Chinese herbal medicine for irritable bowel syndrome.
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Colonic Diseases, Functional↗
Biomedical subjects
W Lu
Publications and source records attributed to W Lu.
HLA-unrestricted killing of HIV-1 gag protein-expressing CD4 T cells by gag-specific CD8 cytotoxic T cells.
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B-Lymphocytes↗
Activation of an MDM2-specific caspase by p53 in the absence of apoptosis.
Cells undergoing p53-mediated apoptosis activate caspase 3-like activities, resulting in the cleavage of the MDM2 oncoprotein and other apoptotic substrates such as poly(ADP-ribose) polymerase. To investigate the mechanism of p53-mediated apoptosis and to determine whether cleavage of MDM2 has a potential role in regulating p53, we examined caspase activation and cleavage of MDM2 in a cell line undergoing p53-mediated growth arrest and delayed apoptosis. We found that in H1299 cells expressing a temperature-sensitive human p53, a distinct caspase activity specific for the MDM2 cleavage site DVPD is induced by p53 prior to the onset of apoptosis and loss of viability. This is accompanied by the cleavage of MDM2 but not the apoptotic substrate poly(ADP-ribose) polymerase. The cleaved MDM2 loses the ability to promote p53 degradation and may potentially function in a dominant-negative fashion to stabilize p53. These results suggest that p53 activation may induce a positive feedback effect by cleavage of MDM2 through a unique caspase.
Apoptosis↗
Fibroblast growth factor-10. A second candidate stromal to epithelial cell andromedin in prostate.
Fibroblast growth factor (FGF)-10, a homologue of FGF-7, is expressed significantly in normal rat prostate tissue, well differentiated rat prostate tumors with an epithelial and stromal compartment and only in derived prostate stromal cells in culture. Similar to FGF-7, recombinant rat FGF-10 was a specific mitogen for prostate epithelial cells. In contrast to FGF-7 which is widely expressed among stromal cells in tissues, the expression of FGF-10 correlated with the presence of stromal cells of muscle origin. Radioreceptor binding assays and covalent cross-linking analysis revealed that FGF-10 binds with an affinity equal to FGF-7 to resident epithelial cell receptor, FGFR2IIIb, but unlike FGF-7 also binds the IIIb splice variant of FGFR1. Analysis of mRNA expression by RNase protection revealed that, similar to FGF-7, the expression of FGF-10 was responsive to androgen in stromal cells from normal prostate and non-malignant differentiated tumors. Although FGF-10 cDNA exhibits a signal sequence for secretion, cultured stromal cells exhibit strictly a cell-associated FGF-10 antigen that correlates with an alternately translated intracellular isoform. FGF-10 requires 1.4 times higher NaCl for elution from immobilized heparin than does FGF-7 and binds to four times the number of sites on the pericellular matrix of epithelial cells. The results show that prostate stromal cell-derived FGF-10, like FGF-7, exhibits the properties of an andromedin which may indirectly mediate control of epithelial cell growth and function by androgen. Although FGF-10 and FGF-7 bind and activate the same resident epithelial cell receptor (FGFR2IIIb), differences in cell type of origin, compartmentation by alternate translation, the affinity for FGFR1IIIb, and access to FGFR by differential interaction with pericellular matrix heparan sulfate suggest they may play both independent and compensatory roles in prostate homeostasis.
Animals↗
Traumatic instabilities of the cervical spine caused by high-speed axial compression in a human model. An in vitro biomechanical study.
