Recombinant forms of glycophorin C as a tool for characterization of epitopes for new murine monoclonal antibodies with anti-glycophorin C specificity

Glycophorin C (GPC) and glycophorin D (GPD) are minor but important components of human RBC membranes. They carry the high-frequency antigens Ge2, Ge3 and Ge4 of the Gerbich blood group system. The epitopes for five new monoclonal antibodies (MoAbs) with anti-GPC specificity were characterized. Two antibodies (4G11 and 5B11) reacted with glycosylated N-terminal epitopes, and three reacted with internal epitopes of GPC. Pepscan analysis showed that the MoAb RB11 required for binding the EPDP sequence, occurring twice in GPC polypeptide chain. The MoAb 7F11 recognized the sequence 13PLSLEPDP20, and the MoAb RB8 did not react with synthetic peptides. Further characterization of the internal epitopes was performed in fluorescence-activated cell sorter (FACS) with the use of recombinant GPC and its variant forms transiently expressed on COS-7 cells. The results indicated that the MoAb RB11 recognized distinctly its target sequence EPDP only in a normal GPC molecule. The reactivity of the MoAb 7F11 with the PLSLEPDP sequence was confirmed and found to be enhanced by the O-glycan at the Ser15 residue. The MoAb RB8 recognized the glycopeptidic epitope in proximity to the Ser15 residue, requiring the presence of O-glycan. The combination of immunochemical techniques with the use of the recombinant forms of GPC has made it possible to define the role of sugar chains in the recognition of peptidic epitopes in glycosylated antigen and sheds new light on the Gerbich system antigens.

beta-Catenin alteration in cancer of the ampulla of Vater

To investigate the contribution of beta-catenin to the development of carcinoma of the ampulla of Vater, genetic alterations of beta-catenin gene, CTNNB-1 were searched. Mutational analysis of exon3 in CTNNB-1, which encodes the serine/threonine residues for GSK-3beta phosphorylation sites, was performed on 21 cases of carcinoma of the ampulla of Vater, by means of polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) followed by nucleotide sequencing. We found one deleted mutation at codon 32 to approximately 65 in one case of carcinoma of the ampulla of Vater. We also analyzed subcellular localization of beta-catenin protein in all cases immunohistochemically, and confirmed its accumulation in the nucleus in four cases including in a CTNNB-1 mutated one. This is the first study to show CTNNB-1 mutation and beta-catenin expression in carcinoma of the ampulla of Vater. These results suggested that abnormal Wnt-wingless signaling and in particular beta-catenin alteration caused accumulation of beta-catenin, which might partially contribute to the development of carcinoma of the ampulla of Vater.

CHIP is a chaperone-dependent E3 ligase that ubiquitylates unfolded protein

The ubiquitin-proteasome system catalyses the immediate destruction of misfolded or impaired proteins generated in cells, but how this proteolytic machinery recognizes abnormality of cellular proteins for selective elimination remains elusive. Here, we report that the C-terminus of Hsc70-interacting protein (CHIP) with a U-box domain is an E3 ubiquitin-ligase collaborating with molecular chaperones Hsp90 and Hsc70. Thermally denatured firefly luciferase was multiubiquitylated by CHIP in the presence of E1 and E2 (Ubc4 or UbcH5c) in vitro, only when the unfolded substrate was captured by Hsp90 or Hsc70 and Hsp40. No ubiquitylating activity was detected in CHIP lacking the U-box region. CHIP efficiently ubiquitylated denatured luciferase trapped by the C-terminal region of Hsp90, which contains a CHIP binding site. CHIP also showed self-ubiquitylating activity independent of target ubiquitylation. Our results indicate that CHIP can be regarded as 'a quality-control E3' that selectively ubiquitylates unfolded protein(s) by collaborating with molecular chaperones.

