Hypoxia-induced hyaluronan synthesis by articular chondrocytes: the role of nitric oxide

OBJECTIVE

Articular cartilage is an avascular tissue in which chondrocytes are exposed to hypoxic conditions. We previously demonstrated that reactive oxygen species (ROS) induced apoptosis of chondrocytes. We also demonstrated that nitric oxide (NO) was induced when chondrocytes were exposed to hypoxia and that NO inhibited the ROS-induced apoptosis. Hyaluronan (HA) is a high molecular weight glycosaminoglycan whose antioxidative effects have been reported. The purpose of the present study was to determine whether HA synthesis was induced in chondrocytes exposed to hypoxia, and, if so, whether the hypoxia-induced HA synthesis is regulated by NO.

METHODS

Bovine articular chondrocytes were used in this study. Levels of HA were determined by the sandwich enzyme-binding assay. Expression of HA synthase (HAS) was determined with reverse transcription-polymerase chain reaction. The production of NO was examined using the Griess reaction. We also determined inducible nitric oxide synthase (iNOS) enzyme synthesis using the histochemistry and Western blot analysis.

RESULTS

Chondrocytes cultured under hypoxic conditions exhibited enhanced HA synthesis. When the NO inhibitors, L-NMMA and L-NAME, were added, the hypoxia-enhanced HA levels in the culture medium were significantly inhibited.

CONCLUSIONS

Endogenous NO synthesis plays an important role in hypoxia-enhanced HA synthesis.

Ovarian Burkitt's lymphoma diagnosed by a combination of clinical features, morphology, immunophenotype, and molecular findings and successfully managed with surgery and chemotherapy

Ovarian involvement as an initial manifestation of lymphoma, without detectable extraovarian disease, is a rare occurrence. The diagnosis of ovarian lymphoma is almost invariably unsuspected until the tumor has been examined histologically. A 25-year-old null gravid woman presented with abdominal distension. Presence of abnormal lymphoid cells in pleural effusion led to presurgical assumption that the pelvic mass noted on computerized tomography examination might be an ovarian lymphoma. We performed left salpingo-oophorectomy. Clinical, histologic, and molecular examination revealed Burkitt's lymphoma of the ovary with c-myc gene rearrangement and mRNA expression of multiple cytokines. She received dose-intensified combination chemotherapy. She is alive and free of disease 30 months after the diagnosis. Immunophenotype and molecular findings allowed reliable discrimination of Burkitt's lymphoma from diffuse large B-cell lymphoma and other lymphomas. If an ovarian tumor is solid and suspected to be of lymphoid origin, we suggest that it is necessary to obtain samples for genetic examination at surgery. This strategy often provides important information to establish therapeutic regimen and predict patient prognosis.

Release of beta-endorphin by caffeic acid to lower plasma glucose in streptozotocin-induced diabetic rats

The role of alpha 1A -adrenoceptors in the regulation of opioid secretion from the adrenal glands of streptozotocin-induced diabetic rats (STZ-diabetic rats) was examined in an attempt to determine the mechanism of plasma glucose-lowering action of caffeic acid. In agreement with a previous report, we showed that caffeic acid produced a dose-dependent lowering of the plasma glucose concentration in STZ-diabetic rats along with an increase of plasma beta-endorphin-like immunoreactivity (BER). These actions of caffeic acid were abolished by pretreatment with WB 4101 or RS 17 056 at doses sufficient to block alpha 1A -adrenoceptors. In addition, naloxone and naloxonazine at doses effective for blocking opioid micro -receptors abolished the plasma glucose-lowering action of caffeic acid. Also, unlike that in wild-type diabetic mice, caffeic acid failed to produce a plasma glucose lowering effect in opioid micro -receptor knockout diabetic mice. We observed that caffeic acid could enhance BER release from isolated rat adrenal medulla in a concentration-dependent manner; inhibitors of alpha 1A -adrenoceptors such as WB 4101 and RS 1705 abolished this action. Investigations of the signal pathways further supported that activation of alpha 1A -adrenoceptor is responsible for the stimulatory effect of caffeic acid on BER secretion from the adrenal medulla. In the presence of U73312, a specific inhibitor of phospholipase C, the caffeic acid-induced increase of BER was reduced in a concentration-dependent manner, but it was not affected by U73343, the negative control of U73312. Chelerythrine and GF 109203X also diminished the action of caffeic acid at concentrations sufficient for inhibiting protein kinase C. Moreover, bilateral adrenalectomy in STZ-diabetic rats resulted in the loss of this plasma glucose-lowering effect of caffeic acid, and there was no increase in plasma BER with caffeic acid. Therefore, beta-endorphin release from the adrenal gland appears to be responsible for the lowering of plasma glucose in STZ-diabetic rats induced by caffeic acid, through the activation of alpha 1A -adrenoceptors.

