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Biomedical subjects

M Iijima

Publications and source records attributed to M Iijima.

At least 235 records · Page 13Linked to original sources
PubMed1984

Epidermal Langerhans cells can function as stimulatory cells but not as accessory cells in CTL induction.

In this study, we determined whether Langerhans cells (LC) can function as both stimulatory and accessory cells (ACC) in alloreactive and syngeneic modified CTL induction in vitro. LC exhibited potent Ia+ stimulatory function, comparable to spleen cells, in both allo-CTL induction and in TNP-modified CTL induction assays. In contrast to spleen cells, however, when LC were syngeneic to the responders in an Ia+-adherent cell-depleted CTL culture, they could not restore the CTL responses. This was due, in part, to the suppression of CTL induction, presumably via secretion of prostaglandin E by epidermal cells (EC), because addition of indomethacin reversed the suppression. Even in the presence of indomethacin, however, LC were unable to exhibit ACC function. Finally, we tested the possibility that both Ia+ and Ia- cells were required to fulfill ACC functions. However, when spleen cells treated with anti-Ia antibody and complement and EC and indomethacin were added to an Ia+-adherent cell-depleted CTL culture, there was no significant restoration of the CTL response. Thus, LC can clearly act as Ia+ stimulatory cells in CTL induction but cannot serve as ACC in CTL induction, whereas Ia+ spleen cells may subserve both functions. These data suggest a functional heterogeneity of Ia+ antigen-presenting cells in spleen and in epidermis.

Animals↗
PubMed1983

A semiquantitative morphologic assessment of chlordecone-potentiated chloroform hepatotoxicity.

A semiquantitative morphologic procedure has been applied to chlordecone potentiation of CHCl3-induced liver injury in male Sprague-Dawley rats. The distance of the injured area from the terminal hepatic venule (THV) to the portal area was measured and the damaged cells were classified by type. The results were plotted graphically, along with elevations in plasma enzyme activities (GPT and OCT), to depict the pattern of damage. Chlordecone pretreatment enhanced the severity of the CHCl3-induced cellular changes and increased the number of cells affected. Dosages of 5 mg/kg of chlordecone did not potentiate CHCl3 toxicity, but higher dosages (10-50 mg/kg) enhanced the toxic response in a dose-dependent manner.

Alanine Transaminase↗
PubMed1983

Specific immunologic tolerance to dinitrofluorobenzene following topical application of dinitrothiocyanobenzene: modulation by suppressor T cells.

In order to determine the mechanism(s) involved in the induction of immunologic tolerance for contact sensitivity via the topical application of a chemical that sensitizes if given with adjuvant, we utilized the hapten dinitrothiocyanobenzene (DNTB). Specific immunologic tolerance to dinitrofluorobenzene (DNFB) was induced in mice by the topical application of DNTB 7 days before sensitization to DNFB. The tolerance could be abrogated if cyclophosphamide (200 mg/kg) was given 3 days before attempted sensitization. Using passive transfer studies we found that DNTB induced hapten-specific Lyt 1+2- suppressor T cells. These suppressor cells prevented the induction of contact sensitivity but did not affect its expression. Lymphocyte proliferation studies, using haptenated epidermal cells as antigen, indicate that lymph node cells obtained 5 days after DNFB sensitization are far less responsive if the mice have received DNTB epicutaneously 7 days before the DNFB. Binding studies demonstrated that DNTB bound to epidermal cells at least as well as did DNFB. It is postulated that DNTB induction of suppressor cells is related to the physicochemical interaction between the hapten and antigen-presenting cells in skin.

Administration, Topical↗
PubMed1983

Development of excitability during the in vitro differentiation of a newly established myogenic cell line.

Developmental changes in the membrane electrical properties during the differentiation of a newly established clonal myogenic cell line MC3T3-A1/M13 (M13) derived from newborn mouse calvaria were studied using the conventional intracellular recording method. M13 cells proliferated in vitro with a population doubling time of about 20 hr when they were cultured in alpha-MEM containing 10% newborn bovine serum at 37 degrees C. After they had achieved confluence and stopped growing, myotube formation by fusion of individual postmitotic mononucleated cells took place within 48 hr, and it advanced until 70-80% of the total number of nuclei were incorporated into such myotubes. Mononucleated M13 cells had a resting membrane potential (Em) of -22.5 +/- 1.7 mV (mean +/- S. D.) and responded passively to current stimuli, indicating that they are non-excitable. On the contrary, multinucleated myotubes had EmS ranging from -25 to -70 mV, depending on the stage of their development. Newly fused myotubes had relatively less negative EmS and showed no response, whereas myotubes later in development showed delayed rectification against depolarizing current pulses, proving the development of a voltage-sensitive outward current system. Further, mature myotubes had an Em of -58.5 +/- 3.2 mV and generated fast action potentials having a maximum rate of rise of 315 +/- 11 V/sec and a duration of 3.0 +/- 0.5 msec (measured at half-height). These action potentials were identified as tetrodotoxin-insensitive Na+ spikes. These results indicate that the membrane excitability of the M13 myogenic cell line develops well after the formation of myotubes, with an increase in Em as maturation proceeds.

Action Potentials↗
PubMed1982

Membranous glomerulonephritis associated with eosinophilic lymphfolliculosis of the skin (Kimura's disease): report of a case and review of the literature.

A 48-year-old male, who had been suffering from eosinophilic lymphfolliculosis of the skin (Kimura's disease) for six years, developed the nephrotic syndrome. Renal biopsy revealed immunopathological and electron microscopic changes characteristic of membranous glomerulonephritis. A review of the literature disclosed a high frequency of renal involvement in Kimura's disease. Out of 175 reported cases of the disease, 21 (12%) were found to have proteinuria including 13 who had the nephrotic syndrome. Some of the patients were noticed to have proteinuria before the onset of the skin lesions, suggesting the existence of common etiological factor(s) capable of inducing both skin and kidney lesions.

Ear Neoplasms↗