Analysis of T wave changes by activation recovery interval in patients with atrial septal defect

We examined the distributions of the activation recovery interval (ARI), which is correlated with the local action potential duration (APD), to clarify the origin of the repolarization changes in ASD. The ECGs, QRST isointegral maps and ARI isochronal maps of 21 children with ASD from 3 to 5 years old in age were studied in comparison with 21 age-matched normal children. A conventional and 87 unipolar body surface ECG were simultaneously recorded. The ARIs were determined from the first derivatives of the ECG waveforms. Abnormal ST-T patterns were observed in 11 of 21 ASD, but only in two normal children. The QRST maps of a split positive area pattern were seen in 15 of ASD but none of the normal. In the ARI maps, all the normal children exhibited a short-ARI area on the left and a long-ARI area on the right side of the chest. In 19 of ASD, the ARI distribution revealed a leftward extension of the long-ARI area on the anterior chest, a relative shortening on the right anterior chest, and a localized prolonged ARI on the left anterior chest. The results suggest that right ventricular (RV) volume overload in ASD produces a localized prolongation of the APD on the RV epicardium.

Cyclo-oxygenase-2 inhibitors suppress epithelial cell kinetics and delay gastric wound healing in rats

BACKGROUND AND AIMS

The present study examined the effects of NS-398, a specific cyclo-oxygenase-2 inhibitor, on gastric mucosal cell kinetics and gastric wound healing following acid-induced injury.

METHODS

Male Sprague-Dawley rats were fasted for 24 h and then 0.6 mol/L hydrochloric acid (HCl; 1 mL) was administered into the stomach; NS-398 or indomethacin was administered to the animals 10 min after the acid. Levels of constitutive cyclo-oxygenase (COX-1) and mitogen-inducible cyclo-oxygenase (COX-2) in the gastric mucosa were analysed using western blotting and immunohistochemical staining. The grade of the lesion was assessed using planimetry and histological examination, including immunohistochemistry for proliferating cell nuclear antigen (PCNA).

RESULTS

Although there was strong expression of COX-1, there was minimal expression of COX-2 in the gastric mucosa. Expression of COX-2 was enhanced mainly in surface epithelial cells and neck cells following HCl administration. Gastric mucosal ulcers and erosions healed within 48 h, during which time the proliferative zone expanded in the control animals. Indomethacin and NS-398 suppressed the expansion of the proliferative zone and delayed the healing of the gastric injury.

CONCLUSION

The present study demonstrated that cyclo-oxygenase-2 inhibitors delay gastric wound healing by suppressing expansion of the mucosal proliferative zone. These results provide evidence that cyclo-oxygenase-2 has an important role in gastric mucosal regeneration.

In vivo conformation of mitochondrial DNA revealed by pulsed-field gel electrophoresis in the true slime mold, Physarum polycephalum

Pulsed-field gel electrophoresis (PFGE) was used to examine the in vivo and in vitro conformations of Physarum polycephalum mitochondrial DNA (mtDNA). We used plugs containing isolated mitochondria, isolated mitochondrial nucleoids (mt-nuclei), and isolated mtDNA, in addition to whole cells. The mtDNA contained in the myxamoebae, plasmodia, isolated mitochondria, and isolated mt-nuclei was circular, but most of the isolated mtDNA had been site-specifically fragmented and linearized during DNA preparation and storage under low ionic strength conditions. Restriction mapping of Physarum mtDNA by the direct digestion of the isolated mt-nuclei from two different strains, DP89 x AI16 and KM88 x AI16, resulted in the circular form. A linear mitochondrial plasmid, mF, is known to promote mitochondrial fusion and integration of itself into the mtDNA in Physarum. Linearization of mtDNA by the integration of the mF plasmid was demonstrated when we used PFGE to analyze isolated mitochondria from the plasmodial strain DP89 x NG7 carrying the mF plasmid (mF+). The PFGE system can be used not only to determine whether the form of mtDNA is linear or circular but also to analyze the dynamic conformational changes of mtDNA.

Role of mucosal blood flow: a conceptional review in gastric mucosal injury and protection

The present article overviews the role of gastric mucosal blood flow (MBF) in gastric mucosal injury and protection. The MBF maintains the structure and function of the stomach and, thereby, is closely associated with the pathogenesis and the healing of gastrointestinal lesions. Gastric blood flow was regulated and modified by systemic and also local metabolic factors, such as prostaglandin, leukotrienes and other endogenous chemical mediators, in the mucosa. In the present article, we review the role of endothelin (ET) and nitric oxide (NO) in the development of gastric mucosal injury and protection via mucosal microcirculation. Endothelin-1 was increased under various stressful conditions and caused microcirculatory disturbances resulting in mucosal injury. Inhibitors of NO aggravated mucosal injury induced by ethanol, which produced mucosal congestion. Thus, regionally disturbed gastric circulation is closely associated with the pathogenesis of ethanol- and non-steroidal anti-inflammatory drug-induced gastric lesions. The endothelium-derived vasoactive substances ET and NO regulate gastric mucosal microcirculation and an imbalance of endothelium-derived factors may play an important pathophysiological role in the development of gastric lesions.

Hematopoietic-specific expression of MEFV, the gene mutated in familial Mediterranean fever, and subcellular localization of its corresponding protein, pyrin

Familial Mediterranean fever (FMF) is a recessively inherited disorder characterized by recurrent, self-limited attacks of fever and serositis and by infiltration of affected tissues by large numbers of neutrophils. A candidate gene for FMF was identified by positional cloning and named "MEFV." The corresponding protein was named "pyrin." To elucidate the currently unknown function of pyrin, we characterized its tissue distribution, regulation of expression during hematopoietic differentiation, and subcellular localization. Reverse transcription-polymerase chain reaction analysis, followed by hybridization with an internal oligonucleotide, demonstrated expression of MEFV in different populations of peripheral blood cells. Among hematopoietic cell lines, MEFV was almost exclusively expressed in cells of the myeloid lineage. Furthermore, MEFV messenger RNA was strongly expressed within 24 hours of dimethyl sulfoxide-induced granulocytic differentiation of HL-60 cells. Analysis of complementary DNA from human solid tumor-derived cell lines revealed expression of MEFV in several cell lines derived from colon and prostate cancers. Expression of MEFV fused to enhanced green fluorescent protein showed that pyrin localized in distinct patches in the cytoplasm, forming a perinuclear cap. Taken together, MEFV is predominantly expressed in myeloid cells and upregulated during myeloid differentiation, and the corresponding protein, pyrin, is expressed in the cytoplasm. (Blood. 2000;95:1451-1455)

In vitro DNA fragmentation of mitochondrial DNA caused by single-stranded breakage related to macroplasmodial senescence of the true slime mold, Physarum polycephalum

