The periodontal pathogen aggregatibacter actinomycetemcomitans deteriorates ventricular remodeling after myocardial infarction in mice

Chronic inflammation plays a fundamental role in coronary heart disease (CHD). Periodontal disease is a common infectious disease and is a potential source of systemic inflammation. However, the effect of periodontal infection on CHD has not yet been proven. The purpose of this study was to determine the effect of periodontopathic bacteria on experimental myocardial infarction (MI). We implanted a chamber into the subcutaneous tissue of each male mouse. Aggregatibacter actinomycetemcomitans (A.a. n = 8), which is a major periodontal pathogen, or PBS (n = 6) was injected into the chamber. Then, MI was induced by permanent ligation of the left anterior descending coronary artery. To exclude the nonspecific effect of the pathogen, we injected A.a. into the mice without MI (n = 4). The plasma level of anti-A.a. antibody was statistically higher in A.a.-infected mice than in vehicle control mice. Seven days after the myocardial ischemia, the A.a.-positive MI hearts showed a larger infarct size and length than the A.a.-negative MI mice. The A.a.-positive MI hearts showed more MOMA-2 positive myocardial infiltrating cells compared to the A.a.-negative MI mice. The injection of A.a. into the mice without MI did not affect their hearts. We concluded that a periodontal pathogen infection might deteriorate ventricular remodeling after MI through inflammatory cell infiltration.     

Clinicopathological features of serrated lesions of the colorectum

We reviewed 428 subjects with colorectal serrated lesions resected endoscopically or surgically at our institution. Colorectal serrated lesions were pathologically divided into 3 groups: hyperplastic polyp (HP), sessile serrated adenoma/polyp (SSA/P), and traditional serrated adenoma (TSA). SSA/P was detected frequently in the right colon and SSA/P was mainly flat-elevated. Cancers occurring in SSA/P were found more frequently than HP or TSA. The incidence of cancer in SSA/P was equivalent to that of cancer in traditional adenoma. Further studies are warranted to clarify clinicopathological features of serrated lesions of the colorectum.     

Expiratory activity of the inspiratory muscles during cough.

To investigate the neural mechanism of the expiratory activity of the inspiratory muscles during a cough, EMG of the respiratory muscles were recorded in anesthetized and tracheostomized dogs. A laparoscope was used to minimize injury to the abdominal muscles for implantation of the electrodes into the costal diaphragm. During the expulsive phase of a cough, the diaphragm was active in 7 of 12 dogs and the external intercostal muscle was active in 3 of 6 dogs. During a cough, the expiratory activity of the diaphragm, after the termination of its inspiratory activity, started at 52.9 +/- 24.6 ms, and that of external intercostal muscle started at 51.1 +/- 20.5 ms. The expiratory activity of the internal intercostal muscle and of the transversus abdominis started at 34.3 +/- 13.0 and 27.8 +/- 15.2 ms, respectively. The onset of expiratory activity of the inspiratory muscles is significantly later than that of expiratory muscles. Continuous activity in the expiratory muscles evoked by airway occlusion, i.e., Hering-Breuer reflex, was suppressed during the inspiratory phase of a cough, but not suppressed during the expulsive phase even when the expiratory activity of the diaphragm was observed. We concluded that the expiratory activity of inspiratory muscles is controlled independently of both expiratory activity of the expiratory muscles and inspiratory activity of the inspiratory muscles.     

Possible role of vascular endothelial cells in immune responses in colonic mucosa examined immunocytochemically in subjects with and without ulcerative colitis

Phenotypic characteristics of vascular endothelial cells of the colonic mucosa in patients with ulcerative colitis and healthy controls were studied with immunoperoxidase staining by light and electron microscopy. The cells could be classified into two groups according to their phenotypes; one was positive for von Willebrand factor and the other had an antigen detected by a monoclonal antibody, OKM5. The endothelial cells positive for von Willebrand factor were usually in relatively large blood vessels, and OKM5-positive cells were mostly located in small capillaries along the glandular epithelium. OKM5-positive endothelial cells also expressed HLA-DR and interleukin-1 (IL-1). In patients with ulcerative colitis, OKM5-positive endothelial cells and spindle-shaped cells that might be precursors of endothelial cells were more numerous in the lamina propria than in the other subjects. Thus, OKM5-positive endothelial cells may be important as antigen-presenting cells and immunoregulatory cells in the intramucosal immune system. Furthermore, colonic epithelial cells in patients with ulcerative colitis synthesized HLA-DR and IL-1, and may have a close relation to immune responses, such as antigen processing and presentation to immunocompetent cells. It was suggested that these cells have a close relation to the pathogenesis of the impaired immune responses in situ in ulcerative colitis.     

