Enforced granulocyte/macrophage colony-stimulating factor signals do not support lymphopoiesis,but instruct lymphoid to myelomonocytic lineage conversion

We evaluated the effects of ectopic granulocyte/macrophage colony-stimulating factor (GM-CSF) signals on hematopoietic commitment and differentiation. Lineage-restricted progenitors purified from mice with the ubiquitous transgenic human GM-CSF receptor (hGM-CSFR) were used for the analysis. In cultures with hGM-CSF alone, hGM-CSFR-expressing (hGM-CSFR+) granulocyte/monocyte progenitors (GMPs) and megakaryocyte/erythrocyte progenitors (MEPs) exclusively gave rise to granulocyte/monocyte (GM) and megakaryocyte/erythroid (MegE) colonies, respectively, providing formal proof that GM-CSF signals support the GM and MegE lineage differentiation without affecting the physiological myeloid fate. hGM-CSFR transgenic mice were crossed with mice deficient in interleukin (IL)-7, an essential cytokine for T and B cell development. Administration of hGM-CSF in these mice could not restore T or B lymphopoiesis, indicating that enforced GM-CSF signals cannot substitute for IL-7 to promote lymphopoiesis. Strikingly, >50% hGM-CSFR+ common lymphoid progenitors (CLPs) and >20% hGM-CSFR+ pro-T cells gave rise to granulocyte, monocyte, and/or myeloid dendritic cells, but not MegE lineage cells in the presence of hGM-CSF. Injection of hGM-CSF into mice transplanted with hGM-CSFR+ CLPs blocked their lymphoid differentiation, but induced development of GM cells in vivo. Thus, hGM-CSF transduces permissive signals for myeloerythroid differentiation, whereas it transmits potent instructive signals for the GM differentiation to CLPs and early T cell progenitors. These data suggest that a majority of CLPs and a fraction of pro-T cells possess plasticity for myelomonocytic differentiation that can be activated by ectopic GM-CSF signals, supporting the hypothesis that the down-regulation of GM-CSFR is a critical event in producing cells with a lymphoid-restricted lineage potential.     

Clarithromycin inhibits the development of dermatitis in NC/Nga mice

BACKGROUND: Colonization of Staphylococcus aureus on the skin is one of the exacerbating factors of atopic dermatitis (AD). Reduction of bacterial colonization in these lesions was reported to be effective for the treatment of subjects with AD. Clinical trials have demonstrated the efficacy of FK-506 (an immunosuppressive macrolide) ointment for AD, and many case reports have been published regarding its positive effects for other inflammatory skin diseases. Clarithromycin (CAM) is a macrolide antibiotic with immunological effects. One patient with AD was treated effectively with oral CAM for Helicobacter pylori infection. NC/Nga (NC) mice have recently been recognized to be a model of AD. METHODS: We examined the effects of CAM on the development of dermatitis, infiltration of mast cells and MHC class II-positive cells in the skin and the colonization of S. aureus on the skin of NC mice. CAM was compared with cefaclor, an antibiotic with no immunological effects. RESULTS: CAM suppressed the development of dermatitis at 5 and 6 weeks to a statistically significant degree, and these effects gradually weakened, but the severity of the dermis of CAM-treated mice was milder than in control mice. Dexamethasone was effective in the case of development of dermatitis at 5 weeks. These effects gradually weakened, and the difference between dexamethasone-treated mice and control mice disappeared. The severity of the skin lesions in CAM-treated mice was the lowest of the three groups at 9 weeks of observation. Histological analyses revealed that infiltration of inflammatory cells, especially degranulated mast cells and MHC class II-positive cells, was significantly reduced. Thickening of the epidermis and hyperkeratosis in CAM-treated mice were less than in control mice. CAM and cefaclor completely inhibited S. aureus on the skin of NC mice, for all experimental periods. Dexamethasone provided inhibition at 5 weeks, but eventually the difference between dexamethasone-treated mice and control mice disappeared. CONCLUSIONS: CAM inhibited the development of dermatitis for the first half of the experimental period in NC mice as a result of antibacterial and immunological effects. Our data show that CAM can be an effective antibiotic for AD with respect to delaying the development of dermatitis.     

Obstruction of St Jude Medical valves in the aortic position: histology and immunohistochemistry of pannus

OBJECTIVE: This study aims to reveal the morphological, histological, and immunohistochemical mechanism of pannus formation using resected pannus tissue from patients with prosthetic valve dysfunction. METHOD: Eleven patients with prosthetic valve (St Jude Medical valve) dysfunction in the aortic position who underwent reoperation were studied. We used specimens of resected pannus for histological staining (hematoxylin and eosin, Grocott's, azan, elastica van Gieson) and immunohistochemical staining (transforming growth factor-beta, transforming growth factor-beta receptor 1, alpha-smooth muscle actin, desmin, epithelial membrane antigen, CD34, factor VIII, CD68KP1, matrix metalloproteinase-1, matrix metalloproteinase-3, and matrix metalloproteinase-9). RESULTS: Pannus without thrombus was observed at the periannulus of the left ventricular septal side; it extended into the pivot guard, interfering with the movement of the straight edge of the leaflet. The histological staining demonstrated that the specimens were mainly constituted with collagen and elastic fibrous tissue accompanied by endothelial cells, chronic inflammatory cells infiltration, and myofibroblasts. The immunohistochemical findings showed significant expression of transforming growth factor-beta, transforming growth factor-beta receptor 1, CD34, and factor VIII in the endothelial cells of the lumen layer; strong transforming growth factor-beta receptor 1, alpha-smooth muscle actin, desmin, and epithelial membrane antigen in the myofibroblasts of the media layer; and transforming growth factor-beta, transforming growth factor-beta receptor 1, and CD68KP1 in macrophages of the stump lesion. CONCLUSIONS: Pannus appeared to originate in the neointima in the periannulus of the left ventricular septum. The structure of the pannus consisted of myofibroblasts and an extracellular matrix such as collagen fiber. The pannus formation after prosthetic valve replacement may be associated with a process of periannular tissue healing via the expression of transforming growth factor-beta.     

