced by the above inducers and the inhibitory effects were related to the dosage of the antibodies.

Chiral separation and determination of R-(-)- and S-(+)-baclofen in human plasma by high-performance liquid chromatography

The method presented here is a high-performance liquid chromatography (HPLC)-UV detection method for the determination of baclofen R-(-)- and S-(+)-enantiomers in human plasma using a chiral separation technique. Baclofen enantiomers were extracted from human plasma with a reversed-phase solid-phase extraction (SPE) cartridge. The extract was then injected onto a HPLC system with a UV detection system set at 220 nm. The separation was achieved by using a 150x4.6 mm, 5 microm Phenomenex chirex 3216 chiral column with a mobile phase consisting of 0.4 mM CuSO(4) in acetonitrile-20 mM sodium acetate (17:83). The calibration curves were linear for both R-(-)- and S-(+)-enantiomers of baclofen in the concentration range of 20-5000 ng/ml. The average regressions were 0.9980 and 0.9991 for R-(-)- and S-(+)-baclofen, respectively. Inter-day precision was 3.3-5.2% for R-(-)-baclofen and 3.5-3.9% for S-(+)-baclofen at a concentration range of 60-4000 ng/ml. Intra-day precisions were 0.6-4.4 and 0.5-3.5% for R-(-)-baclofen and S-(+)-baclofen, respectively. The average extraction recovery was 81.6% for R-(-)-baclofen, 83.0% for S-(+)-baclofen and 94.0% for the internal standard (p-aminobenzoic acid). The limit of quantitation for both R-(-)- and S-(+)-baclofen in human plasma was 20 ng/ml. The method is simple and easy to operate with accuracy and reproducibility and it is suitable for pharmacokinetic studies.

Inhibition of human leukemia in an animal model with human antibodies directed against vascular endothelial growth factor receptor 2. Correlation between antibody affinity and biological activity

Vascular endothelial growth factor (VEGF) and its receptors (VEGFR) have been implicated in promoting solid tumor growth and metastasis via stimulating tumor-associated angiogenesis. We recently showed that certain 'liquid' tumors such as leukemia not only produce VEGF, but also express functional VEGFR, resulting in an autocrine loop for tumor growth and propagation. A chimeric anti-VEGFR2 (or kinase insert domain-containing receptor, KDR) antibody, IMC-1C11, was shown to be able to inhibit VEGF-induced proliferation of human leukemia cells in vitro, and to prolong survival of nonobese diabetic-severe combined immune deficient (NOD-SCID) mice inoculated with human leukemia cells. Here we produced two fully human anti-KDR antibodies (IgG1), IMC-2C6 and IMC-1121, from Fab fragments originally isolated from a large antibody phage display library. These antibodies bind specifically to KDR with high affinities: 50 and 200 pM for IMC-1121 and IMC-2C6, respectively, as compared to 270 pM for IMC-1C11. Like IMC-1C11, both human antibodies block VEGF/KDR interaction with an IC(50) of approximately 1 nM, but IMC-1121 is a more potent inhibitor to VEGF-stimulated proliferation of human endothelial cells. These anti-KDR antibodies strongly inhibited VEGF-induced migration of human leukemia cells in vitro, and when administered in vivo, significantly prolonged survival of NOD-SCID mice inoculated with human leukemia cells. It is noteworthy that the mice treated with antibody of the highest affinity, IMC-1121, survived the longest period of time, followed by mice treated with IMC-2C6 and IMC-1C11. Taken together, our data suggest that anti-KDR antibodies may have broad applications in the treatment of both solid tumors and leukemia. It further underscores the efforts to identify antibodies of high affinity for enhanced antiangiogenic and antitumor activities.

Molecular dynamics study of the connection between flap closing and binding of fullerene-based inhibitors of the HIV-1 protease

The complementary spatial relationship between fullerene C(60) and the hydrophobic cavity region of the human immunodeficiency virus (HIV) protease, which houses the active site of the enzyme, has led to the suggestion that fullerene-based derivatives could have potential use as effective HIV protease inhibitors. The ability of such compounds to desolvate the cavity region leads to a strong hydrophobic interaction between the C(60) moiety and residues in the cavity region. In this study, the connection between the motion of the so-called flexible flaps of the cavity and favorable binding of a fullerene-based protease inhibitor is explored using multiple-time scale molecular dynamics simulations and free energy techniques. In addition, the effect of the interaction between the C(60) moiety and the residues in the cavity region on the water content of the cavity is also investigated. Conformational free energy profiles along a suitably chosen flap opening coordinate show a considerable barrier to flap opening in the presence of the inhibitor, while no such barrier exists for the protease alone. This result is interpreted in terms of a strong hydrophobic interaction between the C(60) moiety and the flexible flaps, which cause the latter to close tightly around the inhibitor, thereby expelling water from the cavity and leading to a favorable binding interaction. This interpretation is rationalized by direct analysis of the water content in the cavity in the presence and absence of the inhibitor.

