Migration of formaldehyde and acetaldehyde into mineral water in polyethylene terephthalate (PET) bottles

The levels of formaldehyde (FA) and acetaldehyde (AA) in polyethylene terephthalate (PET) bottles and in commercial mineral water are reported. All the water samples bottled in Japan contained detectable levels of FA (10.1-27.9 microg l(-1)) and AA (44.3-107.8 microg l(-1)). Of 11 European bottled water samples, eight did not contain either FA or AA, while the remaining three had detectable levels of FA (7.4-13.7 microg l(-1)) and AA (35.9-46.9 microg l(-1)). In three North American bottled water samples, two contained FA (13.6 and 19.5 microg l(-1)) and AA (41.4 and 44.8 microg l(-1)), and one did not. Regardless of the region of origin, all the sterilized water samples contained FA and AA, whilst in contrast, none of the unsterilized water without carbonate contained FA or AA. Of the carbonated water samples, three contained FA and AA, and one did not. When fortified with FA and AA, the commercial water sample without otherwise detectable FA and AA was able to reduce levels, although the commercial water sample containing FA and AA could not. The presence of bacteria in the commercial water samples was investigated using an ATP-based bioluminescent assay and heterotrophic plate count method. The commercial water without FA and AA contained heterotrophic bacteria, whilst the commercial water with FA and AA did not contain detectable bacteria. It is suggested that in this case both FA and AA migrated from PET materials, but were subsequently decomposed by the heterotrophic bacteria in the unsterilized water.

Neuropeptide W is present in antral G cells of rat, mouse, and human stomach

Neuropeptide W (NPW) is a 30-amino-acid peptide initially isolated from the porcine hypothalamus as an endogenous ligand for the G protein-coupled receptors GPR7 and GPR8. An intracerebroventricular administration of NPW increased serum prolactin and corticosterone concentrations, decreased dark-phase feeding, raised energy expenditure, and lowered body weight. Peripherally, GPR7 receptors are abundantly expressed throughout the gastrointestinal tract; the presence of NPW in the gastrointestinal endocrine system, however, remains unstudied. Using monoclonal and polyclonal antibodies raised against rat NPW, we studied the localization of NPW in the rat, mouse, and human stomach by light and electron microscopy. NPW-immunoreactive cells were identified within the gastric antral glands in all three species. Double immunohistochemistry and electron-microscopic immunohistochemistry studies in rats demonstrated that NPW is present in antral gastrin (G) cells. NPW immunoreactivity localized to round, intermediate-to-high-density granules in G cells. NPW-immunoreactive cells accounted for 90% chromagranin A- and 85% gastrin-immunoreactive endocrine cells in the rat gastric antral glands. Using reversed-phase HPLC coupled with enzyme immunoassays specific for NPW, we detected NPW30 and its C-terminally truncated form, NPW23, in the gastric mucosa. Plasma NPW concentration of the gastric antrum was significantly higher than that of the systemic vein, suggesting that circulating NPW is derived from the stomach. Plasma NPW concentration of the gastric antrum decreased significantly after 15-h fast and increased after refeeding. This is the first report to clarify the presence of NPW peptide in the stomachs of rats, mice, and humans. In conclusion, NPW is produced in gastric antral G cells; our findings will provide clues to additional mechanisms of the regulation of gastric function by this novel brain/gut peptide.

Perfusion imaging of meningioma by using continuous arterial spin-labeling: comparison with dynamic susceptibility-weighted contrast-enhanced MR images and histopathologic features

PURPOSE

The goal of the present study was to determine the utility of continuous arterial spin labeling (CASL) for characterization of meningioma by MR perfusion imaging and to compare these results with those obtained from the T2 dynamic susceptibility contrast (T2DSC) method and from histopathologic examination.