We found that mitochondrial DNA (mtDNA) isolated from Physarum polycephalum fragmented itself in weak ionic solutions. The mtDNA was dissolved in STE (saline Tris-EDTA: 150 mM NaCl, 10 mM Tris-HCl, 1 mM EDTA), TE (10 mM Tris-HCl, 1 mM EDTA) and DW, and then electrophoresed in an agarose gel. The intact 86-kbp mtDNA band was seen in STE, but several novel bands appeared in TE and DW. In TE, two discrete bands appeared at 6.7-kbp (alpha-band) and 5.0-kbp (beta-band), whereas at least 17 discrete bands were observed in distilled water (DW). These fragmentation patterns were not stoichiometric, as seen when using restriction endonucleases, but were clearly different from the degradation of DNA caused by a physical shearing force or a contaminating nuclease. In this paper, we characterize this in vitro fragmentation of mtDNA from P. polycephalum. We located 19 fragments, including the alpha and beta fragments, on a mtDNA restriction map, and demonstrated that these cleavage sites were S1 nuclease-sensitive regions, which are single-stranded DNA regions such as nicks and gaps in the mtDNA. The alpha and beta fragments are derived from the region encoding ribosomal RNAs (rRNAs) and the ATP synthase (atpA) gene, while the other 17 fragments are not derived from any specific region, but the cleavage sites are located throughout the mtDNA molecule. In P. polycephalum, it is well known that the growth rate of macroplasmodia decreases with aging. Equal amounts of mtDNA from juvenile and aged macroplasmodia were electrophoresed and the frequency of the beta fragment in each sample was measured. The ratio of the beta band to the total signal including background was estimated to be 3.3-4.0% in juvenile macroplasmodia, whereas it increased to 8.3-28.2% in aged macroplasmodia. This result suggests that the in vitro fragmentation of mtDNA is associated with macroplasmodial senescence. The single-stranded breakage of mtDNA of P. polycephalum may accumulate with age.

Isolation, characterization, and chromosomal mapping of an ftsZ gene from the unicellular primitive red alga Cyanidium caldarium RK-1

The FtsZ protein is involved in eukaryote plastid division, but there is little information on its involvement in the plastid-dividing apparatus. To investigate the relationship between FtsZ and the plastid-dividing ring, the ftsZ gene was isolated from the unicellular primitive red alga Cyanidium caldarium RK-1. Comparison of several prokaryotic and eukaryotic FtsZ proteins shows that there are six highly conserved domains in the core region of FtsZ. To determine the chromosomal location of ftsZ, we first determined the electrophoretic karyotype of C. caldarium RK-1. Southern-hybridization analysis combined with CHEF revealed the chromosomes on which the ftsZ gene exist. Northern-hybridization analysis indicated that the C. caldarium RK-1 ftsZ gene is transcribed as a 1.9-kb molecule, and that the transcripts specifically accumulate just before plastid division. Phylogenetic analysis indicated that C. caldarium RK-1 and other eukaryotic ftsZ genes are the descendants of cyanobacterial ftsZ genes, supporting the current agreement that FtsZ is involved in plastid division.

Effect of pre-reperfusion residual flow on recovery from myocardial stunning: a myocardial contrast echocardiography study

BACKGROUND

Myocardial contrast echocardiography (MCE) may be used to assess coronary microvasculature in patients with myocardial infarction. Myocardial contrast echocardiography-no reflow suggests poor functional outcome; however, MCE with reflow does not necessarily indicate good myocardial salvage or sufficient functional recovery from myocardial stunning. In this study, MCE was performed to assess the effect of pre-reperfusion residual flow (PRF) on the recovery from myocardial stunning.

METHODS AND RESULTS

The size of the occluded bed, an area supplied with an infarct-related artery, was determined by comparing pre- and post-reperfusion MCE images in 40 patients with first acute myocardial infarction. Myocardial contrast echocardiography-no reflow was observed after reperfusion in 8 patients. Significant PRF was not recognizable in any of the 8 patients. The other patients with MCE reflow were subdivided into 2 groups on the basis of the ratio of the area perfused by PRF to that of the occluded bed: 14 patients with the ratio of more than 10% (PRF[+]), and the other 18 patients (PRF[-]). The wall motion score (0, normal to 4, dyskinetic) was obtained in the convalescent stage.

RESULTS

(1) Wall motion of the infarct area after day 3 was better in patients with PRF than in patients without PRF. (2) Left ventricular functional improvement in the long term was remarkable in patients with good reflow and PRF(+), modest in patients with good reflow but PRF(-), and not detectable in patients with MCE-no reflow. No significant correlation was found between angiographic collateral grades and PRF.

CONCLUSIONS

The presence of residual flow within the infarct area before reperfusion results in not only good myocardial salvage but also rapid functional recovery from myocardial stunning.

Cyclooxygenase inhibitors suppress angiogenesis and reduce tumor growth in vivo

Angiogenesis plays a key role in the development of malignant tumors. To clarify the roles of cyclooxygenase (COX) in malignant tumor development and angiogenesis, we investigated the effects of COX inhibitors on two kinds of gastrointestinal cancer xenograft, one of which overexpresses COX-2 and the other expresses no COX, in nude mice in vivo. There was a positive correlation between tumor volume and angiogenesis within the xenograft. Oral administration with a specific COX-2 or a nonspecific COX inhibitors lowered the expression of potent angiogenic factors; vascular endothelial growth factor and basic fibroblast growth factor, reduced angiogenesis and growth, induced apoptosis, and suppressed cell replication of the COX-2 overexpressing cancer xenografts in a dose-dependent manner. A nonspecific COX inhibitor, not a specific COX-2 inhibitor, reduced growth and angiogenesis of non-COX expressing cancer xenograft by inhibition of COX-1 in vascular endothelial cells. These results demonstrate that COX inhibitors suppress angiogenesis and tumor growth by inhibiting expression of angiogenic factors and vascular endothelial cell growth. They support the hypothesis that COX plays an important role in cancer growth via angiogenesis. These findings offer a new strategy against cancer using COX inhibitors (nonsteroidal anti-inflammatory drugs).

Technical advance: single pollen typing combined with laser-mediated manipulation

We combined single pollen typing with laser-mediated manipulation. After drilling a hole in the wall of a pollen grain from a dioecious plant (Silene latifolia) with a UV-laser microbeam, the single pollen grain was recovered directly in the cap of a PCR tube, using a non-contact method called laser pressure catapulting. The entire genome of the single pollen grain was then amplified with improved primer-extension-preamplification PCR (I-PEP PCR). Nested PCR with sequence tagged site (STS)-specific primers was used to analyze several loci in the haploid genome. The single copy gene MROS1 was detected in most of the single pollen grains analyzed. Bgl10, which is localized on the Y chromosome, was detected in approximately half of the pollen grains. MROS3 is reported to be localized on the X chromosome. Using inverse PCR, we isolated two genomic clones of MROS3: MROS3A and MROS3B. The single pollen analysis using nested PCR showed that MROS3A and MROS3B are derived from different loci that are not located on the X chromosome. Single pollen typing not only reveals sex chromosome-linkage within the haploid genome, but can also discriminate between alleles and different loci. This method should also be useful for measuring recombination frequencies without genetic crossover analysis.

