Possible role of hepatocyte growth factor in regeneration of human peritoneal mesothelial cells

Human peritoneal mesothelial cells (HPMCs) play an important role in peritoneal functions. During long term peritoneal dialysis, it has been reported that HPMCs are damaged by high glucose solution via the signal of transforming growth factor (TGF)-beta1 produced by HPMCs. In this study, we focused on the effect of hepatocyte growth factor (HGF), known as an anti-fibrotic and anti-TGF-beta1 agent, on HPMCs damaged by high glucose solution. HPMCs were isolated from specimens of the omentum from nonuremic patients after informed consent had been obtained. After confirming adhesion for 6 hours, 100 microL of DMEM with 0.5%FCS were added at different concentrations (D-glucose; 6, 30 mM) with or without HGF (10, 30, 100 ng/mL) for 48 hours. We examined the effects of a high concentration of glucose and then focused on following four critical points: 1) the production of HGF from HPMCs exposed to a high concentration of glucose, 2) the expression of c-Met on HPMCs, 3) the viability of those cells, and 4) matrix metalloproteinase-2 (MMP-2) and tissue inhibitors of metalloproteinase-2 (TIMP-2). The following significant changes are described herein: high glucose solution and TGF-beta1 i) decreased HGF production from HPMCs and ii) up-regulated expression of c-Met on HPMCs, and addition of HGF iii) restored viability of HPMCs damaged by glucose, iv) suppressed TGF-beta1 production by HGF, and v) induced up-regulation of MMP-2 and decreased TIMP-2 production by HPMCs. Levels of HGF decreased by high concentrations of glucose in the peritoneal cavity may induce the loss of HPMCs and thereby result in peritoneal fibrosis. These results suggest that HGF is an effective agent in the regeneration of peritoneal membrane damaged by high glucose solution.     

Proliferating cell nuclear antigen in malignant and pre-malignant lesions of epithelial origin in the oral cavity and the skin: an immunohistochemical study

Summary Proliferating cell nuclear antigen (PCNA) is a nuclear protein synthesized in the late G₁ and S phase of the cell cycle and immunohistochemical detection of the protein represents a useful marker for the proliferating fraction of cells in tissue specimens. A series of malignant and pre-malignant lesions of the oral cavity and skin were evaluated by the streptavidin biotin immunoperoxidase method for detection of this protein. Monoclonal anti-PCNA antibody (PC 10) labelled proliferating cells in all cases with varying intensity of nuclear staining. In squamous cell carcinoma (n=48), PCNA positivity correlated with the differentiation and atypia of the tumour cells; however, in poorly differentiated tumours, the relationship between PCNA expression and proliferation was lost. Basal cell carcinoma showed an increased growth fraction in tiny epithelial nests (mean 43.8, SD 6.0,n=20) than in neoplastic basal cells (mean 30.1, SD 6.9,n=8). The growth fractions were significantly higher in the pre-malignant lesions (leukoplakia, mean 22.3, SD 7.7,n=14; Bowen's disease, mean 45.2, SD 11.7,n=12; senile keratosis, mean 41.2, SD 7.0,n=12) than in the normal mucosa (mean 9.8, SD 4.9,n=10), suggesting that cellular growth fractions correlate with the degree of dysplasia in pre-malignant lesions.     

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     

Neuropathology of the Central Nervous System in Acquired Immune Deficiency Syndrome (AIDS) in Japan

The neuropathologiesl features of the central nervous system in IS autopsy cases of Japanese male with AIDS were reported. Nine patients had various histological changes including a variety of opportunistic infections in six patients (40%), primary malignant lymphoma of the brain in two (13%), AIDS encephalopathy in four (27%) and vacuolar myelopathy in one (7%). Usually, these pathological changes were present concomitantly. AIDS encephalopathy was characterized by infiltration of mono and multinucleated cells and myelin pallor with astrogliosis located predominantly in the cerebral white matter and subcortical gray matter. Furthermore, unevenly distributed neuronal loss of the cerebral cortex was apparent in one case. Diffuse astrocytosis of the gray matter out of proportion to neuronal loss was also an outstanding finding in another case. The present study suggested that not only the white matter changes but also gray matter alterations might be the morphological substrates of AIDS encephalopathy.     

Distribution of 5'-nucleotidase activity in greater omentum of rats

The aim of the present study is to demonstrate the cellular basis of 5'-nucleotidase (5'-Nase) activity in the greater omentum of rats. Enzyme histochemistry for 5'-Nase showed that lymphatic vessels in the omentum as well as lymphocytes in the milky spots were positively stained. Electron microscopic observation revealed-5'-Nase activity at the luminal surface of the lymphatic endothelial cells, pinocytotic vesicles in the endothelial cells and the surface of fibroblasts located at the intercellular space of adipose cells. Fibroblasts extended long cytoplasmic processes toward adipose cells and inflammatory cells. These findings suggest that lymphatic endothelial cells as well as fibroblasts in the omentum may play an important role in regulation of metabolism and immune mechanisms in the greater omentum by supplying adenosin.