METHODS

Twenty-one cases of meningiomas were examined at 1.5T. CASL perfusion imaging was implemented on the basis of multisection single-shot echo-planar imaging with velocity-driven adiabatic spin-inversion preparation. T2DSC perfusion imaging was also performed by using a double-echo spoiled gradient echo sequence in a section containing the tumor. By focusing on the regions of interest, maps of % signal intensity change and cerebral blood flow (CBF) were determined from CASL and cerebral blood volume (CBV). CBF and mean transit time (MTT) were obtained from T2DSC. The microvessel area (MVA) was determined from specimens immunostained with anti-CD31 in 14 cases by measuring the total amount of staining in each histologic section. Linear regression analysis was performed for rCBF values from both perfusion methods and for % signal intensity change and MVA.

RESULTS

There was a significant correlation between CBF values determined from both perfusion methods (r(2) = 0.73; P < .001); however, the slope from T2DSC to CASL was less than unity, likely because of the different vascular weighting used for each method. There was also a significant correlation between CASL-% signal intensity change and MVA determined by histopathology (r(2) = 0.91; P < .00001). Perfusion values were the greatest for angiomatous meningioma and lowest for fibrous meningioma when using either perfusion method.

CONCLUSIONS

CASL and T2DSC perfusion methods are comparable in the characterization of meningiomas. Further, CASL is of use in assessing tumor microcirculation.

Development of a novel method for operating magnetic particles, Magtration Technology, and its use for automating nucleic acid purification

Magnetic particles are useful for simple and efficient nucleic acid extraction. To achieve fully automated nucleic acid extraction and purification using magnetic particles, a new method for operating magnetic particles, Magtration Technology, was developed. In this method, magnetic separation is performed in a specially designed disposable tip. This enables high recovery of magnetic particles with high reproducibility. The features of this technology are (i) a simple mechanism for process control and (ii) flexible software to enable adaptation to commercially available reagents. Automated instruments based on Magtration Technology were developed and used for nucleic acid extraction. Total DNA, total RNA and plasmids were purified by Magtration Technology at an efficiency comparable to that of manual methods.

Spontaneous reactivation of Shiga toxins in Escherichia coli O157:H7 cells caused by transposon excision

IS1203v is an insertion sequence which has been found in inactivated Shiga toxin 2 genes (stx2) of Escherichia coli O157:H7. Using PCR amplification, we detected the wild-type stx2 genes in colonies of E. coli O157:H7 which possessed stx2 genes inactivated by insertion of IS1203v. This suggests that IS1203v is excised from the inactivated stx2 genes in E. coli O157:H7. We isolated the cells possessing the wild-type stx2 genes, and confirmed Stx2 productivities by reversed passive latex agglutination. We also analyzed the frequency of the appearance of the Stx2-producing cells using a quantitative PCR method. As a result, the frequency was 3.00 x 10(-6) with culturing for 24 h at 37 degrees C, and this increased to 8.83 x 10(-5) when E. coli O157:H7 possessing the inactivated stx2 genes was transformed by an expression plasmid harboring the IS1203v transposase. These results showed that some Stx2-nonproducing E. coli O157:H7 strains could be spontaneously changed into Stx2-producing cells.

Distribution of Pythium porphyrae, the Causal Agent of Red Rot Disease of Porphyrae spp., in the Ariake Sea, Japan

Distribution of Pythium porphyrae, the causal agent of red rot disease of Porphyra spp., in seafloor sediment was investigated in the Ariake Sea, Japan. A total of 170 samples of each 200 ml of sediment was collected from the seafloor at a total of 13 sites across the sea from 1998 to 2002. Each sample was filtered through two layers of nylon mesh with pore sizes of 100 and 15 μm. The residue on 15 μm mesh was assayed by a soil plating technique using a semiselective medium for P. porphyrae and by polymerase chain reaction (PCR) using species-specific primers. P. porphyrae were detected in 6 out of 13 sites and 2 out of 10 sites surveyed by soil plating and PCR, respectively. The representative isolate of P. porphyrae from the sediment was identical to the Porphyra thallus isolate from the same sea based on pathogenicity to the thallus, morphology, and rDNA internal transcribed spacer sequences. Recovery of P. porphyrae propagules in the sediment was up to 60 CFU per 100 ml of the fresh sample and was consistently higher in May than in the other months. The results suggest that P. porphyrae is distributed in the seafloor sediment in a wide area of the Ariake Sea.

