Shared antigenicity between Helicobacter pylori and periodontopathic Campylobacter rectus strains

Periodontopathic Campylobacter rectus strains possess 41- and 68-kDa proteinaceous antigens which share antigenicity with antigens of Helicobacter pylori strains. H. pylori strains have a 54-kDa antigen which reacts with C. rectus strains. We found that the salivary IgA levels against H. pylori were correlated with those against C. rectus. These cross-reactive antigens of C. rectus may affect the serological diagnosis of H. pylori infections, especially when saliva is used. It is possible that these cross-reacting antigens may relate to the induction of immunopathological responses against both microorganisms.

Induction of monocyte chemoattractant protein 1 by Helicobacter pylori involves NF-kappaB

Helicobacter pylori stimulates secretion of monocyte chemoattractant protein 1 (MCP-1) from gastric epithelial cells. Secretion of this chemokine may be instrumental in monocyte infiltration of the gastric epithelium that characterizes H. pylori gastritis. The aim of this study was to identify the mechanism by which H. pylori induces MCP-1 production. Induction of MCP-1 mRNA was assessed by reverse transcription-PCR. We used luciferase reporter assays to monitor activation of the MCP-1 gene promoter and electrophoretic mobility shift assays to explore binding of transcription factors to this promoter. H. pylori infection increased MCP-1 mRNA expression from gastric epithelial cells. Induction of MCP-1 mRNA relies on an intact cag pathogenicity island. We identified two closely spaced NF-kappaB-binding sites within the MCP-1 distal enhancer as required for H. pylori-induced MCP-1 gene transcription. H. pylori infection led to the specific activation of NF-kappaB complexes containing p50 and p65. Kinase-deficient mutants of NF-kappaB-inducing kinase (NIK) and IkappaB kinases (IKK) caused suppression of MCP-1 distal enhancer-dependent reporter activity following H. pylori infection. H. pylori infection induces the activation of NF-kappaB via the NIK-IKK signaling complex, leading to MCP-1 gene transcription in gastric epithelial cells.

Development of hyperfimbriated strains of Vibrio cholerae O1

The Vibrio cholerae O1 and O139 fimbrillin genes (fimA or mshA) were amplified by polymerase chain reaction and cloned into an Escherichia coli pCR vector. These clones were sequenced. The fimA sequences were found to be identical between V cholerae O1 and O139. One of the plasmids was digested with EcoR I and inserted into the EcoR I site of pGEX-3X. The plasmid pVPP thus obtained was transferred into strains of wild-type V cholerae O1 Bgd17 (classical in biotype) and its fimbriated strain by electroporation. The recombinant plasmid pVPP overexpressed mature fimbriae following induction of the tac promoter with isopropyl-beta-D-thiogalactopyranoside. The cloned gene product was purified to homogeneity by sucrose-linear gradient centrifugation (7.8 mg of fimbriae/L-culture). All the properties of the recombinant fimbriae (e.g., subunit structure, hydrophobicity, hemagglutinating activity sensitive to D-mannose and D-glucose and immunogenicity) were identical to those of the wild-type fimbriae. This overexpression system will be extremely useful for rapid, inexpensive preparation of large amounts of fimbriae for vaccine design and development.

Helicobacter pylori-mediated transcriptional regulation of the human beta-defensin 2 gene requires NF-kappaB

Human beta-defensin 2 (hBD-2) is an antimicrobial peptide involved in host defence against bacterial infection in epithelial tissues. Its levels are dramatically increased after bacterial infection. The involvement of NF-kappaB in Helicobacter pylori-mediated induction of hBD-2 promoter activity was examined. A luciferase reporter plasmid containing the hBD-2 promoter extending from -2110 base pairs to -1 was transiently expressed in MKN45 cells, and promoter activity was determined after incubation with H. pylori for 6 h. Deletion or mutation of the NF-kappaB site at -208 abolished activation of the hBD-2 promoter. Only H. pylori strains carrying a cag pathogenicity island (PAI) induced activation of the NF-kappaB site of the hBD-2 promoter gene. By gel retardation analyses, H. pylori increased NF-kappaB binding to hBD-2 promoter gene sequences. Supershift analysis demonstrated that whereas H. pylori activated NF-kappaB p65-p65 and p50-p50 homodimers, and the p65-p50 heterodimer of NF-kappaB, only the p65-p65 homodimer bound to the NF-kappaB site of the hBD-2 promoter. Thus, specific NF-kappaB proteins are important cis-elements for induction of hBD-2 gene transcription by H. pylori.

