Sequential T Cell Response Involved in Tumor Rejection of Sarcoma, Meth A, in Syngeneic Mice

We investigated the type of T cell response involved in Meth A tumor rejection in primary immune and hyperimmune syngeneic mice. It was found that a CD4⁺ T cell-mediated delayed-type hypersensitivity (DTH) response activating non-specific killer cells such as macrophages, NK and LAK cells, without a specific CD8⁺ cytotoxic T lymphocyte (CTL) response, was the major immune response leading to Meth A tumor rejection in primary immune mice. In contrast, the specific CD8⁺ CTL response was the major response leading to the tumor rejection, in addition to CD4⁺ T cell-mediated DTH response, in hyperimmune mice. Analysis of CD4⁺ T cell clones established from primary immune and hyperimmune spleen cells indicated that a CD4⁺ T cell clone (C9) of primary immune mice (although only one clone was established) was of Th1 type, and induced cytotoxicity in accessory cells by classic DTH in vitro. Eight CD4⁺ T cell clones were established from hyperimmune spleen cells. Six out of the eight clones were of the Th2 type and two were Th0-like. However, no Th1-type CD4⁺ T cell clone was established from hyperimmune spleen cells. All of these CD4⁺ T cell clones, even the Th2-type clones, were capable of inducing cytotoxicity in vitro in T cell-depleted accessory cells, as in an in vitro DTH response. We postulate on the basis of these results that the T cell response leading to Meth A tumor rejection in vivo sequentially changed from a CD4⁺ T cell-mediated classic DTH response to a CD8⁺ CTL response, in addition to a cellular response mediated probably by Th2-type cells, during the process of repeated immunization.     

Released washed platelet concentrates are effective and safe in patients with a history of transfusion reactions

Background

Plasma removal by washing is an effective approach to prevent transfusion reactions by platelet concentrates (PCs). Recently, washed PCs were released by the Japanese Red Cross Society (JRCS).

Haemophagocytic lymphohistiocytosis, interferon-gamma-naemia and Epstein-Barr virus involvement

Summary. To clarify the correlation between Epstein-Barr virus (EBV) involvement and hypercytokinaemia in haemophagocytic lymphohistiocytosis (HLH), we analysed serum interferon-gamma levels and EBV-DNA in biological specimens obtained from 25 HLH cases (23 children and two adults). We found that HLH patients showed a wide range of serum IFN-gamma levels from 0.2 to 1300 U/ml, with a median 126U/ml for EBV-DNA-positive (n = 9) and 4.5 U/ml for EBV-DNA-negative (n = 16) groups. The latter group could be classified further into a group with hyper-IFN-gamma-naemia (> 4.5 U/ml) (n = 8) and a group without hyper-IFN-gamma-naemia (n = 8). The survival of the hyper-IFN-gamma-naemic cases was significantly poorer than non-hyper-IFN-gamma-naemic cases. We conclude that EBV is probably involved in one third of the HLH cases, all of whom show hyper-IFN-gamma-naemia, and in the half of the HLH cases with hyper-IFN-gamma-naemia who have a rapidly fatal outcome.     

Vector potential of cockroaches for Helicobacter pylori infection

OBJECTIVES: The routes of human infection with Helicobacter pylori remain unclear. In the present study, we examined cockroaches as possible vectors for transmission of H. pylori. METHODS: We used a common species of cockroach (Periplaneta fuliginosa). After a 3-day fast, cockroaches were placed on agar plates containing freshly grown H. pylori (Sydney strain) (challenge group) or on sterile agar plates without H. pylori (control group). After 24 h of challenge, cockroaches were moved to disinfected containers, and sterile food and water were provided. The external surfaces (legs and body) and excreta of the cockroaches were sampled for culture, rapid urease test, and polymerase chain reaction (PCR). RESULTS: H. pylori were culturable from the excreta of the challenge group for 24 h postchallenge. Positive rapid urease test results were obtained up to day 3, and PCR analysis was positive for H. pylori DNA up to day 7 from the excreta. In contrast, H. pylori were not culturable from the external surfaces of the cockroaches. The rapid urease test was positive for only 8 h, and PCR analysis was positive for H. pylori DNA for 1 day from the external surface. CONCLUSIONS: Cockroaches usually live in unsanitary environments and may contaminate foods and food containment areas such as pantries. Transmission of H. pylori infection could be achieved via inadvertent ingestion of foods contaminated with cockroach excreta containing viable H. pylori.     