Survey of formaldehyde, acetaldehyde and oligomers in polyethylene terephthalate food-packaging materials

Polyethylene terephthalate (PET) is frequently used as a packaging material for beverage bottles, fruit and vegetable trays, and egg crates in Japan. Levels of formaldehyde (FA), acetaldehyde (AA) and PET oligomers in various PET food packaging were determined. PET samples were initially dissolved in trifluoroacetic acid with 2,4-dinitrophenylhydrazine to derivatize formaldehyde and acetaldehyde to their dinitrophenylhydrazones. The stable derivatives along with the oligomers were analysed using HPLC with ultraviolet light detection at 360 and 254 nm, respectively. The PET pellets contained 3.5-12.4 microg g-1 AA and 4.0-7.2 mg g-1 oligomers, while FA was below the determination limit. FA, AA and oligomer levels in Japanese bottles were 0.6-3.0 microg g-1, 8.4-25.7 microg g-1 and 5.0-8.7 mg g-1, ND-1.6 microg g-1, 5.0-13.1 microg g-1 and 4.9-8.2 mg g-1 in French and Italian bottles, and ND-1.2 microg g-1, 9.1-18.7 microg g-1 and 5.6-8.0 mg g-1 in US and Canadian bottles, respectively. Compared with European bottles, Japanese bottles contain higher FA and AA levels. In sheet-moulding products, their contents were determined as ND-1.1 microg g-1, 11.5-43.1 microg g-1 and 4.6-9.2 mg g-1, respectively. The results show that sheet-moulding products contain lower FA and higher AA in comparison with bottles. FA and AA are considered to be generated from PET during the heating process for moulding the pellets to bottles or sheet-moulding articles and de-aeration during the sheet-moulding process is effective in removing FA. In contrast, the level of the oligomers remains unchanged during the moulding process from pellets to bottles or sheet products.

Single nucleotide polymorphisms in the gene encoding Krüppel-like factor 7 are associated with type 2 diabetes

AIMS/HYPOTHESIS

Although genetic susceptibility plays an important role in the pathogenesis of type 2 diabetes, most of the genes that influence susceptibility to type 2 diabetes have yet to be identified. Krüppel-like transcription factors are known to play important roles in development and cell differentiation, and have recently been implicated in the pathogenesis of type 2 diabetes. The present study aimed to examine the associations of single nucleotide polymorphisms (SNPs) in genes encoding members of the Krüppel-like-factor (KLF) family with type 2 diabetes in a large cohort of Japanese subjects.

METHODS

We genotyped 33 SNP loci found in 12 KLF genes in subjects with type 2 diabetes and in subjects from the general population using the PCR-Invader assay. We also examined the effects of the overexpression of KLF7 on adipogenesis in 3T3-L1 cells.

RESULTS

We identified a significant association between an SNP in KLF7 and type 2 diabetes (A vs C: p=0.004 after Bonferroni's correction, odds ratio=1.59, 95% CI 1.27-2.00). The expression of Klf7 decreased in response to the differentiation of 3T3-L1 adipocytes, and the overexpression of KLF7 resulted in significant inhibition of adipogenesis in 3T3-L1 cells.

CONCLUSIONS/INTERPRETATION

These results indicate that the gene encoding KLF7 is a novel candidate for conferring genetic susceptibility to type 2 diabetes.

Effect of long-term half-dose famotidine therapy on corpus gastritis in peptic ulcer disease

BACKGROUND

Recent studies showed that acid-suppressive therapy aggravates corpus gastritis in patients with Helicobacter pylori infection.

AIM

The aim of this study was to evaluate the effect of famotidine, a histamine receptor antagonist on corpus gastritis in patients with peptic ulcer disease.

