The local prevalence of COPD by post-bronchodilator GOLD criteria in Korea

OBJECTIVE

Chronic obstructive pulmonary disease (COPD) is a disease characterised by not fully reversible airflow limitation. The Global Initiative for Chronic Obstructive Lung Disease (GOLD) committee decided to diagnose COPD using post-bronchodilator spirometry values. We aimed to examine the prevalence and risk factors of COPD in Ansan, an industrialised city of Korea, by using the post-bronchodilator GOLD criteria. We then investigated the implications of brenchodilation on the prevalence of COPD.

DESIGN

A total of 3642 participants in the Korean Health and Genome Study were interviewed about age, income, smoking status and respiratory symptoms and completed pulmonary function tests, including postbronchodilator spirometry.

RESULTS

COPD prevalence by post-bronchodilator spirometry was 3.7% (134/3642), which was significantly different from that estimated using pre-bronchodilator criteria (7.7%, 282/3642). Exclusion of subjects with significant bronchodilator response (BDR) significantly lowered the prevalence of COPD to 3.3% (117/3572), compared with including subjects with post-bronchodilatory residual obstruction with significant BDR. Prevalence was associated with old age, smoking history, male sex and respiratory symptoms.

CONCLUSION

COPD prevalence by post-bronchodilator GOLD criteria was 3.7%, which was much lower than that of pre-bronchodilator criteria. The bronchodilator reversibility test substantially affects estimations of COPD prevalence.

Pre-operative chemo-radiotherapy improves the sphincter preservation rate in patients with rectal cancer located within 3 cm of the anal verge

AIMS

To evaluate whether pre-operative chemo-radiotherapy (CRT) improves the sphincter preservation rate for distal rectal cancers within 3 cm of the anal verge.

METHODS

Between January 2001 and December 2004, 49 patients underwent surgery with or without pre-operative CRT for primary rectal adenocarcinoma within 3 cm of the anal verge. Clinical data were retrospectively reviewed, including stage workups, surgical records and pathology records to determine sphincter preservation rate and the factors influencing sphincter preservation.

RESULTS

Of 49 patients with rectal tumours within 3 cm of the anal verge, 31 underwent pre-operative CRT followed by surgery (CRT group), and 18 underwent surgery alone (non-CRT group). Sphincter preservation was possible in 11 of 31 CRT patients, and only one of 18 non-CRT patients (p=0.036). The factors most influencing sphincter preservation were reduction in tumour size (p=0.005) and downstaging (p=0.001) following pre-operative CRT.

CONCLUSION

We could observe that sphincter preservation was improved in CRT group with statistical significance when compared to non-CRT group in our study patients with rectal cancer within 3 cm of the anal verge.

Topiramate stimulates glucose transport through AMP-activated protein kinase-mediated pathway in L6 skeletal muscle cells

The use of topiramate (TPM) in the treatment of binge-eating disorder, bulimia nervosa, and antipsychotic-induced weight gain has recently increased, however, the exact molecular basis for its effects on body weight reduction and improved glucose homeostasis, is yet to be elucidated. Here we investigated the effect and signaling pathway of TPM on glucose uptake in L6 rat skeletal muscle cells, which account for >70% of glucose disposal in the body. Intriguingly, we found that TPM (10 microM) stimulated the rate of glucose uptake up to twofold increase. And TPM-stimulated glucose transport was inhibited with the overexpression of dominant-negative form of AMP-activated protein kinase (AMPK), an important mediator in glucose transport, implicating that AMPK-mediated pathway is involved. The TPM-stimulated glucose transport was blocked by SB203580, a specific inhibitor of AMPK downstream mediator, p38 mitogen-activated protein kinase (MAPK) protein. LY294002, an inhibitor of phosphatidylinositol (PI) 3-kinase, which is another crucial mediator in independent glucose transport pathway, did not inhibit TPM-stimulated glucose transport. We also found that TPM increased the phosphorylation level of AMPK and p38 MAPK, whereas no effect on the activity of PI 3-kinase of TPM, when assessed by PI 3-kinase assay, was observed. These results together suggest that TPM stimulates glucose transport, not via PI 3-kinase mediated, but via AMPK-mediated pathway in skeletal muscle cells, thereby contributing to the body weight regulation and glucose homeostasis.

