Journal of Experimental Pathology最新文献

The macrophage disappearance reaction (MDR) was induced when muramyl dipeptide (MDP) was injected intraperitoneally into guinea pigs bearing macrophage-rich peritoneal exudate cells. Heparin could inhibit the MDR induced by MDP. In the present study, we tested the effect of the immunosuppressive agent cyclosporine A (CsA) on MDR. The MDR was significantly suppressed in guinea pigs given 20 or 100 mg/kg of CsA, although 5 mg/kg of CsA had no effect. The number of macrophages elicited by liquid paraffin was significantly reduced in guinea pigs given with 20 or 100 mg/kg of CsA, but not in those given 5 mg/kg of CsA. These results indicate that CsA could directly affect macrophages in vivo, through a relatively high dose was required. Cyclosporine A (CsA), a cyclic peptide of 11 amino acids, is a fungal metabolite with potent immunosuppressive properties. Numerous experimental and clinical trials have demonstrated its effectiveness in organ transplantation. It has been suggested that primary target cells of CsA were T-lymphocytes, and macrophages were not directly affected. However, recent studies in an in vitro system have shown that some functions of macrophage are affected by CsA. These include chemotaxis (Drath & Kahan, 1983), interleukin-1 generation (Bunjes et al., 1981), prostaglandin E production (Whisler et al., 1984) and procoagulant activity (Carlsen et al., 1985). However, the effect of CsA on macrophages has not been elucidated in vivo. The macrophage disappearance reaction (MDR) is an in vivo manifestation of cell-mediated immunity and/or delayed type hypersensitivity (Sonozaki et al., 1975). Furthermore, our previous study demonstrated a possibility that MDR was an in vivo manifestation of macrophage activation (Ochiya et al., 1982). Muramyl dipeptide (MDP; N-acetyl-muramyl-L-alanyl-D-isoglutamine), a synthetic analogue of water soluble components of bacterial cell wall peptidoglycans, is known to have the ability to activate macrophages (Nagao et al., 1979). In the present study, attempts were made to induce MDR by MDP and the effect of CsA on the MDR was studied.

The fluorescence polarization technique with 1,6-Diphenyl-1,3,5-hexatriene as a probe, was used to determine the lipid rotational mobility (LRM) measured by fluorescence anisotropy of isolated whole mitochondria of the rat kidney following normothermic ischemia of 30, 45, 60 and 90 minutes and upon reperfusion for 24 hours. The LRM of mitochondrial membrane lipids of the ischemic kidney decreased steadily with increasing ischemic times (0.1590 vs. 0.1705, 0.01 less than P less than 0.001 at 60 minutes). Following 24 hours reflow, there were no significant differences in the LRM of mitochondria between ischemic and control groups up to 45 minutes of ischemia, (0.1688 vs. 0.1705, 0.5 less than P less than 0.6). However, when kidney was subjected to ischemic periods longer than 60 minutes, the decreased LRM remained fixed even after reperfusion (0.1783 vs. 0.1738, 0.5 less than P less than 0.6). This suggests that 60 minutes of ischemia probably produces irreversible damage to the mitochondrial membrane whereas lesser degrees of ischemic injury is reversible upon reperfusion.

Proteolytic enzymes may have potential value in the prophylaxis of malignant tumor development. C3H/HEJ mice, used for their ability to produce spontaneous mammary tumors, were injected intraperitoneally (IP) with proteolytic enzyme hydrolysate at a dosage range of 0.038 to 0.462 mg/gm body weight. The injections were given every other day, once a day for six months. The pathology results showed suppression of growth, and necrosis (and in some cases encapsulation) of the mammary tumors in C3H/HEJ mice. Concurrently, SP 2/0-AG 14 cells grown in the presence of 0.25 mg enzyme/ml to 3.75 mg enzyme/ml of proteolytic enzymes, showed little cellular deterioration when the dosage range remained below 1 mg enzyme/ml. When dosage ranges were greater than 1 mg enzyme/ml, cellular necrosis occurred within three days of the addition of the proteolytic enzymes. These results demonstrate that the proteolytic enzymes used in these experiments were beneficial in preventing tumor development and prolonging survival of C3H/HEJ mice when used in the appropriate concentration range. A portion of these results were presented elsewhere (2nd Int. Biotechnol. Expo; Oct. 1989; San Francisco).