Catecholaminergic polymorphic ventricular tachycardia: electrocardiographic characteristics and optimal therapeutic strategies to prevent sudden death

OBJECTIVE

To investigate the clinical outcome, ECG characteristics, and optimal treatment of catecholaminergic polymorphic ventricular tachycardia (CPVT), a malignant and rare ventricular tachycardia.

PATIENTS AND METHODS

Questionnaire responses and ECGs of 29 patients with CPVT were evaluated. Mean (SD) age of onset was 10.3 (6.1) years.

RESULTS

The initial CPVT manifestations were syncope (79%), cardiac arrest (7%), and a family history (14%). ECGs showed sinus bradycardia and a normal QTc. Mean heart rate during CPVT was 192 (30) beats/min. Most cases were non-sustained (72%), but 21% were sustained and 7% were associated with ventricular fibrillation. The morphology of CPVT was polymorphic (62%), polymorphic and bidirectional (21%), bidirectional (10%), or polymorphic with ventricular fibrillation (7%). There was 100% inducement of CPVT by exercise, 75% by catecholamine infusion, and none by programmed stimulation. No late potential was recorded. Onset was in the right ventricular outflow tract in more than half the cases. During a follow up of 6.8 (4.9) years, sudden death occurred in 24% of the patients, 7% of whom had anoxic brain damage. Autosomal dominant inheritance was seen in 8% of the patients' families. beta Blockers completely controlled CPVT in only 31% of cases. Calcium antagonists partially suppressed CPVT in autosomal dominant cases.

CONCLUSIONS

CPVT may arise in certain distinct areas but the prognosis is poor. The onset of CPVT may be an indication for an implanted cardioverter-defibrillator.

Apoptosis induction associated with cell cycle dysregulation by rice bran agglutinin

Effects of rice bran agglutinin (RBA) on human monoblastic leukemia U937 cells were examined in comparison with those of wheat germ agglutinin (WGA) and Viscum album agglutinin (VAA). These lectins inhibit cell growth, and several lines of evidence indicate that the growth inhibition is caused by the induction of apoptosis. We observed that RBA induces chromatin condensation, externalization of membrane phosphatidylserine, and DNA ladder formation, features of apoptosis. DNA ladder formation was inhibited by a general inhibitor against caspases, which are known to play essential roles in apoptosis. Flow cytometric analysis revealed that RBA and WGA cause G2/M phase cell cycle arrest with increased expression of Waf1/p21, while cell cycle arrest was not observed for VAA. These data indicate that RBA induces apoptosis associated with cell cycle arrest in U937 cells, and suggest that the induction mechanism for RBA is similar to that for WGA, but different from that for VAA.

Sequential comparison of peptides containing half-cystine residues from ovalbumins of six avian species

