The role of γδ T cells in priming macrophages to produce tumor necrosis factor-α

The secretion of tumor necrosis factor (TNF)-α from macrophages is regulated by both priming and triggering signals. We found that macrophages from mice lacking γδ T cells [T cell receptor (TCR) δ^?/- mice], which lack the gene encoding the δ chain, produced only small amounts of TNF-α in response to lipopolysaccharide (LPS) and showed a reduced level of expression of CD14. Pre-incubation of macrophages from TCR δ-/- mice with γδ T cells from their TCR δ^+/- littermates restored their capacity to produce TNF-α in response to LPS. The priming activity of γδ T cells was in part inhibited by neutralizing anti-interferon (IFN)-γ monoclonal antibodies. Collectively, these results suggest that γδ T cells play a role in priming macrophages to a steady state of activation via IFN-γ secretion, which allows them to produce TNF-α when exposed to LPS.     

Changes in somatosensory circuits after subcortical infarct in rats

We compared the functional and anatomical alterations of somatosensory circuits in the acute (1-3 days after infarct) and chronic (3 months after infarct) stage after subcortical striatal infarct in Wistar rats. Occlusion of the left middle cerebral artery produced subcortical striatal infarct in approximately 69% of the rats. The others developed cortical infarct. The function of the somatosensory circuits was evaluated by [14C]2-deoxyglucose autoradiography during physiological stimulation of the right vibrissae and face. In rats with subcortical infarct, the areas activated by sensory stimulation of the right vibrissae and face, applied 1 and 3 days after occlusion, were reduced compared to sham-operated controls (P < 0.05). In the chronic stage of subcortical infarct, the areas of metabolic activation of the left anterior vibrissal and facial sensory area were increased compared to rats with acute subcortical infarct (P < 0.05). To evaluate the anatomical changes in the somatosensory pathway, at 1 day and 3 months after occlusion, we injected wheat germ agglutinin-horseradish peroxidase solution as an axonal transport substance bilaterally into the anterior vibrissal and facial sensory area. Tract tracing studies in both the acute and chronic stage of subcortical infarct showed a reduction in the peroxidase-positive area in the left thalamus compared to the control hemispheres (P < 0.01). The functional disturbance and recovery of the somatosensory circuits after subcortical infarct are discussed.     

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.     

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.     

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.     

Nonoperative Removal of Bilateral Intrahepatic Biliary Stones by Endoscopic Electrohydraulic Lithotripsy

We report the successful treatment of bilateral intrahepatic biliary stones by endoscopic electrohydraulic lithotripsy (EHL). EHL is a useful procedure by which large stones can be fragmented easily and complete removal of stones can be attained.     

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.