Immunogenetic analysis of gastric MALT lymphoma-like lesions induced by Helicobacter pylori infection in neonatally thymectomized mice

Most gastric mucosa-associated lymphoid tissue (MALT) lymphomas are caused by Helicobacter pylori (H. pylori) infection. We previously reported that acquired lymphoid follicles with germinal centers were induced by H. pylori infection in neonatally thymectomized (nTx) mice. In the present study, we developed gastric MALT lymphoma-like lesions in nTx mice by long-term H. pylori infection, and performed immunogenetic analyses. BALB/c mice were thymectomized on the 3rd day after birth. At 6 weeks of age, mice were orally infected with 10(8) H. pylori and serially killed 2, 4, 6, and 12 months later. Normal BALB/c and noninfected nTx mice served as controls. Follicle formation occurred after 2 months of H. pylori infection in the nTx mice. Follicle formation and infiltration of intraepithelial lymphocytes progressed in a time-dependent manner. Lymphoepithelial lesions, a characteristic feature of MALT lymphoma, also occurred in a time-dependent manner (100% at 12 months). Serum immunoelectrophoresis revealed a monoclonal band (M-protein) in 30% (3/10) of mice 6 months after infection. M-protein-positive mice had amplification of one or two IgM and/or IgG heavy-chain genes in the gastric B lymphocytes, as determined with polymerase chain reaction, suggesting mono- or oligoclonality. Overexpression of Bcl-X(L) protein was immunohistologically observed in the infiltrating B lymphocytes and in some follicular B lymphocytes in 80% (8/10) of the cases at 12 months. Thus, H. pylori infection is involved in the development of gastric MALT lymphoma-like lesions in nTx mice. Our mouse model is useful for clarifying the pathogenetic mechanism of gastric MALT lymphoma by H. pylori infection.     

Toll-like receptor 9 is expressed on follicle-associated epithelia containing M cells in swine Peyer's patches

The precise distribution and expression of Toll-like receptor (TLR) 9 in gut-associated lymphoid tissues (GALTs) has not been elucidated. In this study, we investigated the expression pattern of TLR9 in adult and neonatal swine GALTs by real-time quantitative PCR, western blot, confocal laser microscopy and flow cytometric analysis. The swine TLR9 gene was preferentially expressed in adult Peyer's patches (Pps) and mesenteric lymph nodes (MLNs), which contained approximately three times higher TLR9 than the spleen. Other tissues exhibited only weak expression of TLR9. In neonatal swine, elevated expression of TLR9 was detected only in MLNs. We firstly showed that highly expressive (TLR9(+)) cells were formed in Pps and MLNs. In addition, TLR9(+) cells were present not only in immune cells such as dendritic cells and B cells but also in follicle-associated epithelia (FAE) including membranous cells (M cells) in Pps. These results suggest that Pps and MLNs provide the host defense with the ability to respond to a variety of bioactive oligonucleotides (ODNs) from bacteria at a conductive site of initial immune responses.     

Vascularization in vivo caused by the controlled release of fibroblast growth factor-2 from an injectable chitosan/non-anticoagulant heparin hydrogel

Addition of various heparinoids to the lactose-introduced, water-soluble chitosan (CH-LA) aqueous solution produces an injectable chitosan/heparinoid hydrogel. In the present work, we examined the capability of the chitosan/non-anticoagulant heparin (periodate-oxidized (IO(4)-) heparin) hydrogel to immobilize fibroblast growth factor (FGF)-2, as well as the controlled release of FGF-2 molecules from the hydrogel in vitro and in vivo. The hydrogel was biodegraded in about 20 days after subcutaneous injection into the back of a mouse. When the FGF-2-incorporated hydrogel was subcutaneously injected into the back of both mice and rats, a significant neovascularization and fibrous tissue formation were induced near the injected site. These results indicate that the controlled release of biologically active FGF-2 molecules is caused by biodegradation of the hydrogel, and that subsequent induction of the vascularization occurs.     