Comparative studies of commercially available particle agglutination assay and enzyme-linked immunosorbent assay for screening of human T-cell leukemia virus type I antibodies in blood donors.

Human T-cell leukemia virus type I (HTLV-I) transmission during blood transfusion can be prevented by screening for and eliminating blood containing anti-HTLV-I antibodies. For this purpose, we evaluated two commercial test kits for HTLV-I antibodies, Serodia-ATLA (particle agglutination assay [PA]) and Eitest-ATL (enzyme-linked immunosorbent assay [ELISA]), by using serum samples from Japanese blood donors. Of 2,316 serum samples, 39 (1.7%), 34 (1.5%), and 28 (1.2%) were positive for the antibody by PA, ELISA, and immunofluorescence (IF), respectively. The coincidence rate for antibody-positive and antibody-negative results was 99.5% between PA and IF, whereas it was 99.6% between ELISA and IF. The serum samples which were positive by IF were also positive by PA, whereas 2 of 26 IF-positive samples were negative by ELISA. All the samples positive by both PA and ELISA were shown to be positive by IF unequivocally. The samples positive by only one of the two methods (PA or ELISA) were different. Eleven and eight serum samples that were negative by IF but positive by PA and ELISA, respectively, were further studied for HTLV-I antibody by radioimmunoprecipitation. Three of the former but none of the latter were found to be positive for antibody. Moreover, a PA-positive but IF-negative serum sample was shown to have significantly decreased PA titers after 2-mercaptoethanol treatment. The PA was further shown to detect not only IgG antibody but also IgM antibody to HTLV-I after separation of this serum sample by high-performance liquid chromatography.     

Enhancement of B7-1 (CD80) expression on B-lymphoma cells by irradiation

Irradiation of A20.2J mouse B-lymphoma cells enhanced their antigen-presenting ability to induce interleukin-2 (IL-2) production by 42-6A T cells specific for ovalbumin (OVA)323-339/I-Ad. Irradiated and fixed A20.2J cells were more efficient antigen-presenting cells (APC) to present OVA323-339 peptide than the unirradiated and fixed cells. Irradiation selectively increased the expression of B7-1 molecules, but not of the major histocompatibility complex class II molecules, B7-2, lymphocyte function-associated antigen-1, or intracellular adhesion molecule-1. Irradiation of A20.2J cells with 100 Gy followed by overnight incubation was optimal for the enhancement of B7-1 expression. Anti-B7-1 monoclonal antibody inhibited the irradiation-induced enhancement of APC function. Irradiation of A20.2J cells induced the accumulation of B7-1 mRNA. Thus, it was concluded that the enhancement of APC function by irradiation was due to the up-regulation of B7-1 molecules through the accumulation of its mRNA. Although partial inhibition of protein synthesis has been shown to enhance the accumulation of B7-1 mRNA and its expression, irradiation did not decrease the protein synthesis in A20.2J cells. The incubation with irradiated A20.2J cells stimulated unirradiated A20.2J cells to increase B7-1 expression, suggesting that irradiation of A20.2J cells induced expression or secretion of some molecule(s) to enhance B7-1 expression.     

Esophageal function worsens with long duration of diabetes

BACKGROUND: The aim of this study was to assess the relationship between the duration of diabetes and esophageal dysfunction. METHODS: We examined 66 patients with type 2 diabetes. Duration of diabetes was determined by asking patients and from their medical records. The patients were divided into three groups according to the duration of their diabetes: group A, 1-4 years, n=26; group B, 5-9 years, n=20; and group C, 10+ years, n=20. Ambulatory esophageal 24-h pH and motility were monitored, and gastroesophageal reflux and esophageal motility disorders were estimated in detail. RESULTS: When the duration of diabetes was long, the percentage of time with pH<4 tended to increase. The amplitude of esophageal peristaltic waves and the frequency of effective peristalsis were reduced when the duration of diabetes was long. A significant correlation was observed between the duration of diabetes and the frequency of effective peristalsis. The number of esophageal peristaltic waves per minute and the percentage of multipeaked peristaltic waves increased significantly in group B, and decreased when the duration of diabetes became longer. CONCLUSIONS: Gastroesophageal reflux and esophageal motility disorders worsened with long duration of diabetes. These esophageal dysfunctions should be considered in patients with long-standing diabetes.