Evaluation of the effective drugs for the prevention of nausea and vomiting induced by morphine used for postoperative pain: a quantitative systematic review

Postoperative nausea and vomiting (PONV) with morphine therapy develops in more than 60% of patients after surgery, markedly reducing patient QOL. The prophylactic effect of several antiemetics has already been studied, but evaluations, and even those using the same drug, are not uniform. The present research involved a meta-analysis of randomized controlled trials on prophylactic drug therapy for PONV in patients receiving morphine for the treatment of postoperative pain. The efficacy of the prophylactic administration of the drugs was examined. As a result, meta-analysis of five drugs was possible and the evidence of efficacy was shown for three drugs ranked in order of an increasing odds ratio (OR) and confidence interval (CI): dexamethasone (OR: 0.23, 95% CI: 0.15-0.35, p < 0.00001), droperidol (OR: 0.27, 95% CI: 0.21-0.34, p < 0.00001), and metoclopramide (OR: 0.48, 95% CI: 0.30-0.75, p < 0.001). These results suggest that the three drugs are effective in prophylactic treatment for PONV. Of them, dexamethasone used as a prophylactic drug for PONV provided the best results. Dexamethasone was shown to reduce the incidence of PONV from 66-80% to 16-50% with a dose of 1.25 to 10 mg and to be suitable as a first drug of choice.

Dynamin is involved in human epithelial cell vacuolation caused by the Helicobacter pylori-produced cytotoxin VacA

The Helicobacter pylori-produced cytotoxin VacA induces intracellular vacuolation. To elucidate the molecular mechanism of vacuole formation by VacA, we examined the participation of dynamin, a GTPase functioning in intracellular vesicle formation, in human HeLa cells. Immunocytochemistry revealed that endogenous dynamin was localized to vacuoles induced by VacA. In cells transiently transfected with a GTPase-defective (dominant-negative) dynamin mutant, VacA failed to induce vacuolation. In contrast, VacA did induce vacuolation in cells transiently transfected with wild-type dynamin. Furthermore, under VacA treatment, neutral red dye uptake, a parameter of VacA-induced vacuolation, was inhibited in cells stably transfected with the dominant-negative dynamin mutant. In contrast, uptake was markedly enhanced in cells stably transfected with wild-type dynamin. Moreover, VacA cytopathic effects on the viability of HeLa cells were inhibited in cells stably transfected with dominant-negative dynamin-1. Sequential immunocytochemical observation confirmed that expression of dominant-negative dynamin did not affect VacA attachment to or internalization into HeLa cells. We suggest that dynamin is involved in the intracellular vacuolation induced by VacA.

Hyperosmotic stress induces a rapid and transient increase in inositol 1,4,5-trisphosphate independent of abscisic acid in Arabidopsis cell culture