[Phototaxis of the green algae: the new class of rhodopsin receptors]

Photomotility behavior in green flagellate algae is mediated by rhodopsin-like receptors, which was initially suggested on the basis of physiological evidence. The cascade of rapid Ca(2+)-dependent electrical responses in the plasma membrane plays a key role in the signal transduction chain during both phototaxis and the photophobic response. The photoreceptor current through the plasma membrane is the earliest detectable event upon photoexcitation of the photoreceptors. Analysis of this current revealed that it consists of at least two components with different characteristics. Genes encoding two archaeal-type rhodopsins (type I rhodopsins) were recently identified in the genome of Chlamydomonas reinhardtii and named (Chlamydomonas Sensory Rhodopsins A and B CSRA and CSRB). The measurements of photoelectric and motor responses in genetic transformants of C. reinhardtii enriched in each of these receptor proteins showed that the two components of the photoreceptor current are mediated by the two rhodopsins, and that both CSRA and CSRB are involved in phototaxis and the photophobic response. The CSRA-mediated current dominates at high light intensities and contributes primarily to the photophobic response. The CSRB-initiated transduction involves an efficient amplification cascade and mediates the highly sensitive phototaxis at low light intensities. CSRA and CSRB expressed heterologously in oocytes of Xenopus laevis act as light-gated proton channels, although it is unclear whether this channel activity plays a functional role in the initiation of motor responses and/or occurs in the native system.

Expression of cyclooxygenase 2, microsomal prostaglandin E synthase 1, and EP receptors is increased in rat oesophageal squamous cell dysplasia and Barrett's metaplasia induced by duodenal contents reflux

BACKGROUND AND AIM

It is known that bile acids can induce mucosal injury, stimulate cell proliferation, and promote tumorigenesis. A large body of genetic and biochemical evidence indicate that the biosynthetic pathway of prostaglandin E2 (PGE2) may play an important role in human and rodent tumours. Therefore, we examined the expression pattern of cyclooxygenase 1 (COX-1), COX-2, and microsomal prostaglandin E synthase 1 (mPGES-1), as well as EP receptor subtypes in rat oesophageal lesions induced by duodenal contents reflux.

METHODS

Oesophagoduodenal anastomosis was performed in rats to induce duodenal contents reflux. We examined histological changes and expression of COX-1, COX-2, mPGES-1, and EP receptor subtypes in the oesophagus by immunohistochemistry and reverse transcription-polymerase chain reaction.

RESULTS

Normal control oesophageal tissues showed COX-1 expression in subepithelial stromal cells, including endothelial cells and muscular cells, and did not reveal expression of COX-2 or mPGES-1. In the case of squamous cell lesions, immunoreactivity of COX-1 was similar to that of normal lesions, and COX-2 was maximally expressed around the vascular papillae of tissues showing dysplasia and surrounding epithelial layer and basal layer. mPGES-1 was highly expressed in stromal cells with COX-2 expression. In the case of Barrett's oesophagus, COX-2 and mPGES-1 were predominantly in subepithelial stromal cells. mRNA levels of COX-2, mPGES-1, EP2, EP3, and EP4 were higher in the experimental groups than in controls.

CONCLUSIONS

We suggest that the biosynthetic pathway of PGE2 may play an important role in oesophageal squamous cell dysplasia and glandular metaplasia induced by duodenal contents reflux.

A phase III randomized trial of 5-fluorouracil, doxorubicin, and mitomycin C versus 5-fluorouracil and mitomycin C versus 5-fluorouracil alone in curatively resected gastric cancer

BACKGROUND

A phase III single-center randomized trial was performed in order to determine whether the addition of mitomycin C (MMC) and/or doxorubicin to 5-fluorouracil (5-FU) as adjuvant chemotherapy could influence survival in patients with curatively resected gastric cancer.

PATIENTS AND METHODS

A total of 416 patients who had undergone curative resection for stage IB-IIIB gastric adenocarcinoma were stratified according to the stage and type of surgery, and then randomized to receive one of the three chemotherapy regimens, 5-FU alone (F) or 5-FU and MMC (FM) or 5-FU, doxorubicin and MMC (FAM) within 5 weeks after surgery.

RESULTS

Of 416 patients registered, 395 (133 in F, 131 in FM and 131 in FAM) were assessable. Median follow-up duration was 91 months. Five-year overall survival rates were 67.2% for F, 67.0% for FM and 66.7% for FAM (P = 0.97). Five-year disease-free survival rates were 62.1% for F, 63.3% for FM and 62.5% for FAM (P = 0.83). Hematological toxicities were more frequent in the FM and FAM groups, whereas stomatitis was more common in the F group.

CONCLUSIONS

Compared with adjuvant 5-FU alone, the addition of MMC and/or doxorubicin to 5-FU did not influence survival in patients with resected gastric cancer.