Texture analysis of fluorescence lifetime images of AT- and GC-rich regions in nuclei

We used intensity and fluorescence lifetime microscopy (FLIM) of 3T3 nuclei to investigate the existence of AT-rich and GC-rich regions of the nuclear DNA. Hoechst 33258 (Ho) and 7-aminoactinomycin D (7-AAD) were used as fluorescence probes specific for AT and GC base pairs, respectively. YOYO-1 (Yo) was used as a dye that displays distinct fluorescence lifetimes when bound to AT or GC base pairs. We combined fluorescence imaging of Ho and 7-AAD with time-resolved measurements of Yo and took advantage of an additional information content of the time-resolved fluorescence. Because a single nucleus could not be stained and measured with all three dyes, we used texture analysis to compare the spatial distribution of AT-rich and GC-rich DNA in 100 nuclei in different phases of the cell cycle. The fluorescence intensity-based analysis of Ho- or 7-AAD-stained images indicates increased number and larger size of the DNA condensation centers in the G2/M-phases compared to G0/1-phases. The lifetime-based study of Yo-stained images suggests spatial separation of the AT- or GC-rich DNA regions in the G2/M-phase. Texture analysis of fluorescence intensity and lifetime images was used to quantitatively study the spatial change of condensation and separation of AT- and GC-rich DNA during the cell cycle.

Substrate recognition mechanism of carboxypeptidase Y

To clarify the substrate-recognition mechanism of carboxypeptidase Y, Fmoc-(Glu)n Ala-OH (n = 1 to 6), Fmoc-(Glu)n Ala-NH2 (1 to 5), and Fmoc-Lys(Glu)3Ala-NH2 were synthesized, and kinetic parameters for these substrates were measured. Km for Fmoc-peptides significantly decreased as peptide length increased from n = 1 to n = 5 with only slight changes in kcat. Km for Fmoc-(Glu)(5,6)Ala-OH were almost the same as one for protein substrates described previously (Nakase et al., Bull. Chem. Soc. Jpn., 73, 2587-2590). These results show that the enzyme has six subsites (S1' and S1-S5). Each subsite affinity calculated from the Km revealed subsite properties, and from the differences of subsite affinity between pH 6.5 and 5.0, the residues in each subsite were predicted. For Fmoc-peptide amide substrates, the priorities of amidase and carboxamide peptidase activities were dependent on the substrate. It is likely that the interactions between side chains of peptide and subsites compensate for the lack of P1'-S1' interaction, so the amidase activity prevailed for Fmoc-(Glu)(3,5)Ala-NH2. These results suggest that these subsites contribute extensively to substrate recognition rather than a hydrogen bond network.

Dye sensitization of nanocrystalline titanium dioxide with square planar platinum(II) diimine dithiolate complexes

A series of platinum-based sensitizers of the general type Pt(NN)(SS), where NN is 4,4'-dicarboxy-2,2'-bipyridine (dcbpy) or 4,7-dicarboxy-1,10-phenanthroline (dcphen) and SS is ethyl-2-cyano-3,3-dimercaptoacrylate (ecda), quinoxaline-2,3-dithiolate (qdt), 1,2-benzenedithiolate (bdt), or 3,4-toluenedithiolate (tdt), that have various ground-state oxidation potentials has been synthesized and anchored to nanocrystalline titanium dioxide electrodes for light-to-electricity conversion in regenerative photoelectrochemical cells with an I(-)/I(-)(3) acetonitrile electrolyte. The intense mixed-Pt/dithiolate-to-diimine charge-transfer absorption bands in this series could be tuned from 440 to 580 nm by choosing appropriate dithiolate ligands, and the highest occupied molecular orbitals varied by more than 500 mV. Spectrophotometric titration of the Pt(dcphen)(bdt) complex exhibits a ground-state pK(a) value of 3.2 +/- 0.1, which can be assigned to the protonation of the carboxylate group of the dcphen ligand. Binding of Pt(dcbpy)(qdt) to porous nanostructured TiO(2) films was analyzed using the Langmuir adsorption isotherm model, yielding an adsorption equilibrium constant of 4 x 10(5) M(-1). The amount of dye adsorbed at the surface of TiO(2) films was 9.5 x 10(-8) mol/cm(2), which is ca. 50% lower than the full monolayer coverage. The resulting complexes efficiently sensitized TiO(2) over a notably broad spectral range and showed an open-circuit potential of ca. 600 mV with an impressive fill factor of > 0.70, making them attractive candidates for solar energy conversion applications. The visible spectra of the 3,4-toluenedithiol-based sensitizers showed an enhanced red response, but the lower photocurrent efficiency observed for these sensitizers stems in part from a sluggish halide oxidation rate and a fast recombination of injected electrons with the oxidized dye.