Myeloid transcription factor C/EBPepsilon is involved in the positive regulation of lactoferrin gene expression in neutrophils

Targeted mutation of the myeloid transcription factor C/EBPepsilon in mice results in gram-negative septic death at 3 to 5 months of age. This study defines the underlying molecular defects in their terminal granulocytic differentiation. The mRNA for the precursor protein of the cathelin-related antimicrobial peptides was almost completely absent in the bone marrow cells of C/EBPepsilon-/- mice. This finding may help explain their susceptibility to gram-negative sepsis, because both are bacteriocidal peptides with potent activity against gram-negative bacteria. Superoxide production was found to be reduced in both granulocytes and monocytes of C/EBPepsilon-/- mice. While gp91 phox protein levels were normal, p47phox protein levels were considerably reduced in C/EBPepsilon -/- granulocytes/monocytes, possibly limiting the assembly of the NADPH oxidase. In addition, expression of mRNA of the secondary and tertiary granule proteins, lactoferrin and gelatinase, were not detected, and levels of neutrophil collagenase mRNA were reduced in bone marrow cells of the knock-out mice. The murine lactoferrin promoter has a putative C/EBP site close to the transcription start site. C/EBPepsilon bound to this site in electromobility shift assay studies and mutation of this site abrogated binding to it. A mutation in the C/EBP site reduced the activity of the promoter by 35%. Furthermore, overexpression of C/EBPepsilon in U937 cells increased the activity of the wild-type lactoferrin promoter by 3-fold. In summary, our data implicate C/EBPepsilon as a critical factor of host antimicrobial defense and suggests that it has a direct role as a positive regulator of expression of lactoferrin in vivo.

Involvement of cyclooxygenase-2 in proliferation and morphogenesis induced by transforming growth factor alpha in gastric epithelial cells

Transforming growth factor alpha is one of the most potent growth factors for gastrointestinal epithelium. In this study, we examined the roles of cyclooxygenase-2 on proliferation and morphogenesis of RGM1 rat gastric epithelial cells after stimulation with transforming growth factor alpha in vitro, RGM1 cells increased expression of cyclooxygenase-2 messenger RNA 20-60 min after stimulation with transforming growth factor alpha. Transforming growth factor alpha stimulated [3H]thymidine incorporation and tubulogenesis of RGM1 cells in collagen matrix, both of which were significantly suppressed by treatment with a cyclooxygenase-2 specific inhibitor, NS-398 or cyclooxygenase-2 antisense oligonucleotide. Both of the treatment lowered prostanoid production by enzyme immunoassay. The transforming growth factor alpha-induced expression of cyclooxygenase-2 is followed by cell proliferation and development of tubular morphology of RGM1 gastric epithelial cells. Treatment with cyclooxygenase-2 inhibitor and cyclooxygenase-2 antisense oligonucleotide suppressed these responses induced by transforming growth factor alpha suggesting the involvement of cyclooxygenase-2 in proliferation and morphogenesis in gastric mucosal epithelium.

A pair of invertedly repeated genes in Chlamydomonas reinhardtii encodes a zygote-specific protein whose expression is UV-sensitive

Uniparental inheritance of the chloroplast genome has been observed in a wide variety of green plants. In Chlamydomonas this phenomenon, which can be selectively inhibited by UV irradiation of mt(+) gametes, has been shown cytologically to be due to the preferential degradation of mt(-)-derived chloroplast nucleoids in young zygotes. The zygote-specific pair of zys1 genes, zys1A and zys1B, is expressed earliest among five genes isolated from a "10-min" zygote library. We report here that the ZYS1 protein, which is encoded by the invertedly duplicated zys1 gene, accumulates in zygotes and is localized in nuclei. In addition, when mt(+) gametes (but not mt(-) gametes) are UV-irradiated before mating, only very limited accumulation of ZYS1 protein can be detected in the resulting zygotes.

Auxin and cytokinin have opposite effects on amyloplast development and the expression of starch synthesis genes in cultured bright yellow-2 tobacco cells

In cultured Bright Yellow-2 (BY-2) tobacco (Nicotiana tabacum) cells, the depletion of auxin (2,4-dichlorophenoxyacetic acid) in the culture medium induces the accumulation of starch. This is accelerated by the addition of cytokinin (benzyladenine). Light and electron microscopic observations revealed that this amyloplast formation involves drastic changes in plastid morphology. The effects of auxin and cytokinin on amyloplast development were investigated by adding auxin or cytokinin to cells grown in a hormone-free culture. Auxin repressed amyloplast development, whereas cytokinin accelerated starch accumulation regardless of the timing of hormone addition. RNA gel-blot analysis revealed that the accumulation of the ADP-glucose pyrophosphorylase small subunit gene (AgpS), granule-bound starch synthase, and starch branching enzyme transcripts were also affected by hormonal conditions. High levels of AgpS, granule-bound starch synthase, and starch branching enzyme transcripts accumulated in amyloplast-developing cells grown in auxin-depleted conditions. Furthermore, the addition of auxin to the cells cultured in hormone-free medium reduced the level of AgpS transcripts, whereas the addition of cytokinin increased it, irrespective of the timing of hormone addition. These results suggest that auxin and cytokinin exert opposite effects on amyloplast development by regulating the expression of the genes required for starch biosynthesis.

Endoscope disinfection using acidic electrolytic water

BACKGROUND AND STUDY AIMS

The aim of the present study was to evaluate a new endoscope disinfector (WM-1) that uses acidic electrolytic water (AEW).

MATERIALS AND METHODS

AEW was produced by electrolysis of a 0.05% NaCl-water mixture, with a redox potential greater than 1000 mV and a pH lower than 2.7. In the first study, an endoscope artificially contaminated with 15 species of bacteria and four strains of viruses was treated using the WM-1. In the second study, endoscopic contamination after clinical use was examined by culture for Helicobacter pylori and other bacteria, and by polymerase chain reaction for the H. pylori urease gene and hepatitis C virus. The extent of contamination was then examined after exposing the WM-1 to AEW. The safety of AEW was examined using both in vivo and in vitro studies.

RESULTS

All of the bacteria and viruses were destroyed or inactivated after the instrument had been exposed to AEW. Clinical contamination was detected from the instrument in 19 of 30 endoscopic procedures, whereas no bacteria or viruses were detected after five minutes' exposure to AEW. AEW was found to be nonirritant, nontoxic to cells, and nonmutagenic.

CONCLUSION

The WM-1 successfully and safely disinfected the endoscopes. With running costs of yen 24 per day ($0.21 per day), the WM-1 provides an effective and inexpensive alternative to conventional disinfection equipment.

Structural analyses of new tri- and tetrasaccharides produced from disaccharides by transglycosylation of purified Trichoderma viride beta-glucosidase

A new beta-glucosidase was partially purified from Trichoderma viride cellulase. This beta-glucosidase catalyzed a transglycosylation reaction of cellobiose to give beta-D-Glc-(1-->6)-beta-D-Glc-(1-->4)-D-Glc (1, yield: 18.8%) and beta-D-Glc-(1-->6)-beta-D-Glc-(1-->6)-beta-D-Glc-(1-->4)-D-Glc (2, 3.7%), regioselectively. Furthermore, the enzyme regioselectively converted laminaribiose and gentiobiose into beta-D-Glc-(1-->6)-beta-D-Glc-(1-->3)-D-Glc (3, 15.3%) and beta-D-Glc-(1-->6)-beta-D-Glc-(1-->6)-D-Glc (4, 20.2%), respectively. The structures (1-4) of the products were determined by 1H and 13C NMR spectroscopies. This high regio- and stereoselectively of the beta-glucosidase could be applied for oligosaccharide synthesis.

