Expression of the long arm sequence of mouse laminin alpha1, beta1, or gamma1 chain in COS1 cells and assembly of monkey-mouse hybrid laminin

Mouse laminin alpha1, beta1, or gamma1 sequence covering truncated regions of the long arm was transiently expressed in monkey COS1 cells. Unlike natural laminins, in which only alpha beta gamma trimers are selectively assembled and disulfide-bonded at the long arm, a large fraction of mouse chains formed disulfide-bonded homopolymers. However, a small fraction of mouse beta1 (or gamma1) formed hybrid beta1gamma1 dimers with endogenous monkey gamma1 (or beta1). These hybrid beta1gamma1 dimers formed alpha1 beta1 gamma1 trimer with monkey alpha1. Mouse alpha1 also formed disulfide bonds with monkey beta1gamma1 dimer. Thus, a common mechanism is shared by laminin chains of different animal origins. Sequences in the E8 region at the C-terminal end of the long arm were crucial for this chain-selective assembly. When the C-terminal sequence of mouse beta1 long arm was extended beyond the alpha-loop, the hybrid trimer formation was diminished. This supported the model of altered chain arrangement around the alpha-loop.

Differentially expressed MHC class II-associated invariant chain in rat stomach pyloric mucosa with N-methyl-N-nitro-nitrosoguanidine exposure

Administration of N-methyl-N'-nitro-N-nitrosoguanidine, a glandular stomach carcinogen, at the concentration of 100 microg/ml in drinking water for 8 days induced the appearance of a MHC class II-associated invariant chain in the target organ of stomach pyloric mucosa of male Lewis rats. The up-regulation of the MHC class II-associated invariant chain was revealed by fluorescent differential display analysis, reverse transcription-PCR, Northern blot, and histochemical staining. The appearance of MHC class II and MHC class I was also demonstrated by reverse transcription-PCR and Northern blot. The results suggest the involvement of MHC-controlled immune reactions in chemically-induced stomach carcinogenesis.

Expression of three membrane-type matrix metalloproteinases (MT-MMPs) in rat vascular smooth muscle cells and characterization of MT3-MMPs with and without transmembrane domain

Matrix metalloproteinases (MMPs) produced by rat smooth muscle cells (SMCs) were investigated. SMCs expressed three kinds of membrane-type MMP, MT1-MMP, MT2-MMP, and MT3-MMP, and the MT-MMP expression was stimulated by the presence of serum. MT3-MMP was characterized further by cloning its cDNA. A rat MT3-MMP cDNA encoding 607 amino acids and a cDNA for its transmembrane domainless variant MT3-MMP-del were cloned from a rat SMC cDNA library; a human MT3-MMP cDNA was cloned from a fetal brain cDNA library. Human brain MT3-MMP was similar but not identical to the previously reported human placenta MT3-MMP (94.4% homology). When the MT3-MMP cDNA was expressed in COS-7 cells, endogenous progelatinase A was processed to the mature form. The transfection of rat MT3-MMP-del efficiently converted progelatinase A to the intermediate form but not to the mature one, indicating that the transmembrane domain is important for the complete processing of progelatinase A to maturation. Both MT3-MMP-del and MT3-MMP hydrolyzed gelatin and casein, indicating their broad substrate specificity. Results of experiments with a synthetic MMP inhibitor suggested that MT3-MMP-del and MT3-MMP are rapidly degraded immediately after maturation. The present study suggests that multiple forms of MMPs including MT3-MMP are involved in the matrix remodeling of blood vessels.

Characterisation of relaxation of the lower oesophageal sphincter in healthy premature infants

BACKGROUND

Gastro-oesophageal reflux disease causes significant morbidity in premature infants, but the role of dysfunction of the lower oesophageal sphincter (LOS) in this condition is unclear.