METHODS

We enrolled 287 patients, 173 with duodenal ulcer and 114 with gastric ulcer and 100 patients with H. pylori-positive gastritis as control subjects. Patients with peptic ulcer were classified according to whether or not they received famotidine-maintenance therapy (20 mg/day) after primary treatment. At the time of endoscopy, biopsy specimens were obtained from the antrum and the corpus. The degrees of neutrophil and lymphocyte infiltration, atrophy and intestinal metaplasia were scored according to the updated Sydney System.

RESULTS

The degrees of neutrophil infiltration and atrophy in the corpus were significantly less in patients with gastric ulcer or duodenal ulcer than in patients with H. pylori-positive gastritis (P < 0.01). Differences in the degrees of neutrophil infiltration and atrophy in the corpus between the non-maintenance group and the maintenance group were not significant.

CONCLUSION

Long-term therapy with famotidine does not appear to lead to an increase in the incidence of corpus gastritis or corpus atrophy in patients with peptic ulcer disease.

Clinical features of gastric cancer discovered after successful eradication of Helicobacter pylori: results from a 9-year prospective follow-up study in Japan

BACKGROUND

Eradication of Helicobacter pylori is expected to prevent the development of gastric cancer. However, gastric cancer is sometimes discovered after successful eradication of H. pylori.

AIM

To conduct a prospective study to determine the clinical features of patients who underwent successful eradication and were later diagnosed with gastric cancer.

METHODS

A total of 1787 patients (1299 males and 488 females; mean age, 58.2 years; range: 15-84) who underwent successful eradication therapy between April 1994 and March 2001 were our study subjects.

RESULTS

Gastric cancer occurred at a rate of 1.1% (20 of 1787) during the follow-up period. Gastric cancer comprises six of 105 (5.7%) with early gastric cancer after endoscopic resection, 12 of 575 (2.1%) with gastric ulcer and two of 453 (0.4%) with atrophic gastritis. Gastric cancer did not develop in any patient with duodenal ulcer. All patients with gastric cancer had baseline severe atrophic gastritis in the corpus.

CONCLUSION

Careful endoscopic examination is necessary even after successful eradication of H. pylori in patients with early gastric cancer or gastric ulcer with severe mucosal atrophy in the corpus.

Imbalance in the production between vascular endothelial growth factor and endostatin in Kawasaki disease

To investigate whether an imbalance exists in the production between angiogenic and antiangiogenic growth factors in patients with Kawasaki disease (KD), we measured the serum levels of vascular endothelial growth factor (VEGF) and endostatin (ES) in 35 patients with KD, 15 patients with acute febrile diseases (disease controls) and 15 healthy children. KD patients had significantly higher VEGF levels and lower ES levels (P < 0.01) in the acute and subacute phases than the disease control and healthy children. KD patients with coronary artery lesions (CAL, n = 10) had significantly higher VEGF levels and lower ES levels (P < 0.05) in the subacute and convalescent phases than those without CAL (n = 25). The ratios of VEGF/ES in sera of KD patients with CAL were significantly higher (P < 0.05) in the acute and convalescent phases compared to those without CAL. Furthermore, the occurrence of CAL significantly correlated with the VEGF/ES ratio above 10 x 10(-3) in the subacute phase of KD (Odds ratio 17.25, P = 0.005). The findings in the present study indicate that an imbalance exists in the production between VEGF and ES in patients with KD while also suggesting that KD patients with a high VEGF/ES ratio have a significantly greater risk of CAL involvement.

Temperament and job stress in Japanese company employees

BACKGROUND

This study aims to demonstrate the relevance of temperament to job stress.

METHOD

The subjects were 848 male and 366 female Japanese company employees. Temperament Evaluation of Memphis, Pisa, Paris and San Diego-Autoquestionnaire version (TEMPS-A) and Munich Personality Test (MPT) were administered to assess temperaments, and the NIOSH Generic Job Stress Questionnaire (GJSQ) to assess job stress. We used hierarchical multiple linear regression analysis in order to demonstrate whether temperament variables added any unique variance after controlling the effects of other predictors such as gender, age and job rank.

