Endoplasmic reticulum stress response is involved in nonsteroidal anti-inflammatory drug-induced apoptosis

Apoptosis induced by nonsteroidal anti-inflammatory drugs (NSAIDs) is involved not only in the production of NSAID-induced gastric lesions but also in the antitumor activity of these drugs. The endoplasmic reticulum (ER) stress response is a cellular mechanism that aids in protecting the ER against ER stressors and is involved in ER stressor-induced apoptosis. Here, we examine the relationship between this response and NSAID-induced apoptosis in cultured guinea-pig gastric mucosal cells. Exposure of cells to indomethacin, a commonly used NSAID, induced GRP78 as well as CHOP, a transcription factor involved in apoptosis. Three factors that positively regulate CHOP expression (ATF6, ATF4 and XBP-1) were activated and/or induced by indomethacin. NSAIDs other than indomethacin (diclofenac, ibuprofen and celecoxib) also induced CHOP. Monitoring of the transcriptional activities of ATF6 and CHOP by luciferase assay revealed that both were stimulated in the presence of indomethacin. Furthermore, indomethacin-induced apoptosis was suppressed in cultured guinea-pig gastric mucosal cells by expression of the dominant-negative form of CHOP, or in peritoneal macrophages from CHOP-deficient mice. These results suggest that ER stress response-related proteins, particularly CHOP, are involved in NSAID-induced apoptosis.

Marked developmental changes in heme oxygenase-1 (HO-1) expression in the mouse placenta: correlation between HO-1 expression and placental development

Heme catabolism during embryonic period is not well understood. It has been suggested that placental heme oxygenase (HO)-1, which is an inducible isoform of the rate-limiting enzyme in the heme degradation pathway, may be involved in supporting normal fetal development. In this study, we examined the distribution of HO-1 protein in the developing mouse embryo, as well as developmental changes of ho-1 gene expression, and the enzyme activity of HO and biliverdin IXalpha reductase (BVR-A) in placenta. Ectoplacental cone in embryonic day (E) 6.5 embryo already showed HO-1 protein expression, which became restricted only to trophoblastic cells after placenta formation was completed on day E14.5. The placenta of E13.5-E14.5 embryos expressed high levels of HO-1 mRNA, which was decreased significantly towards the end of pregnancy. However, HO-1 expression in placenta was significantly higher than uterus throughout the gestational period. In contrast to HO-1, the placental level of BVR-A activity remained low and did not show changes throughout the gestational period. The correlation between HO-1 expression and placental development suggests that HO-1 might be essential for normal embryonic development.

Multiple lymphomatous polyposis of the colon originating from T-cells: a case report

Multiple lymphomatous polyposis is an unusual form of non-Hodgkin's lymphoma characterised by myriad polyps throughout the alimentary tract. Most multiple lymphomatous polyposis cases are derived from B-cell, and there has been little information on multiple lymphomatous polyposis of T-cell origin. A 67-year-old Japanese man presented with lower abdominal pain and diarrhoea of 4-week duration. Colonoscopy revealed numerous small umbilicated polyps and several raised erosions in the colorectum. Biopsy specimens showed diffuse proliferation of lymphoma cells negative for B-cell markers but positive for T-cell markers. Polymerase chain reaction using extracted chromosomal deoxyribonucleic acid from paraffin-embedded samples identified T-cell receptor gamma and delta gene recombination. The patient was treated with combined chemotherapy, leading to complete resolution of the lesions.

Molecular evolution and diversification of snake toxin genes, revealed by analysis of intron sequences

The genes encoding erabutoxin (short chain neurotoxin) isoforms (Ea, Eb, and Ec), LsIII (long chain neurotoxin) and a novel long chain neurotoxin pseudogene were cloned from a Laticauda semifasciata genomic library. Short and long chain neurotoxin genes were also cloned from the genome of Laticauda laticaudata, a closely related species of L. semifasciata, by PCR. A putative matrix attached region (MAR) sequence was found in the intron I of the LsIII gene. Comparative analysis of 11 structurally relevant snake toxin genes (three-finger-structure toxins) revealed the molecular evolution of these toxins. Three-finger-structure toxin genes diverged from a common ancestor through two types of evolutionary pathways (long and short types), early in the course of evolution. At a later stage of evolution in each gene, the accumulation of mutations in the exons, especially exon II, by accelerated evolution may have caused the increased diversification in their functions. It was also revealed that the putative MAR sequence found in the LsIII gene was integrated into the gene after the species-level divergence.