Prediction of the permanent dentition in deciduous anterior crossbite

Early prospective evaluation for self-correction of deciduous anterior crossbite can enable identification of patients who require early treatment as well as those who do not. The purpose of the present study was to generate an algorithm that can be used to predict self-correction in the transitional dentition in 3-year-old subjects. The subjects were divided into 2 groups. One group comprised 22 subjects whose anterior crossbite self-corrected during the transitional stage (hereafter referred to as group N). The other group was comprised of 22 subjects whose anterior crossbite persisted during the transitional dentition (hereafter referred to as group R). All subjects were examined using lateral cephalometric radiography in order to evaluate differences in occlusion. Fifteen measurements were used for the evaluation. For each measurement, the variance ratio and the difference in the population mean between groups N and R were tested and t-values were derived. Based on the Student's t-test results, only measurements that had statistically significant differences (P < .05) were extracted. Predictor variables that had a partial F value of 5 or greater were selected for stepwise discriminant analysis, and the following equation was obtained: deciduous indicator (DI) = -0.58(cranial length anterior) + 1.31(posterior facial height) - 0.76(porion location) - 2.02(Wits appraisal) - 70.28. The lower the DI value (negative), the higher the probability that the crossbite will self-correct at the transitional dentition. On the other hand, a high (positive) discriminant score strongly suggests that the subject requires treatment in the primary dentition. The result of this analysis showed that the apparent error rate was 95.46% and the Maharanobis' generalized distance was 8.99.

Upregulation of Bcl-2 through caspase-3 inhibition ameliorates ischemia/reperfusion injury in rat cardiac allografts

BACKGROUND

Oxidative stress after ischemia/reperfusion of cardiac allografts leads to cytokine production. Bcl-2, an inhibitor of apoptosis, also has strong antioxidant properties. Caspase-3 is known to cleave bcl-2. This study tests the hypothesis that bcl-2 is downregulated while tumor necrosis factor-alpha (TNF-alpha) levels increase after cardiac transplantation. Furthermore, the use of caspase-3 inhibition was investigated as a strategy for preserving myocardial bcl-2 and mitochondrial cytochrome c after transplantation.

METHODS AND RESULTS

PVG-to-ACI rat heterotopic cardiac transplantations were performed in 4 groups designed with 30 minutes' ischemia and 4 or 8 hours of reperfusion (n=4 per group). Treatment consisted of DEVD-CHO 500 microgram IP per animal to donor and recipient 2 hours before transplantation and 250 microgram IC into allograft. Controls were treated with saline. Grafts were analyzed by reverse transcription-polymerase chain reaction for bcl-2 mRNA, by ELISA for TNF-alpha, for myeloperoxidase activity, and by Western blot for cytochrome c. In untreated groups, bcl-2 mRNA decreased significantly over time, whereas TNF-alpha increased significantly at 4 hours (P=0.003) and returned to baseline after 8 hours' reperfusion (P=NS compared with normal hearts). Treatment with caspase-3 inhibitor showed significant upregulation of bcl-2 mRNA expression after 4 and 8 hours of reperfusion (P<0.001 versus control), with a concomitant decrease in TNF-alpha to baseline levels. Myeloperoxidase activity in all groups was no different from that of normal hearts. Mitochondrial cytochrome c release increased in both control and treatment groups.

CONCLUSIONS

Bcl-2 is actively downregulated and TNF-alpha is upregulated in this model of cardiac allograft ischemia/reperfusion. Furthermore, the caspase-3 pathway is linked to this process, and blockade of caspase-3 can ameliorate reperfusion injury by upregulating bcl-2 and inhibiting TNF-alpha without affecting cytochrome c release.

Hepatic falciform artery: angiographic observations and significance

BACKGROUND

The purpose of this study was to assess the angiographic incidence and appearance of the hepatic falciform artery (HFA) and discuss its clinical significance.

