New developments in oxidative fermentation

Oxidative fermentations have been well established for a long time, especially in vinegar and in L-sorbose production. Recently, information on the enzyme systems involved in these oxidative fermentations has accumulated and new developments are possible based on these findings. We have recently isolated several thermotolerant acetic acid bacteria, which also seem to be useful for new developments in oxidative fermentation. Two different types of membrane-bound enzymes, quinoproteins and flavoproteins, are involved in oxidative fermentation, and sometimes work with the same substrate but produce different oxidation products. Recently, there have been new developments in two different oxidative fermentations, D-gluconate and D-sorbitol oxidations. Flavoproteins, D-gluconate dehydrogenase, and D-sorbitol dehydrogenase were isolated almost 2 decades ago, while the enzyme involved in the same oxidation reaction for D-gluconate and D-sorbitol has been recently isolated and shown to be a quinoprotein. Thus, these flavoproteins and a quinoprotein have been re-assessed for the oxidation reaction. Flavoprotein D-gluconate dehydrogenase and D-sorbitol dehydrogenase were shown to produce 2-keto- D-gluconate and D-fructose, respectively, whereas the quinoprotein was shown to produce 5-keto- D-gluconate and L-sorbose from D-gluconate and D-sorbitol, respectively. In addition to the quinoproteins described above, a new quinoprotein for quinate oxidation has been recently isolated from Gluconobacter strains. The quinate dehydrogenase is also a membrane-bound quinoprotein that produces 3-dehydroquinate. This enzyme can be useful for the production of shikimate, which is a convenient salvage synthesis system for many antibiotics, herbicides, and aromatic amino acids synthesis. In order to reduce energy costs of oxidative fermentation in industry, several thermotolerant acetic acid bacteria that can grow up to 40 degrees C have been isolated. Of such isolated strains, some thermotolerant Acetobacter species were found to be useful for vinegar fermentation at a high temperature such 38-40 degrees C, where mesophilic strains showed no growth. They oxidized higher concentrations of ethanol up to 9% without any appreciable lag time, while alcohol oxidation with mesophilic strains was delayed or became almost impossible under such conditions. Several useful Gluconobacter species of thermotolerant acetic acid bacteria are also found, especially L-erythrulose-producing strains and cyclic alcohol-oxidizing strains. Gluconobacter frateurii CHM 43 is able to rapidly oxidize meso-erythritol at 37 degrees C leading to the accumulation of L-erythrulose, which may replace dihydroxyacetone in cosmetics. G. frateuriiCHM 9 is able to oxidize cyclic alcohols to their corresponding cyclic ketones or aliphatic ketones, which are known to be useful for preparing many different physiologically active compounds such as oxidized steroids or oxidized bicyclic ketones. The enzymes involved in these meso-erythritol and cyclic alcohol oxidations have been purified and shown to be a similar type of membrane-bound quinoproteins, consisting of a high molecular weight single peptide. This is completely different from another quinoprotein, alcohol dehydrogenase of acetic acid bacteria, which consists of three subunits including hemoproteins.

Quantitative assessment of the total myocardial uptake ratio of 123I-BMIPP by using the Ishii-MacIntyre method is useful for predicting cardiac complications in patients with mitochondrial encephalomyopathy or myotonic dystrophy

We evaluated the usefulness of the total myocardial uptake ratio (TMUR) of 15-(p-[123I]iodophenyl)-3(R,S)-methyl-pentadecanoic acid (123I-BMIPP) for predicting cardiac complications in patients with mitochondrial encephalomyopathy or myotonic dystrophy. Six patients with mitochondrial encephalomyopathy, four with myotonic dystrophy, and 10 control subjects were studied. Quantitative assessment of 123I-BMIPP dynamic myocardial imaging was performed, and the TMUR of 123I-BMIPP was calculated according to the Ishii-MacIntyre method. Then, the TMUR was compared in the 10 patients and 10 healthy controls, and all patients were followed for 56.1+/-22.1 months to evaluate cardiac complications. TMUR in patients (2.69+/-0.64) was significantly (P =0.01) lower than that in controls (3.28+/-0.25). Three patients in whom the TMUR value was above 3.00 had no cardiac complications. On the other hand, all patients in whom TMUR was below 3.00 had some kind of cardiac complication during the follow-up period. Two patients showed progressive conduction abnormality and underwent pacemaker implantation, one patient had sick sinus syndrome and underwent pacemaker implantation, another patient showed non-sustained ventricular tachycardia and paroxysmal atrial fibrillation, and four of seven patients, including one with a pacemaker, showed an increased cardiothoracic ratio value over 50%. In conclusion, measurement of the TMUR by the Ishii-MacIntyre method is useful for evaluating the development of cardiac complications in patients with mitochondrial encephalomyopathy or myotonic dystrophy.

Pharmacodynamics of menatetrenone and effects on bone metabolism in continuous ambulatory peritoneal dialysis patients

Prevention of osteoporosis and renal osteodystrophy are important for the long-term quality of life in dialysis patients. We examined whether administration of menatetrenone (vitamin K2) improves bone metabolism in continuous ambulatory peritoneal dialysis (CAPD) patients. Administration of a single dose of menatetrenone (15 mg) revealed that the 24-h pharmacodynamics in CAPD patients were comparable to those in control individuals. In a 12-month period of oral menatetrenone administration (45 mg/day), eight stable CAPD patients were studied for blood-bone metabolism parameters and for bone mineral content. Blood concentration of menatetrenone was detectable during the experiment period. Only at 12 months did active vitamin D3 and bone-type alkaline phosphatase (ALP) fall significantly, while total ALP rose significantly. Bone mineral density measured by dual-energy X-ray absorptiometry remained at the same level throughout the study period, suggesting that menatetrenone may protect against bone mineral loss in CAPD patients. These results show that the same dose of oral menatetrenone can be given to CAPD patients as to control individuals, and that menatetrenone can be used safely for 1 year in CAPD patients.

Supraclavicular and axillary lymphadenopathy as the initial manifestation in Wegener's granulomatosis

Wegener's granulomatosis (WG) is a systemic granulomatous vasculitis that typically affects the upper airways, lungs and kidneys. Lymphadenopathy is rare in patients with WG. Here, we present the first case of WG whose initial manifestation was superficial lymphadenopathy (i.e. supraclavicular and axillary lymphadenopathy). One year after the initial presentation, a mass appeared in the lung. Biopsy specimens obtained from supraclavicular lymph nodes and lung demonstrated granulomatous vasculitis. This patient was negative for classic antineutrophil cytoplasmic antibodies (c-ANCA). Treatment with glucocorticoids, cyclophosphamide and trimethoprim-sulfamethoxazole has induced complete remission.

[Mediastinal signet-ring cell carcinoma of unknown primary site; report of a case]

The question whether the tumor is primary or metastatic sometimes arises in patients with intrathoracic tumor. Especially, adenocarcinoma presents more difficulties in distinguishing primary tumors from secondary or deciding its origin. We reported a case of mediastinal signet-ring cell carcinoma. A 51-year-old female was admitted because of an abnormal shadow during mass screening. Chest X-ray showed a semicircular, well-demarcated shadow on right cardiophrenic angle. Chest computed tomography (CT) revealed a homogeneous mass, approximately 4 cm in diameter. The investigations of whole body failed to reveal any other tumor. At operation, the tumor was adherent to the esophagus but easily resected. Histologically, the tumor was mainly composed of signet-ring cells. Immunohistochemically, surfactant apoprotein (SPA) was strongly demonstrated in tumor cells. SPA is specific to the lung and the tumor was diagnosed as the metastasis in mediastinal lymph nodes. The primary site was considered to exist in lung. But the primary site was not found over 46 months in spite of repeated further examinations.