Endotoxin contamination in wound dressings made of natural biomaterials

Contamination by endotoxin of nine kinds of wound dressings made of natural biomaterials (calcium alginate, collagen, chitin, and poly-L-leucine) was examined with the use of water extracts. By applying the Limulus amoebocyte lysate (LAL) test, high concentrations of endotoxin were detected in extracts from three kinds of products made of calcium alginate. These extracts evoked fever in rabbits and induced the release of a proinflammatory (pyrogenic) cytokine, interleukin-6 (IL-6), from human monocytic cells (MM6-CA8). The effects disappeared when the extracts were treated with endotoxin-removing gel column chromatography or with an endotoxin antagonist, B464, confirming that the contaminating pyrogen was endotoxin. A noteworthy finding was that one of the endotoxin-containing extracts showed very weak IL-6-inducibility in human monocytic cells in contrast to its high pyrogenicity to rabbits. The discrepancy could be explained based on differences between humans and rabbits in sensitivity to the endotoxin, because the extract showed higher proinflammatory-cytokine (TNF-alpha)-inducibility in rabbit whole-blood cells (WBCs) than human WBCs. The results suggest that the LAL test is a useful method of detecting endotoxin contamination in wound dressings and the MM6-CA8 assay is a good supplement to the LAL test for evaluating pyrogenicity in humans accurately.

Propagation of surface plasmon polariton in nanometre-sized metal-clad optical waveguides

Using a local anodic-oxidation method with a probe tip of a scanning near-field optical microscope (SNOM) as the electrode, we have fabricated an oxide core with subwavelength dimensions on metal. The propagation of the surface plasmon polariton (SPP), which is excited at the interface between the oxide core and the metal clad, has been investigated using the same SNOM. Altering the wavelength of input light from 532 nm to 830 nm, the propagation length of the SPP extends from 2 micro m to 6 micro m. We carried out a simulation of the SPP propagation, and obtained a similar wavelength dependence.

Near-field observation of carrier diffusion in GaAs quantum structures under high magnetic fields

Photoluminescence from a two-dimensional electron-gas system in GaAs single hetero-structures was investigated using a scanning near-field optical microscope (SNOM) operated at cryogenic temperatures under high magnetic fields. The local intensity of the luminescence increased 600-fold that at 0 T as the magnetic field was increased up to 6 T. The enhancement depended on the spatial resolution of the SNOM. These characteristics are explained by the suppression of the diffusion of photocarriers caused by the Lorentz force in magnetic fields.

Effect of gamma-ray irradiated poly(L-lactide) on the differentiation of mouse osteoblast-like MC3T3-E1 cells

The purpose of this study was to clarify the effects of gamma-ray irradiated poly(L-lactide) (PLLA) on the proliferation and differentiation of mouse osteoblast-like MC3T3-E1 cells. The PLLA was y-irradiated at the dose of 10, 25 or 50 kGy, and the molecular weight of irradiated PLLA decreased with increasing irradiation dose. The proliferation and differentiation of MC3T3-E1 cells cultured on irradiated PLLA for 2 weeks were evaluated using micromass culture. The y-irradiation of PLLA did not affect the proliferation, but stimulated the differentiation of MC3T3-E1 cells cultured on irradiated PLLA. These results suggested that lower change in the molecular weight of PLLA was responsible for stimulation of the differentiation of MC3T3-E1 cells cultured on irradiated PLLA. Furthermore, the proliferation and calcification of MC3T3-E1 cells cultured in the medium containing low molecular weight PLLA for 2 weeks were evaluated. The low molecular weight PLLA also stimulated the calcification of MC3T3-E1 cells with no effect on the proliferation. The y-irradiation was suitable for PLLA on the differentiation of mouse osteoblasts.