Effects of lumbar skin warming on gastric motility and blood pressure in humans

We examined the possibility that lumbar skin warming can increase gastrointestinal motility by investigating the electrogastrogram (EGG), blood pressure, and heart rate with psychometric ratings in healthy humans. Scores of mood state profiles showed that lumbar skin warming (42 degrees C, 20 min) decreased tension-anxiety, depression, anger-hostility, fatigue, and confusion of the participants. A multiple bandpass filter analysis of EGGs showed that a postural transition from orthostatic to supine for measurement caused an increase in dominant frequency of 25-29% towards the frequencies of the normal interdigestive migrating motor complex (IMC). The spectral power of the IMC band, 2.55-3.05 cycles/min, was increased by 20 min-warming, reflecting the increase in gastric contractility. No increase in the spectral power was observed in the time-matched control group without skin warming. Therefore, an increase in contractility is a characteristic of lumbar skin warming. The systolic blood pressure increased by 15% during warm stimulation. Interbeat intervals were not influenced by warm stimulation. An analysis of interbeat intervals by a fast Fourier transform method showed that the cardiac sympathetic and parasympathetic nerves did not play a major role in raising the blood pressure. Vasoconstriction of the mesenteric artery was therefore considered to cause a blood pressure increase during warming. It is hypothesized that vasoconstriction of the visceral arteries by lumbar skin warming increases the blood pressure and gastrointestinal contractility.     

Gaps and fragmentation of the superficial cortex in the abdominal and pelvic lymph nodes of elderly Japanese

Gaps and fragmentation of the superficial lymph node cortex are considered to provide intranodal shunt flow between the afferent and efferent vessels. Using serial sections of 205 nodes obtained from 27 donated cadavers more than 70 years of age, we examined the histological architecture of the abdominal and pelvic nodes in elderly Japanese. Secondary follicles were rare in the specimens. Cortex gaps were, to a greater or lesser degree, found in all nodes. We classified these nodes into three types according to how often the gap occurred. Type 1 nodes, with a relatively complete shield for the afferent lymph, were most frequently found in gastric nodes, whereas type 3 nodes, with numerous gaps, were often observed in the colic, para-aortic and pelvic nodes. The type 3 nodes showed a specific architecture characterized by a fragmented superficial cortex, three-dimensionally assembled cords and a common sinus between them. Primary follicles were located in the assembled cord structures as well as at the superficial cortex. Irrespective of the type, B and T lymphocyte areas were intermingled in the cortex-like areas. The present results reveal region-specific histological heterogeneity in aged human visceral nodes. Due to increased surface areas, the type 3 architecture seemed to accelerate systemic immunity rather than act as a local barrier in the para-aortic and pelvic nodes, which are located centrally along the lymphatic drainage routes. However, thick trabeculae often seemed to develop in the type 3 sinus to decrease nodal function with aging.     

Bcl11b is required for differentiation and survival of alphabeta T lymphocytes

The gene Bcl11b, which encodes zinc finger proteins, and its paralog, Bcl11a, are associated with immune-system malignancies. We have generated Bcl11b-deficient mice that show a block at the CD4-CD8- double-negative stage of thymocyte development without any impairment in cells of B- or gammadelta T cell lineages. The Bcl11b-/- thymocytes showed unsuccessful recombination of V(beta) to D(beta) and lacked the pre-T cell receptor (TCR) complex on the cell surface, owing to the absence of Tcrb mRNA expression. In addition, we saw profound apoptosis in the thymus of neonatal Bcl11b-/- mice. These results suggest that Bcl11b is a key regulator of both differentiation and survival during thymocyte development.     

Clinical significance of a highly sensitive enzyme immunoassay of hepatitis B surface antigen using a novel electron spin resonance technique.

We developed a highly sensitive enzyme immunoassay (EIA), the p-AP/HHTIO method, that detects serum hepatitis B surface antigen (HBsAg) by measuring stabilized nitroxide radicals using a novel electron spin resonance technique [Matsuo et al. (1998) Free Radic Biol Med 25:929-935]. To demonstrate the clinical significance of this method and to reveal occult hepatitis B virus (HBV) infection in patients, we used the method to analyze serum samples of 30 patients with acute or fulminant hepatitis who were negative for HBsAg by standard EIA, and those of seven chronic HBV carriers who became negative for HBsAg during a follow-up period by standard EIA. We also examined serum HBV DNA by amplification of the HBV S gene, using the polymerase chain reaction (PCR) technique. The p-AP/HHTIO method showed that 9 of 20 (45%) patients with acute hepatitis and 2 of 10 (20%) with fulminant hepatitis were positive for HBsAg; PCR detected HBV DNA in these HBsAg-positive patients. Antibody against hepatitis B core antigen was detected in one patient with fulminant hepatitis. The p-AP/HHTIO method demonstrated prolonged seropositivity of HBsAg even after standard EIA showed a loss of HBsAg in all seven HBV carriers. Our p-AP/HHTIO method is useful for screening and diagnosing HBV infection in patients with liver diseases who are negative for conventional HBV-related serological markers.