METHODS

Oesophageal manometry was performed after gavage feeding in 13 healthy preterm neonates (postmenstrual age > or = 33 weeks) with a perfused sleeve with side hole assembly. Swallow related (both single and multiple) and transient LOS relaxations (TLOSRs) were identified and the characteristics of these events defined. Reflux was identified with manometric criteria (common cavity episodes).

RESULTS

Five hundred and eleven relaxation of the LOS were observed, 55% related to single swallows, 23% related to multiple swallows, and 22% TLOSRs. The time to maximal LOS relaxation was longer for TLOSRs than for single or multiple swallows (mean (SEM) 5.0 (0.3) s v 3.0 (0.1) s and 3.3 (0.1) s, p < 0.0001 and p < 0.005). The durations of multiple swallows and TLOSRs were longer than single swallows (12.2 (0.5) s and 11.2 (0.4) s v 5.3 (0.2) s, p < 0.0001). Most of the oesophageal body common cavity episodes (94%) occurred during TLOSRs.

CONCLUSIONS

In healthy preterm infants (postmenstrual age > or = 33 weeks) the motor events associated with LOS relaxation were similar to those seen in healthy adults. TLOSRs may be an important mechanism of reflux in premature infants.

Substratum-dependent and region-specific control of attachment and proliferation of gastrointestinal epithelial cells in primary serum-free culture

A system for the primary serum-free culture of fetal rat gastrointestinal epithelial cells was used to examine the role of the extracellular matrix (ECM) in the attachment and proliferation of these epithelial cells. Forestomach epithelial cells (FSEC) were able to attach to and proliferate on plastic dishes without a substratum, while glandular stomach epithelial cells (GSEC) and duodenal epithelial cells (DEC) were unable to do so. The presence of a substratum promoted the attachment and proliferation of these epithelial cells. The effects of various components of the ECM differed depending on the type of cell. FSEC attached most efficiently to a substratum of fibronectin, while GSEC did so to laminin. DEC attached more efficiently to type I collagen and fibronectin than to any other substratum. FSEC proliferated most rapidly on laminin, while GSEC and DEC did so on collagen gels. These substrata induced the most efficient attachment and proliferation of FSEC, and they were effective in promoting the attachment and proliferation of GSEC and DEC in decreasing order of efficiency, indicating the existence of a head-to-tail gradient in the response of epithelial cells to substrata. The expression of c-myc mRNA in these cells differed depending upon the substratum on which they were cultured and the mRNA level was well correlated with the extent of the cell proliferation, indicating that the cell proliferation is mediated by c-myc gene expression, which is regulated by cell-ECM interactions. The results of the present study demonstrate that proliferation of gastrointestinal epithelial cells is regulated region-specifically not only by soluble factors but also by insoluble components of the ECM.

An increase in noradrenaline excretion during prolonged mental task load

To investigate the effects of prolonged mental work, urinary excretion of catecholamines and cortisol was measured in 18 human subjects from 9:30 to 17:00. On the "task day,' the subjects performed mental tasks during the morning (10:20-11:45) and afternoon sessions (13:00-17:00), otherwise taking chair rest. On the "control day,' the subjects took chair rest in the afternoon after performing mental tasks in the morning. In the morning session, urinary excretion of adrenaline during mental work increased greatly compared to that before the mental work. Mental work in the afternoon session also caused a marked increase in adrenaline excretion compared to the rest level in the afternoon on the control day. Cortisol levels in the first hour of the afternoon mental work were significantly higher than those during the corresponding time on the control day. Urinary excretion of noradrenaline during mental work in the morning session only increased slightly compared to that before the mental work. In the afternoon session, however, noradrenaline excretion during mental work on the task day was markedly elevated compared to that during the rest condition at the corresponding time on the control day. These findings suggest that prolonged exposure to mental work, but not short-term mental work, produces a marked increase in noradrenaline excretion in human subjects.