Magnetic resonance analysis of abnormal diaphragmatic motion in patients with emphysema

The purpose of this study was to quantitatively evaluate paradoxical diaphragmatic motion using magnetic resonance (MR) imaging. A total of 27 subjects were examined, including 12 normal young adults, six control individuals, and nine patients with emphysema. With subjects in the supine position, 30 sequential sagittal MR images of the entire right lung were obtained during tidal and deep slow breathing. Diaphragmatic movement between sequential images was estimated as the displacement area and the total diaphragmatic movement in a respiratory cycle was calculated. The paradoxical motion of the diaphragm, representing the inverted movement to increase or decrease lung area, since paradoxical movement ratio (Mpr=(total paradoxical diaphragmatic movement/total diaphragmatic movement)x100), was evaluated. In patients with emphysema, paradoxical diaphragmatic motion was observed on MR images during deep breathing. The mean Mpr in emphysematous patients during deep breathing was 10+/-4%, which was significantly higher than 0.5+/-0.2% in young adults (p<0.05), and 1.2+/-0.6% in aged-matched controls (p<0.05). The present results indicate that magnetic resonance images could be used to detect paradoxical diaphragmatic motion in patients with emphysema.

Quinoproteins: structure, function, and biotechnological applications

A new class of oxidoreductase containing an amino acid-derived o-quinone cofactor, of which the most typical is pyrroloquinoline quinone (PQQ), is called quinoproteins, and has been recognized as the third redox enzyme following pyridine nucleotide- and flavin-dependent dehydrogenases. Some quinoproteins include a heme c moiety in addition to the quinone cofactor in the molecule and are called quinohemoproteins. PQQ-containing quinoproteins and quinohemoproteins have a common structural basis, in which PQQ is deeply embedded in the center of the unique superbarrel structure. Increased evidence for the structure and function of quinoproteins has revealed their unique position within the redox enzymes with respect to catalytic and electron transfer properties, and also to physiological and energetic function. The peculiarities of the quinoproteins, together with their unique substrate specificity, have encouraged their biotechnological application in the fields of biosensing and bioconversion of useful compounds, and also to environmental treatment.

Activation of human gingival epithelial cells by cell-surface components of black-pigmented bacteria: augmentation of production of interleukin-8, granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor and expression of intercellular adhesion molecule 1

Black-pigmented anaerobic bacteria, such as Porphyromonas gingivalis and Prevotella intermedia, are amongst the predominant bacteria in periodontal pockets and have been implicated in periodontal diseases. To elucidate the roles of gingival keratinocytes, which are the first cells encountered by oral bacteria in periodontal diseases, human gingival keratinocytes in primary culture were stimulated with cell-surface components of P gingivalis and Pr. intermedia. A glycoprotein fraction from Pr. intermedia (PGP) clearly augmented the release of interleukin-8, granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor, as determined by enzyme-linked immunosorbent assay. This PGP also induced expression of intercellular adhesion molecule-1 (ICAM-1), as determined by flow cytometry. The augmentation of mRNA expression for these molecules was also confirmed by reverse transcription PCR. In contrast, lipopolysaccharide (LPS) from Pr. intermedia and Escherichia coli was completely inactive in these assays. LPS fraction and purified fimbriae from P gingivalis exhibited weak activities. Cytokine production and ICAM-1 expression by gingival keratinocytes might cause accumulation and activation of neutrophils in the epithelium and, therefore, may be involved in the initiation and development of inflammation in periodontal tissues.

C-terminal periplasmic domain of Escherichia coli quinoprotein glucose dehydrogenase transfers electrons to ubiquinone

Membrane-bound quinoprotein glucose dehydrogenase (GDH) in Escherichia coli donates electrons directly to ubiquinone during the oxidation of d-glucose as a substrate, and these electrons are subsequently transferred to ubiquinol oxidase in the respiratory chain. To determine whether the specific ubiquinone-reacting site of GDH resides in the N-terminal transmembrane domain or in the large C-terminal periplasmic catalytic domain (cGDH), we constructed a fusion protein between the signal sequence of beta-lactamase and cGDH. This truncated GDH was found to complement a GDH gene-disrupted strain in vivo. The signal sequence of the fused protein was shown to be cleaved off, and the remaining cGDH was shown to be recovered in the membrane fraction, suggesting that cGDH has a membrane-interacting site that is responsible for binding to membrane, like peripheral proteins. Kinetic analysis and reconstitution experiments revealed that cGDH has ubiquinone reductase activity nearly equivalent to that of the wild-type GDH. Thus, it is likely that the C-terminal periplasmic domain of GDH possesses a ubiquinone-reacting site and transfers electrons directly to ubiquinone.

Membrane-bound quinoprotein D-arabitol dehydrogenase of Gluconobacter suboxydans IFO 3257: a versatile enzyme for the oxidative fermentation of various ketoses

Solubilization of membrane-bound quinoprotein D-arabitol dehydrogenase (ARDH) was done successfully with the membrane fraction of Gluconobacter suboxydans IFO 3257. In enzyme solubilization and subsequent enzyme purification steps, special care was taken to purify ARDH as active as it was in the native membrane, after many disappointing trials. Selection of the best detergent, keeping ARDH as the holoenzyme by the addition of PQQ and Ca2+, and of a buffer system involving acetate buffer supplemented with Ca2+, were essential to treat the highly hydrophobic and thus labile enzyme. Purification of the enzyme was done by two steps of column chromatography on DEAE-Toyopearl and CM-Toyopearl in the presence of detergent and Ca2+. ARDH was homogenous and showed a single sedimentation peak in analytical ultracentrifugation. ARDH was dissociated into two different subunits upon SDS-PAGE with molecular masses of 82 kDa (subunit I) and 14 kDa (subunit II), forming a heterodimeric structure. ARDH was proven to be a quinoprotein by detecting a liberated PQQ from SDS-treated ARDH in HPLC chromatography. More preliminarily, an EDTA-treated membrane fraction lost the enzyme activity and ARDH activity was restored to the original level by the addition of PQQ and Ca2+. The most predominant unique character of ARDH, the substrate specificity, was highly versatile and many kinds of substrates were oxidized irreversibly by ARDH, not only pentitols but also other polyhydroxy alcohols including D-sorbitol, D-mannitol, glycerol, meso-erythritol, and 2,3-butanediol. ARDH may have its primary function in the oxidative fermentation of ketose production by acetic acid bacteria. ARDH contained no heme component, unlike the type II or type III quinoprotein alcohol dehydrogenase (ADH) and did not react with primary alcohols.

