Endocytosis of human thyroglobulin (TG) in adenomatous goiter studied by an immuno-electron microscopic procedure

Five cases of adenomatous goiter have been studied by an electron microscope using an immuno-reaction for thyroglobulin (TG) and focusing on the mechanism of endocytosis. Positive stain for TG was demonstrated in follicular lumina, large reabsorbed colloid droplets and small subapical vesicles. Endocytotic vesicles ranging from 320 nm to 1600 nm in diameter were observed in the cytoplasm as pits in the apical plasma membrane. Some of them showed direct connection with the positive stain for TG in the follicular lumen and the others were completely ingested in the cytoplasm. With statistic analysis, a majority of the vesicles showing the positive stain for TG in the cytoplasm distributed in the range of 200 nm to 1200 nm in diameter with the peak in 300 nm to 399 nm and was situated within an extent of the diameter measured from the endocytotic vesicles. Engulfment of colloid by pseudopods and fusion of the reabsorbed colloid droplets were encountered as extremely rare findings and appeared to play no major role for formation of large colloid droplets in adenomatous goiter.     

Telomerase activity in the human endometrium throughout the menstrual cycle

In a total of 41 endometrial tissue samples, the relationship between telomerase activity and proliferating cell nuclear antigen (PCNA) labelling index was studied. In samples of endometrium from the proliferative phase of the menstrual cycle, telomerase activity was found in 15 out of 17 cases (88%). Two samples from the early proliferative phase showed negative telomerase activity and a low PCNA labelling index. However, three out of 16 samples of early secretory phase endometrium showed telomerase activity and a PCNA labelling index. In mid- to late secretory phase endometrium, in menopausal endometrium and in decidualized endometrium induced by progesterone neither telomerase activity nor PCNA labelling was found. These results suggest that telomerase activity of the endometrium may be correlated with the proliferative potential of the epithelial cells and that its activity may be regulated by oestrogen.      

Further development of a recombinant feline herpesvirus type 1 expressing the Gag protein of feline immunodeficiency virus

Summary.  We have previously reported the construction of a recombinant feline herpesvirus type 1 (FHV-1), designated C7301ddlTK-gag, expressing the Gag precursor protein of feline immunodeficiency virus (FIV). In this study, we report the construction of a further recombinant FHV-1 (ddlTK(gBp)-gag) which carries an FHV-1 gB promoter sequence upstream of the FIV gag gene of C7301ddlTK-gag. Strong expression of the FIV Gag protein by ddlTK(gBp)-gag was confirmed by immunoblot analyses and enzyme-linked immunosorbent assays. Although C7301ddlTK-gag and ddlTK(gBp)-gag failed to induce anti-FIV Gag antibodies in cats, we confirmed the infectivity and stability of these recombinants in cats. Received January 14, 2000 Accepted August 4, 2000     

Radiation-induced reactive oxygen species formation prior to oxidative DNA damage in human peripheral T cells

Previously, we demonstrated that human peripheral T lymphocytes revealed early apoptotic changes (annexin V-positive) and late apoptotic changes (propidium iodide-positive), at 13 and 24 h, respectively, after irradiation of 5 Gy. Changes in mitochondrial membrane potential were observed at 10 h after irradiation of 5 Gy. Subsequently, mitochondrial cytochrome c-release was confirmed. In order to elucidate the mechanism which acts prior to the mitochondrial membrane potential changes, we examined in the previous study the radiation dose and the timing of oxidative DNA damage induced in human peripheral T lymphocytes following 10 MV X-ray irradiation. As a result, the production of 8-oxoguanine, i.e., the product of oxidative DNA damage, was clearly identified starting at 10, 6, and 3 h, after 2, 5, and 20 Gy of irradiation, respectively. Therefore, we examined in the present study reactive oxygen species (ROS) formation in T lymphocytes following 5 Gy of irradiation. Using a CCD camera system, we monitored fluorescence in T lymphocytes loaded with the succinimidyl ester of dichlorodihydrofluorescein diacetate (H2DCFDA), which is non-fluorescent until oxidized by ROS. We found that ROS formation occurred immediately after irradiation, continued for several hours, and resulted in oxidative DNA damage. Therefore, the origin of hyper-radiosensitivity of T lymphocytes seemed to be the high production of ROS in the mitochondrial DNA following irradiation.     

Behçet Disease and the HLA System

Seventy-three unrelated patients with Behçet disease together with 33 members of seven families with at least two patients per family were tissue typed for 26 antigens of the HLA system. The patients with the complete type of Behçet disease were found to have HLA-B5 more significanth than healthy individuals. Family studies suggest that the genes closely linked to HLA locus influence the degree of severity of Behçet disease.     

An abnormal signal transduction pathway in CD4-CD8- double-negative lymph node cells of MRL lpr/lpr mice.

We describe here a novel 26-kDa posphoprotein (p26), associated to the T cell receptor of CD4-CD8- lymph node cells of lpr/lpr mice, but not present in significant amounts in control mouse cells including polyclonally activated T cells. lpr p26 is constitutively phosphorylated on a tyrosyl residue. It is most likely a member of the G protein family and displays high GTP-binding and GTPase activities both unsensitive to interleukin 2. Bordetella pertussis toxin has no effect on the spontaneously enhanced GTP hydrolysis. The traits associated to p26 could contribute to the distinctive features of lpr/lpr double-negative cells.