STUDY DESIGN: Traumatic injury of the cervical spine was produced on human cadavers and evaluated with instability tests and radiographs. OBJECTIVE: To relate traumatic injuries of the cervical spine to instability and patterns of traumatic injury to different levels of impact energy. SUMMARY OF BACKGROUND DATA: Data from young human cadavers are rare in traumatic models of the cervical spine, and instabilities caused by axial compression with different impacts remain unknown. METHODS: Fourteen cervical spine specimens (C2-C4) obtained from fresh human cadavers were divided evenly into two groups and subjected to axial compressive impact with 30 J and 50 J impact energy, respectively. Pure moments in flexion-extension, left/right lateral bending, and left/right axial rotation were applied to each specimen before and after trauma. The maximum moment was 2.0 Nm in each case. Ranges of motion and neutral zones were measured using stereophotogrammetry. RESULTS: Ranges of motion and neutral zones for both groups increased after trauma. No bony injury was observed on the radiographs after trauma with 30 J, but motions increased significantly in flexion, extension, and axial rotation. All specimens showed bony injuries after trauma with 50 J, whereas motions continued to increase significantly in all directions. The relative neutral zone values were larger than the corresponding range of motion values, except in flexion-extension after trauma with 50 J. CONCLUSIONS: The injury patterns of the cervical spine were associated with impact energy, and a high level of impact energy could produce either three-column injury or anterior middle-column injury. Instabilities of the cervical spine caused by compressive trauma increased with the level of impact energy. The neutral zone was more sensitive than the range of motion in representing spinal instability, whereas instability testing was more sensitive than radiographs in evaluating traumatic injury of cervical spine.
Adult↗
Suppression of angiogenesis, tumorigenicity, and metastasis by human prostate cancer cells engineered to produce interferon-beta.
We determined whether the IFN-beta gene can be used to suppress angiogenesis, tumor growth, and metastasis of human prostate cancer cells growing in the prostate of nude mice. Highly metastatic PC-3M human prostate cancer cells were engineered to constitutively produce murine IFN-beta subsequent to infection with a retroviral vector containing murine IFN-beta cDNA. Parental (PC-3M-P), control vector-transduced (PC-3M-Neo), and IFN-beta-transduced (PC-3M-IFN-beta) cells were injected into the prostate (orthotopic) or subcutis (ectopic) of nude mice. PC-3M-P and PC-3M-Neo cells produced rapidly growing tumors and regional lymph node metastases, whereas PC-3M-IFN-beta cells did not. PC-3M-IFN-beta cells also suppressed the tumorigenicity of bystander nontransduced prostate cancer cells. PC-3M-IFN-beta cells produced small tumors (3-5 mm in diameter) in nude mice treated with anti-asialo GM1 antibodies and in severe combined immunodeficient/Beige mice. Immunohistochemical staining revealed that PC-3M-IFN-beta tumors were homogeneously infiltrated by macrophages, whereas control tumors contained fewer macrophages at their periphery. Most tumor cells in the control tumors were stained positive by an antibody to proliferative cell nuclear antigen; very few were positively stained by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling. In sharp contrast, PC-3M-IFN-beta tumors contained fewer proliferative cell nuclear antigen-positive cells and many terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling-positive cells. Staining with antibody against CD31 showed that control tumors contained more blood vessels than PC-3M-IFN-beta tumors. PC-3M-IFN-beta cells were more sensitive to lysis mediated by natural killer cells in vitro or to cytostasis mediated by macrophages than control transduced cells. Conditioned medium from PC-3M-IFN-beta cells augmented splenic cell-mediated cytolysis to control tumor cells, which could be neutralized by antibody against IFN-beta. Collectively, the data suggest that the suppression of tumorigenicity and metastasis of PC-3M-IFN-beta cells is due to inhibition of angiogenesis and activation of host effector cells.
Animals↗
Mechanism of activation of Pak1 kinase by membrane localization.
Pak kinases are a family of serine/threonine protein kinases homologous to Ste20p of yeast. Paks can be activated in vivo and in vitro by binding to GTP-bound Cdc42 and Rac1, members of the Rho family of small GTPases implicated in regulating the organization of the actin cytoskeleton. We have previously reported that the SH2/SH3-containing adaptor protein Nck binds Pak kinase through its second SH3 domain. Pak1 can be targeted to the membrane by Nck in response to tyrosine phosphorylation, and membrane association of Pak1 is sufficient to increase its specific activity. The mechanism whereby Pak is activated by membrane localization, however, is unknown. We show here that expression of three proteins that inhibit Rho-family GTPases by different mechanisms (RhoGDI, Bcr and D57Y Cdc42) all block the activation of Pak by a membrane-targeted Nck SH3 domain, demonstrating that the in vivo activation of Pak1 induced by membrane localization is dependent on Rho-family GTPases. This implies that Pak activity can be regulated in cells both by the level of GTP loading of various Rho-family GTPases and the local concentration of Pak relative to these GTPases. Our data also suggest the existence of Rho-family GTPases in addition to Cdc42 and Rac1 that can activate Pak on membranes.