Purification and characterization of membrane-bound quinoprotein cyclic alcohol dehydrogenase from Gluconobacter frateurii CHM 9

A quinoprotein catalyzing oxidation of cyclic alcohols was found in the membrane fraction for the first time, after extensive screening among aerobic bacteria. Gluconobacter frateurii CHM 9 was finally selected in this study. The enzyme tentatively named membrane-bound cyclic alcohol dehydrogenase (MCAD) was found to occur specifically in the membrane fraction, and pyrroloquinoline quinone (PQQ) was functional as the primary coenzyme in the enzyme activity. MCAD catalyzed only oxidation reaction of cyclic alcohols irreversibly to corresponding ketones. Unlike already known cytosolic NAD(P)H-dependent alcohol-aldehyde or alcohol-ketone oxidoreductases, MCAD was unable to catalyze the reverse reaction of cyclic ketones or aldehydes to cyclic alcohols. MCAD was solubilized and purified from the membrane fraction of the organism to homogeneity. Differential solubilization to eliminate the predominant quinoprotein alcohol dehydrogenase (ADH), and the subsequent two steps of column chromatographies, brought MCAD to homogeneity. Purified MCAD had a molecular mass of 83 kDa by SDS-PAGE. Substrate specificity showed that MCAD was an enzyme oxidizing a wide variety of cyclic alcohols. Some minor enzyme activity was found with aliphatic secondary alcohols and sugar alcohols, but not primary alcohols, differentiating MCAD from quinoprotein ADH. NAD-dependent cytosolic cyclic alcohol dehydrogenase (CCAD) in the same organism was crystallized and its catalytic and physicochemical properties were characterized. Judging from the catalytic properties of CCAD, it was apparent that CCAD was distinct from MCAD in many respects and seemed to make no contributions to cyclic alcohol oxidation.

NADH dehydrogenase of Corynebacterium glutamicum. Purification of an NADH dehydrogenase II homolog able to oxidize NADPH

NADPH oxidase activity, in addition to NADH oxidase activity, has been shown to be present in the respiratory chain of Corynebacterium glutamicum. In this study, we tried to purify NADPH oxidase and NADH dehydrogenase activities from the membranes of C. glutamicum. Both the enzyme activities were simultaneously purified in the same fraction, and the purified enzyme was shown to be a single polypeptide of 55 kDa. The N-terminal sequence of the enzyme was consistent with the sequence deduced from the NADH dehydrogenase gene of C. glutamicum, which has been sequenced and shown to be a homolog of NADH dehydrogenase II. In addition to high NADH-ubiquinone-1 oxidoreductase activity at neutral pH, the purified enzyme showed relatively high NADPH oxidase and NADPH-ubiquinone-1 oxidoreductase activities at acidic pH. Thus, NADH dehydrogenase of C. glutamicum was shown to be rather unique in having a relatively high reactivity toward NADPH.

Optimization of atrioventricular delay and follow-up in a patient with congestive heart failure and with bi-ventricular pacing

Cardiac function is improved by bi-ventricular pacing in patients with severe reduced cardiac function. Atrioventricular (AV) delay optimization is also important in this therapy. However, the AV delay required to achieve the optimal AV synchrony varied from time to time. We have reported that the critical AV delay that induces diastolic mitral regurgitation (MR) may represent the upper limit of the optimal AV delay. The optimal AV delay can be predicted by a simple method; slightly prolonged AV delay-interval between the end of atrial kick and complete closure of the mitral valve (duration of diastolic MR) at the AV delay setting. [Case] 60 year old Japanese male with dilated cardiomyopathy. He was repeatedly admitted to our hospital due to congestive heart failure. Ejection fraction was 14%. ECG showed complete left bundle branch block and his PQ interval was 0.22 sec. He was dependent on intravenous injections of catecolamine and could not be discharged from the hospital for over one year. Optimal AV delay was predicted as 80 msec during bi-ventricular pacing by our formula. Cardiac output was 4.9, 6.0, 5.1 l/min when the AV delay was set at 50, 80, 110 msec. Cardiac function was improved from NYHA class III to II and he has been relieved from the dependency on intravenous catecholamine injections. AV delay was optimized (70-100 msec) by our method during follow-up for one year. This case indicates that AV delay optimization is important in bi-ventricular pacing.

The significance of cytomegalovirus infection over the clinical course of adult T-cell leukemia/lymphoma

The significance of cytomegalovirus (CMV) infections developed over the clinical course of adult T-cell leukemia/lymphoma (ATLL) were evaluated in relation to the patient survival rate, ATL activity and immunocompetent cells. ATLL patients with CMV infections on admission exhibited a poor survival rate, while patients with CMV infections at any time after admission survived longer than those not infected with this virus. ATLL patients who exhibited a numbers of CMV infection on admission showed higher ATL activity and had lower numbers of CD8-positive and CD56-positive cells than those who developed CMV infections at any time after admission. Therefore, it appears likely that patients with CMV infections on admission were in an immunosuppressive state due to aggressive ATL activity.

Upregulation of matrix metalloproteinase-1 production by prostaglandin F2alpha in human gingival fibroblasts

In the present study, we investigated the effect of prostglandin F2alpha (PGF2alpha) and combination of PGF2alpha and interleukin(IL)-1beta on matrix metalloproteinase (MMP)-1 production in human gingival fibroblasts (HGF). PGF2alpha enhanced MMP-1 production in a dose-dependent manner in HGF. Combination of PGF2alpha and IL-1beta induced a synergistic increase of MMP-1 production in HGF. Furthermore, fluprostenol, a specific FP receptor agonist, increased MMP-1 production and induced a synergistic enhancement of IL-1beta-induced MMP-1 production in HGF, similar to PGF2alpha. FP receptor mRNA expression was detected in HGF, by reverse transcription-polymerase chain reaction. Northern blot analysis revealed that PGF2alpha enhanced MMP-1 mRNA expression in HGF and that PGF2alpha increased MMP-1 mRNA levels induced by IL-1beta. In conclusion, we suggest that PGF2alpha increases MMP-1 production in HGF and synergistically enhances MMP-1 production in IL-1beta-stimulated HGF. PGF2alpha may be involved in degradation of connective tissue in periodontal lesions.

Inhibition of trypsin-like cysteine proteinases (gingipains) from Porphyromonas gingivalis by tetracycline and its analogues

Extracellular cysteine proteinases, referred to as gingipains, are considered important virulence factors for Porphyromonas gingivalis, a bacterium recognized as a major etiologic agent of chronic periodontitis. We investigated the effect of tetracycline and its analogues, doxycycline and minocycline, on the enzymatic activities of gingipains. Tetracyclines at 100 microM totally inhibited the amidolytic activity of arginine-specific gingipains (HRgpA and RgpB). In contrast, inhibition of Kgp was less efficient and required a somewhat higher concentration of the antibiotic to achieve the same effect. Among tetracycline derivatives, the most potent gingipain inhibitor was doxycycline, followed by tetracycline and minocycline. RgpB was inhibited by doxycycline in an uncompetitive and reversible manner with a 50% inhibitory concentration of 3 microM. Significantly, inhibition was unaffected by calcium, excluding the chelating activity of tetracyclines as the mechanism of gingipain inactivation. In contrast, the inhibitory activities of the tetracyclines were reduced by cysteine, a reducing agent, suggesting an interference of the drug at the oxidative region with the catalytic system of the enzyme. Doxycycline, at 10 microM, significantly inhibited the RgpB-mediated production of vascular permeability-enhancing activity from human plasma, thus proving an effective inhibition of gingipain in vivo. These results indicate a new activity of tetracyclines as cysteine proteinase inhibitors and may explain the therapeutic efficiency of these antibiotics in the treatment of periodontitis.

Light induced apoptosis is accelerated in transgenic retina overexpressing human EAT/mcl-1, an anti-apoptotic bcl-2 related gene

BACKGROUND/AIM

EAT/mcl-1 (EAT), an immediate early gene, functions in a similar way to bcl-2 in neutralising Bax mediated cytotoxicity, suggesting that EAT is a blocker of cell death. The aim of this study was to determine the effect of overexpression of the human EAT gene on light induced retinal cell apoptosis.