Phospholipid metabolism is involved in hyperosmotic-stress responses in plants. To investigate the role of phosphoinositide-specific phospholipase C (PI-PLC)-a key enzyme in phosphoinositide turnover-in hyperosmotic-stress signaling, we analyzed changes in inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) content in response to hyperosmotic shock or salinity in Arabidopsis thaliana T87 cultured cells. Within a few s, a hyperosmotic shock, caused by mannitol, NaCl, or dehydration, induced a rapid and transient increase in Ins(1,4,5)P3. However, no transient increase was detected in cells treated with ABA. Neomycin and U73122, inhibitors of PI-PLC, inhibited the increase in Ins(1,4,5)P3 caused by the hyperosmotic shock. A rapid increase in phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) in response to the hyperosmotic shock also occurred, but the rate of increase was much slower than that of Ins(1,4,5)P3. These findings indicate that the transient Ins(1,4,5)P3 production was due to the activation of PI-PLC in response to hyperosmotic stress. PI-PLC inhibitors also inhibited hyperosmotic stress-responsive expression of some dehydration-inducible genes, such as rd29A (lti78/cor78) and rd17 (cor47), that are controlled by the DRE/CRT cis-acting element but did not inhibit hyperosmotic stress-responsive expression of ABA-inducible genes, such as rd20. Taken together, these results suggest the involvement of PI-PLC and Ins(1,4,5)P3 in an ABA-independent hyperosmotic-stress signal transduction pathway in higher plants.

Somatic mutations of synaptic cadherin (CNR family) transcripts in the nervous system

BACKGROUND

Cadherin-related neuronal receptor (CNR) family genes have been identified in the nervous system by screening molecules bound to Fyn-tyrosine kinase. The CNR family is comprised of diverse synaptic cadherins. The genomic organization of the CNR genes, composed of variable and constant regions, is similar to that of the immunoglobulin gene cluster. The nervous system is characterized by the acquisition of diverse function. This feature is similar to the immune system. In the immune system, the generation and selection of immunoglobulin gene mutants is the underlying basis for acquired immunity. We therefore examined somatic regulation of the CNR family genes in the nervous system to determine whether a similar mechanism controls nervous system development.

RESULTS

We first demonstrated that approximately 10% of the CNR3 transcripts were trans-transcripts between the variable and constant exons at the adult stage. Furthermore, somatic mutations of CNR3 transcripts accumulated during brain development, with a marked bias for A-to-G and U-to-C transitions. Approximately 70% of the CNR3 transcripts exhibited a mutation characterized by the addition of a CU-repeat; these transcripts contained seven continuous CU-repeats in the 3' untranslated region at the adult stage, whereas the CNR genomic DNA contained six continuous CU-repeats. Interestingly, a high rate of replacement mutations was detected in the first cadherin domain that functions in acquisition of specificity for cell adhesion in cadherins, while in the other regions the occurrence of silent mutations increased during development.

CONCLUSION

The present report is the first description of the generation and possible selection of somatic mutations of synaptic cadherin transcripts. The somatic alterations of CNR family transcripts and their synaptic localization have interesting implications for the molecular basis underlying the establishment of somatic rearrangement of neuronal networks.

[A case of a left atrial primary malignant fibrous histiocytoma]

Primary malignant fibrous histiocytoma (MFH) of the heart is very rere. We report a case of a primary intracardiac MFH. A 50-year-old woman underwent an operation for congestive heart failure due to left atrial (LA) tumor. Cardiac echocardiogram showed the tumor attached to the septal wall and posterior wall of LA. We extendedly resected the tumor with septal and partially posterior wall and reconstructed there with pericardial substitute. Pathological diagnosis was MFH. Although she did well postoperatively, cardiac echocardiogram showed a recurrent tumor in the LA at 10 days after operation. She developed respiratory failure, and chest and abdominal CT demonstrated metabolism to the lung, liver and bladder at post operative 47 days. At 77 days after operation, she expired. The prognosis of MFH is poor despite surgery. We recommend extended surgery, if the LA tumor had wide base attached to the septal or posterior wall.