Sensitization potential of gold sodium thiosulfate in mice and guinea pigs

Since gold sodium thiosulfate (GST) has been included in a standard patch test series for diagnosis of allergic contact dermatitis from gold, the incidence of patients showing positive reactions to gold is increasing. However, there were little reports on induction of gold sensitization in animals. In this study, we have examined the sensitization potential of GST using mice and guinea pigs. In the guinea pig maximization test, 2 or 6 out of 10 animals showed positive skin responses, mainly edema, by challenge with 2% or 5% GST in 50% ethanol solution, respectively. In the mouse ear swelling test, positive ear swelling (20% greater increase in ear thickness) after challenge with GST was shown in 2 out of 6 mice those previously treated with GST. Topical exposure of mice to GST in 70% dimethylsulfoxide solution induced small increases in the lymph node weight and the lymph node cell (LNC) number in the murine local lymph node assay (LLNA). A greater degree of LNC responses were observed in the sensitive mouse lymph node assay (SLNA) compared with the LLNA, but the stimulation index of total lymph node response by GST was not so high. From these results, GST was identified as a contact allergen, but the sensitization potential was not so strong. In the mouse IgE test, treatment of mice with GST resulted in a statistically significant increase in the serum IgE antibody concentration that associated with immediate-type hypersensitivity reaction. It may suggest that the sensitization responses from gold would appear not only at the contact site but also systematically.

Non-HTLV-1-associated primary gastric T-cell lymphomas show cytotoxic activity: clinicopathological, immunohistochemical characteristics and TIA-1 expression in 31 cases

AIMS

Most primary gastrointestinal lymphomas are of B-cell origin and T-cell origin is very rare. Recent studies have suggested that human T-cell lymphotrophic virus type 1 (HTLV-1) may be involved in the development of primary gastric T-cell lymphoma. We analysed 31 patients with primary gastric T-cell lymphoma in south-west Japan, an area endemic for HTLV-1, and determined their phenotypes, genotypes, and HTLV-1 status.

METHODS AND RESULTS

Here we present 31 cases of primary gastric T-cell lymphoma in a HTLV-1-endemic area in Japan and analyse the clinical status, histology, phenotype and virus status. The median age at onset of primary gastric T-cell lymphoma was 57 years with a gender ratio of M:F = 1.58:1. Six of the 31 primary gastric T-cell lymphoma cases had HTLV-1 proviral DNA (five males, one female), nine of the 31 cases were positive for anti-adult T cell leukaemia antibody, without examination of HTLV-1 proviral DNA (five males, four females), eight were non-HTLV-1-associated primary gastric T-cell lymphoma (four males, four females) and the other eight cases were unknown. Primary gastric T-cell lymphoma usually presented as a large ulcerated tumour at the corpus to the antrum and histologically consisted of anaplastic large cell type (n = 2), pleomorphic large cell type (n = 3), pleomorphic medium and large cell type (n = 14), pleomorphic medium cell type (n = 11), and angioimmunoblastic T-cell lymphoma type (n = 1). There were no clear macroscopic and microscopic differences between HTLV-1-associated and non-HTLV-1-associated primary gastric T-cell lymphoma. Most patients died within 2 years of diagnosis, and both types of primary gastric T-cell lymphoma (with and without HTLV-1) were associated with poor prognosis. Cytotoxic marker analysis showed that HTLV-1-associated lymphomas were negative for TIA-1, while non-HTLV-1-associated lymphomas were positive for TIA-1.

CONCLUSIONS

Our results suggest that in HTLV-1-endemic areas, patients with HTLV-1-associated primary gastric T-cell lymphoma should be managed carefully and that TIA-1 seems to be useful for identifying the aetiology of this lesion.

Effects of preconditioning on ischemia/reperfusion injury of hepatocytes determined by immediate early gene transcription

Ischemia reperfusion (I-R) of the liver induces various events leading to cell death (apoptosis) and subsequent cells proliferation. Recent experimental studies have described the protective effect of ischemic preconditioning (IPC) on I-R injury of the liver. However, the mechanisms involved in this protection remain unknown. The protein products of immediate early genes (IEGs) behave as crucial transcriptional regulators not only in apoptosis but also in cell proliferation. Here, we evaluated the effects of IPC on IEG transcription after I-R injury, using a rat liver I-R injury model. Injury to hepatocytes was evaluated by measuring serum levels of aspartate transaminase (AST), alanine transaminase (ALT), and lactate dehydrogenase (LDH) and that to endothelial cells by plasma concentration of hyaluronic acid (HA). The extent of necrosis was evaluated by H&E staining, while cell proliferation and apoptosis were evaluated by proliferating cell nuclear antigen (PCNA) and terminal deoxy(d)-UTP nick end labelling (TUNEL) staining, respectively. Alterations in the transcription of IEGs (c-fos and c-jun) were examined by Northern blotting. Rats subjected to 40-min liver ischemia, preceded by 10-min preconditioning, showed significantly lower AST, ALT, LDH, and HA levels at 6 h after I-R than untreated animals (P < 0.05; n at least 5 rats per group). The percentage of necrotic areas at 24 h after I-R was significantly lower in IPC-treated animals than in the controls. The numbers of apoptotic cells at 24 h after I-R and the numbers of PCNA-positive cells at 24 and 48 h after I-R were significantly lower in IPC-treated rats than in controls. Transcription levels of IEGs were low in IPC-treated rats, particularly c-jun at 1 and 1.5 h after I-R (P < 0.05). Our results indicate that IPC provides a significant protective effect on for liver cells against I-R injury and that its effect is evidenced by a significant decrease in the transcription levels of IEGs following the insult.

