Journal of Experimental Pathology最新文献

Interferon inhibits the normal replication of C-type virus particles grown in vitro. The ability of interferon to produce a similar effect in vivo was tested in rhesus monkey placentas which are known to contain C-type virus particles. Samples of placenta from 6 monkeys treated with recombinant leukocyte A interferon (25 x 10(6) units/kg) for 7 to 21 days and from 6 control monkeys were examined in the electron microscope. Budding and immature C-type virus particles were present in every placenta examined from both interferon-treated and control monkeys. Mature particles were found in placentas from 3 of 6 monkeys in both treated and control groups. Possible explanations for the absence of detectable effects of interferon in C-type virus particle formation in these placentas are unresponsiveness of the trophoblast to interferon or inadequate exposure time to interferon of placental sites from which C-type particles are produced.

The glycoconjugate composition of intestinal goblet cell mucin was characterized according to the anatomical distribution of lectin-binding sites in surgically resected intestinal tissues and mucosal biopsy specimens obtained from 38 control subjects, and from 32 patients with the active phase of ulcerative colitis, and 12 with Crohn's disease. Immunoperoxidase labeling studies found that in control tissues binding by Soybean Agglutinin (SBA), Dolichos Biflorus Agglutinin (DBA), Wheatgerm Agglutinin (WGA), and Ricinus Communis Agglutinin-120 (RCA-120) was consistently higher than that of Peanut Agglutinin (PNA), Ulex Europaeus Agglutinin-1 (UEA-1), Concanavalin A (ConA) and Helix Pomatia Agglutinin (HPA). Tissues from ulcerative colitis and Crohn's disease patients, showed increases in DBA and SBA binding, a reduction in HPA binding, and changes in the distribution of PNA, UEA-1, RCA-120, and HPA labeling sites. These results demonstrated that the expression of lectin-binding sites on human intestinal goblet mucin was specifically altered in ulcerative colitis and Crohn's disease, thus possibly providing another approach to the assessment of neoplastic risk on these diseases.

In a framework of a study on retrovirus expression in Syrian hamster (mesocricetus auratus), three cell lines were examined by electron microscopy. As we had previously demonstrated the efficacy of demethylating drug in activating the formation of retroviral particles, we used 5-azacytidine to activate endogenous retrovirus expression. Proceeding to a more detailed survey we were able to observe various types of retrovirions. All of them were present in the different activated cell lines. They were: intracisternal R-type particles (IRP), intracisternal A-type particles (IAP), intracytoplasmic A-type particle (ICAP), intramitochondrial A-type particle (IMAP) and M-432 virus-like particles. Some of these particles have never been described before in Syrian hamster cells. The significance of their presence is discussed here.

We examined the oxidation of different chain length fatty acids in the leukocytes and the quantity of lipid peroxides in the plasma of two Reye syndrome patients. We have found that the oxidation of [1-14C] octanoic acid in homogenates of leukocytes from one of the Reye syndrome patients was only 38 percent of the control, whereas oxidation of [1-14C] palmitic and [1-14C] lignoceric acid was slightly increased. The level of lipid peroxides in the serum of both of the Reye Syndrome patients was 4.42 and 3.04 times higher than the control level. These results suggest that impaired oxidation of medium chain fatty acids (octanoic acid) and higher levels of lipid peroxides may contribute to the pathogenesis of cellular toxicity in Reye Syndrome. Reye Syndrome (RS) was first described by Reye et. al. in 1963 and is now recognized as an important cause of morbidity and mortality in infants and children. The clinical course in RS consists of an antecedent viral illness with subsequent encephalopathy and hepatic dysfunction. Laboratory findings in RS include hypoglycemia, hyperammonemia, free fatty acidemia, elevated organic acids and amino aciduria. The ultrastructural findings in RS patients include changes in mitochondria, smooth endoplasmic reticulum morphology, and an increase in the number of peroxisomes. The elevation of serum free fatty acids in RS and their decrease in patients who improve clinically suggests a disturbance in fatty acid metabolism. To understand the role of free fatty acids in the pathogenesis of RS, we examined the levels of lipid peroxides in plasma and catabolism of fatty acids of different chain lengths in leukocytes from RS patients.

Healing gastric ulcers were examined immunohistochemically for the presence of myofibroblasts containing actin microfilaments. Twenty five surgical specimens of the gastric ulcer corresponding to the initial healing stage and the proliferative healing stage, and 30 surgical specimens of the acetic acid-induced ulcers in rats at 3, 8 (initial healing stage), and 15 (proliferative healing stage) days after ulcer induction were fixed and cut into 4-micron sections, which were then treated with anti-actin serum, peroxidase-antiperoxidase and incubated for the localization of actin. Controls were prepared using non-immune serum or preabsorbed immune serum. Actin-positive fibroblasts were seen at the edge and the floor of the ulcer in the initial healing stage, but not in the edge of the ulcer in the proliferative healing stage. Such cells may be responsible for the contraction of the ulcer caliver observed clinically in the initial healing stage of the gastric ulcer.

N-acetyl-D-galactosamine binding lectins from winged bean (Psophocarpus tetragonolobus) and jack fruit (Artocarpus integrifolia) were isolated, purified and conjugated with horse radish peroxidase and their tissue staining properties studied. Despite having an apparently common inhibiting sugar, the lectins showed differences in their staining properties. The lectin from the winged bean stained none of the mouse and human tissues tried even after neuraminidase treatment whereas the jack fruit lectin stained most of the untreated cells. The staining was found to be improved by the prior treatment of the cells with neuraminidase and inhibited completely by the inhibiting sugar. The differences in the staining properties of the lectins are discussed.

Interferons are natural proteins with important regulatory functions. Impairment of their production may help to explain many of the immunologic abnormalities and disease susceptibilities of AIDS patients, while excessive production of an unusual type of interferon may explain some of the systemic symptoms associated with the syndrome. In a subset of patients, alpha interferons may have therapeutic potential against a major complication of the syndrome, Kaposi's sarcoma. Finally, both alpha and gamma interferons have potential, but as yet unexplored roles to play in the treatment of HTLV-III/LAV viremia and in the control of secondary infectious complications of the syndrome.