High-performance liquid chromatographic method for the determination of gabapentin in human plasma

A sensitive high-performance liquid chromatography (HPLC) method using UV detection for the determination of gabapentin in human plasma has been developed. In this method, gabapentin was extracted from human plasma with a reversed-phase solid-phase extraction (SPE) cartridge followed by derivatization with phenylisothiocyanate. Analysis was achieved by using a HPLC system that was equipped with a UV detector. The quantitation limit of gabapentin in human plasma was 0.03 microg/ml. The method is sensitive with excellent selectivity and reproducibility and it has been applied to a bioequivalence clinical study with great success.

Mechanical properties of the periosteum in the pig, Sus scrofa

The fibrous periosteum forms an intermediary between muscle and ligament forces and the underlying osteoblastic tissue, thus the mechanical properties of the periosteum are critical to understanding osteogenic stimuli. Regional and directional variation in periosteal properties may contribute to the biomechanical regulation of growth in some bones. Periostea of the pig mandibular body, zygomatic arch and metacarpal were loaded to failure under continuous tension. Each tissue type was tested in both the long-axis and transverse orientation. Stiffness, peak stress and peak strain were compared between orientations and among regions. Within the zygomatic periosteum there was little indication of regional difference, and neither zygomatic nor mandibular periosteum showed directional differences. The metacarpal periosteum showed a directional effect only in peak strain, which was greater longitudinally than transversely. There were striking differences, however, among the periostea of the three bones. The zygomatic arch periosteum was the stiffest tissue (91.7+/-30.5 MPa) and showed the highest strength (12.3+/-4.6 MPa). The metacarpal periosteum demonstrated slightly lower stiffness and strength (84.7+/-35.1 and 11.3+/-5.3 MPa), and peak strains in zygomatic and metacarpal periostea were similarly high (17.7+/-3.7 and 17.9+/-3.7 MPa, respectively). The periosteum of the mandibular body was the most deformable tissue (63.0+/-25.4 MPa), with the lowest-peak strain (15.6+/-3.0 MPa) and the least strength (8.2+/-4.1 MPa). These results correspond with those of previous work in long bones, in that periosteum interfacing with ligament or muscle (e.g. zygomatic, metacarpal) demonstrates greater stiffness and strength than periosteum adjacent to loose connective tissue (e.g. mandibular body). Therefore, the degree to which the periosteal tissue serves as a functional interface between bone and muscle is reflected in the different failure properties of periostea from different bones. The structural fortification of the zygomatic arch periosteum relative to other periosteal tissues suggests a role for the periosteum in stabilizing the zygomatic arch-muscle functional complex. On the other hand, the similar failure properties of zygomatic and squamosal periostea from the zygomatic arch mean that the differential growth of these bones cannot be attributed to mechanical stimuli intrinsic to the periosteal tissue.

[Studies on the experimental transmission of Rattus-borne Hantavirus by Ornithonyssus bacoti]

AIM

To demonstrate the role of rat mite (Ornithonyssus bacoti) in the transmission of Rattus-borne hemorrhagic fever with renal syndrome (HFRS).

METHODS

In the transmission experiments, about 100 O. bacoti per pool were isolated and placed in a jar, unfed for 4 d at 23 +/- 1 degrees C. Suckling Wistar rats inoculated with Hantavirus strain Z45 or Seoul virus strain UR were placed in each jar for free attack by the mites for 12 hours. After 14 d the normal suckling Wistar rats were bitten by the mites. Fifteen days later, the lung tissues and sera of the infected rats were collected and detected for Hantaviral antigen by indirect fluorescent antibody technique (IFAT). For demonstration of the infection of O. bacti with Rattus-borne Hantavirus PCR technique was applied to detect Rattus-borne Hantaviral RNA.