METHODS

Hepatic angiograms of 53 patients obtained with digital subtraction angiography were prospectively evaluated with regard to incidence, anatomic features, and flow speed of the HFA. We analyzed whether the background of chronic liver disease affected the incidence of the HFA. Transcatheter arterial chemoinfusion or chemoembolization for liver tumors was performed in 33 patients. We noted the occurrence of supraumbilical skin complications.

RESULTS

The HFA was observed in 13 (24.5%) of 53 patients on celiac or common hepatic angiograms. The blood flow of the HFA was slower than that of the peripheral hepatic arteries in all patients. No significant difference in the incidence of HFA between the 34 patients with chronic liver disease and the 19 patients with normal livers was found. One treated patient with an HFA and a history of gastrectomy developed a supraumbilical red skin rash.

CONCLUSION

The angiographic incidence of the HFA is more common than previously reported. The delayed and persistent opacification of the HFA on hepatic angiograms caused by its slow blood flow is considered the key to its identification.

Pericaval fat collection mimicking an intracaval lesion on CT in patients with chronic liver disease

BACKGROUND

Localized fat collections, which mimic fat-containing lesions of the inferior vena cava (IVC) on computed tomographic (CT) images, have been reported as rare incidental findings. Our goal was to evaluate the association of this CT finding with chronic liver disease.

METHODS

Sixty-one patients with chronic liver disease were prospectively studied with contrast-enhanced abdominal CT. The prevalence, attenuation, location, shape, and size of the pericaval fat collections were assessed. Multidirectional reformatted CT images were obtained from helical CT data to identify origins of the pericaval fat collections. Sixty-one patients without chronic liver disease were studied as control subjects.

RESULTS

Pericaval fat collections were seen on abdominal CT in 16 (26.2%) of the 61 patients. On the reformatted images, the fat collections were contiguous to the fat tissue around the subdiaphragmatic esophagus in all 16 patients. The fat collections were located at the posterior aspect of the IVC in 12 patients. In the control group, pericaval fat collection mimicking an intracaval lesion was not seen.

CONCLUSION

In patients with chronic liver disease, pericaval fat collections are not rare CT findings and their characteristic location is considered to be posterior to the IVC. It is important not to misinterpret such CT findings as abnormalities of the IVC, such as thrombus or tumors.

Vasoactive intestinal peptide regulates its receptor expression and functions of human keratinocytes via type I vasoactive intestinal peptide receptors

Vasoactive intestinal peptide has been suggested to play some roles in inflammatory dermatoses such as atopic dermatitis and psoriasis. The aim of this study is to clarify the precise mechanisms of how vasoactive intestinal peptide is implicated in the pathogenesis of these disorders. We investigated the expression of vasoactive intestinal peptide and its receptors in normal human fibroblasts and keratinocytes, as well as in a human epidermal keratinocyte cell line DJM-1, using reverse transcription polymerase chain reaction and northern blotting. Type I VIP receptor mRNA was expressed in normal human keratinocytes and DJM-1 cells, and the latter also expressed type II receptor in lesser amounts. Neither type I nor type II VIP receptor mRNA was detected in fibroblasts, and vasoactive intestinal peptide transcript was not found in any cells examined. Type I VIP receptor mRNA was upregulated by Th1 cytokines (interferon-gamma), Th2 cytokines (interleukin-4), and tumor necrosis factor alpha, as well as vasoactive intestinal peptide itself, suggesting the presence of an autoregulatory loop. Vasoactive intestinal peptide increased cAMP production and cell proliferation of DJM-1 cells, and also induced the production of inflammatory cytokines such as interleukin-6, interleukin-8, and RANTES. The production of cAMP and cytokines was abrogated by a type I VIP receptor selective antagonist, indicating that type I receptor mediates these effects. Overall, these results suggest that upregulation of vasoactive intestinal peptide receptors by cytokines from inflammatory cells in the dermis enhances the proliferation and cytokine production of keratinocytes in response to vasoactive intestinal peptide from nerve endings. This cytokine network around keratinocytes may be involved in the pathogenesis of inflammatory dermatoses.