METHODS

EAT transgenic mice incorporating the EF-1alpha promoter were utilised, and expression of human EAT was detected by RT-PCR. Light damage was induced by raising mice under constant illumination. Two groups of animals, EAT transgenic mice (n=14) and littermates (n=13), were examined by ERG testing and histopathology at regular time points up to 20 weeks of constant light stimulation. Electrophysiological and histopathological findings were evaluated by established systems of arbitrary scoring as scores 0-2 and scores 0-3, respectively.

RESULTS

The mean score (SD) of ERG response was significantly lower in EAT transgenic mice (0.79 (0.89)) than in littermates (1.69 (0.48)) (p<0.01). Although the differences between the two survival curves did not reach statistical significance (p=0.1156), the estimated incidence of electrophysiological retinal damage was higher in EAT mice (0.0495/mouse/week; 95% confidence interval (CI) 0.0347-0.0500) than in littermates (0. 0199/mouse/week; 95% CI 0.0035-0.0364). The mean scores (SD) for histopathological retinal degeneration were 2.31 (0.63) in littermates and 1.43 (1.22) in EAT transgenic mice (p=0.065). However, Kaplan-Meier curves for histopathological failure in two groups of mice showed that retinal photoreceptor cells were preserved significantly against constant light in the littermate compared with transgenic mice (p=0.0241). The estimated incidence of histopathological retinal damage was 0.0042/mouse/week in the littermates (95% CI 0-0.0120) and 0.0419/mouse/week in the EAT mice (95% CI 0.0286-0.0500).

CONCLUSION

Retinal photoreceptor cell apoptosis under constant light stimulation is likely to be accelerated in transgenic retina overexpressing EAT.

Intravenous administration of MEK inhibitor U0126 affords brain protection against forebrain ischemia and focal cerebral ischemia

Brain subjected to acute ischemic attack caused by an arterial blockage needs immediate arterial recanalization. However, restoration of cerebral blood flow can cause tissue injury, which is termed reperfusion injury. It is important to inhibit reperfusion injury to achieve greater brain protection. Because oxidative stress has been shown to activate mitogen-activated protein kinases (MAPKs), and because oxidative stress contributes to reperfusion injury, MAPK may be a potential target to inhibit reperfusion injury after brain ischemia. Here, we demonstrate that reperfusion after forebrain ischemia dramatically increases phosphorylation level of extracellular signal-regulated kinase 2 (ERK2) in the gerbil hippocampus. In addition, i.v. administration of U0126 (100-200 mg/kg), a specific inhibitor of MEK (MAPK/ERK kinase), protects the hippocampus against forebrain ischemia. Moreover, treatment with U0126 at 3 h after ischemia significantly reduces infarct volume after transient (3 h) focal cerebral ischemia in mice. This protection is accompanied by reduced phosphorylation level of ERK2, substrates for MEK, in the damaged brain areas. Furthermore, U0126 protects mouse primary cultured cortical neurons against oxygen deprivation for 9 h as well as nitric oxide toxicity. These results provide further evidence for the role of MEK/ERK activation in brain injury resulting from ischemia/reperfusion, and indicate that MEK inhibition may increase the resistance of tissue to ischemic injury.

[Activation of ATP-sensitive K+ channels by ADP and K+ channel openers: homology model of sulfonylurea receptor carboxyl-termini]

The ATP-sensitive K+ channels (KATP) are composed of Kir6.0 subunits and sulfonylurea receptors (SUR1, 2A and 2B). SUR2A and SUR2B are splice variants and differ only in the C-terminal 42 amino acid residue (C42). SURs are supposed to be the subunit that determines the different response of KATPs to intracellular nucleotides, K+ channel openers and inhibitors. In this study, we report that C42 of SURs plays critical roles in differential activation of various KATPs by ADP and K+ channel openers such as diazoxide and nicorandil. KATPs containing distinct SURs and Kir6.2 were reconstructed on HEK293T cells. Much higher concentrations of ADP were necessary to activate channels which SUR1 or SUR2B. In all KATPs containing different SUR, diazoxide increased the potency of ADP for channel activity without affecting its efficacy. From the electrophysiological data obtained from C-terminal chimeras and point mutants in the second nucleotide binding domain (NBDs), we developed the homology model of each SUR-NBD2 based on the crystallgraphically determined structure of HisP, a member of the ABC protein superfamily. In this model, C42 is located just beneath the Walker A motif of NBD2 and regulates the binding of nucleotide to NBD2 by affecting the 3-D construct of NBD2. This homology model well explains the different response of KATPs to ADP. Based on this model, it will be possible to develop new ligands for KATPs.

[Drug-induced pneumonitis caused by sulfamethoxazole-trimethoprim]

A 33-year-old man was treated with sulfamethoxazole-trimethoprim (SMT-TMP) for an infection in the cervical vertebrae by methicillin-resistant Staphylococcus aureus (MRSA). Two weeks later a fever of 39 degrees C appeared, and a productive cough, hemosputum, and dyspnea developed a further three weeks later. Chest radiographs showed bilateral ground-glass opacity. Cell differentiation of bronchoalveolar lavage fluid (BALF) revealed increases of lymphocytes and eosinophils, and the CD4/CD8 ratio of the BALF lymphocytes was decreased. A thoracoscopic lung biopsy specimen showed fibroedematous thickening of the alveolar walls, hypertrophic alveolar cells, and cell infiltration with neutrophils and lymphocytes. The pathological diagnosis was nonspecific interstitial pneumonia, group II. The fever resolved 6 days after discontinuance of SMX-TMP. The lymphocyte stimulation test for SMX-TMP gave a positive result. Administration of glucocorticoid improved both the symptoms and the laboratory data.

Effect of arginine mutation of alanine-556 on DNA recognition of zinc finger protein Sp1

Human transcription factor Sp1, which contains three Cys(2)His(2)-class zinc finger motives, specifically binds to the so-called GC box DNA. It has been indicated that finger 1 has a unique DNA-binding mode compared with fingers 2 and 3, or the Zif268 model. Therefore, we investigate the role of Ala at position 6 on the recognition helix, which is not responsible for guanine recognition and highly conserved among Sp1 family. Several Ala-556 mutations of Sp1 bind to DNA with different DNA-binding features. In particular, the Ala-->Arg substitution alters the DNA-binding contribution of the three zinc fingers in Sp1. In this case, the DNA-binding specificity of each finger decreases in the order 2>1>3. This result reveals that one amino acid in position 6 plays an important role not only for the selectivity to the putative finger 1 subsite, but also for the binding mode of the three fingers to each finger subsite. Probably, Ala-556 is indispensable to characterize the binding mode of the Sp1 zinc fingers, namely the diverse binding contribution of finger 1 and the rigid binding one of finger 3. In Sp1, the N-terminal finger 1 serves as a 'hinge finger'.