Presence in Pieris rapae of cytotoxic activity against human carcinoma cells

Cytotoxic activity in extracts of pupae and adults of various kinds of butterflies and moths was tested in vitro against the human gastric carcinoma cell line, TMK-1, which was chosen as an example of human carcinoma cells. Among the species examined, cytotoxicity was limited to Pieris rapae, Pieris napi and Pieris brassicae. Activity was found down to a dilution of 1/10(4), while with the other butterflies and moths no activity was observed, even at 1/10(2). When the cytotoxicity of the three developmental stages, larvae, pupae and adults, of Pieris rapae was compared, the pupae showed the strongest activity, the IC50 against TMK-1 cells being at the 1/10(6) dilution. For larvae and adults, the respective IC50 values were at the 1/10(5) and 5/10(5) dilutions. The active principle in the pupae of Pieris rapae was found to be heat-labile and not extractable with organic solvents, but precipitated with ammonium sulfate and digested by proteases, suggesting that it is a protein. This cytotoxic factor was named pierisin.

Early induction of the NGFI-B/Nur77 family genes in nephritis induced by anti-glomerular basement membrane antibody

We recently isolated a novel nuclear receptor NOR-1, which is a member of the steroid/thyroid receptor superfamily, and belongs to the NGFI-B/Nur77 family. In the present study, we examined gene expression of NOR-1 and its closely related members in nephritis induced by anti-glomerular basement membrane (GBM) antibody. The mRNA levels for NOR-1, NGFI-B and RNR-1 increased 24 h after injection of anti-GBM antibody (day 1). Gene expression of NOR-1 and NGFI-B reached maximum levels on day 3, gradually decreased thereafter and returned to control levels on day 28. RNR-1 reached a peak on day 7, and then decreased. Renal injuries were most prominent on day 7 and persisted until day 28, indicating that NOR-1, NGFI-B and RNR-1 genes are induced during the early stage of glomerulonephritis and may be associated with the progression of glomerulonephritis. The induction of the NGFI-B gene was less remarkable than that of NOR-1 and RNR-1. In addition, administration of glucocorticoid hormone suppressed NOR-1 and RNR-1 gene expression to almost normal levels, whereas NGFI-B gene expression was not significantly repressed. These findings also suggest that the NGFI-B/Nur77 family may possess different biological roles and NGFI-B might act as a general transcription factor in cell function.

Enterobacter kobei sp. nov., a new species of the family Enterobacteriaceae resembling Enterobacter cloacae

The name Enterobacter kobei sp. nov. is proposed for a group of organisms referred to as NIH Group 21 at the National Institute of Health, Tokyo. The members of this species are Gram-negative, motile rods conforming to the definition of the family Enterobacteriaceae. The DNA relatedness of 23 strains of NIH Group 21 to the representative proposed as the type strain of this species averaged 82% at 70 degrees C, whereas the relatedness to other species within the family Enterobacteriaceae was less than 42%. Because the phenotypic resemblance to Enterobacter cloacae is very close and the DNA relatedness (12-42%) is closer to species of the genus Enterobacter than to other species of the family, the members of NIH Group 21 were placed in the genus Enterobacter. Close phenotypic and genetic relationships were also found between NIH Group 21 and a member of a group of organisms referred to as Enteric Group 69 at the Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, USA. It is suggested that the latter could be regarded as a subspecific rank of E. kobei, though this is subject to study of further strains. The majority of strains of E. kobei were isolated from clinical specimens. A culture of the type strain (NIH 1485-79) has been deposited in the Japan Collection of Microorganisms as JCM 8580.