Loss of p73 gene expression in leukemias/lymphomas due to hypermethylation

The p73 gene, a member of the p53 family, is a new candidate tumor suppressor gene. To investigate the possibility of genetic alteration of p73 in leukemia and lymphoma, we examined 55 cell lines and 39 patient samples together with 17 nonhematopoietic cancer cell lines. Gene expression of p73 was detected by reverse transcriptase-polymerase chain reaction (RT-PCR) in cell lines (5 of 7 pre B/B-acute lymphoblastic leukemia [ALL], 13 of 21 T-ALL/lymphoblastic lymphomas [LBL], 9 of 10 B-non-Hodgkin's lymphomas [B-NHL], 8 of 9 acute myelogenous leukemias [AML], 2 of 2 T-NHL, 3 of 3 multiple myeloma), and in patient samples (16 of 23 pre B-ALL, 5 of 8 T-ALL/LBL, 5 of 8 B-NHL). PCR-single-strand conformation polymorphism (SSCP) of cDNAs showed no mutation in 43 p73-expressing cell lines within the regions that corresponded to the 5 mutational hotspots of the p53 gene. Neither homologous deletion nor rearrangement of the p73 gene were found by Southern blot analysis in any of the cell lines that lack expression of p73. In contrast to prior published data, analysis of a polymorphic site showed that the p73 gene was expressed biallelically in cell lines and normal peripheral blood. Notably, the p73-negative cell lines were hypermethylated at a CpG island in the 5' untranslated region of the p73 mRNA, and treatment of these cell lines with 5-azacytidine (5-AC), a demethylation reagent, induced p73 expression. Taken together, we found that a sizable proportion (32%) of ALL/B-NHL cell lines and primary tumors had negligible or limited expression of the p73 gene associated with hypermethylation of the gene. These findings suggest that silencing of the p73 gene by hypermethylation may contribute to development and/or progression of lymphoid neoplasms.

Peripheral vascular resistances during total left heart bypass with an oscillated blood flow

For development aimed at a totally implantable type ventricular assist device (VAD), the vibrating flow pump (VFP) has been developed at Tohoku University. A transcutaneous energy transmission system (TETS) using amorphous fibers was developed to power the totally implantable VAD system. The VFP works at a high frequency compared to that of a natural heart of a biological system. It is a frequency of 10-50 Hz. In this research, animal experiments with left heart bypass were carried out with healthy adult goats. For comparison between nonpulsatile flow and oscillated flow, a rotary pump (RP) and the VFP were used in the experiments. For the achievement of total left heart bypass, left ventricular approaches were carried out, and blood was pumped from the left ventricle to the descending aorta. Adequate support of the left heart was provided by both pumps. In terms of the results, the vascular resistances tended to decrease during the use of both pumps during 100% bypass driving. When we compared these pumps at the same flow rate, the resistances during RP driving were significantly smaller than those during VFP driving. These results may suggest that the influences of the VFP upon the peripheral vessels may be relatively small compared to those of the RP. This may be an important result when a stable hemodynamic condition is required during artificial circulation. The VFP was considered as a candidate for a totally implantable VAD as a result.

Two types of ftsZ genes isolated from the unicellular primitive red alga Galdieria sulphuraria

FtsZ plays a crucial role in bacterial cell division, and may be involved in plastid division in eukaryotes. To investigate the evolution of the dividing apparatus from prokaryotes to eukaryotes, the ftsZ genes were isolated from the unicellular primitive red alga Galdieria sulphuraria. Two ftsZ genes (GsftsZ1 and GsftsZ2) were isolated. This suggests that duplication and divergence of the ftsZ gene occurred in an early stage of plant evolution. A comparison of the FtsZs of G. sulphuraria and other organisms shows that FtsZ is highly and universally conserved among prokaryotes, primitive eukaryotic algae, and higher plants. The GsftsZ2 gene seems to contain an intron. Southern hybridization analysis of the G. sulphuraria chromosomes separated by CHEF revealed that each ftsZ gene and its flanking region may be duplicated.

Calmodulin mediates calcium-dependent inactivation of the cerebellar type 1 inositol 1,4,5-trisphosphate receptor

The dependency of purified mouse cerebellar type 1 inositol 1,4,5-trisphosphate receptor (IP3R1)/Ca2+ channel function on cytoplasmic Ca2+ was examined. In contrast to the channels in crude systems, the purified IP3R1 reconstituted into planar lipid bilayers did not show the bell-shaped dependence on Ca2+. It was activated with increasing Ca2+ sublinearly without inhibition even up to 200 microM. The addition of calmodulin to the cytoplasmic side inhibited the channel at high Ca2+ concentrations. Calmodulin antagonists reversed the Ca2+-dependent inactivation of the native channels in cerebellar microsomes. These results indicate that the bell-shaped dependence on cytoplasmic Ca2+ is not an intrinsic property of the IP3R1, and the Ca2+-dependent inactivation is directly mediated by calmodulin.

Molecular cloning of transferrin receptor 2. A new member of the transferrin receptor-like family

Transferrin receptor (TfR) plays a major role in cellular iron uptake through binding and internalizing a carrier protein transferrin (Tf). We have cloned, sequenced, and mapped a human gene homologous to TfR, termed TfR2. Two transcripts were expressed from this gene: alpha (approximately 2.9 kilobase pairs), and beta (approximately 2.5 kilobase pairs). The predicted amino acid sequence revealed that the TfR2-alpha protein was a type II membrane protein and shared a 45% identity and 66% similarity in its extracellular domain with TfR. The TfR2-beta protein lacked the amino-terminal portion of the TfR2-alpha protein including the putative transmembrane domain. Northern blot analysis showed that the alpha transcript was predominantly expressed in the liver. In addition, high expression occurred in K562, an erythromegakaryocytic cell line. To analyze the function of TfR2, Chinese hamster ovary TfR-deficient cells (CHO-TRVb cells) were stably transfected with FLAG-tagged TfR2-alpha. These cells showed an increase in biotinylated Tf binding to the cell surface, which was competed by nonlabeled Tf, but not by lactoferrin. Also, these cells had a marked increase in Tf-bound (55)Fe uptake. Taken together, TfR2-alpha may be a second transferrin receptor that can mediate cellular iron transport.

Factor XII Tenri, a novel cross-reacting material negative factor XII deficiency, occurs through a proteasome-mediated degradation

A homozygous cross-reacting material negative factor XII-deficient patient with 3% antigen and activity levels of factor XII was screened for the identification of a mutation at the genomic level. Low-ionic strength single-stranded conformation polymorphism (SSCP) analysis and sequence analysis showed that the proband's gene for factor XII had an A-->G substitution at nucleotide position 7832 in exon 3, resulting in a Tyr34 to Cys substitution in the NH2-terminal type II domain of factor XII. We designated this mutation as factor XII Tenri. Mutagenic polymerase chain reaction (PCR), followed by KpnI digestion, showed a homozygous mutation in the proband's gene and heterozygous mutations in his parents and sister. Immunoprecipitation and Western blot analyses of plasma samples from the factor XII Tenri family indicated that the proband had a trace amount of variant factor XII with an apparent molecular mass of 115 kD, which was converted to the normal 80-kD form after reduction, suggesting that factor XII Tenri was secreted as a disulfide-linked heterodimer with a approximately 35-kD protein, which we identified as alpha1-microglobulin by immunoblotting. Pulse-chase experiments using baby hamster kidney (BHK) cells showed that Tenri-type factor XII was extensively degraded intracellularly, but the addition of cystine resulted in increased secretion of the mutant. Using membrane-permeable inhibitors, we observed that the degradation occurred in the pre-Golgi, nonlysosomal compartment and a proteasome appeared to play a major role in this process. On the basis of these in vitro results, we speculate that the majority of the factor XII Tenri is degraded intracellularly through a quality control mechanism in the endoplasmic reticulum (ER), and a small amount of factor XII Tenri that formed a disulfide-linked heterodimer with alpha1-microglobulin is secreted into the blood stream.