Interaction between the RGS domain of RGS4 with G protein alpha subunits mediates the voltage-dependent relaxation of the G protein-gated potassium channel

1. In native cardiac myocytes, there is a time dependence to the G protein-gated inwardly rectifying K(+) (K(G)) channel current during voltage steps that accelerates as the concentration of acetylcholine is increased. This phenomenon has been called 'relaxation' and is not reproduced in the reconstituted Kir3.1/Kir3.4 channel in Xenopus oocytes. We have shown that RGS4, a regulator of G protein signalling, restores relaxation to the reconstituted Kir3.1/Kir3.4 channel. In this study, we examined the mechanism of this phenomenon by expressing various combinations of membrane receptors, G proteins, Kir3.0 subunits and mutants of RGS4 in Xenopus oocytes. 2. RGS4 restored relaxation to K(G) channels activated by the pertussis toxin (PTX)-sensitive G protein-coupled m(2)-muscarinic receptor but not to those activated by the G(s) protein-coupled beta(2)-adrenergic receptor. 3. RGS4 induced relaxation not only in heteromeric K(G) channels composed of Kir3.1 and Kir3.4 but also in homomeric assemblies of either an active mutant of Kir3.1 (Kir3.1/F137S) or an isoform of Kir3.2 (Kir3.2d). 4. Truncation mutants of RGS4 showed that the RGS domain itself was essential to reproduce the effect of wild-type RGS4 on the K(G) channel. 5. The mutation of residues in the RGS domain which interact with the alpha subunit of the G protein (G(alpha)) impaired the effect of RGS4. 6. This study therefore shows that interaction between the RGS domain and PTX-sensitive G(alpha) subunits mediates the effect of RGS4 on the agonist concentration-dependent relaxation of K(G) channels.

Long-term survival after resection for small cell carcinoma of the esophagus

We describe the rare case of a patient with esophageal small cell carcinoma who was completely cured. A 77-year-old man had small cell carcinoma of the esophagus with extensive lymph node metastases. Treatment comprised a subtotal esophagectomy and extended lymph node dissection. He has survived for more than 7 years with no evidence of recurrent disease. We suggest that radical operations should be considered for future patients if curative resection can be expected.

Adult T-cell leukemia with anti-HTLV-I antibody but no HTLV-I DNA in tumor cells

Adult T-cell leukemia (ATL) is usually defined as a malignant disease of T cells infected by human T-lymphotropic virus type I (HTLV-I). In the present study, we describe a 49-year-old woman with an acute type ATL, whose leukemic cells do not contain the HTLV-I genome. Laboratory tests revealed an increase in abnormal lymphocytes with convoluted nuclei, elevated serum lactate dehydrogenase levels, increased thymidine kinase activity and soluble interleukin-2 receptor-alpha levels. Serum examination demonstrated positive anti-HTLV-I antibody, but Southern blot analysis using the whole HTLV-I genome as a probe did not detect any integration of the viral genome. In contrast, PCR detected the HTLV-I pX region in the same DNA samples as used for Southern blot analysis. These findings suggest two possibilities. One possibility is that ATL in this patient is generated by other pathogens than HTLV-I virus. She is also an HTLV-I carrier. The other possibility is that her leukemic T cell clone derived its malignant phenotype from HTLV-I infection, and once this malignant phenotype was obtained, partial deletions of viral genome repeated until the whole viral genome was deleted. Although there is no direct evidence, the former possibility is more likely in the present case.

Volume-scanning three-dimensional display that uses an inclined image plane

A novel three-dimensional display based on a volume-scanning method that uses an inclined light-source array and a mirror scanner is proposed. With this technique it is possible to display three-dimensional images that satisfy all factors for human stereoscopic vision. Three-dimensional images of 8 x 8 x 8 pixels, 40 mm x 40 mm x 40 mm in size, with a frame rate of 12.7 Hz were obtained as real images through an experimental system that uses a galvanometer mirror and a LED array.

Azurin involved in alcohol oxidation system in Pseudomonas putida HK5: expression analysis and gene cloning

Expression of azurin in Pseudomonas putida HK5 was examined by immunoblot analysis. Similar amounts of azurin were found in the cells grown into the stationary phase on any carbon sources, including LB medium without alcohol, where no quinoprotein alcohol dehydrogenases appeared. In the early exponential phase, the highest amount of azurin was found in the cells grown on 1-butanol, but here was none in the case of LB medium, suggesting that expression of azurin is cooperative with that of the alcohol oxidase system, especially the system including quinohemoprotein alcohol dehydrogenase IIB. The azurin gene (azu) was cloned and sequenced. azu is monocistronic, and in its promoter region, FNR-binding consensus sequence was found. However, its relative position suggests different transcriptional regulation from that in azu of P. aeruginosa. The molecular weight of the mature protein without copper ion calculated from the amino acid sequence was consistent with the value of the purified azurin measured by mass spectrometry.

P21WAF1/CIP1 messenger RNA expression in hepatitis B, C virus-infected human hepatocellular carcinoma tissues

BACKGROUND

The primary objective of this study was to clarify the significance of p21WAF1/CIP1(p21) gene expression in the tumorgenicity of hepatitis B virus (HBV) and hepatitis C virus (HCV) infected human hepatocelluar carcinoma (HCC).

METHODS

The authors performed Northern blot hybridization to compare the p21 messenger (m) RNA expression levels among 16 HCC cases. They detected tissue HBVx mRNA (Northern blot) and plus- and minus-strand HCV RNA (reverse transcription-polymerase chain reaction) in liver tissues. They also measured alanine transaminase (ALT) levels and indocyanine green retention rate at 15 minutes (ICG-R15).

RESULTS

The p21 transcripts of tumor (T) tissues could be identified with lower intensity than nontumor (N) tissues in all 4 HBVx mRNA(+) cases, 8 of 10 HCV RNA(+) cases, and 1 of 3 B(-), C(-) cases (1 case was positive for both viruses). p21 mRNA expression levels of N tissues were significantly higher in HCV RNA(+) cases than in HBVx mRNA(+) cases. p21 mRNA expression levels of N tissues were significantly correlated with serum ALT levels.

CONCLUSIONS

In HCV hepatitis, p21 mRNA expression is up-regulated to control cell cycle under regeneration stress. Once the liver develops HCC, the p21 mRNA expression decreases to prominently low levels. The up-regulated p21 expression may play a role as a guard to prevent hepatocytes from tumorgenicity in HCV hepatitis.

P21WAF1/CIP1 messenger RNA expression in hepatitis B, C virus-infected human hepatocellular carcinoma tissues

BACKGROUND

The primary objective of this study was to clarify the significance of p21WAF1/CIP1(p21) gene expression in the tumorgenicity of hepatitis B virus (HBV) and hepatitis C virus (HCV) infected human hepatocelluar carcinoma (HCC).

METHODS

The authors performed Northern blot hybridization to compare the p21 messenger (m) RNA expression levels among 16 HCC cases. They detected tissue HBVx mRNA (Northern blot) and plus- and minus-strand HCV RNA (reverse transcription-polymerase chain reaction) in liver tissues. They also measured alanine transaminase (ALT) levels and indocyanine green retention rate at 15 minutes (ICG-R15).

RESULTS

The p21 transcripts of tumor (T) tissues could be identified with lower intensity than nontumor (N) tissues in all 4 HBVx mRNA(+) cases, 8 of 10 HCV RNA(+) cases, and 1 of 3 B(-), C(-) cases (1 case was positive for both viruses). p21 mRNA expression levels of N tissues were significantly higher in HCV RNA(+) cases than in HBVx mRNA(+) cases. p21 mRNA expression levels of N tissues were significantly correlated with serum ALT levels.

CONCLUSIONS

In HCV hepatitis, p21 mRNA expression is up-regulated to control cell cycle under regeneration stress. Once the liver develops HCC, the p21 mRNA expression decreases to prominently low levels. The up-regulated p21 expression may play a role as a guard to prevent hepatocytes from tumorgenicity in HCV hepatitis.