The inhibitory mechanism of gap junctional intercellular communication induced by polyethylene and the restorative effects by surface modification with various proteins

Gap junctional intercellular communication (GJIC) is a function that plays an important role in maintaining cell and tissue homeostasis and in regulating cell growth, development, and differentiation. Change in this function of V79 fibroblasts cultured on polyethylene films modified with albumin or collagen was estimated using fluorescence redistribution after photobleaching (FRAP) analysis. The GJIC function of V79 cells on nontreated polyethylene was strongly inhibited in comparison with those on a glass coverslip. When the cells were culture on collagen-immobilized polyethylene film, this function was recovered to about 70% of the cells cultured on the coverslip. However, albumin immobilization did not recover the function as much as collagen immobilization. Western blotting analysis and immunostaining of connexin 43, which is a major protein constituting gap junctional channel of these cells, revealed its abnormal expression and distribution in the cells on nontreated polyethylene, whereas its almost normal distribution was observed in the cells on collagen-immobilized polyethylene. This abnormal expression and distribution of connexin 43 induced by the surface of polyethylene may be ascribed to a strong inhibition of GJIC of V79 fibroblasts.

Primary low-grade MALT lymphoma of the gallbladder

We report a case of primary low-grade B-cell lymphoma of the mucosa-associated lymphoid tissue (low-grade MALT lymphoma) in the gallbladder. A 58-year-old woman suspected of gallbladder carcinoma underwent laparoscopic cholecystectomy. Microscopic examination of the gallbladder demonstrated lymphoid cell infiltration forming lymphoid follicles with hyperplastic secondary follicles. The surrounding monocytoid B cells and centrocyte-like cells selectively infiltrated the crypt epithelium forming lympho-epithelial lesions. Plasma cells were also noted beneath the mucosal epithelium. Bile culture revealed the Gram-negative bacilli Enterococcus faecalis and Morganella morganii. Immunoglobulin heavy chain gene rearrangement was confirmed using polymerase chain reaction (PCR) and oligoclonal lymphoid proliferations was detected. Because autoimmune diseases, or chronic inflammatory disorders, seem to correlate with the occurrence of MALT lymphoma, Gram-negative bacterial infection could also be considered as a prodrome of MALT lymphoma of the gallbladder.

Enhancement of chondrogenic differentiation of human articular chondrocytes by biodegradable polymers

Biodegradable polymers are attractive candidates for chondrocyte embedding and transplantation in cartilage tissue engineering. In an attempt to determine the effects of a variety of biodegradable materials on cartilage proliferation and extracellular matrix production, poly-L-lactic acid (PLLA) with a molecular weight of 5,000, polyglycolic acid (PGA) with a molecular weight of 3,000, and copolymer of poly(L-lactic acid-glycolic acid) 50:50 (PLGA) with a molecular weight of 5,000, were dissolved in DMSO and added into the medium for 4 weeks in in vitro high-density micromass culture of multiplied human articular chondrocytes (HAC). PLLA with a molecular weight of 270,000 (PLAO3) was used as thin film. Cell proliferation and differentiation in these biomaterials were compared with tissue culture polystyrene (TCPS) as a control. Alamar blue and alcian blue staining were carried out to determine the chondrocyte proliferation and differentiation, respectively. Samples exposed to these biomaterials promoted cell proliferation in the range of 86-105% of the control proliferation, and a slight but significant increase in cell proliferation was noted only in the culture exposed to PLGA. The sample exposed to PGA elicited a significant 3.7-fold higher (p < 0.01) cell differentiation than controls and was significantly higher than that of the samples exposed to PLLA, PLAO3, and PLGA. After 4 weeks of culture, the cell differentiation from most to least was in the following order PGA > PLAO3 > PLGA = PLLA > Cont. = DMSO. Chondrocyte differentiation of the samples exposed to various biomaterials were significantly higher compared with controls. Thus, serially passage chondrocytes are competent for cell growth and quantifiable matrix production, and biodegradable polymers, especially PGA, hold promise as suitable substrates for scaffolding materials for human cartilage tissue engineering.

