Studies of several gene knockout mice suggest an interesting association of a moderate T cell response with systemic autoimmune diseases. In addition, CD95 ligand (FasL) expression in some strains of these mice is impaired. Because FasL is critically involved in regulating peripheral tolerance, there may be a link between autoimmune diseases and a moderate T cell response that cannot activate the FasL gene. Here, we propose that there are two thresholds of T cell activation. When moderately stimulated, T cells can be activated to the low (1st) threshold, which permits the induction of CD40L, IL-2, IL-4, and other components that help the immune response. The high (2nd) activation threshold can only be achieved by a strong and concurrent stimulation through TCR and IL-2R. Once the high threshold is reached, FasL is produced to induce apoptosis of the activated T and B cells. In the absence of the FasL-mediated downregulation, the activated B cells become efficient antigen-presenting cells for self-antigens and excellent responders for T cell help. Such an exacerbating condition, induced by recurrent and moderate activation, favors the development of autoreactive T cells and autoantibody production. Evidence supporting this hypothesis and some predictions that can be tested are described.

Animals↗

PubMedDate not supplied

Sudden increase of plasma fibrinopeptide A levels after induced abortion.

Plasma fibrinopeptide A levels were studied before and after abortion induced during the first trimester of pregnancy. Fibrinopeptide A levels were significantly increased 15 min after the induced abortion, and returned to preoperative values 2h later. This finding suggests that thrombotic activity is transiently increased immediately after the induced abortion. Activation of the clotting factors during the induced abortion appears to be important in controlling uterine hemorrhage.

Abortion, Induced↗

PubMedDate not supplied

Evaluation of the median forehead flap and the nasolabial flap in nasal reconstruction.

Basal cell carcinoma, which accounts for 70%-80% of all cutaneous malignancies in the United States, has increased recently in Japan. We compared methods for reconstruction after surgery for basal cell carcinoma, which is expected to increase further in the future. Thus patients who underwent reconstruction after surgery for basal cell carcinoma of the nose using medial forehead flaps and nasolabial flaps were selected, and the effectiveness of these flaps was compared by taking the size and location of the tissue defect into consideration. As a result, possibly because of anatomical and histological differences of the face between Caucasians and Asians, better results were obtained with nasolabial flaps than with median forehead flaps.

Basal Cell Carcinoma↗

PubMedDate not supplied

Appearance of drug-resistant tumor cells in a maxillary cancer patient undergoing chemotherapy and chemoradiotherapy.

In this study, we examine drug resistance and sensitivity in tumor cell lines cultured from a patient undergoing prolonged chemotherapy. Four serially established primary tumor cell lines (KKM-A, -B, -C, and -D) were cultured from a case of maxillary sinus carcinoma: KKM-A from the nontreated primary tumor; KKM-B from the residual tumor after chemotherapy with cisplatin (CDDP) and 5-fluorouracil (5-FU); KKM-C from the local tumor that recurred following complete remission with chemoradiotherapy (combination of 5-FU, vitamin A, and radiation); and KKM-D from a metastatic lymph node tumor after further chemotherapy with CDDP and peplomycin. The sensitivity of the four cell lines to CDDP, 5-FU bleomycin (BLM), carboquone (CQ), and colchicine was assessed according to the reduction in colony formation. The KKM-A cell line was very sensitive to CDDP, BLM, CQ, and colchicine, whereas the posttreatment cell lines were resistant to these four drugs. The resistant cell lines were probably selected as a result of chemotherapy and radiotherapy. The nontreated KKM-A cell line was naturally somewhat resistant to 5-FU. The 5-FU-resistance of the KKM-B, -C, and -D cell lines was reduced in that order, corresponding to their relative degree of treatment. The KKM-D cell line from the metastatic lymph node showed a different sensitivity from the KKM-B and -C cell lines from the primary site, suggesting a heterogeneity in drug sensitivity between primary and metastatic tumor cells.

Adult↗