P21WAF1/CIP1 messenger RNA expression in hepatitis B, C virus-infected human hepatocellular carcinoma tissues

BACKGROUND

The primary objective of this study was to clarify the significance of p21WAF1/CIP1(p21) gene expression in the tumorgenicity of hepatitis B virus (HBV) and hepatitis C virus (HCV) infected human hepatocelluar carcinoma (HCC).

METHODS

The authors performed Northern blot hybridization to compare the p21 messenger (m) RNA expression levels among 16 HCC cases. They detected tissue HBVx mRNA (Northern blot) and plus- and minus-strand HCV RNA (reverse transcription-polymerase chain reaction) in liver tissues. They also measured alanine transaminase (ALT) levels and indocyanine green retention rate at 15 minutes (ICG-R15).

RESULTS

The p21 transcripts of tumor (T) tissues could be identified with lower intensity than nontumor (N) tissues in all 4 HBVx mRNA(+) cases, 8 of 10 HCV RNA(+) cases, and 1 of 3 B(-), C(-) cases (1 case was positive for both viruses). p21 mRNA expression levels of N tissues were significantly higher in HCV RNA(+) cases than in HBVx mRNA(+) cases. p21 mRNA expression levels of N tissues were significantly correlated with serum ALT levels.

CONCLUSIONS

In HCV hepatitis, p21 mRNA expression is up-regulated to control cell cycle under regeneration stress. Once the liver develops HCC, the p21 mRNA expression decreases to prominently low levels. The up-regulated p21 expression may play a role as a guard to prevent hepatocytes from tumorgenicity in HCV hepatitis.

[A case of pneumonitis possibly due to isocyanate associated with high levels of serum KL-6]

A 47-year-old automobile painter developed dry cough, chills and dyspnea after four months of painting work. The spray contained isocyanates (HDI). A chest radiograph showed bilateral ground-glass shadows. The serum KL-6 level was very high: 11,100 U/ml. Marked lymphocytosis and a striking decrease in the CD4/CD8 ratio were observed in the bronchoalveolar lavage fluid. Transbronchial lung biopsy specimens showed alveolitis and bronchiolitis. Cessation of exposure to isocyanates improved the symptoms and laboratory data. We suspected that the patient was suffering from hypersensitivity pneumonitis induced by isocyanates. Specific IgG antibodies for TDI, MDI, and HDI were not demonstrated by enzyme-linked immunosorbent assay. Because abnormal shadows in the chest radiograph did not improve quickly after admission, we administered glucocorticoids which improved the symptoms, the chest radiograph findings, and the serum KL-6 level.

Osteoclast-like cells in an in vitro model of bone destruction by rheumatoid synovium

OBJECTIVE

Osteoclasts may be involved in the process of rheumatoid bone destruction. To test this hypothesis, we developed an in vitro model of bone destruction by osteoclast-like cells derived from cultured rheumatoid synovial tissue without using any inducers.

METHODS

Synovial tissues were obtained from rheumatoid arthritis and osteoarthritis patients and tissue pieces of about 2 mm(3) that contained synovial lining were cultured. Multinucleated cells derived from cultured synovial tissues were studied cytochemically and morphologically for osteoclast-specific markers.

RESULTS

Fibroblast-like and macrophage-like cells from the tissue pieces proliferated in the coexistence of lymphocytes. After 14 days of culture, multinucleated cells with tartrate-resistant acid phosphatase activity appeared. These cells expressed vacuolar H(+)-ATPase, the vitronectin receptor and cathepsin K. Although binding of (125)I-labelled salmon calcitonin was very low, the cells contained ringed structures of F-actin and showed strong bone-resorbing activity on ivory slices. Proliferation of macrophage-like cells and formation of multinucleated cells continued during 6 months of culture in the presence of fibroblast-like cells. The bone-resorbing activity of multinucleated cells derived from rheumatoid synovial tissue was much higher than that of cells from osteoarthritis synovial tissue, and was related to the disease activity of rheumatoid arthritis.

CONCLUSION

Our culture system reproduced in vitro the process of bone destruction by rheumatoid synovium, including the proliferation and fusion of precursor cells, polarization, activation and bone tissue resorption. This system may provide a tool for understanding the mechanisms of bone destruction in rheumatoid arthritis and for the development of new therapies to prevent bone destruction.

Cloning of a cDNA for a constitutive NRT1 transporter from soybean and comparison of gene expression of soybean NRT1 transporters

We have isolated a cDNA for a putative transporter, named GmNRT1-3, in the NRT1 family from soybean. It was predicted to have a similar topological structure not only to both GmNRT1-1 and GmNRT1-2 reported previously, but also to other members of the family. Two other cDNAs isolated have parts of the sequence for putative NRT1 transporters, GmNRT1-4 and GmNRT1-5, suggesting that at least five NRT1 transporters occur in soybean. These GmNRT1 genes and the GmNRT2 gene, encoding a soybean NRT2 nitrate transporter, showed different expression patterns to each other under various nitrogen conditions. Specifically, GmNRT1-3 was constitutively expressed in both roots and leaves, while GmNRT1-2 was gradually expressed as the roots developed in the presence of ammonium as a nitrogen source, but not in the presence of both ammonium and nitrate. Based on these results, we discussed the possible regulation in the expression and role of these transporters in nitrate uptake.

Functional Kir7.1 channels localized at the root of apical processes in rat retinal pigment epithelium

1. The inwardly rectifying K+ channel current (IK(IR)) recorded from isolated retinal pigmented epithelial (RPE) cells showed poor dependence on external K+ ([K+]o) and low sensitivity to block by Ba2+. We examined the molecular identity and specific subcellular localization of the KIR channel in RPE cells. 2. The Kir7.1 channel current heterologously expressed in HEK293T cells (human embryonic kidney cell line) showed identical properties to those of the RPE IK(IR), i.e. poor dependence on [K+]o and low sensitivity to Ba2+ block. 3. Expression of Kir7.1 mRNA and protein was detected in RPE cells by RT-PCR and immunoblot techniques, respectively. 4. Immunohistochemical studies including electron microscopy revealed that the Kir7.1 channel was localized specifically at the proximal roots of the apical processes of RPE cells, where Na+,K+-ATPase immunoreactivity was also detected. 5. The middle-distal portions of apical processes of RPE cells in the intact tissue exhibited immunoreactivity of Kir4.1, a common KIR channel. In the isolated RPE cells, however, Kir4.1 immunoreactivity was largely lost, while Kir7.1 immunoreactivity remained. 6. These data indicate that the only IK(IR) recorded in isolated RPE cells is derived from the functional Kir7.1 channel localized at the root of apical processes. Co-localization with Na+,K+-ATPase suggests that the Kir7.1 channel may provide the pathway for recycling of K+ to maintain pump activity and thus is essential for K+ handling in RPE cells.