Hen ovalbumin contains one cystine disulfide (Cys73-Cys120) and four cysteine sulfhydryl groups (Cys11, Cys30, Cys367, and Cys382) in a single polypeptide chain of 385 amino acid residues. To investigate whether or not such a structure is shared by related avian species, the contents of disulfide-involved half-cystine residues and their positions in the primary structure of ovalbumins from five species were compared with those of hen ovalbumin. Ovalbumins were alkylated with a fluorescent dye, IAEDANS, under disulfide-reduced and disulfide-intact conditions and digested with a number of proteolytic enzymes. The sequences were deduced from peptides containing half-cystine residues labeled with the fluorescent dye. The results showed that the number of free cysteine sulfhydryl groups of ovalbumins was different among the species, three for guinea fowl and turkey (Cys11, Cys367, and Cys382); and two for Pekin duck, mallard duck, and Emden goose (Cys11 and Cys331). On the other hand, a single intrachain disulfide bond could be identified from ovalbumins of five species using a combination of peptide mapping and N-terminal amino acid sequencing analysis under reduced and non-reduced conditions, in which the intrachain disulfide bond was like that of hen ovalbumin (Cys73-Cys120). The results also indicated that the variations in amino acid sequences on these peptides containing half-cystine residues bear a close relationship with the phylogeny of the six species.

[Long-term outcome after extracorporeal shock wave lithotripsy for gallstones]

We retrospectively reviewed 289 cases followed for a long time after extracorporeal shock wave lithotripy (ESWL) for gallstones. Follow-up periods ranged from 0.5 years to 9.2 years, with a median of 4.1 years. The complete resolution rate was 45.6%. A solitary gallstone, non-calcified gallstones on CT, and Tsuchiya's sonographic type Ia and Ib gallstones were found to be statistically significant variable for resolution of the disease. With a maximum follow-up period of 9 years, the cumulative recurrence rate was 30.7%. Among the 156 patients whose gallstones did not resolve, 70 were symptomatic and the other 86 were asymptomatic. Thirty-eight of the symptomatic patients (54.3%) became symptom-free, while 23 asymptomatic patients (29.1%) became symptomatic. The cumulative rate of occurrence of colic attacks and/or acute cholecystitis was significantly higher in the cases with lithotripsy fragments 4 mm or more in size than in the cases wih fragments 3 mm or less in size (51.8% vs. 16.7%; p < 0.05). ESWL was followed by surgery in 23.1% because symptoms developed or became aggravated after ESWL in 58.3% of them. Gallbladder cancer was discovered in one case. Patients undergoing ESWL should be followed by focusing on postoperative recurrence, symptoms, and gallbladder cancer.

Ammonium eneselenolates: stereochemistry and electronic properties

Ammonium eneselenolates were generated with high efficiency by reacting selenothioic acid S-esters with a THF solution of TBAF. The methylation of ammonium eneselenolates gave ketene selenothioacetals as stereoisomeric mixtures. The ratio of the two stereoisomers depended on the duration of the reaction before the addition of MeI. Ammonium eneselenolates were characterized by examining their (1)H, (13)C, and (77)Se NMR spectra, which indicated that ammonium eneselenolates were present almost exclusively as Z-isomers. These results suggested that ammonium eneselenolates are kinetically generated as stereoisomeric mixtures, and isomerization of E-isomers to Z-isomers then takes place to result in the exclusive formation of Z-isomers. During the methylation of Z-isomers of ammonium eneselenolates, the isomerization of Z-isomers to E-isomers occurs to give stereoisomeric mixtures of ketene selenothioacetals. NMR spectra of ammonium eneselenolates implied that the electrons at the selenium atom are somewhat delocalized to the carbon-carbon double bond and the carbon-selenium bond shows partial double-bond character.

Epidemiological study of vancomycin-resistant enterococcus isolated from a single medical university hospital in Japan

Since 1998 more than 50 reports have described the isolation of high-level vancomycin-resistant enterococci (VRE) in Japan. Here, we report on our clinical isolates of VRE and an epidemiological study carried out using chemical and genetic techniques. VRE isolates were screened for high resistance to vancomycin (VCM) with a cutoff value of 6 microg/ml and VCM-resistant gene was confirmed by polymerase chain reaction (PCR). The epidemiological studies used pulsed-field gel electrophoresis (PFGE) and plasmid analysis. Six strains of VRE were isolated from six different patients on two wards during a 3-months period. All of the isolates possessed vanA on their plasmid, and the isolates were divided into two similar groups. Furthermore, three different patterns were defined by PFGE. Although all of the asymptomatic carriers were hospitalized for more than 3 months, we were able to prevent an outbreak of VRE in our hospital by using our guidelines for infection control, which are stricter than those for methicillin-resistant Staphylococcus aurens. From the results of this epidemiological study, we propose that there was a possibility of contamination in this hospital, and that three of the six isolates may have acquired vanA independently. In this study, we demonstrated that infection control, according to appropriate prevention guidelines, as well as regular surveillance for VRE, are essential for designing interventions to prevent the further spread of VRE.