Distribution of synaptosomal-associated protein 25 in nerve growth cones and reduction of neurite outgrowth by botulinum neurotoxin A without altering growth cone morphology in dorsal root ganglion neurons and PC-12 cells

Synaptosomal-associated protein 25 has been regarded as one of the target-associated soluble N-ethylmaleimide-sensitive fusion attachment protein receptors essential for exocytosis of vesicles in synapses. We have previously reported that cleavage of syntaxin, which is another target-associated soluble N-ethylmaleimide-sensitive fusion attachment protein receptor, with botulinum neurotoxin C1 resulted in inhibition of neurite extension and morphological changes including growth cone collapse and large vacuole formation. As an attempt to explore the mechanism of growth cone extension, we examined the ultrastructural localization of synaptosomal-associated protein 25 in growth cones with or without treatment of botulinum neurotoxin A, which cleaves synaptosomal-associated protein 25. In dorsal root ganglion neurons, light microscopy demonstrated synaptosomal-associated protein 25 immunoreactivity throughout the neurons, including the cell bodies, neurites and growth cones. Using electron microscopy, gold signals immunoreactive for synaptosomal-associated protein 25 were identified diffusely in the cytoplasm of the growth cones. In contrast, in PC-12 cells, a large number of gold signals were localized on the plasma membranes. High levels of signal were also found in the cytoplasm in the central region of the growth cones. We also confirmed that botulinum neurotoxin A treatment reduced neurite extension by about 50%. However, both in dorsal root ganglion neurons and in PC-12 cells we found no differences in the ultrastructure nor in the localization of synaptosomal-associated protein 25 between growth cones with and without toxin treatment. These results indicate that cleavage of synaptosomal-associated protein 25 inhibits growth cone extension in a manner different than that of syntaxin cleavage. The results of this study suggest the possibility that synaptosomal-associated protein 25 is involved in growth cone extension through a process independent of vesicle fusion.

A new scorpion toxin (BmK-PL) stimulates Ca2+-release channel activity of the skeletal-muscle ryanodine receptor by an indirect mechanism

A peptide toxin isolated from the Chinese scorpion Buthus martensi Karsch (BmK-PL) stimulated Ca2+-release channel activity in both triad membranes and reconstituted ryanodine receptors partially purified from rabbit skeletal muscle. In [3H]ryanodine binding experiments, the toxin increased the affinity of ryanodine for the receptor, from a Kd of 24.3 nM to 2.9 nM, which is an enhancement similar to that seen with known receptor activators, such as ATP and high concentrations of KCl. In contrast, toxin enhancement was not observed with purified receptors, although intrinsic binding activity and stimulation by the conventional receptor activators were retained. In single channel recordings of Ca2+-release activity, the toxin increased the open channel probability (Po) from 0.019 to 0.043 (226% of control) in triad preparations. Further toxin enhancement of Po from 0.07 to 0.37 (529% of control) was observed using partially-purified receptors in the presence of ATP. When purified receptors were assayed in the presence of ATP, however, they showed a high value of Po (0.33) and no further increase was observed following application of the toxin. Results derived from two different experimental methods consistently suggest that a molecule(s) required for toxin-induced enhancement is absent from the purified receptor preparation. Western blot analysis of receptors prepared using three different protocols showed that triadin was missing from the purified receptor preparation. The scorpion toxin minimally enhanced Ca2+-release channel activity of cardiac preparations. From these results, we conclude that the toxin preferentially increases the activity of skeletal-muscle ryanodine receptors by an indirect mechanism, possibly binding to associated protein molecule(s). Triadin is a strong candidate for such a molecule.

Characterization of Chlamydomonas reinhardtii zygote-specific cDNAs that encode novel proteins containing ankyrin repeats and WW domains

Genes that are expressed only in the young zygote are considered to be of great importance in the development of an isogamous green alga, Chlamydomonas reinhardtii. Clones representing the Zys3 gene were isolated from a cDNA library prepared using zygotes at 10 min after fertilization. Sequencing of Zys3 cDNA clones resulted in the isolation of two related molecular species. One of them encoded a protein that contained two kinds of protein-to-protein interaction motifs known as ankyrin repeats and WW domains. The other clone lacked the ankyrin repeats but was otherwise identical. These mRNA species began to accumulate simultaneously in cells beginning 10 min after fertilization, and reached maximum levels at about 4 h, after which time levels decreased markedly. Genomic DNA gel-blot analysis indicated that Zys3 was a single-copy gene. The Zys3 proteins exhibited parallel expression to the Zys3 mRNAs at first, appearing 2 h after mating, and reached maximum levels at more than 6 h, but persisted to at least 1 d. Immunocytochemical analysis revealed their localization in the endoplasmic reticulum, which suggests a role in the morphological changes of the endoplasmic reticulum or in the synthesis and transport of proteins to the Golgi apparatus or related vesicles.

Cyclooxygenase-2 overexpression enhances lymphatic invasion and metastasis in human gastric carcinoma

OBJECTIVE

Recent epidemiological studies indicate that there is reduced risk of all digestive carcinomas in patients who regularly take nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin. Cyclooxygenase (COX) is a target enzyme for NSAIDs. We investigated the role of two isoforms, COX-1 and COX-2, in the development and metastasis of gastric carcinoma.

METHODS

Fifteen gastric carcinoma tissue specimens and accompanying adjacent mucosa specimens were obtained from surgical resections. COX-1 and COX-2 protein expression were evaluated using Western blotting analysis, and their relative band densities were semi quantified using standard densitometry scanning techniques.

RESULTS

Compared with paired noncancerous specimens, COX-2 was overexpressed in 10 of 15 carcinoma tissue specimens (66.7%). Overall, COX-2 levels in carcinoma tissue were significantly higher. Two early carcinomas (confined to the mucosa and submucosa) and three of 13 advanced carcinomas (extended below the submucosa into the muscular wall) had weak or similar COX-2 expression in paired tissue specimens. COX-2 overexpression in tumors significantly correlated with tumor invasion into the lymphatic vessels in the gastric wall and metastasis to the lymph nodes. Furthermore, the stage grouping in the TNM classification significantly correlated with COX-2 overexpression. In contrast, COX-2 overexpression did not correlate with histopathological grading, surface size, and venous vessel invasion of the tumors. COX-1 levels were similar between paired tissues.

CONCLUSION

COX-2 overexpression might enhance lymphatic invasion and metastasis in patients with gastric carcinoma, implicating a poor prognosis. Therefore, the use of COX-2-specific inhibitor to suppress lymphatic metastasis in humans should be investigated.