Examination of electrostatic potential distribution across an implanted p-n junction by electron holography

In the manufacture of semiconductor microelectronic devices, a p-n junction is formed usually by implanting a high concentration of impurity into a less heavily doped region and then heat annealing. A Si/Si p-n junction test sample has been made following the above practical process and thinned for electron holographic observation by using argon ion-milling. From the reconstructed phase image, the phase shift induced by potential drop across p-n junction can be seen clearly. To characterize quantitatively this potential drop, the mean inner potential V0 of silicon was measured precisely by electron holographic method. By measuring 25 different crystalline silicon spheres with diameter ranging from 40 to 170 nm, an average result of V0 = 12.16 +/- 0.83 V was obtained. By using this V0 value, a quantitative measurement yields the potential drop approximately 0.70 V, which is reasonably consistent with expected Si/Si junction parameter. The thickness of electric dead layer in depletion region produced from this measuring is approximately 20 nm on each sample surface.

[Clinical effects of meropenem on infectious diseases in obstetrics and gynecology]

The efficacy and the safety of meropenem (MEPM) were examined in obstetric and gynecological infections and the results shown below were obtained. 1. The subjects were patients with infectious diseases during a non-pregnant period (n = 14), a pregnant period (n = 13) and a puerperal period (n = 11). After intravenous drip infusion of MEPM at 1-2 g/day, the response rate was 38/39 (97.4%) (Excellent: 13/39 (33.3%), Effective: 25/39 (64.1%)). 2. The response rates in a group receiving 1 g/day, a group receiving 2 g/day and a group receiving a combination of both were, respectively, 25/26 (96.2%), 9/9 (100%) and 4/4 (100%). 3. In cases that did not respond to previous treatments, the response rate to MEPM was 20/20 (100%). 4. In clinical efficacy classified by causative organisms, the rate of Excellent was 10/23 (43.5%) and the rate of Effective was 13/23 (56.5%), and the bacterial eradication rate was 21/23 (91.3%). 5. No subjective and objective adverse reactions or abnormalities in clinical laboratory tests due to administration of MEPM were observed.

[Clinical effects of cefoselis (CFSL) on infections in obstetric and gynecologic field and prevention of postoperative infections]

Clinical effects of cefoselis (CFSL) on various infections and prevention of postoperative infections in the field of obstetrics and gynecology were investigated with a total of 100 patients of 8 facilities in Yamagata and the following results were obtained: 1. For the patients (n = 70) who received the treatment with CFSL at 2 g/day for 5 days to prevent postoperative infections, the treatment was effective for such infections in 68 of 69 (98.6%) except one to whom the treatment was discontinued during the course. 2. For the patients with infections (n = 30) who were treated with CFSL at 2-4 g/day for 5-7 days, the treatment was markedly effective in 8/30 (26.7%), effective in 21/30 (70%) and not effective in 1/30 (3.3%). The overall rate of efficacy was 29/30 (96.7%). Based on the clinical effects for each isolate, the bacteriological efficacy was evaluated as 29/29 and the rate of bacterial eradication for each isolate was 23/29 (79.3%). 3. Laboratory test revealed liver functional abnormalities in one patient and eruption, a subjective/objective symptom caused by CFSL was noted in two patients. These results suggest that CFSL is effective for various infections in obstetric and gynecologic field and also the prevention of postoperative infections.

Effects of lisinopril and nitrendipine on urinary albumin excretion and renal function in patients with mild to moderate essential hypertension

The present study was designed to evaluate the effects of an ACE inhibitor, lisinopril, and a calcium antagonist, nitrendipine, on urinary albumin excretion (UAE) and renal function in mild to moderate essential hypertensive patients with microalbuminuria. After the 4-week drug-free period, 17 patients were randomly divided into two groups. The first group (group 1: n=8) received lisinopril 10-20 mg daily for 8 weeks followed by nitrendipine 5-10 mg daily for another 8 weeks. The second group (group 2: n=9) received nitrendipine 5-10 mg daily for 8 weeks followed by lisinopril 10-20 mg daily for another 8 weeks. The mean blood pressure (MBP) significantly decreased in a similar manner in both groups. UAE significantly decreased after 8 weeks of treatment with lisinopril in group 1 and after 8 weeks of subsequent treatment with lisinopril in group 2. On the other hand, UAE was not altered by treatment with nitrendipine. The changes in UAE were significantly correlated with changes in MBP after 8 weeks of treatment with nitrendipine, but not after 8 weeks of treatment with lisinopril. No significant changes in creatinine clearance, urinary excretion of sodium or urinary N-acetyl-beta-D-glucosaminide were observed by any treatment in either group. These results suggest that lisinopril, not nitrendipine, reduces UAE in essential hypertensive patients with microalbuminuria independently of its effective antihypertensive properties.