Apoptosis induction by epigallocatechin gallate involves its binding to Fas

Epigallocatechin gallate (EGCG) is known to induce apoptosis in various types of tumor cells, but the precise mechanism by which EGCG induces apoptosis remains to be elucidated. The Fas-Fas ligand system is one of the major pathways operating in the apoptotic cascade. The aim of this study was to examine the possibility that EGCG-binding to Fas triggers the Fas-mediated apoptosis. The EGCG treatment of human monocytic leukemia U937 cells resulted in elevation of caspase 8 activity and fragmentation of caspase 8. The DNA ladder formation caused by the EGCG treatment was inhibited by the caspase 8 inhibitor. These findings suggested the involvement of the Fas-mediated cascade in the EGCG-induced apoptosis in U937 cells. Affinity chromatography revealed the binding between EGCG and Fas. Thus, the results suggest that EGCG-binding to Fas, presumably on the cell surface, triggers the Fas-mediated apoptosis in U937 cells.

Interleukin-10 expressed at early tumour sites induces subsequent generation of CD4(+) T-regulatory cells and systemic collapse of antitumour immunity

We investigated the relationship between transforming growth factor-beta (TGF-beta)-secreting T-regulatory (Tr) cells and anti-B16 melanoma immunity, and studied the association of early cytokines expressed at tumour sites with the generation of Tr cells. A large number of CD4(+) Tr cells producing interleukin (IL)-4, IL-10 and TGF-beta accumulated with functionally depressed CD8(+) cytotoxic T lymphocytes (CTLs) at tumour sites on day 20 after subcutaneous (s.c.) inoculation of B16 tumour cells. Tr cells consisted of two populations, which were termed T helper 3 (Th3) and Tr1 cells. B16-infiltrating Tr cells strongly inhibited the generation of B16-specific T helper 1 (Th1) cells in a TGF-beta-dependent manner and were assumed to suppress effective generation of CTLs. In addition, B16 cells markedly progressed in mice transferred adoptively by the cultured B16-infiltrating Tr cells compared with untreated mice. The capacity of these Tr cells to produce TGF-beta was hampered by neutralizing anti-IL-10 and partly anti-IL-4 monoclonal antibodies (mAbs) injected intralesionally during the early development of B16 tumours, and this treatment markedly attenuated B16 growth. Furthermore, a lesional injection of recombinant mouse IL-10 at an early tumour site resulted in the vigorous progression of B16 tumours. These results provide evidence that Tr cells, belonging to the T helper 3/T-regulatory 1 (Th3/Tr1) type, are activated in B16-bearing hosts under the influence of T helper 2 (Th2) cytokines, mainly IL-10 (produced at early tumour lesions), and that this regulatory T-cell population functions as a suppressor of anti-B16 immunity.

Cloning and nucleotide sequence of the mycodextranase gene from Streptomyces sp. J-13-3

Mycodextranase (EC 3.2.1.61) is an alpha-glucanase that cleaves alpha-1,4-bonds of alternating alpha-1,3- and alpha-1,4-linked D-glucan (nigeran). The gene encoding mycodextranase from Streptomyces sp. J-13-3 was cloned by hybridization with a degenerate oligonucleotide probe from the amino-terminal amino acid sequence of the enzyme and its nucleotide structure was analyzed. The open reading frame consisted of 1,803 base pairs encoding a signal peptide of 60 amino acids and a mature protein of 540 amino acids with a calculated molecular weight of 56,078. The deduced amino acid sequence showed weak similality to a chitinase homolog from Streptomyces lividans and a chitinase from Xanthomonas sp.