Cell Cycle Proteins↗
Common and specific determinants for fibroblast growth factors in the ectodomain of the receptor kinase complex.
The assembly and activation of oligomeric complexes of FGF, the transmembrane receptor kinase (FGFR), and heparan sulfate transmit intracellular signals regulating growth and function of cells. An understanding of the structural relationships between the three subunits and their redundancy and specificity is essential for understanding the ubiquitous FGF signaling system in health and disease. Previously, we reported that a primary heparin or heparan sulfate binding site resides in a distinct sequence in immunoglobulin (Ig)-like module II of the three modules of FGFR. Here we report that in the absence of flanking sequences, isolated Ig module II of FGFR1 supports the binding of FGF-1, FGF-2, and FGF-7 in respective order of affinity. None of the three FGFs detectably bind Ig module I or the IIIb and IIIc splice variants of Ig module III in the absence of flanking sequences. Ig module I and the C-terminus of Ig module III are dispensable for high-affinity binding of FGF-1, FGF-2, and FGF-7. Alterations in highly conserved Ig module II in the heparin binding domain and substitution of individual sequence domains spanning the entire sequence of Ig module II with those from Ig module I obliterated FGF binding. Addition of a specific number of FGFR sequences to the C-terminus of Ig module II resulted in a gain in affinity for FGF-7. Several site-specific alterations in the C-terminus of full-length FGFR1IIIc, an isoform that otherwise absolutely rejects FGF-7, resulted in gain of FGF-7 binding. These results suggest that a complex of Ig module II and heparan sulfate is the base common active core of the FGFR ectodomain and that flanking structural domains modify FGF affinity and determine specificity.
Amino Acid Sequence↗
Repeated amphetamine administration alters AMPA receptor subunit expression in rat nucleus accumbens and medial prefrontal cortex.
Glutamate is critical for the induction and maintenance of behavioral sensitization and associated neuroadaptations in the mesocorticolimbic dopamine (DA) system. We have shown previously [Lu et al. (1997) Synapse 26:269-280] that repeated amphetamine administration alters AMPA receptor subunit mRNA levels in rat nucleus accumbens (NAc) and medial prefrontal cortex (PFC). The present study determined if amphetamine elicits corresponding changes in AMPA receptor subunit immunolabeling. Rats were injected with amphetamine sulphate (5 mg/kg/day) or saline for 5 days and perfused 3 or 14 days after the last injection. AMPA receptor subunit immunolabeling was quantified using autoradiographic immunocytochemistry. In the NAc, GluR1 and GluR2 immunolabeling were unchanged after 3 days of withdrawal, but both were decreased significantly after 14 days of withdrawal (GluR1, 85.5+/-2.6% of control group, P<0.01; GluR2, 79.2+/-3.2%, P<0.01). Analysis of core and shell subregions at the 14-day withdrawal time indicated that GluR1 immunolabeling decreased significantly in shell, while GluR2 immunolabeling decreased significantly in both core and shell. No changes in GluR2/3, GluR2/4, or GluR4 immunolabeling in NAc were found at either withdrawal time. In the PFC, GluR1 immunolabeling increased after 3 days of withdrawal (115.3+/-7.0%, P<0.01) but returned to control levels after 14 days. The present results correspond well with our previous findings at the mRNA level. These alterations in AMPA receptor expression may account for previously described changes in the electrophysiological responsiveness of NAc and PFC neurons to glutamate and AMPA. Along with alterations in DA function, they may contribute to drug-induced dysregulation of reward-related neurotransmission.
Amphetamine↗
Synthesis of 9Z,11E-octadecadienoic and 10E,12Z-octadecadienoic acids, the major components of conjugated linoleic acid.