Plasma leptin levels in patients with burn injury: a preliminary report

The purpose of this study was to investigate the relationship between the plasma leptin level and clinical parameters in patients with burn injury. Six patients with burn injury were admitted to the Emergency and Critical Care Medicine Center of St. Marianna University Hospital within 1h after injury. Plasma levels were monitored for leptin, proinflammatory cytokines (interleukin (IL)-1 beta, IL-6, tumor necrosis factor alpha (TNF alpha)), stress-related parameters (adrenocorticotropic hormone (ACTH), cortisol, and C-reactive protein (CRP)). The change in individual plasma leptin levels did not show similar pattern in all these patients. However, leptin levels remained within the normal range, except in a patient (Case 1) complicated with severe hypovolemic shock. Plasma ACTH and cortisol levels were also elevated in most of the patients. Examination of relationships among plasma leptin, proinflammatory cytokines, and stress-related parameters revealed a significant positive correlation between the plasma leptin level and IL-1 beta or IL-6. These results suggest that the plasma leptin level may have some relations to plasma proinflammatory cytokines in pathophysiologic responses to critical conditions of burn injury.     

Initial medical management of patients severely irradiated in the Tokai-mura criticality accident

A nuclear criticality accident occurred in Japan on September 30, 1999, which resulted in severe exposure of three victims to mixed flux of neutrons and gamma-rays. Estimated average doses for the three victims were 5.4 Gy of neutrons and 8.5 Gy of gamma-rays for Patient A, 2.9 Gy of neutrons and 4.5 Gy of gamma-rays for Patient B, and 0.81 Gy of neutrons and 1.3 Gy of gamma-rays for Patient C. They then suffered the consequences of the effects of ionizing radiation resulting in acute radiation syndrome. In Patients A and B, bone marrow failure was so severe that they received haematopoietic stem cell transplantation. The graft initially took successfully in both patients, although in Patient B it was later taken over by his own haematopoietic cells. They also suffered from severe skin lesions, later exhibited gastrointestinal bleeding and eventually died of multiple organ failure 82 and 210 days after the accident, respectively. The survival of these patients beyond the period of agranulocytosis means that bone marrow failure per se caused by exposure to ionizing radiation may now be overcome. Patient C also developed bone marrow failure and was treated with granulocyte colony-stimulating factor as well as supportive care. He recovered without major complications and is now under periodical follow-up. Remarkably, during the prodromal phase, all the patients exhibited hypoxaemia, two of whom also showed interstitial oedema of the lungs. In Patient C these manifestations improved within a week. The circumstances of the accident and the initial medical treatment of the victims are described.     

Non-methylated CpG motif packaged into fusogenic liposomes enhance antigen-specific immunity in mice

DNA rich in non-methylated CG motifs (CpGs) enhances induction of immune responses against co-administered antigen encoding genes. CpGs are therefore among the promising adjuvants known to date. However, naked plasmid DNA, even which contains CpG motifs, are taken up by antigen presenting cells via the endocytosis pathway. Endocytosed DNAs are thus degraded and their gene expression levels are inefficient. In this context, an effective plasmid delivery carrier is required for DNA vaccine development. We show in the present study that packaging plasmids containing CpGs into fusogenic liposomes (FL) derived from conventional liposomes and Sendai virus-derived active accessory proteins is an attractive method for enhancing the efficacy of a DNA vaccine. These CpG-enhanced plasmids (possessing 16 CpG repeats) that were packaged into FL, enhanced ovalbumin (OVA)-specific T cell proliferation and cytotoxic T cell activity after immunization. In fact, vaccination with CpG enhanced plasmid-loaded FL induced effective prophylactic effects compared with 13 repeats CpG containing plasmid in a tumor challenge experiment. Thus, the development of a CpG-enhanced DNA-FL genetic immunization system represents a promising tool for developing candidate vaccines against some of the more difficult infectious, parasitic, and oncologic disease targets.     

Hemagglutination of epizootic hemorrhagic disease virus

Summary Hemagglutination of epizootic hemorrhagic disease virus (EHDV) with a variety of erythrocyte species at 4° C, room temperature and 37° C was dependent on the NaCl molarity and the pH of the diluent. The hemagglutination inhibition test was used to identify EHDV serotypes.     

Occurrence of hematogenous metastasis and serum levels of thymidine phosphorylase in colorectal cancer

Thymidine phosphorylase (dThdPase) is known to promote the development of new blood vessels. Increased dThdPase expression in solid tumors has been shown to correlate with tumor growth, invasion and metastasis. In the present study, we measured dThdPase levels in the tumor tissue and in the serum from the tumor drainage and peripheral venous blood obtained from patients with resectable colorectal cancer. Serum dThdPase levels, measured by a modified ELISA method, were significantly higher in patients with hematogenous metastasis. In the tumor tissue specimens, no significant difference was observed between patients with or without hematogenous metastasis. These results suggest that the serum dThdPase levels are a novel marker to predict occurrence of hematogenous metastasis in patients with resectable colorectal cancer.