Isotachophoretic separation behavior of rare-earth EDTA chelates and analysis of minor rare-earth elements in an iron ore by bidirectional isotachophoresis-particle-induced X-ray emission

Mobilities of 16 anions of rare-earth-EDTA 1:1 chelate (RE-EDTAs) were isotachophoretically measured by using two leading electrolytes (pH 3.6 and 6.0) in order to assess their separation behavior. The leading electrolyte was 20 mM hydrochloric acid. The pH of the solution was adjusted to 3.6 by adding beta-alanine and to 6.0 by adding histidine. The obtained mobilities were very close to each other in the range 20.1x10(-5)-21.9x10(-5) cm2 V(-1) s(-1) with the minimum mobilities for Pr-EDTA and Nd-EDTA for pH 3.6 and 6.0, respectively, and pH dependence was hardly observed. On the basis of the above knowledge. minor rare-earth elements in a standard iron ore sample were determined as RE-EDTAs by bidirectional isotachophoresis-particle-induced X-ray emission (PIXE), where the Fe(II) matrix digested by alkali fusion was separated as Fe(II)Phen3(2+) (phen = 1,10-phenanthroline). Since 5% of the total iron was still detected as Fe(III)EDTA- and might disturb PIXE analysis of RE-EDTA-, itaconic acid was used as the spacer for Fe(III)EDTA- and RE-EDTA-. The fractions of RE-EDTA- were successfully analyzed off-line by a multielemental analytical method, PIXE [analytical result (3.62% (w/w) as RE2O3]; the nominal value was 3.37% (w/w) as RExOy.

Thermally induced aggregates in mixtures of alpha-lactalbumin with ovalbumins from different avian species

Interactions between alpha-lactalbumin (alpha-La) and ovalbumin (OVA) in mixed systems (1:1 ratios; 2, 4, and 8% w/w total protein, respectively) heated at pH 7 and 80 degrees C for 15 min were studied using sodium dodecyl sulfate--polyacrylamide gel electrophoresis (SDS-PAGE), gel filtration chromatography (GFC), and competitive enzyme-linked immunosorbent assay (ELISA). Although alpha-La alone did not form aggregates upon heating, it formed large aggregates when heated with OVA. The aggregated molecules eluted at the void volume had a molecular mass >300 kDa. The aggregation process was quantitatively affected by different avian OVAs from five species, possessing different numbers of free sulfhydryl groups. The amount of aggregates (M(w) > 300 kDa) increased in proportion to total protein concentration, and the amount of intermediate components (M(w) < 300 kDa) and monomeric OVA and alpha-La also changed, correlating with total protein concentration during heating. The results also indicated that the aggregates and intermediates, which contained dimeric and trimeric alpha-La, were mainly formed by the intermolecular disulfide bonds. The different interactions observed in several avian OVAs may explain heat-induced gelation of various avian OVAs as well as the enhancement of heat-induced gelation of OVA by alpha-La.

In vivo evaluation of bone-bonding of titanium metal chemically treated with a hydrogen peroxide solution containing tantalum chloride

Apatite formation on implants is important in achieving a direct bonding to bone tissue. We recently showed that titanium metal chemically treated with a hydrogen peroxide solution containing tantalum chloride has the ability to form a hydroxyapatite layer in simulated body fluid which had inorganic ion composition similar to human blood plasma. In this study, a pure titanium cylinder (4.0 mm in diameter, 20.0 mm in length) treated with this method was implanted into a hole (4.2 mm in diameter) in a rabbit's tibia. After implantation for predetermined periods up to 16 weeks, the specimens were extracted with bone tissue, and were examined by push-out test to evaluate the shearing force between the implant and bone tissue. The results were compared with those of non-treated pure titanium. Eight weeks after surgery, the shearing force of the treated titanium implanted in the 4.2 mm-hole was significantly higher than that of non-treated titanium, although the surface roughness was not changed after the treatment. Scanning electron microscopic (SEM) observation and energy-dispersive X-ray (EDX) microanalysis showed that the bone comes very close to the surface of the treated titanium. Moreover, the shearing force was higher for the implanted sample in the 4.0 mm-hole than that in the 4.2 mm-hole. Thus, it is confirmed that the treatment with hydrogen peroxide solution containing tantalum chloride provides higher bonding ability on titanium implants in vivo.