An archaeal photosignal-transducing module mediates phototaxis in Escherichia coli

Halophilic archaea, such as Halobacterium salinarum and Natronobacterium pharaonis, alter their swimming behavior by phototaxis responses to changes in light intensity and color using visual pigment-like sensory rhodopsins (SRs). In N. pharaonis, SRII (NpSRII) mediates photorepellent responses through its transducer protein, NpHtrII. Here we report the expression of fusions of NpSRII and NpHtrII and fusion hybrids with eubacterial cytoplasmic domains and analyze their function in vivo in haloarchaea and in eubacteria. A fusion in which the C terminus of NpSRII is connected by a short flexible linker to NpHtrII is active in phototaxis signaling for H. salinarum, showing that the fusion does not inhibit functional receptor-transducer interactions. We replaced the cytoplasmic portions of this fusion protein with the cytoplasmic domains of Tar and Tsr, chemotaxis transducers from enteric eubacteria. Purification of the fusion protein from H. salinarum and Tar fusion chimera from Escherichia coli membranes shows that the proteins are not cleaved and exhibit absorption spectra characteristic of wild-type membranes. Their photochemical reaction cycles in H. salinarum and E. coli membranes, respectively, are similar to those of native NpSRII in N. pharaonis. These fusion chimeras mediate retinal-dependent phototaxis responses by Escherichia coli, establishing that the nine-helix membrane portion of the receptor-transducer complex is a modular functional unit able to signal in heterologous membranes. This result confirms a current model for SR-Htr signal transduction in which the Htr transducers are proposed to interact physically and functionally with their cognate sensory rhodopsins via helix-helix contacts between their transmembrane segments.

Retinylidene proteins: structures and functions from archaea to humans

Retinylidene proteins, containing seven membrane-embedded alpha-helices that form an internal pocket in which the chromophore retinal is bound, are ubiquitous in photoreceptor cells in eyes throughout the animal kingdom. They are also present in a diverse range of other organisms and locations, such as archaeal prokaryotes, unicellular eukaryotic microbes, the dermal tissue of frogs, the pineal glands of lizards and birds, the hypothalamus of toads, and the human brain. Their functions include light-driven ion transport and phototaxis signaling in microorganisms, and retinal isomerization and various types of photosignal transduction in higher animals. The aims of this review are to examine this group of photoactive proteins as a whole, to summarize our current understanding of structure/function relationships in the best-studied examples, and to report recent new developments.

Production and characterization of recombinant guamerin, an elastase-specific inhibitor, in the methylotrophic yeast Pichia pastoris

The elastase-specific inhibitor, guamerin, was expressed and secreted into a culture medium using the methylotrophic yeast Pichia pastoris, and the resulting recombinant guamerin was purified from the culture media using a two-step procedure composed of a hydrophobic interaction and reverse-phase chromatography. Up to 90 g/L of dry cell weight, the guamerin-producing recombinant P. pastoris was cultivated and guamerin was secreted into the culture medium at a level of 0.69 g/L. The recombinant guamerin was highly purified (>98%) with a recovery yield of 68%. Analyses of the purified guamerin revealed the same N-terminal amino acid sequence, amino acid composition, and molecular mass as found in the native leech protein. The recombinant guamerin exhibited the tight binding to porcine pancreatic elastase. Furthermore, the recombinant guamerin did not produce a humoral immune response in mice.

Molecular characterization of xynX, a gene encoding a multidomain xylanase with a thermostabilizing domain from Clostridium thermocellum

A Clostridium thermocellum gene, xynX, coding for a xylanase was cloned and the complete nucleotide sequence was determined. The xylanase gene of Clostridium thermocellum consists of an ORF of 3261 nucleotide encoding a xylanase (XynX) of 1087 amino acid residues (116 kDa). Sequence analysis of XynX showed a multidomain structure that consisted of four different domains: an N-terminal thermostabilizing domain homologous to sequences found in several thermophilic enzymes, a catalytic domain homologous to family 10 glycosyl hydrolases, a duplicated cellulose-binding domain (CBD) homologous to family IX CBDs, and a triplicated S-layer homologous domain. A deletion mutant of xynX having only the catalytic region produced a mutant enzyme XynX-C which retained catalytic activity but lost thermostability. In terms of half-life at 70 degrees C, the thermostability of XynX-C was about six times lower than that of the other mutant enzyme, XynX-TC, produced by a mutant containing both the thermostabilizing domain and the catalytic domain. The optimum temperature of XynX-C was about 5-10 degrees C lower than that of XynX-TC.