Unsaturated thiacrown ethers: synthesis, physical properties, and formation of a silver complex

The 6-, 9-, 12-, 15-, 18-, 21-, 24-, and 27-membered unsaturated thiacrown ethers 1-8 were formed by reaction of cis-1,2-dichloroethylene with sodium sulfide in acetonitrile. Crystal structures of 4-8 were determined by X-ray crystallography, and it was found that all sulfur atoms of 5-8 direct to the inside of the ring (endodentate). All of the ORTEP drawings show that there are cavities in these molecules, and the cavity sizes in 4-8 were 1.76, 2.34, 3.48, 4.43, and 5.36 A, respectively. The UV spectra of 4-8 showed absorption maximums at the range of 255-276 nm in acetonitrile, and the absorption maximums of 4-8 were found to shift to longer wavelengths by changing the solvent from acetonitrile to cyclohexane. The cyclic voltammograms of 4-8 indicate that the larger unsaturated thiacrown ethers were oxidized more easily than the smaller systems, and unsaturated thiacrown ethers were oxidized more easily than corresponding saturated systems. The reaction of 4 with silver trifluoroacetate in acetone afforded the colorless complex Ag(I)(C2H2S)5(CF3COO) 9. The crystal structure of 9 was determined by X-ray analysis, and it was found that three of the five sulfur atoms bonded to the silver atom.

nhaG Na(+)/H(+) antiporter gene of Bacillus subtilis ATCC9372, which is missing in the complete genome sequence of strain 168, and properties of the antiporter

We cloned a gene which enabled Escherichia coli mutant host cells lacking all of the major Na(+)/H(+) antiporters to grow in the presence of 0.2 M NaCl from chromosomal DNA of Bacillus subtilis ATCC9372. An Na(+)/H(+) antiport activity was observed with membrane vesicles prepared from E. coli cells possessing the cloned gene, but not with vesicles from the host cells. Lithium ion was also a substrate for the antiporter. We sequenced the cloned DNA and found one open reading frame (designated nhaG) preceded by a promoter-like sequence and a Shine-Dalgarno sequence, and followed by a terminator-like sequence. The deduced amino acid sequence of NhaG suggested that it consisted of 524 residues and that the calculated molecular mass was 58.1 kDa. None of the bacterial Na(+)/H(+) antiporters so far reported, except NhaP of Pseudomonas aeruginosa and SynNhaP (NhaS1) of Synechocystis sp., showed significant sequence similarity with the NhaG. However, the NhaP, the SynNhaP, animal NHEs (Na(+)/H(+) exchangers), and some hypothetical Na(+)/H(+) antiporters of several organisms showed significant sequence similarities with the NhaG. Interestingly, the entire DNA region corresponding to the nhaG gene is missing in the reported complete genome sequence of B. subtilis strain 168. We detected a band that hybridized with the nhaG DNA in chromosomal DNA from B. subtilis ATCC9372 but not with that from strain 168. The missing DNA region (1,774 base pairs) is sandwiched by two identical sequences, TTTTCTT.

Mutations/deletions of the WT1 gene, loss of heterozygosity on chromosome arms 11p and 11q, chromosome ploidy and histology in Wilms' tumors in Japan

Incidence rates of Wilms' tumor (WT) markedly differ in East Asian and Caucasian children. In the present study, we examined WT1 deletions/mutations and loss of heterozygosity (LOH) on 11p and 11q in a large number of WTs and compared our findings with those from 4 series of Caucasian WTs. Incidence rates of the subtle WT1 mutation in 3 of the 5 series of sporadic and unilateral WTs including ours were 4.3-6.2% and similar. However, gross homozygous WT1 deletion was more frequent in our series than in some others. In addition, our series tended to show a higher incidence of LOH limited to 11p13 and a lower incidence of LOH including 11p15 than the Caucasian one. These findings indicate some genetic differences in WT between the 2 regions. One of the 4 Caucasian series reported a correlation of germinal WT1 mutation with the predominantly stromal histology. The present study not only confirms the correlation of germinal WT1 deletion/mutation with predominant stromal histology but also establishes a correlation with somatic WT1 deletion/mutations with predominant stromal histology. While WTs with WT1 abnormalities usually showed pseudodiploidy and predominant stromal histology, those without WT1 abnormalities showed various chromosome numbers and histologic subtypes.