The effect of heparin on tissue factor and tissue factor pathway inhibitor in patients with acute myocardial infarction

We examined plasma TF and free TFPI levels in 26 consecutive patients with AMI, 26 patients with stable exertional angina, and 25 patients with chest pain syndrome. In patients with AMI, blood samples were obtained immediately after admission and at 4, 8, 16, 24, and 48 h, and the third, fifth, seventh, and fourteenth day after initiation of reperfusion therapy. Plasma TF levels in patients with AMI on admission were significantly higher than in the chest pain syndrome and stable exertional angina groups (248.0+/-117. 4 vs. 179.5+/-29.2 vs. 189.5+/-29.6 pg/ml, P<0.01). In patients with AMI, the level subsequently decreased after heparin administration and was maintained at significantly lower levels compared to those on admission. Plasma free TFPI levels in patients with AMI on admission were significantly higher than in the chest pain syndrome and stable exertional angina groups [33.5+/-12.4 vs. 26.0+/-7.6 ng/ml (P<0.01) vs. 27.5+/-6.3 ng/ml, P<0.05]. In patients with AMI, it reached the maximum level at 4 h after the administration of heparin, and gradually decreased over the time course. These data indicated that continuous administration of a low dose of heparin was effective in decreasing TF levels without affecting TFPI levels. Our results elucidate one of the mechanisms by which the administration of heparin is beneficial in AMI patients undergoing percutaneous revascularization.     

O2 activation by core–shell Ru13@Pt42 particles in comparison with Pt55 particles: a DFT study

The reaction of O₂ with a Ru₁₃@Pt₄₂ core–shell particle consisting of a Ru₁₃ core and a Pt₄₂ shell was theoretically investigated in comparison with Pt₅₅. The O₂ binding energy with Pt₅₅ is larger than that with Ru₁₃@Pt₄₂, and O–O bond cleavage occurs more easily with a smaller activation barrier (E_a) on Pt₅₅ than on Ru₁₃@Pt₄₂. Protonation to the Pt₄₂ surface followed by one-electron reduction leads to the formation of an H atom on the surface with considerable exothermicity. The H atom reacts with the adsorbed O₂ molecule to afford an OOH species with a larger E_a value on Pt₅₅ than on Ru₁₃@Pt₄₂. An OOH species is also formed by protonation of the adsorbed O₂ molecule, followed by one-electron reduction, with a large exothermicity in both Pt₅₅ and Ru₁₃@Pt₄₂. O–OH bond cleavage occurs with a smaller E_a on Pt₅₅ than on Ru₁₃@Pt₄₂. The lower reactivity of Ru₁₃@Pt₄₂ than that of Pt₅₅ on the O–O and O–OH bond cleavages arises from the presence of lower energy in the d-valence band-top and d-band center in Ru₁₃@Pt₄₂ than in Pt₅₅. The smaller E_a for OOH formation on Ru₁₃@Pt₄₂ than on Pt₅₅ arises from weaker Ru₁₃@Pt₄₂–O₂ and Ru₁₃@Pt₄₂–H bonds than the Pt₅₅–O₂ and Pt₅₅–H bonds, respectively. The low-energy d-valence band-top is responsible for the weak Ru₁₃@Pt₄₂–O and Ru₁₃@Pt₄₂–OH bonds. Thus, the low-energy d-valence band-top and d-band center are important properties of the Ru₁₃@Pt₄₂ particle.

In this theoretical study by DFT computations, characteristic features of the Ru₁₃@Pt₄₂ core–shell particle in O₂ activation are clearly discussed in comparison with Pt₅₅.     

Successful laparoscopic extirpation of a large omental lipoblastoma in a child

Omental lipoblastoma is extremely rare among benign tumors. We herein report the case of a child who underwent laparoscopic extirpation of a large omental lipoblastoma. A 4‐year‐old girl was diagnosed with an intra‐abdominal solid tumor. Abdominal imaging revealed a fat density mass that was well encapsulated and measured 18 × 15 × 7.5 cm in size. Considering the MRI findings and movability of the tumor, we strongly suspected that the lesion was an omental lipoblastoma. We initially decided to perform laparoscopic exploration and, if possible, extirpation of the solid tumor sequentially. A total of five trocars were used, and the tumor was found to originate from the omentum. We successfully performed complete resection of the tumor laparoscopically. A histological examination revealed lipoblastoma. For large abdominal tumors in children, the laparoscopic approach is recommended as the first procedure when the tumor is preoperatively considered to be benign and resectable.     

Coexpression of CD40 and CD40 ligand in Epstein-Barr virus-infected T and NK cells and their role in cell survival

We investigated the role that CD40-CD40 ligand (CD40L) signaling plays in survival of Epstein-Barr virus (EBV)-infected T and NK cells. EBV-infected T and NK cell lines derived from patients with either chronic active EBV infection (CAEBV) or nasal T/NK cell lymphoma, as well as virus-infected peripheral T cells freshly isolated from a patient with CAEBV, were shown to express both CD40 and CD40L on their surface. Apoptosis of these cells was enhanced by blockade of CD40-CD40L signaling by a fusion protein of CD40 and immunoglobulin G (CD40Ig). Expression of CD40 was induced in human CD40L-positive Jurkat T cells after experimental EBV infection, and apoptosis of infected cells was enhanced by CD40Ig. These results suggest that CD40-CD40L signaling promotes survival of EBV-infected T and NK cells and, thus, plays an important role in the pathogenesis of T/NK lymphoproliferative disorders associated with the virus.