The cell dynamics of the receptor on tumor necrosis factor (TNF) were studied with the use of TNF-sensitive KYM cells derived from human myosarcoma. With receptor synthesis inhibited by cycloheximide, the half-life of the surface TNF receptor was 2h in the absence of TNF and 30min in its presence, suggesting that the TNF receptor was non-recycling and that its internalization was accelerated by TNF. During cell incubation with suppression of TNF receptor degradation by chloroquine, the number of surface TNF receptors remained approximately constants, but the total number of surface and internal TNF receptors increased gradually, at 3h reaching 1.5 times of the initial number, thus suggesting continuous synthesis, externalization, internalization, and degradation of the TNF receptor in the absence of cycloheximide. When the cells were incubated with 125I-TNF, the intracellular quantity of the pulse-labeled TNF-receptor complex promptly increased, reaching a maximum at 20 min, and then declining gradually. Thus, it was confirmed that the TNF receptor is internalized as a TNF-receptor complex in the presence of TNF. In incubation with suppression of protein synthesis by cycloheximide following surface TNF receptor digestion by trypsin, TNF receptors reappeared on the cell surface, increasing in the number to a peak level at 60 min and gradually decreasing. The cells previously exposed to cycloheximide with or without TNF showed no recurrence of surface TNF receptors, suggesting that the TNF receptor is non-recycling. The results thus suggest that the TNF receptor is continuously internalized and degraded intracellularly by lysosomes without being recycled regardless of the presence or absence of TNF, and further that its internalization is accelerated when it is part of the TNF-receptor complex.
We describe a patient with transformed follicular lymphoma(FL), expressing p53 but remaining in complete remission(CR) due to bendamustine-rituximab(BR)therapy. She was a 64-year-old female diagnosed with stage IV FL(grade 3A)in July 2007 when she was admitted with right lower abdominal pain and body weight loss. Colonoscopy revealed Bauhin' valve lymphoma of the terminal ileum, and computed tomography(CT)scan showed lymphadenopathy, involving the cervical, mediastinal para-aortic lymph nodes and right tonsil. She received chemotherapy with eight courses of CHOP therapy with rituximab and achieved CR. Two and a half years later, mediastinal lymph node swelling relapsed, and ibritumomab tiuxetan therapy induced the second CR. After ten months, however, a third relapse occurred as a submucosal tumor(SMT)of the stomach. Gastric SMT biopsy showed diffuse large B cell lymphoma(DLBCL)transformation with immunohistochemical expression of p53. Although gastric SMT disappeared after radiotherapy, which achieved the third CR, lymph node swelling was detected again in the para-aortic and-iliac artery lymph nodes in September 2011. Subsequently, she was treated with five courses of BR therapy, because bendamustine had been reported to be effective for p53 gene-deficient B cell neoplasms. The therapy was successful and achieved the fourth CR, demonstrating that BR therapy was effective for p53-expressing DLBCL.
Murine collagen-induced arthritis (CIA) is widely used as an experimental model for human rheumatoid arthritis (RA) . The antibodies specific for type II collagen have an important role in the onset of RA. In technical cooperation with Chondrex Inc. (Seattle, U.S.A), we have developed the novel reagent kit to induce murine arthritis with high efficiency. The kit, referred to Arthritogenic mAb Cocktail (Immuno-Biological Laboratories, Chondrex), is comprised of four kinds of mouse monoclonal antibody (mAb) and LPS. Each of antibodies recognizes different epitopes on type II collagen.The arthritis in multiple joints of limbs was successfully induced within 4 days after treatment of mouse with intravenous injection of 2 mg of mAb mixture and intraperitoneal injection of 50μg of LPS three days after the mixture injection in BALB/c and DBA/1 strain, while iv injection of 5 mg of mAb mixture followed by ip injection of 50μg of LPS was required for induction of arthritis in C57BL/6 strain.Severity of arthritis in BALB/c mice was augmented according to increase in amount of mAb mixture injected. The disease lasted for about three weeks and it could become more chronic by additional administration of either the antibody cocktail or LPS.In BALB/c strain, the arthritis was developed on four limbs with equal grade, whereas in DBA/1 and C57BL/6 strains the forefeet were affected more prominent than the hindfeet.BALB/c-Nude and C.B-17/Icr SCID mice were also subjected to the induction experiment and the arthritis was brought on SCID but not on nude mice.These results show that antibody production for type II collagen in vivo is bypassed with use of the kit and the arthritis can be induced easily and constantly on various kinds of mouse strain without restriction of MHC class. Thus, these stable mouse models for acute and chronic polyarthritis could be useful for screening and/or invention of anti-inflammatory as well as anti-arthritic remedies.
A 75-year-old woman consulted her doctor in January 2014 because of pain in the dorsum of the hands, elbows, shoulders, and knees, bilaterally, and was diagnosed as having remitting seronegative symmetrical synovitis with pitting edema (RS3PE) syndrome. Although the joint pain improved with low-dose prednisolone administration, she was referred to our department in April of 2014 because she had become aware of swelling of the right cervical lymph node. Biopsy of the lymph node demonstrated that she had Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphoma (DLBCL) of the elderly, and colonoscopy revealed early colon cancer. Also, both the lymphoma and colon cancer stained positive for vascular endothelial growth factor (VEGF). Complete remission was achieved after two courses of R-CHOP, and RS3PE syndrome did not relapse. This case suggested the involvement of VEGF produced by EBV-positive DLBCL in the pathogenesis of RS3PE syndrome.
Abstract Protective effects of intracellular glutathione (GSH) against the cytotoxicity of human recombinant tumor necrosis factor (TNF) were investigated. Three tumor cell lines (L‐M, B‐16, HeLa) were used as target cells. Exposure of these cells to buthionine sulfoximine (BSO) or diethyl maleate (DEM) resulted in the depletion of intracellular GSH content to 5.2‐43.0% of control values and enhancement of their susceptibility to TNF cytotoxicity. The hydroxyl radical production in L‐M cells stimulated by TNF was increased by treatment with BSO or DEM. These results are consistent with the suggestion that intracellular GSH exerts its protective function against the cytocidal effect of TNF by inhibiting the hydroxyl radical production stimulated by TNF.
Muscle cramps are side effects commonly associated with tyrosine kinase inhibitor (TKI) treatment. Patients suffering from muscle cramps are treated with various medications such as calcium, magnesium and vitamin supplements, but these therapies are often ineffective. We report two patients with chronic myelogenous leukemia who developed muscle cramps caused by TKI. These patients were treated successfully with levocarnitine. Both of our cases revealed the beneficial effects of levocarnitine treatment on TKI-induced muscle cramps.