RESULTS

In all subscales of the GJSQ, temperament predicted a large share of the variance in job stress. Remarkably, for interpersonal relationship stressors, the temperament variables added greater variance than that predicted by gender, age and job rank. Summary of the hierarchical linear regression analysis showed that the irritable temperament was associated with the most prominent vulnerability, followed by cyclothymic and anxious temperaments. The schizoid temperament had difficulty in the area of social support. On the other hand, the hyperthymic temperament displayed significant robustness in facing most job stressors; the melancholic type showed a similar pattern to a lesser degree.

LIMITATION

The findings may be different in a clinical Japanese sample, or a cohort of healthy employees from a different cultural background.

CONCLUSIONS

Temperament influences job stress significantly-indeed, it impacts on such stress with greater magnitude than age, gender and job rank in most areas examined. Temperament influences interpersonal relationship stressors more than workload-related stressors. Interestingly, in line with previous clinical and theoretical formulations, the hyperthymic and melancholic types actually appear to be "hyper-adapted" to the workplace.

Mouse Embryos and Chimera Cloned from Neural Cells in the Postnatal Cerebral Cortex

Cloning of mice has been achieved by transferring nuclei of various types of somatic cell nuclei into enucleated oocytes. However, all attempts to produce live cloned offspring using the nuclei of neurons from adult cerebral cortex have failed. Previously we obtained cloned mice using the nuclei of neural cells collected from fetal cerebral cortex. Here, we attempted to generate cloned mice using differentiated neurons from the cerebral cortex of postnatal (day 0-4) mice. Although we were unable to obtain live cloned pups, many fetuses reached day 10.5 days of development. These fetuses showed various abnormalities such as spherical omission of the neuroepithelium, collapsed lumen of neural tube, and aberrant expressions of marker proteins of neurons. We produced chimeric mice in which some hair cells and kidney cells were originated from differentiated neurons. In chimeric fetuses, LacZ-positive donor cells were in all three germ cell layers. However, chimeras with large contribution of donor-derived cells were not obtained. These results indicate that nuclei of differentiated neurons have lost their developmental totipotency. In other words, the conventional nuclear transfer technique does not allow nuclei of differentiated neurons to undergo complete genomic reprogramming required for normal embryonic development.

Eradication of Helicobacter pylori increases the incidence of hyperlipidaemia and obesity in peptic ulcer patients

BACKGROUND

Eradication of Helicobacter pylori improves clinical symptoms and quality of life in patients with peptic ulcer.

AIM

To investigate the effect of eradication of H. pylori on body mass index and incidence of hyperlipidaemia in patients with peptic ulcer.

PATIENTS AND METHODS

The study population comprised 50 patients (42 men, 8 women; mean age, 51 years; 28 gastric ulcer, 22 duodenal ulcer) who underwent physical and blood examination before and 1 year after undergoing eradication therapy and 100 sex- and age-matched control subjects. Body mass index, total cholesterol and triglyceride were measured before and 1 year after therapy.

RESULTS

The eradication therapy group showed a significant increase in body mass index (22.7+/-2.5 kg/m2 before eradication versus 23.6+/-2.6 kg/m2 after eradication, p < 0.01), serum total cholesterol (204.1+/-33.2 mg/dL versus 221.2+/-38.8 mg/dL, p < 0.01), and triglyceride. Additionally, the eradication therapy group showed a significant increase in the incidence of hypercholesterolemia (30% versus 58%, p<0.01), hypertriglyceridaemia (28% versus 44%, p < 0.01) and obesity (12% versus 22%, p <0.05) 12 months after therapy.

CONCLUSION

Our findings show that eradication of H. pylori significantly increases the incidence of hyperlipidaemia and obesity in patients with peptic ulcer.