Anion permeability and conduction of adenine nucleotides through a chloride channel in cardiac sarcoplasmic reticulum

Cardiac sarcoplasmic reticulum (SR) membrane contains several chloride (Cl-) channels. We have characterized a 116-pS Cl- channel (500 mM cis, 50 mM trans Cl-) in cardiac SR that is activated by protein kinase A-dependent phosphorylation. To understand its function further, we examined the permeation of various anions and adenine nucleotides using the planar lipid bilayer-vesicle fusion technique. This Cl- channel showed a high selectivity to anions and its permeability sequence was Br- > Cl- > I- > NO3- > F-. When all anions were replaced with ATP in the cis solution, channel activity persisted. The conductance was 78 pS with 200 mM ATP and 68 pS with 100 mM ATP. The reversal potentials were +63 mV and +41 mV in 200 mM ATP and in 100 mM ATP, respectively. With 100 mM ADP or AMP in the cis solution, channel activities were also observed. The conductances were 87 pS with 100 mM ADP and 115 pS with 100 mM AMP. The apparent adenine selectivity of this channel was ATP > ADP > AMP, assuming that they exist as divalent anions. These results suggest that the SR Cl- channel in cardiac cells may serve as a transporter for the movement of adenine nucleotides between cytosol and SR lumen.

Effects of NSAIDs on proliferation of gastric cancer cells in vitro: possible implication of cyclooxygenase-2 in cancer development

The roles of cyclooxygenase-2 (COX-2) in the development of gastric cancer are unknown. We investigated the effects of nonsteroidal antiinflammatory drugs (NSAIDs), which are specific and nonspecific inhibitors of COX-2, on proliferation of the gastric cancer cell lines KATOIII, MKN28, and MKN45. The protein level of COX-2 was examined in these cell lines by Western analysis, and mRNA levels of COX-1/2 by Northern analysis. These cell lines expressed comparable levels of COX-1 mRNA. However, mRNA and protein expression of COX-2 in these cell lines was different. MKN45 expressed higher levels of COX-2 mRNA and protein than KATOIII and MKN28. We also examined the effects of NS-398 and indomethacin, specific and nonspecific inhibitors of COX-2, on the increase in cell number and [3H]thymidine uptake of these cell lines. NS-398 and indomethacin suppressed proliferation of MKN45 cells that overexpressed COX-2, although they exerted minimal effects on proliferation of KATOIII and MKN28, which expressed lower levels of COX-2. These results are consistent with the hypothesis that COX-2 is expressed in certain groups of gastric cancers and is related to their cell proliferation. It was proposed that COX-2 plays an important role in development of gastric cancer cells. Furthermore, NSAIDs may exert antiproliferative activity against gastric adenocarcinomas that overexpress COX-2.

[Possible availability of rapid urease tests for diagnosis of Helicobacter pylori eradication: comparative study with culture and histology]

Rapid urease tests (RUTs) are simple and economical methods to detect Helicobacter pylori infection. However, they have been thought to be unreliable to confirm successful eradication of the infection following treatment. We reviewed the efficiency of RUTs and investigated their possible indication for use after eradication therapy. The sensitivity of highly sensitive RUTs seemed to be comparable to that of culture regardless of the timing for testing, but remarkably lower than that of histology within a few months after treatment. Highly sensitive RUTs, used several months after therapy, produced excellent accuracy, suggesting that they might be available to confirm successful treatment, taking cost and time factors into consideration.

Semi-automatic laser beam microdissection of the Y chromosome and analysis of Y chromosome DNA in a dioecious plant, Silene latifolia

Silene latifolia has heteromorphic sex chromosomes, the X and Y chromosomes. The Y chromosome, which is thought to carry the male determining gene, was isolated by UV laser microdissection and amplified by degenerate oligonucleotide-primed PCR. In situ chromosome suppression of the amplified Y chromosome DNA in the presence of female genomic DNA as a competitor showed that the microdissected Y chromosome DNA did not specifically hybridize to the Y chromosome, but hybridized to all chromosomes. This result suggests that the Y chromosome does not contain Y chromosome-enriched repetitive sequences. A repetitive sequence in the microdissected Y chromosome, RMY1, was isolated while screening repetitive sequences in the amplified Y chromosome. Part of the nucleotide sequence shared a similarity to that of X-43.1, which was isolated from microdissected X chromosomes. Since fluorescence in situ hybridization analysis with RMY1 demonstrated that RMY1 was localized at the ends of the chromosome, RMY1 may be a subtelomeric repetitive sequence. Regarding the sex chromosomes, RMY1 was detected at both ends of the X chromosome and at one end near the pseudoautosomal region of the Y chromosome. The different localization of RMY1 on the sex chromosomes provides a clue to the problem of how the sex chromosomes arose from autosomes.

Guidance in vitro of the pollen tube to the naked embryo sac of torenia fournieri

The precise guidance of the pollen tube to the embryo sac is critical to the successful sexual reproduction of flowering plants. We demonstrate here the guidance of the pollen tube to the embryo sac in vitro by using the naked embryo sac of Torenia fournieri, which protrudes from the micropyle of the ovule. We developed a medium for culture of both the ovule and the pollen tube of T. fournieri and cocultivated them in a thin layer of solid medium. Although pollen tubes that had germinated in vitro passed naked embryo sacs, some pollen tubes that grew semi-in vitro through a cut style arrived precisely at the site of entry into the embryo sac, namely, the filiform apparatus of the synergids. When pollen tubes were unable to enter the embryo sac, they continuously grew toward the same filiform apparatus, forming narrow coils. Pollen tubes selectively arrived at complete, unfertilized embryo sacs but did not arrive at those of heat-treated ovules or those with disrupted synergids. These results convincingly demonstrate that pollen tubes are specifically attracted to the region of the filiform apparatus of living synergids in vitro.

Detection of varicella-zoster virus DNA in peripheral mononuclear cells from patients with Ramsay Hunt syndrome or zoster sine herpete

On the basis of alterations in varicella-zoster virus (VZV) antibody titers, it appears that Bell's palsy in some patients could be associated with VZV reactivation, that is, zoster sine herpete. To obtain stronger evidence of this association, polymerase chain reaction (PCR) was used to detect VZV DNA in auricular lesions or peripheral blood mononuclear cells (PBMCs) from Bell's palsy or Ramsay Hunt syndrome patients. VZV DNA was detected in the auricular lesions of Ramsay Hunt syndrome, in PBMCs from 2 Ramsay Hunt syndrome patients, and in 4 of 17 samples from 16 Bell's palsy patients. Three of these four positive patients were thought to have zoster sine herpete because of hearing difficulty, vertigo, and pain. VZV IgM antibodies were positive in 1 of the 2 patients with Ramsay Hunt syndrome, and in 2 of the 17 samples from the Bell's palsy patients. VZV IgG antibody titers during the acute phase were significantly higher in the patients positive for the PCR or VZV IgM antibody than in those negative for them. These findings provide evidence that Bell's palsy in some patients could be associated with VZV reactivation.