Finger-positional change in three zinc finger protein Sp1: influence of terminal finger in DNA recognition

The connection of functional modules is effective for the design of DNA binding molecules with the desired sequence specificity. C(2)H(2)-type zinc finger proteins have a tandemly repeated array structure consisting of independent finger modules and are expected to recognize any DNA sequences by permutation, multi-connection, and the substitution of various sets of zinc fingers. To investigate the effects of the replacement of the terminal finger on the DNA recognition by other fingers, we have constructed the three zinc finger peptides with finger substitution at the N- or C-terminus, Sp1(zf223), Sp1(zf323), and Sp1(zf321). From the results of gel mobility shift assays, each mutant peptide binds preferentially to the target sequence that is predicted if the fingers act in a modular fashion. The methylation interference analyses demonstrate that in the cases of the N-terminal finger substitution mutants, Sp1(zf223) and Sp1(zf323), the N-terminal finger recognizes bases to different extents from that of the wild-type peptide, Sp1(zf123). Of special interest is the fact that the N-terminal finger of the C-terminal finger substitution mutant, Sp1(zf321), shows a distinct base recognition from those of Sp1(zf123) and Sp1(zf323). DNase I footprinting analyses indicate that the C-terminal finger (active finger) induces a conformational change in the DNA in the region for the binding of the N-terminal finger (passive finger). The present results strongly suggest that the extent of base recognition of the N-terminal finger is dominated by the binding of the C-terminal finger. This information provides an important clue for the creation of a zinc finger peptide with the desired specificity, which is applicable to the design of novel drugs and biological tools.

Viral serostatus and coexisting inflammatory activity affect metachronous carcinogenesis after hepatectomy for hepatocellular carcinoma. A further report

Little data are available regarding the effects of hepatitis virus serostatus and the severity of coexisting chronic inflammation on intrahepatic recurrence after hepatectomy for hepatocellular carcinoma (HCC). We investigated the extent to which these factors modified the prognosis of hepatectomized patients. A total of 274 patients treated in the period January 1981 to December 1996 were divided into three groups: antihepatitis C-positive (HCV; n = 144), hepatitis B surface antigen-positive and HCV antibody (Ab)-negative (HBsAg; n = 106), and HBsAg-negative and HCV Ab-negative (NBNC; n = 20). Positivity for HBV-related antibody in the HCV group was 76%. Histologic grading of inflammatory activity from coexisting hepatitis was determined according to Knodel's histological activity index (HAI) scoring system. Post-hepatectomy crude survival rates and disease-free survival (DFS) rates were compared, according to tumor characteristics, between the three groups. In the patients overall and also in the patients with a single nodular HCC, the HCV group had significantly higher HAI scores and preoperative serum aspartate aminotransaminase (AST) levels than the other two groups. When the patients were limited to those with a single nodular HCC, the crude survival was similar in the three groups with comparable tumor characteristics; however, the DFS was different (NBNC > HBsAg > HCV). When the patients were further limited to those with a single nodular HCC without microscopic extracapsular spread, in whom removal of the tumor was expected to be microscopically complete, the difference in the DFS became more marked. Irrespective of the viral serostatus, better crude and disease-free survivals were observed in the patients with lower AST levels (< or =50 IU/ 1) than in those with higher AST levels (>50IU/l). In contrast, there were no differences in survivals and HAI scores according to the presence or absence of HBV-related antibody in the HCV group. From our univariate analysis, we can conclude that the severity of virally induced inflammation, which was well correlated with viral serostatus, may be a factor that affects intrahepatic recurrence, which is more likely to originate from metachronous carcinogenesis. Prior co-infection of HBV in HCV patients may not be an adverse risk factor for intrahepatic recurrence.

Membrane-bound sugar alcohol dehydrogenase in acetic acid bacteria catalyzes L-ribulose formation and NAD-dependent ribitol dehydrogenase is independent of the oxidative fermentation

To identify the enzyme responsible for pentitol oxidation by acetic acid bacteria, two different ribitol oxidizing enzymes, one in the cytosolic fraction of NAD(P)-dependent and the other in the membrane fraction of NAD(P)-independent enzymes, were examined with respect to oxidative fermentation. The cytoplasmic NAD-dependent ribitol dehydrogenase (EC 1.1.1.56) was crystallized from Gluconobacter suboxydans IFO 12528 and found to be an enzyme having 100 kDa of molecular mass and 5 s as the sedimentation constant, composed of four identical subunits of 25 kDa. The enzyme catalyzed a shuttle reversible oxidoreduction between ribitol and D-ribulose in the presence of NAD and NADH, respectively. Xylitol and L-arabitol were well oxidized by the enzyme with reaction rates comparable to ribitol oxidation. D-Ribulose, L-ribulose, and L-xylulose were well reduced by the enzyme in the presence of NADH as cosubstrates. The optimum pH of pentitol oxidation was found at alkaline pH such as 9.5-10.5 and ketopentose reduction was found at pH 6.0. NAD-Dependent ribitol dehydrogenase seemed to be specific to oxidoreduction between pentitols and ketopentoses and D-sorbitol and D-mannitol were not oxidized by this enzyme. However, no D-ribulose accumulation was observed outside the cells during the growth of the organism on ribitol. L-Ribulose was accumulated in the culture medium instead, as the direct oxidation product catalyzed by a membrane-bound NAD(P)-independent ribitol dehydrogenase. Thus, the physiological role of NAD-dependent ribitol dehydrogenase was accounted to catalyze ribitol oxidation to D-ribulose in cytoplasm, taking D-ribulose to the pentose phosphate pathway after being phosphorylated. L-Ribulose outside the cells would be incorporated into the cytoplasm in several ways when need for carbon and energy sources made it necessary to use L-ribulose for their survival. From a series of simple experiments, membrane-bound sugar alcohol dehydrogenase was concluded to be the enzyme responsible for L-ribulose production in oxidative fermentation by acetic acid bacteria.

C-terminal tails of sulfonylurea receptors control ADP-induced activation and diazoxide modulation of ATP-sensitive K(+) channels

The ATP-sensitive K(+) (K(ATP)) channels are composed of the pore-forming K(+) channel Kir6.0 and different sulfonylurea receptors (SURs). SUR1, SUR2A, and SUR2B are sulfonylurea receptors that are characteristic for pancreatic, cardiac, and vascular smooth muscle-type K(ATP) channels, respectively. The structural elements of SURs that are responsible for their different characteristics have not been entirely determined. Here we report that the 42 amino acid segment at the C-terminal tail of SURs plays a critical role in the differential activation of different SUR-K(ATP) channels by ADP and diazoxide. In inside-out patches of human embryonic kidney 293T cells coexpressing distinct SURs and Kir6.2, much higher concentrations of ADP were needed to activate channels that contained SUR2A than SUR1 or SUR2B. In all types of K(ATP) channels, diazoxide increased potency but not efficacy of ADP to evoke channel activation. Replacement of the C-terminal segment of SUR1 with that of SUR2A inhibited ADP-mediated channel activation and reduced diazoxide modulation. Point mutations of the second nucleotide-binding domains (NBD2) of SUR1 and SUR2B, which would prevent ADP binding or ATP hydrolysis, showed similar effects. It is therefore suggested that the C-terminal segment of SUR2A possesses an inhibitory effect on NBD2-mediated ADP-induced channel activation, which underlies the differential effects of ADP and diazoxide on K(ATP) channels containing different SURs.