Tissue-preferential expression of a rice alpha-tubulin gene, OsTubA1, mediated by the first intron

The genomic clone encoding an alpha-tubulin, OsTubA1, has been isolated from rice (Oryza sativa L.). The gene consists of four exons and three introns. RNA-blot analysis showed that the gene is strongly expressed in actively dividing tissues, including root tips, young leaves, and young flowers. Analysis of chimeric fusions between OsTubA1 and beta-glucuronidase (GUS) revealed that the intron 1 was required for high-level GUS expression in actively dividing tissues, corresponding with normal expression pattern of OsTubA1. Fusion constructs lacking the intron 1 showed more GUS staining in mature tissues rather than young tissues. When the intron 1 was placed at the distal region from 5'-upstream region or at the 3'-untranslated region, no enhancement of GUS expression was observed. Sequential deletions of the OsTubA1 intron 1 brought about a gradual reduction of GUS activity in calli. These results suggest that tissue-preferential expression of the OsTubA1 gene is mediated by the intron 1 and that it may be involved in a mechanism for an efficient RNA splicing that is position dependent.

Secondary polycythemia associated with idiopathic membranous nephropathy

A 58-year-old male patient had secondary polycythemia associated with idiopathic nephrotic syndrome. The renal biopsy revealed membranous nephropathy, and the bone marrow biopsy disclosed hypercellular marrow with mild panhyperplasia. The concentration of serum erythropoietin was 8.5 mU/ml. The erythrocytosis was characterized by an increased red cell volume (40.2 ml/kg) and normal arterial oxygen saturation. There were no associated lesions that could induce secondary polycythemia, except the biopsy-proven membranous nephropathy. He was treated with prednisolone and cyclophosphamide, and the nephrotic syndrome was partially remitted after 6 weeks. With partial remission of nephrotic syndrome, the erythrocytosis was resolved. This case illustrates the rarely reported association of the nephrotic syndrome and erythrocytosis, and the resolution of erythrocytosis with improvement of nephrotic syndrome.

T-DNA insertional mutagenesis for functional genomics in rice

We have produced 22 090 primary transgenic rice plants that carry a T-DNA insertion, which has resulted in 18 358 fertile lines. Genomic DNA gel-blot and PCR analyses have shown that approximately 65% of the population contains more than one copy of the inserted T-DNA. Hygromycin resistance tests revealed that transgenic plants contain an average of 1.4 loci of T-DNA inserts. Therefore, it can be estimated that approximately 25 700 taggings have been generated. The binary vector used in the insertion contained the promoterless beta-glucuronidase (GUS) reporter gene with an intron and multiple splicing donors and acceptors immediately next to the right border. Therefore, this gene trap vector is able to detect a gene fusion between GUS and an endogenous gene, which is tagged by T-DNA. Histochemical GUS assays were carried out in the leaves and roots from 5353 lines, mature flowers from 7026 lines, and developing seeds from 1948 lines. The data revealed that 1.6-2.1% of tested organs were GUS-positive in the tested organs, and that their GUS expression patterns were organ- or tissue-specific or ubiquitous in all parts of the plant. The large population of T-DNA-tagged lines will be useful for identifying insertional mutants in various genes and for discovering new genes in rice.

Synthesis and cytotoxic effects of deoxy-tomentellin

Cannabigerol (1, CBG), methyl 4-[(2E)-3,7-dimethyl-2,6-octadienyl)oxy]-3-methoxybenzoate (2, DTM), 5-fluorouracil (3, FU) as a reference, and cannabidiol (4, CBD) were tested for their growth inhibitory effects against KB(ATCC NO, OCL 17) cell lines using two different assays, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazoliumbromide (MTT) assay and the sulforhod-amine B protein (SRB) assay. These compounds showed inhibitory activity in vitro in the micromolar range against KB cell lines. In general, the antitumor activities of these compounds (1, 2, 3 and 4) were dose-dependent over the micromolar concentration range of 1 to 100 M. The comparison of IC50 values of these compounds in tumor cell lines showed that their susceptibility to these compounds decreases in the following order: DTM > CBD > 5-FU > CBG by MTT assay and DTM = CBD > 5-FU > CBG by SRB assay. CBG 1, DTM 2, 5-FU 3, and CBD 4 were tested for their cytotoxic effects on NIH 3T3 fibroblasts using two different assays, the MTT assay and SRB assay. These compounds exhibited potent cytotoxic activities in vitro in the micromolar range against NIH 3T3 fibroblasts. In general, the cytotoxic activities of these compounds (1, 2, 3 and 4) were dose-dependent over the micromolar concentration range of 1 to 100 M. The comparison of CD50 values of these compounds in NIH 3T3 fibroblasts shows that their susceptibility to these compounds in decreases the following order(:) CBD > 5-FU > DTM > CBG by MTT assay, CBD > 5-FU > CBG > DTM by SRB assay. These results suggest that DTM 2 has the most growth-inhibitory activity against KB cell lines.