Effect of flow competition on internal thoracic artery graft: postoperative velocimetric and angiographic study

OBJECTIVES

To assess the effects of competitive blood flow on internal thoracic artery grafts, we investigated postoperative flow velocity characteristics and angiographic findings of the grafts with various grades of native coronary artery stenosis.

METHODS

Fifty patients who had an internal thoracic artery graft to the left anterior descending artery underwent intravascular Doppler graft velocimetry during postoperative angiography. Patients were divided into 3 groups according to the grade of native coronary stenosis: group H (28 patients), 80% stenosis or greater; group M (16 patients), 60% to 79% stenosis; and group L (6 patients), 40% to 59% stenosis. Phasic flow velocity of the grafts was measured with an intravascular Doppler ultrasound-tipped guide wire during angiography. Graft flow volume was calculated from the diameter and the average peak velocity.

RESULTS

Average peak velocity (group H, 27.1 +/- 8.6 cm/s; group M, 16.9 +/- 3.9 cm/s; group L, 7.2 +/- 3.7 cm/s), distal graft diameter (group H, 2.27 +/- 0.23 mm; group M, 2. 00 +/- 0.28 mm; group L, 1.07 +/- 0.27 mm), and calculated graft flow volume (group H, 33.1 +/- 12.0 mL/min; group M, 16.2 +/- 5.8 mL/min; group L, 2.3 +/- 2.0 mL/min) significantly differed among the 3 groups. Graft flow in diastole and systole also differed among the 3 groups.

CONCLUSIONS

Competitive blood flow reduces internal thoracic artery graft flow and diameter according to the grade of the native coronary artery stenosis. These data suggest that grafting the internal thoracic artery to the coronary artery with stenosis of a low grade can cause graft atrophy and failure.

Gene transfer into hepatoma cells mediated by galactose-modified alpha-helical peptides

To develop a receptor-mediated gene delivery system into hepatoma cells using the cationic alpha-helical peptide as the gene carrier molecule, we modified an alpha-helical peptide, which is known to have transfection abilities into cells, with a multi-antennary ligand containing several galactose residues that provide efficient binding to the asialoglycoprotein receptor. The galactose-modified peptides formed complexes with a plasmid DNA and showed gene transfer abilities into HuH-7 cells, a human hepatoma cell line. The transfection efficiency of the peptide was increased by increasing the number of modified galactose residues on the peptide. Furthermore, considerable inhibition of the transfection efficiency by the addition of asialofetuin, which is a ligand for the asialoglycoprotein receptor, was observed in all galactose-modified peptides. Based on this result, we could confirm that the internalization of the galactose-modified peptides occurred by the receptor-mediated endocytosis pathway. In addition, to understand the transport route of the peptide-DNA complex in the cell, the effects on the transfection efficiencies with several endocytosis inhibitors were examined. As a result, it was suggested that the translocation of the peptide-DNA complex from the endocytic compartments to the cytosol mainly occurred during an early endosome step.

Role of multinuclear cells in granulation tissue in osteomyelitis: immunohistochemistry in 66 patients

We investigated the origin of multinuclear cells (MNCs) in the granulation tissue in osteomyelitis by immunohistochemical techniques in 66 patients. 12 samples were analyzed for the presence of CD68, cathepsin K, CD11b and tartrate-resistant acid phosphatase (TRAP) activity. Many MNCs were present in the granulation tissue adjacent to a sequestrum. MNCs in contact with the sequestrum were also noted, however, no osteoblasts were found. Immunohistochemically, CD68, cathepsin K and TRAP were strongly expressed in most of the MNCs, while CD11b positive cells were not found. MNCs remote from and in contact with the sequestrum showed the same immunohistochemical features which are characteristic of osteoclasts. Further, MNCs in contact with the sequestrum had originally developed in the granulation tissue and directly infiltrated towards the sequestrum without cell-to-cell interaction with osteoblasts.