[Therapy for ROD and measurement of the bone mass]

The kidney deeply takes part in phosphorus and vitamin D metabolism. The chronic kidney disease patients usually suffer from serious bone disease. They are prescribed the glucocorticoid medication for primary kidney disease, as nephrotic syndrome and collagen renal disease, with aging. The end of therapeutic target is normal bone structure with normal bone turnover in CKD patients. The control of serum Ca and phosphorus level is important step and also another target. This issue describes the problem and the advancement of treatment and the measurement of the bone mass from this viewpoint.

Translucency of glass-fibre-reinforced composite materials

summary The purpose of this study was to examine the translucency of glass-fibre-reinforced composite framework materials. Vectris and FibreKor, as well as an experimental material, were the glass-fibre-reinforced framework materials used. Targis, Sculpture and Estenia were the types of particulate filler composites veneered onto frameworks. Specimens were fabricated from each material, 0.5 and 1.0 mm thick. In addition, laminate specimens, 1.5 mm thick, were fabricated. The translucency of each specimen was evaluated by determining its contrast ratio. The laminate specimens were examined for colour differences. The experimental framework material was more translucent than the enamel composite when it was not coloured, and was nearly as translucent as the dentine composite when coloured. The commercial tooth-coloured framework materials were nearly as translucent as the dentine composite. It was found that it was possible to reproduce the same colour as the veneering dentine composite, when the framework thickness was 0.5 mm, except in the case of FibreKor. Within the limitations of this study, tooth-coloured, glass-fibre-reinforced framework materials are nearly as translucent as the veneering dentine composite, but these materials affect the colour of the prosthesis if the thickness of the framework material is increased beyond a certain point.

Proteomics of the rice cell: systematic identification of the protein populations in subcellular compartments

Despite recent progress in sequencing the complete genome of rice ( Oryza sativa), the proteome of this species remains poorly understood. To extend our knowledge of the rice proteome, the subcellular compartments, which include plasma membranes (PM), vacuolar membranes (VM), Golgi membranes (GM), mitochondria (MT), and chloroplasts (CP), were purified from rice seedlings and cultured suspension cells. The proteins of each of these compartments were then systematically analyzed using two-dimensional (2D) electrophoresis, mass spectrometry, and Edman sequencing, followed by database searching. In all, 58 of the 464 spots detected by 2D electrophoresis in PM, 43 of the 141 spots in VM, 46 of the 361 spots in GM, 146 in the 672 spots in MT, and 89 of the 252 spots in CP could be identified by this procedure. The characterized proteins were found to be involved in various processes, such as respiration and the citric acid cycle in MT; photosynthesis and ATP synthesis in CP; and antifungal defense and signal systems in the membranes. Edman degradation revealed that 60-98% of N-terminal sequences were blocked, and the ratios of blocked to unblocked proteins in the proteomes of the various subcellular compartments differed. The data on the proteomes of subcellular compartments in rice will be valuable for resolving questions in functional genomics as well as for genome-wide exploration of plant function.

A cardiac sodium channel mutation identified in Brugada syndrome associated with atrial standstill

Mutations in the cardiac Na+ channel gene SCN5A are responsible for multiple lethal ventricular arrhythmias including Brugada syndrome and congenital long QT syndrome. Here we report a case of Brugada syndrome with ST elevation in the right precordial and inferior leads accompanied by atrial standstill and spontaneous ventricular fibrillation. Atrial standstill and J wave elevation were provoked by procainamide. Genetic analysis revealed a missense mutation (R367H) in SCN5A. The resultant mutant Na+ channel was nonfunctional when expressed heterologously in Xenopus oocytes. Our study suggests that genetic defects in SCN5A may be associated with atrial standstill in combination with ventricular arrhythmias.