Characterization of NKT cells in human peripheral blood and decidual lymphocytes

PROBLEM

To examine whether natural killer (NKT) cells are present in human pregnancy decidua.

METHOD OF STUDY

We calculated the percentage of CD3+CD161+Valpha 24+-NKT cells in peripheral blood and early pregnancy decidua, and analyzed intracellular cytokines, interleukin (IL)-4 and interferon (IFN)gamma in NKT cells using flow cytometry.

RESULTS

A distinct subset of CD3+ CD161+ lymphocytes expressing an invariant antigen receptor encoded by the Valpha24 and Vbeta11 segment was accumulated in the decidua. In pregnant subjects the percentages of NKT cells were significantly increased in the decidua compared with peripheral blood. Both NKT cells in the decidua and the peripheral blood had an ability to rapidly produce cytokine associated with Th1 (IFNgamma) and Th2 (IL-4). Interestingly, the percentages of IL-4 and IFNgamma producing NKT cells were significantly higher in the decidua compared with the peripheral blood.

CONCLUSIONS

These findings suggest that NKT cells might control the Th1/Th2 balance by producing IL-4 and IFNgamma at the feto-maternal interface.

Frequent presence of Helicobacter pylori genome in the saliva of patients with hyperemesis gravidarum

Recently, possible involvement of Helicobacter pylori (H. pylori) in hyperemesis gravidarum have been reported based on serological studies and the therapeutic effects of antibiotics. In this study, we examined for the presence of H. pylori genome [by (PCR) of saliva] in combination with serological techniques. Thirty-four patients with hyperemesis and 29 normal pregnant subjects were examined for serum anti-H. pylori IgG antibodies and PCR of saliva. By serum antibody test, 16 of 34 hyperemesis patients (47.5%) were positive for anti-H. pylori IgG antibody, while 6 of 29 control subjects (20.6%) were positive (chi2 p < 0.0005). PCR revealed positive H. pylori genome in 21 cases out of 34 hyperemesis (61.8%, 14 of 16 patients positive for H. pylori antibody and 7 of H. pylori-antibody-negative 18 patients) and 8 of 29 control subjects (27.6%) (chi2 p < 0.000001). We suggest chronic infection of H. pylori as one of the important factors on the pathogenesis of hyperemesis gravidarum even though it may not be the single cause of the disorder.

Generation of an X-ray microbeam for spectromicroscopy at SPring-8 BL39XU

A pair of elliptical mirrors (KB mirror) was designed and fabricated to realize an energy tunable x-ray microbeam for spectromicroscopy at SPring-8 BL39XU. As is commonly recognized, the obtainable beam size with the aspherical total reflection mirrors is strongly affected with the slope error of the mirror. Considering that the extremely high brilliance of the undulator radiation from the SPring-8, the small mirror size and the small mirror-to-focus distance were employed to minimize effects of the slope error. Preliminary evaluation of the KB mirror was carried out using 10 keV monochromatized undulator radiation. Alignment of the mirror was assisted by the beam monitor system composed of a scintillator and a CCD, and the beam size less than 5 microm can be easily achieved even when the source was fully used. The beam size obtained with this experiment was 2 x 4 microm2 with the photon flux of 1 x 10(10) photons/s. Smaller beam size may be expected with the use of intermediate slits. Characterization of trace elements with the spatial resolution will be carried out by using x-ray fluorescence (XRF) analysis and x-ray absorption fine structure (XAFS) measurements with XRF yield method.

Apoptosis-inducing activity of high molecular weight fractions of tea extracts

High molecular weight fractions of green tea, black tea, oolong tea, and pu-erh tea were found to induce apoptosis in human monoblastic leukemia U937 cells by examination of their ability to inhibit cell proliferation and to induce apoptotic body formation and DNA ladder formation. These tea fractions were also shown to induce apoptosis in stomach cancer MKN-45 cells. In addition to known antitumor-promoting activity of tea high molecular weight fractions, their apoptosis-inducing activity may contribute to cancer chemopreventive effects of tea.