Required structure of cationic peptide for oligonucleotide-binding and -delivering into cells

Improvement of the methods for oligonucleotide delivery into cells is necessary for the development of antisense therapy. In the present work, a new strategy for oligonucleotide delivery into cells was tested using cationic peptides as a vector. At first, to understand what structure of the peptide is required for binding with an oligonucleotide, several kinds of alpha-helical and non-alpha-helical peptides containing cationic amino acids were employed. As a result, the amphiphilic alpha-helix peptides were best for binding with the oligonucleotide, and the long chain length and large hydrophobic region in the amphiphilic structure of the peptide were necessary for the binding and forming of aggregates with the oligonucleotide. In the case of non-alpha-helical peptides, no significant binding ability was observed even if their chain lengths and number of cationic amino acid residues were equal to those of the alpha-helical peptides. The remarkable ability of oligonucleotide delivery into COS-7 cells was observed in the alpha-helical peptides with a long chain length and large hydrophobic region in the amphiphilic structure, but was not observed in the non-alpha-helical peptides. It is considered that such alpha-helical peptides could form optimum aggregates with the ODN for uptake into cells. Based on these results, the alpha-helical peptide with a long chain length and large hydrophobic region is applicable as a vector for the delivery of oligonucleotides into cells.

Intracerebral steal phenomenon associated with global hyperemia in moyamoya disease during revascularization surgery

OBJECT

The collateral vessels in moyamoya disease appear to retain their ability to constrict during hypocapnia but not to dilate during hypercapnia. It has been claimed that hypercapnia, as well as hypocapnia, decreases the blood flow in regions perfused by collateral vessels, presumably because of intracerebral steal. If this holds true, the decrease in blood flow may be proportional to the global hyperemia in the brain. To establish appropriate hemodynamic control during revascularization surgery, the authors monitored the jugular bulb oxygen saturation (SjO2) intraoperatively, a method that could sensitively detect global hyperemia.

METHODS

A total of 17 patients, most of whom presented with transient ischemic attacks or fluctuating neurological deficits, underwent intraoperative monitoring of their SjO2 and end-tidal carbon dioxide (ETCO2) after a state of anesthesia had been induced with isoflurane (Group 1) or propofol (Group 2). In eight of these patients, the regional cerebral blood flow (rCBF) of the collateral vessel territory was also monitored by laser Doppler flowmetry during the period of cortical exposure, and a total of 113 data sets (averaged values during 2.5-minute intervals) was collected. There was fluctuation in the ETCO2 levels ranging from 36 to 44 mm Hg. The mean SjO2 level was clearly greater (p < 0.01) in Group 1 (71.8 +/- 2.2%) than in Group 2 (63.3 +/- 2.1%). An episodic fall in rCBF was observed in association with a transient increase in SjO2. Such an event was not uncommon in Group 1 and there was a greater risk of rCBF decreasing when SjO2 exceeded a cutoff level of 76% (p < 0.01). This level could sometimes be reached at a broad range of ETCO2 readings (37-44 mm Hg). In Group 2, similar events sometimes occurred when SjO2 increased beyond 70%. However, this level could be reached only with a higher ETCO2 (42-44 mm Hg). The rCBF level was negatively correlated to SjO2 (p < 0.01), but not always to ETCO2, indicating that the episodic fall in rCBF was closely related to global hyperemia rather than the absolute level of hypercapnia.