Linoleic acid was efficiently converted into the two major components of conjugated linoleic acid, 9Z,11E-octadecadienoic (1a) and 10E,12Z-octadecadienoic acid (1b) using either the superbase (n-butyllithium/potassium tert-butoxide) or by simply refluxing with KOH in 1-butanol. In turn, 1a and 1b were separated from each other using the lipase from Aspergillus niger via stereoselective esterification in 1-butanol. This enzyme has a preference for the 9Z,11E isomer, 1a, and has excellent selectivity. This method has allowed the ready preparation of gram quantities of 1a and 1b in their highly purified forms, which are not readily accessible by current methods.
Animals↗
Probing intermolecular backbone H-bonding in serine proteinase-protein inhibitor complexes.
BACKGROUND: Intermolecular backbone H-bonding (N-H.O=C) is a common occurrence at the interface of protein-protein complexes. For instance, the amide NH groups of most residues in the binding loop of eglin c, a potent serine proteinase inhibitor from the leech Hirudo medicinalis, are H-bonded to the carbonyl groups of residues in the target enzyme molecules such as chymotrypsin, elastase and subtilisins. We sought to understand the energetic significance of these highly conserved backbone-backbone H-bonds in the enzyme-inhibitor complexes. RESULTS: We synthesized an array of backbone-engineered ester analogs of eglin c using native chemical ligation to yield five inhibitor proteins each containing a single backbone ester bond from P3 to P2' (i.e. -CONH-to -COO-). The structure at the ligation site (P6-P5) is essentially unaltered as shown by a high-resolution analysis of the subtilisin-BPN'-eglin c complex. The free-energy changes (DeltaDeltaGNH-->O) associated with the binding of ester analogs at P3, P1 and P2' with bovine alpha-chymotrypsin, subtilisin Carlsberg and porcine pancreatic elastase range from 0-4.5 kcal/mol. Most markedly, the NH-->O substitution at P2 not only stabilizes the inhibitor but also enhances binding to the enzymes by as much as 500-fold. CONCLUSIONS: Backbone H-bond contributions are context dependent in the enzyme-eglin c complexes. The interplay of rigidity and adaptability of the binding loop of eglin c seems to play a prominent role in defining the binding action.
Amino Acid Sequence↗
Stereoselective total synthesis of (3R,8S)-falcarindiol, a common polyacetylenic compound from umbellifers
The first stereoselective total synthesis of (3R,8S)-falcarindiol (1) from L-tartaric acid and D-xylose is reported, via the Cadiot-Chodkiczwicz reaction, to couple 1-bromoalkyne (2) with 3(R)-(tert-butyldiphenylsilyloxy)-1-penten-4-yne (3).
Journal Article↗
Equivalent amplification of intrinsically variable nucleic acid sequences by multiple-primer-induced overlapping amplification assay: applications for universal detection and quantitation.
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Cloning, Molecular↗
Late onset of renal and hepatic cysts in Pkd1-targeted heterozygotes.
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Age Factors↗
Withdrawal from repeated amphetamine administration reduces NMDAR1 expression in the rat substantia nigra, nucleus accumbens and medial prefrontal cortex.
Glutamate plays a critical role in neuroadaptations induced by drugs of abuse. This study determined whether expression of the NMDAR1 subunit of the NMDA receptor is altered by repeated amphetamine administration. We quantified NMDAR1 mRNA (using in situ hybridization with 35S-labelled oligonucleotide probes) and immunolabelling (using immunocytochemistry with 35S-labelled secondary antibodies) in rat ventral midbrain, nucleus accumbens and prefrontal cortex after 3 or 14 days of withdrawal from five daily injections of saline or amphetamine sulphate (5 mg/kg/day). No changes in NMDAR1 expression were observed after 3 days of withdrawal, whereas significant decreases were observed in all regions after 14 days. NMDAR1 mRNA levels in midbrain were too low for reliable quantification, but immunolabelling was decreased significantly in intermediate and caudal portions of the substantia nigra. This may indicate a reduction in excitatory drive to substantia nigra dopaminergic neurons. In the nucleus accumbens, there were significant decreases in NMDAR1 mRNA levels (74.8 +/- 7. 7% of control, P < 0.05) and immunolabelling (76.7 +/- 4.4%, P < 0. 05). This may account for previously-reported decreases in the electrophysiological responsiveness of nucleus accumbens neurons to NMDA after chronic amphetamine treatment, and contribute to dysregulation of goal-directed behaviour. In prefrontal cortex, there was a significant decrease in NMDAR1 mRNA levels (76.1 +/- 7. 1%, P < 0.05) and a trend towards decreased immunolabelling (89.5 +/- 7.0%). This may indicate decreased neuronal excitability within prefrontal cortex. A resultant decrease in activity of excitatory prefrontal cortical projections to nucleus accumbens or midbrain could synergize with local decreases in NMDAR1 to further reduce neuronal excitability in these latter regions.