In almost all studies using paraffin embedded tissue, c-myc protein has been found in the cytoplasm of cells. Since the protein is normally localized in the nucleus it is difficult to determine which histochemical observations are real and which are artefactual. The study designed here evaluated several different methods of fixation prior to paraffin embedding in an attempt to identify which would prevent the diffuse of the protein out of the nucleus. Using various fixation procedures (formalin, paraformaldehyde, B-5, Zamboni and AMeX) we found that fixation in cold acetone (-20 degrees C) overnight followed by 2x15 min fixation in acetone at +4 degrees c and at room temperature, cleared in methyl benzoate and xylene (AMeX procedure) gives reproducible nuclear staining when a variety of normal and tumor tissues are treated with an anti c-myc protein antibody. This method was then compared to frozen sections. While there was no cytoplasmic staining in same tissue specimens in both AMeX processed and frozen sections, the tissue architecture was much better preserved in AMeX processed samples. Our data strongly suggest that AMeX fixation, originally developed for T and B lymphocyte antigens, should be used for immunolocalization of c-myc oncoprotein in paraffin embedded tissues.

We surgically removed lenses and as much retina as accessible in one eye of six pigmented rabbits which were followed for up to four months postsurgically. Clinically, pre-RPE membranes were noted to form within the first weeks after surgery, and eyes remained hypotensive in the absence of notable inflammation. Morphologic studies demonstrated a variable response of RPE, ranging from atrophy to hypertrophy and hyperplasia. Pre-RPE membranes appeared to arise from both the RPE as well as from tags of peripheral retina and were of two morphologic types: spindle cell-collagenous membranes, and a highly cellular glial membrane. Bone formation within collagenous membranes was seen in four of six eyes studied.

We have investigated lipid peroxidation and oxidation of lignoceric acid in response to oral thioridazine administration, to better understand the effects of phenothiazines, which are one of the more commonly used therapeutic agents. Measurements at different time intervals showed that levels of lipid peroxides in rat kidney were markedly decreased after thioridazine feeding, however, the oxidation of lignoceric acid was found to be elevated immediately after the start of thioridazine treatment. These biochemical changes were noted to be associated with mitochondrial proliferation and lipid accumulation in renal epithelial cells. The observed renal biochemical and morphological changes following thioridazine feeding return to the normal levels after two weeks of withdrawal of the drug. This study suggests that phenothiazines could be beneficial in reducing cellular injury by reducing the levels of lipid peroxides during pathological conditions like ischemia.

The time course of lesion development in mice induced by a single intraperitoneal (ip) LD50 dose of Pseudomonas aeruginosa slime glycolipoprotein (GLP) was studied. Slime GLP exerted a marked effect on the lungs, liver and kidneys without any microscopic changes in other organs. The first histological lesions were observed in the lungs 7h after ip injection and were characterized by thickening and pleomorphic inflammatory infiltration of the intraalveolar septae leading to focal atelectasis by 28 h. The initial morphological alterations in the liver were observed at 14 h and consisted of balloon degeneration of the hepatocytes, especially around the central veins, leading to fatty change within 21 h and confluent hepatocellular necrosis at 28 h. The kidneys showed hydropic degeneration of the renal tubular epithelial cells at 14 h and frank necrosis by 28 h post ip injection. The kidney and liver lesions were accompanied by a parallel rise in serum levels of blood urea nitrogen and aspartate and alanine aminotransferases.

Cytokines including interferon (IFN) and tumor necrosis factor (TNF) are potent modulators of immune processes. They are synthesized in response to microbial infections and inflammation. TNF and IFN interact with other cytokines to elicit differentiation and cellular responses of specific target cells. In view of their multiple biological effects, we have postulated that dysregulation of IFN and TNF may contribute to the pathogenesis of HIV infection. Here, we review data showing that the expression of IFN-alpha receptors is down-regulated in patients with AIDS. As a consequence, HIV-infected cultured cells and cells from AIDS patients show hyporesponsiveness to IFN action. This could contribute to mechanisms by which HIV evades the antiviral activity of IFN-alpha in HIV-infected cells and raise the question of the usefulness of IFN-alpha in the treatment of end-stage AIDS. TNF is a major mediator of inflammation and sepsis and also is capable of inducing the replication of HIV. TNF synthesis and its receptor expression are upregulated by the acid-labile IFN-alpha subtype present in the sera of HIV-infected individuals. In addition, the acid-labile IFN present in AIDS sera may contribute to the pathophysiological changes in sepsis by rendering the cells from AIDS patients hypersensitive to endotoxin stimulation resulting in further synthesis of TNF. Thus aberrant regulation of these cytokines and their cognate receptors are likely contributing factors to the pathogenesis of AIDS.

MRL1/1 & NZB/WF1 female mice were treated with high-dose cyclophosphamide (20 mg/kg/week), and the distribution of T cells in the Peyer's patches was examined in treated and untreated mice. A multiple layering technique was used for immunohistochemical detection of the lymphocyte surface antigens of T cells (Thy1.2, L3T4, Lyt2). High-dose cyclophosphamide inhibited the increase of the T cell population of MRL1/1 female mice with age, but little change was observed NZB/WF1 female mice.