Carbohydrate-mediated adhesion of human colon carcinoma cells to human liver sections

Clinicopathological observations have revealed that the expression level of a carbohydrate antigen recognized by the monoclonal antibody (mAb) FH6 in colorectal carcinomas is higher at advanced stages than at early stages. The present study aimed to elucidate whether human colon carcinoma cell surface glycans recognized by mAb FH6 determine the ability of these cells to adhere to sections of human liver. Variant human colon carcinoma cell lines selected for high and low binding of mAb FH6 were compared with respect to their adhesive capacity. The cells expressing the higher level of FH6 binding also showed a greater ability to adhere to liver sections. This adhesion was not blocked by anti-E-selectin monoclonal antibodies, but pretreatment of the carcinoma cells with endo-beta-galactosidase significantly reduced both cell surface binding of mAb FH6 and the ability of the cells to adhere to liver sections. Our observations suggest that endo-beta-galactosidase-sensitive carbohydrate chains containing an epitope recognized by mAb FH6 play an important role in the adhesion of human colon carcinoma cells to human liver sections. Whether these interactions have any relationship to the mechanism(s) of liver metastasis remains to be elucidated.

Prevalence of Helicobacter pylori in NSAID users with gastric ulcer

OBJECTIVE

Regarding the interaction of Helicobacter pylori and non-steroidal anti-inflammatory drugs (NSAIDs), we cannot accept unanimous conclusions in inducing gastric ulcer. We therefore evaluated the role of Helicobacter pylori and NSAIDs in inducing gastric ulcer.

METHODS

Dyspeptic patients receiving NSAIDs underwent endoscopic examination. Gastric ulcer formation and H. pylori status were investigated. Biopsy specimens from the antrum and lower body of the stomach were prepared for the rapid urease test and pathological evaluation. Anti-H. pylori antibody was measured by enzyme-linked immunosorbent assay.

RESULTS

Two hundred and twenty-six patients receiving NSAIDs (220 chronic and six on-demand users) underwent gastrofibrescopic examination. There were 110 patients with gastric ulcer and 111 non-ulcer patients with gastritis. The remaining five patients had neither. NSAID users with gastric ulcer showed a low prevalence of H. pylori compared with those without them [55/110 (50.0%) vs 79/111 (71.2%), P < 0.01]. The same tendency was seen when patients receiving low-dose aspirin and those with rheumatoid arthritis were analysed separately [13/29 (44.8%) vs 50/62 (80.6%), P < 0.01, and 11/33 (33.3%) vs 16/26 (61.5%), P < 0.06 with Yates' correction, respectively].

CONCLUSION

Helicobacter pylori infection appeared to be a risk factor for developing gastritis, but we found no evidence that it increases gastric ulcer formation in NSAID users with dyspepsia.

Optical detection of dendritic spike initiation in hippocampal CA1 pyramidal neurons

Previous studies have shown that spikes can be generated in the dendrites of CA1 pyramidal neurons. Some have suggested that, in response to synaptic inputs, spikes are initiated near the soma and propagate back into the dendrites, but some recent studies have shown that intense synaptic inputs initiate spikes in the dendrite. Here, we report the optical detection of spike propagation along the apical dendrites of hippocampal pyramidal neurons. Rat hippocampal slices were stained with the fluorescent voltage-sensitive dye, JPW1114, and optical signals monitored using a 16 x 16 photodiode array system at a frame rate of 4 kHz. A stimulating electrode was placed at the boundary between the stratum (str.) lacnosum-moleculare and the str. radiatum to stimulate the Schaffer collateral, and fast and slow signal components were detected in the dendritic and somatic regions. By comparing the optical signals with whole-cell recordings, we confirmed that the fast component was due to a population of dendritic spikes in pyramidal neurons. The fast component appeared in dendritic locations near the input sites in response to synaptic activation, and signal onset at the soma was delayed by a few milliseconds compared with that at the input sites. Local perfusion of a Na(+) channel blocker near the soma eliminated the fast component at the soma, but had no effect on the fast component at the input sites. Our results indicate that dendritic spikes can be initiated in dendrites near the input site and propagate orthodromically toward the proximal dendrites and the soma.