[Simultaneous cholecystectomy and CABG for acute cholecystitis and post-infarction angina]

A 71-year-old man was admitted to our hospital with massive GI bleeding and followed by acute myocardial infarction. Severe three vessel coronary artery disease with poor left ventricular performance (EF: 40%) was demonstrated by coronary angiography. He was referred for CABG. He had also cholecystitis, which needed surgical treatment simultaneously. Combined CABG and cholecystectomy were performed without using gastroepiploic artery as a bypass graft, and through separate median sternotomy and through right upper transrectal laparotomy. Postoperative course was uneventful. This combined procedure is beneficial for the patients with acute cholecystitis and unstable angina.

Impaired peripheral vasoconstriction in response to alpha-adrenergic stimulation in patients with idiopathic hypertrophic cardiomyopathy

Exercise hypotension has been documented in patients with hypertrophic cardiomyopathy (HCM). Some investigators reported that this is due to an inadequate increase of systemic vascular resistance during or after exercise. The aim of this study was to investigate the pathogenesis of limb vascular response abnormalities in patients with idiopathic HCM. Thirteen patients with HCM and 9 healthy controls were administered an endothelium-dependent dilator (acetylcholine), a direct smooth muscle dilator (nitroglycerin), an alpha-adrenergic stimulator (phenylephrine), and a beta-adrenergic stimulator (isoproterenol) by intra-arterial infusion. Peripheral vascular resistance was assessed by forearm plethysmography at rest and during each infusion to obtain the percentage change in vascular resistance. Isoproterenol, acetylcholine and nitroglycerin produced dose-related vasodilatation with no significant differences between HCM patients and healthy controls. The percentage increase in vascular resistance was significantly less in HCM patients than in healthy controls after phenylephrine infusions of 0.5 microg/min (155+/-38% vs 195+/-47%, mean+/-SD, p<0.05) and 1.0 microg/min (174+/-49% vs 238+/-65%, p<0.05). Vasoconstriction mediated by alpha-adrenergic receptors appeared to be impaired in the peripheral vasculature of patients with HCM.

Dual mechanisms of Mg2+ block of ryanodine receptor Ca2+ release channel from cardiac sarcoplasmic reticulum

We investigated the effects of cytosolic Mg2+ on ryanodine receptor Ca2+ release channel (RyR) of bovine cardiac sarcoplasmic reticulum incorporated into planar lipid bilayers recording single channel activities. Channels were activated by > or = 0.1 microM Ca2+ in the cis solution. At constant Ca2+, application of Mg2+ (0.1-1 mM) to cis side decreased channel activity in a concentration-dependent manner. A half maximal blocking concentration (Kd) was 35 microM and a complete block was obtained at 1 mM. In the presence of 1 mM free Mg2+ in cis solution, the relation between the channel open probability (Po) and concentration of free Ca2+ in cis solution ([Ca2+]cis) shifted to the right, indicating the competition of Mg2+ and Ca2+. Blocking effects of Mg2+ on RyR were antagonized by increasing [Ca2+]cis > or = 0.1 mM. In the presence of 1 m Mg2+ and 1 mM Ca2+ in cis solution, the channel conductance was markedly depressed to approximately 400 pS (n = 7) from 603 +/- 40 pS (mean +/- S.D., n = 22) in the absence of Mg2+, indicating the flickering block. These results show that Mg2+ causes a direct inhibition of RyR in cardiac SR and this inhibition may be mediated through two different mechanisms. A competition of Mg2+ and Ca2+ at a Ca2+ sensitive site on the RyR and a flickery block of the open channel by Mg2+.

Activation of Ca2+-sensitive Cl- current by reverse mode Na+/Ca2+ exchange in rabbit ventricular myocytes

We investigated how Ca2+-sensitive transient outward current, Ito(Ca), is activated in rabbit ventricular myocytes in the presence of intracellular Na+ (Na+i) using the whole-cell patch-clamp technique at 36 degreesC. In cells dialysed with Na+-free solutions, the application of nicardipine (5 microM) to block L-type Ca2+ current (ICa) completely inhibited Ito(Ca). In cells dialysed with a [Na+]i>/=5 mM, however, Ito(Ca) could be observed after blockade of ICa, indicating the activity of an ICa-independent component. The amplitude of ICa-independent Ito(Ca) increased with voltage in a [Na+]i-dependent manner. The block of Ca2+ release from the sarcoplasmic reticulum by caffeine, ryanodine or thapsigargin blocked ICa-independent Ito(Ca). In Ca2+-free bath solution Ito(Ca) was completely abolished. The application of 2 mM Ni2+ or the newly synthesized compound KBR7943, a selective blocker of the reverse mode of Na+/Ca2+ exchange, or perfusion with pipette solution containing XIP (10 microM), a selective blocker of the exchanger, blocked ICa-independent Ito(Ca). From these results we conclude that, in the presence of Na+i, Ito(Ca) can be activated via Ca2+-induced Ca2+ release triggered by Na+/Ca2+ exchange operating in the reverse mode after blockade of ICa.

Non-dipolarity of heart potentials estimated by magnetocardiography in normal subjects

We studied non-dipolarity characteristics during ventricular excitation in normal adults and children by magnetocardiography (MCG) by recording magnetic field on the thorax. The source and currents of the electrical dipole from the onset up to 60 ms of ventricular excitation were analyzed in 16 adults and 5 children. A single equivalent current dipole (ECD) was estimated by Sarvas' formula for the sphere model at 1 ms intervals. The non-dipole value (NDV) was calculated from the magnetic field strength at each recording point and theoretically estimated by ECD, representing an index for the non-dipolarity. At 32-34 ms from the beginning of QRS, the mean NDV was a minimum in all subjects suggesting at least a non-dipole component during this period. High NDV (over 5%) were present in most subjects in both the early and late phase compared to this period. Thirteen of 16 adults had a high NDV in the early phase (9.3 +/- 3.0%, mean +/- SD) and all 16 subjects had a high NDV in the late phase (21.5 +/- 10.5%). All 5 children had high NDV in both the early (10.5 +/- 5.4%) and late phases (16.8 +/- 7.9%). A single ECD estimation by MCG showed a relatively low non dipolar component and MCG could be applied to the clinical evaluation of cardiac excitation in both normal and pathological conditions.

Disturbed pyloric motility in Ws/Ws mutant rats due to deficiency of c-kit-expressing interstitial cells of Cajal

Interstitial cells of Cajal (ICC) are believed to initiate the basic contractile activity of the gastrointestinal tract. Interstitial cells of Cajal express c-kit receptor tyrosine kinase and are deficient in Ws/Ws mutant rats with a small deletion of the c-kit gene. As Ws/Ws rats show remarkable bile reflux to the stomach, the contraction pressure of the pylorus was compared between Ws/Ws and control +/+ rats. The contraction pressure of the pylorus was measured using a microtransducer, which was inserted through a pin-hole in the anterior wall of the stomach under anesthesia. The magnitude of bile reflux was estimated by measuring the content of bile acids in the stomach. The c-kit messenger RNA-expressing cells were detected by in situ hybridization. Frequency and the maximum pressure of the contraction were comparable between Ws/Ws and +/+ rats, but the duration of the contraction was significantly shorter in Ws/Ws rats than in +/+ rats. The number of c-kit messenger RNA-expressing ICC in the pylorus of Ws/Ws rats was 1.7% that of +/+ rats. The bile reflux observed in Ws/Ws rats was attributed to the decrease in the duration of the pyloric contraction, which appeared to result from the deficiency of c-kit messenger RNA-expressing ICC.