Structure, mapping and expression of a human NOR-1 gene, the third member of the Nur77/NGFI-B family

We identified a human homologue of NOR-1 (neuron-derived orphan receptor) from the fetal brain. There are two transcripts for human NOR-1, encoding 626 amino acid residues with a calculated molecular mass of 68 kDa. The high homology between hNOR-1, mNur77/rNGFI-B/hTR3, and mNurr1/rRNR-1/hNOT indicated that these three orphan receptors form a distinct subfamily within the steroid/thyroid receptor superfamily. Human NOR-1 mRNA was detected in the adult heart and skeletal muscle as well as in the fetal brain, indicating that its expression is not restricted to events that occur during neural development. The hNOR-1 gene is more than 35 kilobases long and interrupted by seven introns. The exon-intron structure of the gene is generally conserved when compared with the steroid/thyroid receptor superfamily and is remarkably similar to that of the Nur77/NGFI-B genes. This suggests that the Nur77/NGFI-B family has evolved from a common ancestral gene. Fluorescence in situ hybridization (FISH) revealed that the gene is located on chromosome 9q.

Electrostatic properties deduced from refined structures of NADH-cytochrome b5 reductase and the other flavin-dependent reductases: pyridine nucleotide-binding and interaction with an electron-transfer partner

Electrostatic properties on the protein surface were examined on the basis of the crystal structure of NADH-cytochrome b5 reductase refined to a crystallographic R factor of 0.223 at 2.1 A resolution and of the other three flavin-dependent reductases. A structural comparison of NADH-cytochrome b5 reductase with the other flavin-dependent reductases, ferredoxin-NADP+ reductase, phthalate dioxygenase reductase, and nitrate reductase, showed that the alpha/beta structure is the common motif for binding pyridine nucleotide. Although the amino acid residues associated with pyridine nucleotide-binding are not conserved, the electrostatic properties and the location of the pyridine nucleotide-binding pockets of NADH-requiring reductases were similar to each other. The electrostatic potential of the surface near the flavin-protruding side (dimethylbenzene end of the flavin ring) of NADH-cytochrome b5 reductase was positive over a wide area while that of the surface near the heme-binding site of cytochrome b5 was negative. This implied that the flavin-protruding side of NADH-cytochrome b5 reductase is suitable for interacting with its electron-transfer partner, cytochrome b5. This positive potential area is conserved among four flavin-dependent reductases. A comparison of the electron-transfer partners of four flavin-dependent reductases showed that there are significant differences in the distribution of electrostatic potential between inter-molecular and inter-domain electron-transfer reactions.

[The relationship between hemorrhagic gastric ulcers often appearing among in the great Hanshin-Awaji earthquake sufferers and Helicobacter pylori infections]

Hemorrhagic gastric ulcer were often found in the population who suffered from the Great Hanshin-Awaji earthquake. Gastric biopsy samples taken from 136 patients in the population were examined for Helicobacter pylori by culture and PCR methods. Furthermore, production of CagA protein from isolates was investigated. Number of positive cases with culture and PCR method were 20 (50.0%) and 26 (65.0%) in hemorrhagic ulcer, 62 (86.1%) and 65 (90.3%) in other ulcers, respectively. Number of CagA positive strains from the patients of the hemorrhagic ulcer and other ulcers were 20 (76.9%) and 21 (32.3%), respectively. The significance in both ulcers was observed (p < 0.001). From the present results, it was considered that the stress of the earthquake, the infection of H. pylori and the production of CagA protein of the organism were combined and this caused hemorrhagic gastric ulcers.

Ventral tegmental injection of nicotine induces locomotor activity and L-DOPA release from nucleus accumbens

Effects of nicotine systemically or locally on locomotor activity and L-3,4-dihydroxyphenylalanine (L-DOPA) release were studied using microdialysis in the nucleus accumbens of freely moving rats. The basal L-DOPA release was Ca2(+)-dependent and tetrodotoxin-sensitive. Systemic nicotine (1 mg/kg s.c.) increased locomotor activity and L-DOPA release preferentially in the nucleus accumbens as compared with the striatum. Injection of nicotine (30 micrograms) into the ventral tegmental area increased locomotor activity and L-DOPA release from the nucleus accumbens. These increases were antagonized by prior injection of mecamylamine into the ventral tegmental area. Nicotine induces locomotor activity and L-DOPA release from the nucleus accumbens via nicotinic receptors in the ventral tegmental area. The release may be relevant to behavioral actions of nicotine.