CONCLUSIONS

The observed association between a fall in rCBF and global hyperemia supports the intracerebral steal hypothesis and indicates that it is prudent to avoid excessive global hyperemia. The optimal range of CO2 for isoflurane is more restricted than that for propofol, presumably because isoflurane induces hyperemia by itself. Monitoring of SjO2 appears to represent the most practical technique for detecting global hyperemia as well as global ischemia, both of which may cause ischemic complications in moyamoya disease.

Morphologic differentiation of HL-60 cells is associated with appearance of RPTPbeta and induction of Helicobacter pylori VacA sensitivity

Phorbol 12-myristate 13-acetate (PMA) induces differentiation of human leukemic HL-60 cells into cells with macrophage-like characteristics and enhances the susceptibility of HL-60 cells to the Helicobacter pylori VacA toxin (de Bernard, M., Moschioni., M., Papini, E., Telford, J. L., Rappuoli, R., and Montecucco, C. (1998) FEBS Lett. 436, 218-222). We examined the mechanism by which HL-60 cells acquire sensitivity to VacA, in particular, looking for expression of RPTPbeta, a VacA-binding protein postulated to be the VacA receptor (Yahiro, K., Niidome, T., Kimura, M., Hatakeyama, T., Aoyagi, H., Kurazono, H., Imagawa, K., Wada, A., Moss, J., and Hirayama, T. (1999) J. Biol. Chem. 274, 36693-36699). PMA induced expression of RPTPbeta mRNA and protein as determined by RNase protection assay and indirect immunofluorescence studies, respectively. Vitamin D(3) and interferon-gamma, which stimulate differentiation of HL-60 cells into monocyte-like cells, also induced VacA sensitivity and expression of RPTPbeta mRNA, whereas 1. 2% Me(2)SO and retinoic acid, which stimulated the maturation of HL-60 into granulocyte-like cells, did not. RPTPbeta antisense oligonucleotide inhibited induction of VacA sensitivity and expression of RPTPbeta. Double immunostaining studies also indicated that newly expressed RPTPbeta colocalized with VacA in PMA-treated HL-60 cells. In agreement with these data, BHK-21 cells, which are insensitive to VacA, when transfected with the RPTPbeta cDNA, acquired VacA sensitivity. All data are consistent with the conclusion that acquisition of VacA sensitivity by PMA-treated HL-60 cells results from induction of RPTPbeta, a protein that functions as the VacA receptor.

Ethylene captures a metal! Metal ions are involved in ethylene perception and signal transduction

More than three decades ago, transition metal such as copper or zinc were postulated to be required for the ethylene perception. However, there was no direct evidence for this metal requirement until very recently. Two studies using Arabidopsis thaliana, one genetic and the other biochemical, have provided complementary evidence for the role of copper in ethylene perception, closing this argument. Additional evidence for the importance of the metal in the ethylene-signaling pathway came with the recent discovery that EIN2, a central signal transducer in the ethylene-signaling pathway, has significant homology to the Nramp divalent cation transporters. These studies suggest that metal metabolism may have a critical role not only in ethylene perception but also in ethylene signaling.

Damage-induced neuronal endopeptidase (DINE) is a unique metallopeptidase expressed in response to neuronal damage and activates superoxide scavengers

We isolated a membrane-bound metallopeptidase, DINE (damage-induced neuronal endopeptidase), by differential display PCR using rat normal and axotomized hypoglossal nuclei. The most marked properties of DINE were neuron-specific expression and a striking response to axonal injury in both the central nervous system and peripheral nervous system. For instance, cranial and spinal nerve transection, ischemia, corpus callosum transection, and colchicine treatment increased DINE mRNA expression in the injured neurons, whereas kainate-induced hyperexcitation, immobilization, and osmotic stress failed to up-regulate DINE mRNA. Expression of DINE in COS cells partially inhibited C2-ceramide-induced apoptosis, probably because of the activation of antioxidant enzymes such as Cu/Zn-superoxide dismutase, Mn-superoxide dismutase, and glutathione peroxidase through the proteolytic activity of DINE. These data provide insight into the mechanism of how injured neurons protect themselves against neuronal death.