Pharmacological characterization of KUR-1246, a selective uterine relaxant

The aim of the present study was to evaluate the efficacy and beta 2-adrenoceptor (AR) selectivity of KUR-1246, a new uterine relaxant. Inhibition of spontaneous or drug-induced uterine contractions by KUR-1246 was evaluated in pregnant rats and rabbits by an organ bath method or by a balloon method. The selectivity of KUR-1246 was assessed simultaneously in organs isolated from late-pregnant rats. The affinity of KUR-1246 for human beta 1-, beta 2-, and beta 3-ARs was determined using two radioligands. KUR-1246 suppressed both spontaneous and drug-induced contractions in isolated uteri, the rank order of potency being isoproterenol > KUR-1246 > terbutaline > ritodrine. ICI-118551 (selective beta 2-AR antagonist) competitively antagonized the KUR-1246-induced inhibition of spontaneous uterine contractions, but CGP-20712A (selective beta 1-AR antagonist) and SR-58894A (selective beta 3-AR antagonist) did not. All beta-AR agonists tested produced significant inhibition of spontaneous uterine contractions in vivo: ED(30) value for KUR-1246 was 0.13 microg/kg/min, a potency about 6 times and 400 times greater than that of terbutaline and ritodrine, respectively. In contrast, the positive chronotropic effect was minimal in KUR-1246-treated rats. KUR-1246 displaced radioligand binding to beta 1-, beta 2-, and beta 3-ARs, the pK(i) values being 5.75 +/- 0.03, 7.59 +/- 0.08, and 4.75 +/- 0.03 for beta 1-, beta 2-, and beta 3-ARs, respectively. For the selectivity of KUR-1246 for human beta 2-AR, we obtained values of 39.2 ([IC(50) for beta 1-AR]/[IC(50) for beta 2-AR]) and 198.2 ([IC(50) for beta 3-AR]/[IC(50) for beta 2-AR]), indicating an apparently higher affinity for human beta 2-AR than for other beta-AR subtypes. The present study clearly demonstrated that KUR-1246 is a more selective beta 2-AR agonist than the drugs presently used for relaxing uterine muscle.

L-arginine polymers inhibit the development of vein graft neointimal hyperplasia

OBJECTIVE

We sought to determine whether L -arginine polymer treatment of vein grafts enhances vascular production of nitric oxide and inhibits the development of neointimal hyperplasia.

METHODS

External jugular veins of New Zealand White rabbits (n = 42) were harvested; treated intraluminally for 15 minutes with phosphate-buffered saline solution or L -arginine polymer 5, 7, or 9 at either 10 or 100 micromol/L; and then grafted into the contralateral carotid artery. Rabbits were killed after 28 days, and 5-microm sections of vessels were stained with hematoxylin and scored for intima/media ratio by using computerized morphometric analysis. Separate veins were treated in a similar fashion with biotinylated polymers and phosphate-buffered saline solution to assess for translocation efficiencies. Finally, vein segments pretreated with either phosphate-buffered saline solution or L -arginine polymers were cultured in Dulbecco's modified Eagle's medium containing lipopolysaccharide (100 microg/mL) and interferon gamma (200 U/mL) for 48 hours before measuring nitric oxide levels by means of the Griess reaction.

RESULTS

Biotinylated L -arginine polymers demonstrated a dose- and length-dependent uptake into intimal and medial cells of treated vessels. Nitric oxide levels were significantly higher in vein segments treated with 100 micromol/L of L -arginine polymer 9 compared with control segments. Finally, the intima/media ratio also reflected both length- and concentration-dependent inhibition of neointimal hyperplasia.intima/media ratio PBS R5 R7 R9 10 micromol/L 0.909 +/- 0.072 0.920 +/- 0.073 0.861 +/- 0.138 0.710 +/- 0.122 100 micromol/L 0.924 +/- 0.061 0.581 +/- 0.089* 0.529 +/- 0.093* PBS, Phosphate-buffered saline solution; R, L -arginine polymer. *P <.001 versus phosphate-buffered saline solution and L -arginine polymer 5 controls (Bonferroni-corrected value).