Structures of three inclusion compounds of cholanamide with either (S)-enantiomer, (R)-enantiomer or an optically resolved mixture of butan-2-ol

The three types of inclusion compounds of cholanamide (CAM, 3α, 7α, 12α-trihydroxy-5β-cholan-24-amide) have been crystallized from the solutions of (S)-butan-2-ol (CAMSB), (R)-butan-2-ol (CAMRB) and racemic butan-2-ol (CAMSRB), respectively. The crystal structures have been determined. The three crystal structures are isomorphous to each other and revealed that the host CAM molecules form the same layered arrangements, providing channel spaces for the guest butan-2-ol molecules. As expected, the CAMSB and CAMRB crystals include the pure (S)- and (R)-enantiomers of butan-2-ol, whereas the (S)-enriched mixture of enantiomers is accommodated in CAMSRB with a molar ratio between the host CAM and guest butan-2-ol molecules of 1:1. The hydrogen-bond network is rigidly formed between the CAM molecules and also between CAM and butan-2-ol molecules. CAMSB and CAMRB have slightly different unit-cell dimensions: the channels in CAMRB have a larger section, resulting in a larger unit-cell volume. In CAMSRB, although both enantiomers of the guest alcohol are included, the (S)-enantiomer is more abundant, indicating that the optical resolution occurs during the crystallization step.

Evaluation of L-pyrrolidonyl peptidase paper strip test for differentiation of members of the family Enterobacteriaceae, particularly Salmonella spp

The L-pyrrolidonyl peptidase activities of 1,033 strains of the family Enterobacteriaceae were investigated by the paper strip method to evaluate their usefulness for screening those organisms, especially Salmonella cultures. We also evaluated the usefulness of indole and tryptophan deaminase paper strip tests as supplements to the L-pyrrolidonyl peptidase test for the rapid identification of Salmonella cultures. The paper strip tests are simple, and the results are obtainable within 10 min.

Potential sites for processing of the human invariant chain by cathepsins D and E

Seven peptides of 15-30 amino acid residues were synthesized that covered almost the entire sequence of the lumenal domain of the human invariant chain (Ii), and their hydrolysis by cathepsins D and E was investigated. Two sites were identified that were very susceptible to such cleavage. One site, the Leu174-Phe175 bond, was cleaved by both cathepsins, and the other site, the Met99-Gln100 bond, was specifically cleaved by cathepsin E. These two sites could be the sites at which native Ii is cleaved by aspartic proteinases. The cleavage of the Met99-Gln100 bond by cathepsin E might be important in the inactivation of Ii and its functional derivatives.

Stage-specific elevated expression of the genes for hepatocyte growth factor, keratinocyte growth factor, and their receptors during the morphogenesis and differentiation of rat stomach mucosa

Hepatocyte growth factor (HGF) and keratinocyte growth factor (KGF) are two factors considered to be involved in the morphogenesis of several organs. To understand the role of HGF and KGF in the stomach development, we analyzed changes in the levels of expression of the genes for the two growth factors and their receptors in the fetal rat stomach by competitive RT-PCR. Resembling our previous results for HGF, the expression of the genes for KGF and its receptor was observed in the mesenchyme and epithelium of 16.5 day fetal stomach, respectively, indicating the possibility that KGF mediates the epithelial-mesenchymal interaction in the early stage of stomach development. The developmental profile of the expression of the genes for the two growth factors and their receptors were different, indicating a difference in their roles; the genes for HGF and c-met, the receptor for HGF, are expressed mainly during the morphogenetic period, while the genes for KGF and its receptor mainly after the morphogenetic period. Thus, it is probable that HGF controls the proliferation of epithelial cells during the morphogenetic process. The expression of the genes for KGF and its receptor is not correlated with epithelial proliferation during morphogenesis, but it does appear to be linked with epithelial differentiation. These results, together with the absence of significant mitogenic effect of KGF on the epithelial cells of the fetal rat glandular stomach in vitro, suggest a role for KGF as a differentiation factor. In addition, the expression profile of the genes for KGF and its receptor towards the end of fetal period appears to be closely correlated with that of mesenchymal cell proliferation, suggesting another role for the growth factor that is not regulated by the epithelial-mesenchymal interaction.