Isolation and characterization of thermotolerant Gluconobacter strains catalyzing oxidative fermentation at higher temperatures

Thermotolerant acetic acid bacteria belonging to the genus Gluconobacter were isolated from various kinds of fruits and flowers from Thailand and Japan. The screening strategy was built up to exclude Acetobacter strains by adding gluconic acid to a culture medium in the presence of 1% D-sorbitol or 1% D-mannitol. Eight strains of thermotolerant Gluconobacter were isolated and screened for D-fructose and L-sorbose production. They grew at wide range of temperatures from 10 degrees C to 37 degrees C and had average optimum growth temperature between 30-33 degrees C. All strains were able to produce L-sorbose and D-fructose at higher temperatures such as 37 degrees C. The 16S rRNA sequences analysis showed that the isolated strains were almost identical to G. frateurii with scores of 99.36-99.79%. Among these eight strains, especially strains CHM16 and CHM54 had high oxidase activity for D-mannitol and D-sorbitol, converting it to D-fructose and L-sorbose at 37 degrees C, respectively. Sugar alcohols oxidation proceeded without a lag time, but Gluconobacter frateurii IFO 3264T was unable to do such fermentation at 37 degrees C. Fermentation efficiency and fermentation rate of the strains CHM16 and CHM54 were quite high and they rapidly oxidized D-mannitol and D-sorbitol to D-fructose and L-sorbose at almost 100% within 24 h at 30 degrees C. Even oxidative fermentation of D-fructose done at 37 degrees C, the strain CHM16 still accumulated D-fructose at 80% within 24 h. The efficiency of L-sorbose fermentation by the strain CHM54 at 37 degrees C was superior to that observed at 30 degrees C. Thus, the eight strains were finally classified as thermotolerant members of G. frateurii.

Benign and malignant oncocytoma of the salivary glands with an immunohistochemical evaluation of Ki-67

We present two cases of benign oncocytoma derived from the parotid gland and minor salivary gland and one case of malignant oncocytoma from the parotid gland. The proliferative activity of the tumor cells was evaluated immunohistochemically for Ki-67. The average frequency of Ki-67-positive cells was 3.3% in the benign oncocytomas and 6.5% in the malignant oncocytoma. The higher frequency of Ki-67-positive cells in the malignant oncocytoma might reflect active cell proliferation. Ki-67 immunostaining may be useful in distinguishing a benign oncocytoma from a malignant oncocytoma.

Edge enhancement and edge-enhanced correlation with photorefractive polymers

We demonstrate a simple all-optical realization of programmable edge enhancement and edge-enhanced correlation using novel photorefractive polymers. We show that the higher non-Bragg order in a two-beam coupling scheme contains the edge enhancement of the object when placed in the path of one of the incident beams. Also, this arrangement provides a scheme for writing joint transform correlation dynamic holograms, which can be read by a third beam. The correlation is edge enhanced, and the correlation peak increases with the applied bias voltage. Numerical results without and with beam fanning are presented. Theoretical predictions are reconciled with experimental results.

Management of malignant ovarian tumors in young women. 21 nulliparous cases

To evaluate the management of malignant ovarian tumors in young women who wish to maintain fertility, we retrospectively reviewed ovarian malignancies in 21 young women who were both nulliparous and under 40 years of age. With stage 1a disease, all 9 patients were treated with conservative surgical therapies, and all of them are still alive, irrespective of histological type. With stage 1c disease, 5 (83%) of 6 patients were treated with conservative surgical therapies. Among them, 2 patients with epithelial tumors, who were treated with conservative surgical therapies and potent cis-diamminedichloroplatinum (CDDP)-based combined chemotherapies, are still alive. Furthermore, one of them had a successful pregnancy. On the other hand, 3 out of 4 patients with nonepithelial tumors were treated with conservative surgical therapies. However, 2 (67%) out of 3 died; both of them were treated with non-CDDP-based chemotherapy. In 6 patients with disease beyond stage 2, 4 (67%) were treated with radical surgical therapies, but 2 (33%) were treated with conservative surgery and CDDP-based combined chemotherapy, one of which was followed by a successful pregnancy in spite of nonepithelial tumor. As above, we could obtain some successful pregnancies in cases beyond stage 1c after conservative surgery by adding definite CDDP-based combined chemotherapy. However, we must carefully select the patients with nonepithelial tumors for conservative therapy by adding definite CDDP-based combined chemotherapy and inform them of the risks of therapy.

Cytomegalovirus infection is not necessarily a poor prognostic factor in adult T-cell leukemia/lymphoma

The relationship between cytomegalovirus (CMV) antigenemia and the clinical course was examined in 57 patients with adult T-cell leukemia/lymphoma (ATLL). All patients included had the acute/lymphoma type of ATL according to the criteria of the Japan Lymphoma Study Group (LSG). CMV antigenemia was assessed on admission and at the time when the patients had fever higher than 37. 5 degrees C, which did not respond to antibiotics for longer than 3 days. The incidence of CMV antigenemia was 44%. Approximately 90% of patients with CMV antigenemia died of infections with viruses, bacteria, and/or fungi, while approximately 40% of patients without CMV antigenemia died of deterioration of ATLL (P<0.0001). In this study, the patients with CMV antigenemia tended to survive longer than those negative for it (321.4 days vs. 266.2 days), although there was no statistical significance (P=0.09). Kaplan-Meier analysis revealed that CMV antigenemia was not a poor prognostic factor. When the disease status of ATLL was evaluated by thymidine kinase (TK) and soluble interleukin 2 receptor (sIL-2R), both had lower titers during CMV antigenemia (TK: P=0.01, sIL-2R: P=0.03, respectively). Therefore, CMV infections in ATLL patients seemed to have bimodal meanings; CMV infection at the end of clinical course were life-threatening, but infection during the first half of clinical course seemed to suppress ATLL activity and to contribute to the longer survival of the patients.

Effects of roxithromycin on tumor necrosis factor-alpha-induced vascular endothelial growth factor expression in human periodontal ligament cells in culture

BACKGROUND

Aberrant angiogenesis is associated with lesion formation in chronic periodontitis. However, little is known about the mediators that contribute to angiogenesis or about therapeutic agents that control the production of the mediators. Roxithromycin (RXM), which is a new 14-member macrolide antibiotic, has a wide antibacterial spectrum against oral pathogens and an immunomodulatory effect. In the present study, we examined the effects of RXM on tumor necrosis factor (TNF)-alpha-induced vascular endothelial growth factor (VEGF) in human periodontal ligament (HPDL) cells. In addition, the effect of RXM on VEGF expression in HPDL cells was examined.

METHODS

HPDL cells were plated at 5 x 10(5) cells/ml in 150 cm2 cell culture dishes. The confluent-stage cells were pretreated with or without 10 microg/ml of RXM or other antibiotics in 1% FBS-containing alpha-MEM for 24 hours, followed by simultaneous treatment with 10 ng/ml of TNF-alpha and 10 microg/ml of these antibiotics. After incubation for various periods, the culture supernatants and sediments were collected and analyzed by ELISA, Northern blot, and gel shift assays.

RESULTS

VEGF mRNA and its protein were constitutively expressed in HPDL cells, and the level of expression was markedly enhanced by stimulation with TNF-alpha. RXM strongly inhibited the expression of VEGF mRNA and the production of VEGF. Furthermore, RXM suppressed activation of transcription factors AP-1 and SP-1, which were critical factors in VEGF transcription, in TNF-alpha-stimulated HPDL cells.

CONCLUSION

These results indicate that TNF-alpha, one of the proinflammatory cytokines implicated in the pathogenesis of periodontitis, induces excess induction of VEGF in HPDL, which may account for increased angiogenesis in periodontitis lesions. Interestingly, the antibiotic roxithromycin inhibits TNF-mediated VEGF induction, suggesting its possible therapeutic utility in periodontitis and other chronic inflammatory conditions involving VEGF induction.