Production characteristics of interferon-alpha using an L-arabinose promoter system in a high-cell-density culture

Using high-cell-density culture of Escherichia coli under the control of an L-arabinose promoter (ParaB), several factors affecting the production of recombinant protein and the formation of inclusion bodies were studied. The inducer, L-arabinose, showed a maximal induction level above 10.7 mM in the final concentration. The concentration of inducer also affected the partition of interferon-alpha (IFN-alpha) into the soluble form and inclusion bodies. Induction kinetics of the rate of accumulation of IFN-alpha on the ParaB promoter showed a slower rate than those of other promoter systems, for example T7, lac or tac. These innate characteristics of ParaB enabled cells to grow continuously in spite of the metabolic burden induced by the expression of foreign protein. The duration time of induction could control the expression of both soluble and insoluble protein. The ratio of yeast extract to glycerol (N/C ratio) in feeding media significantly affected both the production level of recombinant protein and inclusion body formation. The reason for decreasing specific bioactivity during induction can be explained by the increased proportion of inclusion bodies in the total expressed IFN-alpha.

Ethambutol-induced vacuolar changes and neuronal loss in rat retinal cell culture: mediation by endogenous zinc

Ethambutol is an efficacious antituberculosis agent. However, its use has been limited by the occurrence of ocular toxicity. To investigate characteristics and possible mechanisms of ethambutol ocular toxicity, we used primary rat retinal cultures as a model. Primary rat retinal cultures were obtained from newborn Sprague-Dawley rats and used for experiments after maturation (DIV > or = 10). Cytopathologic changes were examined under light and electron microscopes. Thy-1 (a membrane glycoprotein expressed by retinal ganglion neurons)-containing neurons and gamma-aminobutyric acid (GABA)-ergic neurons were identified immunocytochemically. Exposure of retinal cultures for 24-48 h to ethambutol induced cytoplasmic vacuolar changes and neuronal loss. Vacuolar changes were partially reversible with the termination of ethambutol exposure. Of neurons, Thy-1(+) ganglion neurons were more vulnerable than GABA(+) neurons. Glutamate antagonists, an antioxidant (trolox), or cycloheximide, did not attenuate either vacuolar changes or neuronal loss. A cell-permeant zinc chelator N,N,N',N'-tetrakis (2-pyridylmethyl) ethylenediamine (TPEN) markedly attenuated vacuolar degeneration and neuronal loss, while the addition of zinc augmented both. In rat retinal cultures, ethambutol induces reversible vacuolar degeneration as well as irreversible neuronal loss, more preferentially of Thy-1(+) ganglion neurons. Contrary to the current theories, ethambutol-induced retinal cytotoxicity in the present study is mediated not by excitotoxicity or zinc deficiency but by a mechanism requiring intracellular zinc. In addition, features of the ethambutol-induced cell death were not consistent with those of apoptosis.

Transducer-binding and transducer-mutations modulate photoactive-site-deprotonation in sensory rhodopsin I

Sensory rhodopsin I (SRI) is a seven-transmembrane helix retinylidene protein that mediates color-sensitive phototaxis responses through its bound transducer HtrI in the archaeon Halobacterium salinarum. Deprotonation of the Schiff base attachment site of the chromophore accompanies formation of the SRI signaling state, S(373). We measured the rate of laser flash-induced S(373) formation in the presence and absence of HtrI, and the effects of mutations in SRI or HtrI on the kinetics of this process. In the absence of HtrI, deprotonation occurs rapidly (halftime 10 micros) if the proton acceptor Asp76 is ionized (pK(a) = approximately 7), and only very slowly (halftime > 10 ms) when Asp76 is protonated. Transducer-binding, although it increases the pK(a) of Asp76 so that it is protonated throughout the range of pH studied, results in a first order, pH-independent rate of S(373) formation of approximately 300 micros. Therefore, the complexation of HtrI facilitates the proton-transfer reaction, increasing the rate approximately 50-fold at pH6. Arrhenius analysis shows that HtrI-binding accelerates the reaction primarily by an entropic effect, suggesting HtrI constrains the SRI molecule in the complex. Function-perturbing mutations in SRI and HtrI also alter the rate of S(373) formation and the lambda(max) of the parent state as assessed by laser flash-induced kinetic difference spectroscopy, and shifts to longer wavelength are correlated with slower deprotonation. The data indicate that HtrI affects electrostatic interactions of the protonated Schiff base and not only receives the signal from SRI but also optimizes the photochemical reaction process for SRI signaling.