Pericytes from microvessel fragment produce type IV collagen and multiple laminin isoforms

In the microvascular system, pericytes are located at the abdominal side of capillary endothelial cells. To discover the role of pericytes in the microvascular system, we have analyzed the extracellular proteins secreted from pericytes isolated from microvessel fragments of rat epididymal fat pads and found that they synthesize substantial amounts of basement membrane components such as type IV collagen and laminins. Secretion of type IV collagen was markedly stimulated by ascorbic acid phosphate. Reducing and nonreducing sodium dodecyl sulfate gel electrophoresis showed that pericytes produce six laminin chains assembled into different trimeric isoforms. Two of them were similar to laminin variants produced by aortic and pulmonal endothelial cells but others were suggested to be novel variants.

Cellular differentiation and development of pyloric mucosal metaplasia in the human gall-bladder

The development of pyloric mucosal metaplasia (PMM) with regard to cellular differentiation in the human gallbladder was studied by mucin staining (paradoxical concanavalin A (Con A), galactose oxidase-Schiff (GOS) and alcian blue (pH 2.5) PAS (AB-PAS) and immunohistochemistry (pepsinogen II (PgII) and SH-9, and proliferating cell nuclear antigen (PCNA). PMM was divided into three stages of development by three-dimensional (3D) computer graphic reconstruction analysis. In the early stage, a transitional zone of PCNA positive cells was observed between areas of SH-9 and/or GOS reactive cells and class III and/or Pg II positive cells in flat monolayered epithelium. In the middle stage, shallow pits became apparent as areas enlarged, with these becoming deeper in the advanced stage, whereby SH-9 and/or GOS reactive cells and class III and/or Pg II positive cells were observed at the upper and lower portion of the pits, respectively, with PCNA-positive cells forming a narrow zone between the two cell populations. Consequently, the structure of PMM gradually resembles that of the normal gastric pyloric mucosa.

Association between family history and gastric carcinoma among young adults

The relationship between family history of gastric carcinoma and gastric carcinoma in Japanese under 40 years of age was analyzed. The subjects were 108 gastric carcinoma patients (86% were diffuse type) at 9 hospitals in the Kanto area of Japan. Firstly, incidence of gastric carcinoma among the parents of the subjects were compared with that in the general population. Observed/expected (O/E) ratios (P-value) were 1.8 (0.06) for all subjects, 1.3 (0.62) for male subjects, 2.1 (0.04) for female subjects, 0.5 (0.41) for early carcinoma, 2.6 (P<0.01) for advanced carcinoma, 2.3 (0.22) for intestinal-type carcinoma and 1.7 (0.13) for diffuse-type carcinoma. Association between gastric carcinoma and parents' history of gastric carcinoma was strong among women and regarding advanced carcinoma, and the difference in O/E ratios between early and advanced carcinoma was remarkable. Secondly, factors related to advanced-stage gastric carcinoma were analyzed. Histological type (diffuse and intestinal types) was not related, but family history of gastric carcinoma among parents and grandparents was related to advanced stage, and the relationship was independent of other factors. The odds ratio (95% confidence interval) was 3.3 (1.1-9.9). Family history may be related to stage of gastric carcinoma through its relationship to the manner or speed of the tumor's progression. We hypothesis that some genetic factor exists which is involved both in progression from early to advanced stage and in occurrence of gastric carcinoma.