Amphetamine↗
Intramedullary fixation by resorbable rods in a comminuted phalangeal fracture model. A biomechanical study.
The mechanical rigidity of three different methods of resorbable intramedullary fixation (bone peg, and polyglycolide rods with and without interlocking) was assessed in a comminuted phalangeal fracture model and the results compared with two commonly used internal fixation devices (lateral plate, crossed K-wires) in a cadaver model. Each fixation technique was tested for its biomechanical strength in apex palmar bending, compression and torsion. Failure testing for the three resorbable methods was also done. The results showed that lateral plating provided the best rigidity in apex palmar bending and torsion, followed by intramedullary bone peg fixation. All resorbable intramedullary fixations had rigidity that was at least the same as crossed K-wires. For the torque test, polyglycolide rods with interlocking provided better rigidity than without interlocking. There was no significant difference between the different methods in the compression test, except that the intramedullary bone peg was significantly stiffer than K-wires.
Biomechanical Phenomena↗
Lessons from analysis of World Wide Web server activity data: http://www.swsahs.nsw.gov.au/livtrauma.
OBJECTIVE: To establish visiting patterns and use of resources within an educational world wide web site, to develop strategies for its more effective use as a teaching medium. DESIGN: Prospective descriptive study. SETTING: A web site maintained by a major Australian metropolitan trauma service. SUBJECTS: All visitors to the web site over a 40 day period. MAIN OUTCOME MEASURES: Number of visitors, requests for pages, and transfer of files; timing and duration of visits; first and last pages viewed during visits; pages viewed most often; source of referral and country of origin of visitors. RESULTS: There were 2237 visits, and a mean of 5.8 pages/visit were viewed. Mean duration of each visit was 4 minutes 35 seconds, and only half the visitors entered through the home page. The collection of radiographs was most commonly consulted. Visitors came from 26 different countries, 42% from Australia. CONCLUSIONS: Factors that influenced the use of the site were identified and have altered our plans for development.
Australia↗
Image/patient registration from (partial) projection data by the Fourier phase matching method.
A technique for 2D or 3D image/patient registration, PFPM (projection based Fourier phase matching method), is proposed. This technique provides image/patient registration directly from sequential tomographic projection data. The method can also deal with image files by generating 2D Radon transforms slice by slice. The registration in projection space is done by calculating a Fourier invariant (FI) descriptor for each one-dimensional projection datum, and then registering the FI descriptor by the Fourier phase matching (FPM) method. The algorithm has been tested on both synthetic and experimental data. When dealing with translated, rotated and uniformly scaled 2D image registration, the performance of the PFPM method is comparable to that of the IFPM (image based Fourier phase matching) method in robustness, efficiency, insensitivity to the offset between images, and registration time. The advantages of the former are that subpixel resolution is feasible, and it is more insensitive to image noise due to the averaging effect of the projection acquisition. Furthermore, the PFPM method offers the ability to generalize to 3D image/patient registration and to register partial projection data. By applying patient registration directly from tomographic projection data, image reconstruction is not needed in the therapy set-up verification, thus reducing computational time and artefacts. In addition, real time registration is feasible. Registration from partial projection data meets the geometry and dose requirements in many application cases and makes dynamic set-up verification possible in tomotherapy.
Algorithms↗