Helicobacter pylori infection induces cyclooxygenase-2 expression in human gastric mucosa

Recent studies indicate that expression of mitogen-inducible cyclooxygenase-2 (COX-2) occurs in gastrointestinal tumors. We investigated the effects of Helicobacter pylori (H. pylori) infection, a class I carcinogen for the human stomach, on gastric COX-2 expression using immunohistochemistry. Human subjects without macroscopic lesions, as determined by endoscopic screening, were biopsied for H. pylori infection. The biopsy samples were immunohistochemically examined for COX-2 expression. COX-2 was expressed in gastric epithelia and subepithelial inflammatory cells in all H. pylori-infected subjects. There was no expression of COX-2 in the gastric mucosa of H. pylori-negative subjects. COX-2 expression has been reported in gastrointestinal carcinomas, gastrointestinal cancer cell-lines, and in the gut after carcinogenic treatment. The present study demonstrates that H. pylori infection leads to gastric mucosal expression of COX-2, indicating that the enzyme is involved in H. pylori-related gastric pathology in humans.

Increase of mast cells in the liver and lung may be associated with but not a cause of fibrosis: demonstration using mast cell-deficient Ws/Ws rats

Tissue fibrosis is frequently associated with an increase of mast cells, and mast cells are regarded as playing a role in the induction of tissue fibrosis. We attempted to examine whether mast cells influenced the induction of fibrosis using Ws/Ws mast cell-deficient rats. The mast cell deficiency of Ws/Ws rats is due to a 12-base pair deletion of the c-kit gene. The activity of c-kit receptor tyrosine kinase is remarkably reduced in Ws/Ws rats. Liver fibrosis was induced by the repeated injections of pig serum, and lung fibrosis was induced by the instillation of bleomycin. Marked fibrosis in the liver and lung did occur in the Ws/Ws rats, and the magnitude of fibrosis was more severe in Ws/Ws rats than in control normal (+/+) rats. The mast cell increase was observed in the liver of +/+ and Ws/Ws rats and in the lung of +/+ rats. However, the number of mast cells in the liver of treated Ws/Ws rats with marked fibrosis was comparable to that observed in the liver of nontreated +/+ rats without fibrosis. Histamine content increased in the liver and lung of +/+ rats after the treatment, but it remained in low levels even after the treatment in Ws/Ws rats. Mast cells and histamine did not appear to play important roles in the induction of fibrosis. Thus, an increase in mast cell number and histamine content may be associated with but not a cause of fibrosis.

Orally administered cholera toxin prevents murine intestinal T cells from staphylococcal enterotoxin B-induced anergy

BACKGROUND & AIMS

Cholera toxin (CT) has been shown to be a strong mucosal adjuvant for the induction of antigen-specific secretory immunoglobulin A (IgA). The mechanism of adjuvant activity of CT is still unknown. The aim of this study was to examine the immunomodulatory function of CT on mucosal T cells using staphylococcal enterotoxin B (SEB) as coadministered oral antigen, because SEB has been shown to directly regulate alpha beta T-cell responses.

METHODS

C3H/HeN mice were orally or systemically immunized with SEB and/or CT. The levels of SEB-specific antibodies and frequencies of CD4(+)Vbeta8(+) T cells were analyzed. SEB-specific T-cell proliferation and cytokine production were also determined.

RESULTS

Neither SEB-specific IgA nor IgG antibodies were induced in feces when SEB was administered alone. This was a result of the clonal deletion and partial unresponsiveness of CD4(+)Vbeta8(+)T cells in Peyer's patches. On the other hand, SEB-specific antibodies were induced by oral immunization with SEB and CT. Although some degree of clonal deletion was induced by oral immunization with SEB and CT, coadministered CT prevented the induction of anergy for CD4(+)Vbeta8(+) T cells in Peyer's patches.

CONCLUSIONS

CT is a powerful immunomodulatory molecule that prevents mucosal T cells from SEB-induced anergy.

Evaluation of the PyloriTek test for detection of Helicobacter pylori infection in cases with and without eradication therapy

OBJECTIVE

The accuracy of the PyloriTek test (a 1-h rapid urease test) used after eradication therapy of Helicobacter pylori (H. pylori) has not been well clarified. This study was done to evaluate the accuracy of the PyloriTek test results for cases with and without eradication therapy, using culture and histology as gold standard methods, and to establish the suitable timing of the PyloriTek test after eradication treatment.

METHODS

One hundred sixty-three patients undergoing upper endoscopy were randomly selected; 100 patients had not received eradication therapy and 63 had. Three biopsy specimens each were obtained from the gastric antrum and the body for examination by PyloriTek, culture, and histology. The absence of H. pylori was established with negative results from both culture and histology.

RESULTS

In cases without eradication therapy, PyloriTek, correctly identified 66 of 67 H. pylori-positive cases and 30 of 33 H. pylori-negative cases, yielding 98.5% sensitivity and 90.9% specificity. In cases with eradication therapy, PyloriTek gave correct diagnoses in 10 of 17 H. pylori-positive cases and in 45 of 46 H. pylori-negative cases, for 58.8% sensitivity and 97.8% specificity. However, when PyloriTek was used more than 4 months after the end of eradication therapy, both the sensitivity and the specificity increased to 100%.

CONCLUSION

Considering time and cost, the use of PyloriTek alone may be satisfactory for detecting H. pylori infection in cases without eradication therapy. When patients are examined more than 4 months after intervention, the use of PyloriTek alone may be sufficient for correctly diagnosing H. pylori infections.

Evaluation of the PyloriTek test for detection of Helicobacter pylori infection in cases with and without eradication therapy

OBJECTIVE

The accuracy of the PyloriTek test (a 1-h rapid urease test) used after eradication therapy of Helicobacter pylori (H. pylori) has not been well clarified. This study was done to evaluate the accuracy of the PyloriTek test results for cases with and without eradication therapy, using culture and histology as gold standard methods, and to establish the suitable timing of the PyloriTek test after eradication treatment.

METHODS

One hundred sixty-three patients undergoing upper endoscopy were randomly selected; 100 patients had not received eradication therapy and 63 had. Three biopsy specimens each were obtained from the gastric antrum and the body for examination by PyloriTek, culture, and histology. The absence of H. pylori was established with negative results from both culture and histology.

RESULTS

In cases without eradication therapy, PyloriTek, correctly identified 66 of 67 H. pylori-positive cases and 30 of 33 H. pylori-negative cases, yielding 98.5% sensitivity and 90.9% specificity. In cases with eradication therapy, PyloriTek gave correct diagnoses in 10 of 17 H. pylori-positive cases and in 45 of 46 H. pylori-negative cases, for 58.8% sensitivity and 97.8% specificity. However, when PyloriTek was used more than 4 months after the end of eradication therapy, both the sensitivity and the specificity increased to 100%.

CONCLUSION

Considering time and cost, the use of PyloriTek alone may be satisfactory for detecting H. pylori infection in cases without eradication therapy. When patients are examined more than 4 months after intervention, the use of PyloriTek alone may be sufficient for correctly diagnosing H. pylori infections.