RESULTS

Sukling Wistar rats inoculted Hantavirus strain Z45 or Seoul virus strain UR were bitten by O. bacoti and then these mites were fed on 4 and 5 of normal suckling rats in each jar, respectively. The antigens of Hantavirus strain Z45 were positive in all the lungs of the normal rats bitten by the mites, the sera titers of the rats were from 1:10 to 1:40. The antigens were positive in 3 of the 4 rats, the sera titers were from 1:20 to 1:40. Both of the viruses could be maintained in O. bacoti for 22 days. The blocking test showed when 1:30 Hantavirus immunosera were exposed to the lung samples and then reacted with the sera from the patients with HFRS, all the specific fluorescence reactions of the samples were blocked, whereas the control group including the normal rat lung tissues and sera were all negative (Fig. 1).

CONCLUSION

O. bacoti might play a role as the vector of HFRS and a reservoir host as well.

Using novel variable transformations to enhance conformational sampling in molecular dynamics

One of the computational "grand challenges" is to develop methodology capable of sampling conformational equilibria in systems with rough energy landscapes. Here, a significant step forward is made by combining molecular dynamics with a novel variable transformation designed to enhance sampling by reducing barriers without introducing bias and, thus, to preserve, perfectly, equilibrium properties.

Genome segment S8 of grass carp hemorrhage virus encodes a virion protein

The complete nucleotide sequence of the genome segment S8 of grass carp hemorrhage virus (GCHV) was determined from cDNA corresponding to the viral genomic RNA. It is 1,287 nucleotides in length and contains a large open reading frame that could encode a protein of 409 amino acids with a predicted molecular mass of 44 kD. The S8 was expressed using the pET fusion protein vector and detected by Western blotting analysis using the chicken egg IgY against intact GCHV particles, indicating that S8 encodes a virion protein. Amino acid sequence comparisons revealed that the protein encoded by S8 is closely related to protein sigma2 of mammalian reovirus, suggesting that the deduced protein of S8 is an inner capsid protein.

Determinants of the broad recognition of exocytic Rab GTPases by Mss4

Rab GTPases function as essential regulators of vesicle transport between subcellular compartments of eukaryotic cells. Mss4, an evolutionarily conserved Rab accessory factor, facilitates nucleotide release and binds tightly to the nucleotide-free form of exocytic but not endocytic Rab GTPases. A structure-based mutational analysis of residues that are conserved only in exocytic Rab GTPases reveals three residues that are critical determinants of the broad specificity recognition of exocytic Rab GTPases by Mss4. One of these residues is located at the N-terminus of the switch I region near the nucleotide binding site whereas the other two flank an exposed hydrophobic triad previously implicated in effector recognition. The spatial disposition of these residues with respect to the structure of Rab3A correlates with the dimensions of the elongated Rab interaction epitope in Mss4 and supports a mode of interaction similar to that of other exchange factor-GTPase complexes. The complementarity of the corresponding interaction surfaces suggests a hypothetical structural model for the complex between Mss4 and Rab GTPases.

Optimizing nitrogen management in food and energy production and environmental protection: summary statement from the Second International Nitrogen Conference

Human efforts to produce food and energy are changing the nitrogen (N) cycle of the Earth. Many of these changes are highly beneficial for humans, while others are detrimental to people and the environment. These changes transcend scientific disciplines, geographical boundaries, and political structures. They challenge the creative minds of natural and social scientists, economists, engineers, business leaders, and decision makers. The Second International Nitrogen Conference was designed to facilitate communications among all stakeholders in the "nitrogen community" of the world. The Conference participants" goal in the years and decades ahead is to encourage every country to make optimal choices about N management in food production and consumption, energy production and use, and environmental protection. Scientific findings and recommendations for decision makers that emerged from the Conference are presented.

Synthesis and ring-expanding oligomerization of an extremely strained macrocyclic aromatic ether-sulfone

[reaction: see text] An extremely strained, 5-ring, macrocyclic aromatic ether-sulfone, [-1,4-C(6)H(4)SO(2)-1,4-C(6)H(4)O-1,3-C(6)H(4)O-1,4-C(6)H(4)SO(2)-1,4-C(6)H(4)-], synthesized by nickel-catalyzed intramolecular coupling of a bis-chlorophenylene-terminated precursor, undergoes fluoride-promoted ring expansion in dilute solution, giving a series of higher macrocyclic oligomers including cyclic dimer, trimer, and tetramer. The latter contains 20 aromatic residues in a 92-atom ring and is one of the largest synthetic organic macrocycles to be crystallographically characterized. The synthesis, structure, and ring expansion of a related macrocyclic ether-ketone are also reported.