CONCLUSIONS

Arginine polymers of sufficient length and concentration were effective in increasing nitric oxide levels and reducing neointimal hyperplasia in this vein graft model.

A diagnostic index of vertical problems for Class III malocclusions

A cephalometric investigation was undertaken to derive a vertical indicator--a single value derived from a series of cephalometric variables that can be used in the differential diagnosis of Class III patients. The subjects consisted of 76 Japanese female patients whose chief complaint was anterior crossbite and who presented with either open bite or anterior deep overbite. All the data were derived from the initial lateral cephalometric radiographs. The main skeletal measurements that characterize vertical problems were selected using cluster analysis, principal component analysis, and discriminant analysis. As a result, a Class III vertical indicator was derived. The vertical indicator score for deep overbite was -2.5 +/- 2.2, whereas the vertical indicator score for open bite was +2.5 +/- 2.3. This vertical indicator may be used in diagnosing the nature of vertical problems and determining the appropriate treatment and prognosis for the individual Class III female patient.

Nucleotide sequence analysis of the approximately 35-kb segment containing interferon-gamma-inducible mouse proteasome activator genes

The proteasome activator PA28 is an interferon-gamma-inducible complex made up of two related subunits, named PA28 alpha and PA28 beta, with approximately 50% amino acid sequence identity. Accumulated evidence indicates that binding of this complex to the 20S proteasome enhances the generation of class I-binding peptides. Previously, we showed that the genes coding for PA28 alpha and PA28 beta, designated Psme1 and Psme2, respectively, are located approximately 6 kb apart with their 3' ends pointing toward each other on mouse Chromosome 14. In the present study, we sequenced the regions adjacent to Psme1 and Psme2. In a contiguous stretch of approximately 35 kb, we identified six genes arranged in the following order: Cg10671-like (a gene similar to Drosophila CG10671)-Psme1-Cgi112 (a ubiquitously expressed gene with no known function)-Psme2-Flj10111 (a gene coding for a protein with two RING finger domains)-Isgf3g (an interferon-gamma-inducible gene coding for an interferon-dependent, positive-acting transcription factor 3 gamma). Interestingly, the 3' untranslated region of Psme1 overlaps with that of Cgi112 by 7 bp. Database analysis indicates that the corresponding human genes also overlap by up to 7 bp in their 3' untranslated regions. The 5' end of the mouse, but not the human, gene coding for PA28 beta undergoes alternative splicing that is predicted to alter the N-terminal amino acid sequence. Comparison of the mouse sequence with a human draft sequence deposited in the NCBI database revealed that the overall organization of the region coding for the interferon-gamma-inducible proteasome activator is conserved between human and mouse.

Effects of human lung fibroblasts on eosinophil degranulation

BACKGROUND

Although eosinophils and fibroblasts are thought to contribute to the mechanisms of chronic asthmatic inflammation, the interaction between eosinophils and fibroblasts has not been thoroughly clarified. We examined eosinophil cationic protein (ECP) release from human eosinophils cultured in the presence of human lung fibroblast HFL-1.

METHODS

Eosinophils from healthy donors were cultured with or without C5a for 16 h in the presence of human fetal lung fibroblasts which had previously been incubated with or without TNF for 4 h. ECP in supernatants was measured by RIA.

RESULTS

ECP release was potentiated only when both eosinophils and fibroblasts were activated by C5a and TNF, respectively, while it was not significantly potentiated when either eosinophils or fibroblasts were activated. Paraformaldehyde fixation of fibroblasts had some suppressive effect on ECP enhancement, and mAb against GM-CSF partly inhibited ECP enhancement. Coculture of eosinophils and fibroblasts with stimulus treatment resulted in the enhancement of both eosinophil adhesion and ECP release. The potentiation of ECP release was partially inhibited by anti-ICAM-1 mAb, anti-CD18 mAb, and anti-CD29 mAb, which caused partial and comparable inhibition of the enhancement of eosinophil adhesion.

CONCLUSIONS

This study suggests that the activation of fibroblasts may have some role in the potentiation of ECP release from cocultured eosinophils, and that adhesion of eosinophils to fibroblasts may partly be involved in the mechanism of ECP potentiation.