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Query: UMLS:C0014070 (encephalomyelitis)
 13,017 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We performed studies to characterize the mechanisms responsible for development during gestation of a placental barrier to Theiler's murine encephalomyelitis virus (TMEV) in a murine model of gestational enterovirus infection. Electron microscopy of placentae infected in early gestation revealed TMEV-induced changes in the decidua, giant cell, spongiotrophoblast, and labyrinth layers; in contrast, placentae infected in middle and late pregnancy demonstrated degenerative changes in the decidua, giant cell, and spongiotrophoblast layers but not in the labyrinth. Immunohistochemistry and in situ hybridization of placentae infected in early or late gestation demonstrated accumulation of monocytes/macrophages in infected, histologically damaged labyrinths, but no infiltration of immune cells into infected but histologically normal placental regions. Silver staining of placentae from dams inoculated in late gestation with inert gold beads the size of TMEV virions revealed beads within the decidua, giant cell, and spongiotrophoblast layers, but restriction of beads from labyrinths, similar to the usual distribution of TMEV in placentae infected in late pregnancy. These experiments suggest that anatomical relationships, and not systemic immune response, appear to be a major contributor to the murine placental barrier to TMEV.
Placenta 1995 Mar
PMID:Characterization of the placental barrier to murine enterovirus infection. 779 83

Theiler's murine encephalomyelitis virus (TMEV), a murine enterovirus, infects the majority of murine placentae and fetuses following inoculation in early gestation and infects most placentae but almost no fetuses in late gestation. The sequence of infection of TMEV following early gestation inoculation was studied. Mice were inoculated with TMEV on day 6 or 7 of pregnancy and sacrificed at intervals between 1 h and 4 days later. Culture of placenta-embryo units identified infection at 2, 3, and 4 days post-inoculation. In situ hybridization revealed TMEV RNA primarily in giant cells around the yolk cavity and in giant cells situated between the decidua and spongiotrophoblast layers of the placenta. Occasional decidual cells located near giant cells were also hybridization-positive. The giant cells were immunohistochemically identified as fetally derived trophoblast cells. Giant cells are the earliest predominant target of TMEV infection following early gestation inoculation and appear to be an integral part of the pathogenesis of gestational murine enterovirus infection.
Placenta
PMID:Identification of trophoblastic giant cells as the initial principal target of early gestational murine enterovirus infection. 850 47

Mice were inoculated with Theiler's murine encephalomyelitis virus (TMEV) on gestational days 1-3 (pre-implantation) or days 4-5 (peri- or post-implantation) or with control cell lysate (days 1-5). Dams were subsequently sacrificed between days 11-14 of gestation, and placentae and fetuses were harvested. Few placentae from dams inoculated with virus on days 1-3 were positive by virus culture (2 per cent) or in situ hybridization (6 per cent), and no fetuses were positive by either technique. In contrast, most placentae from dams inoculated with virus on days 4-5 were virus-positive by culture (96 per cent) or in situ hybridization (100 per cent), and a moderate number of fetuses were also positive (30 per cent by culture, 19 per cent by in situ hybridization). Necrosis was present more frequently in placentae from mice inoculated with virus on days 4-5 (55 per cent) than in placentae from dams inoculated with virus on days 1-3 (19 per cent) or with control cell lysate (18 per cent). Viral infection, mononuclear inflammation and cell necrosis were identified in the heart and great vessels of TMEV-infected fetuses. These results indicate that gestational tissues are largely protected from viral infection before implantation. After implantation, gestational tissues are more readily infected and damaged by maternal picornavirus infection.
Placenta 2000 May
PMID:Protection of murine gestational tissues from picornavirus infection in the preimplantation period. 1083 80

To evaluate whether maternal illness following picornavirus infection during pregnancy adversely affects placental and fetal health, mice were inoculated with the GDVII strain of Theiler's murine encephalomyelitis virus or control cell lysate during days 4-7 of gestation. Gross appearance, histopathology and viral culture, and in situ hybridization positivity of placentae and fetuses from ill GDVII-infected, healthy GDVII-infected and control mice were compared. Twenty of 34 (59 per cent) GDVII-infected dams became clinically ill. More placenta-fetus pairs from ill mice were grossly abnormal (68 per cent) than from well GDVII-infected (51 per cent;P< 0.01) or control mice (9 per cent;P< 0.001). Virus was detected by in situ hybridization in 73 per cent of placentae and 29 per cent of fetuses from sick GDVII-infected dams, and in 85 per cent of placentae and 19 per cent of fetuses from healthy GDVII-infected mice (differences not significant). Histological abnormalities consisting of necrosis or an increase in hyaline tissue in the vascular labyrinth layer were similarly frequent in placentae from ill and well GDVII-infected mice (58 per cent versus 67 per cent, P=0.5). Viral RNA, inflammation and necrosis were evident in the heart, great vessels, brain and spinal cord of GDVII-infected fetuses. Infection with GDVII in early pregnancy produces a high rate of gross placental and fetal abnormalities. The rate of gross abnormalities exceeds the incidence of fetal infection and more closely parallels the rates of infection and histopathology in the placenta, suggesting that much of the damage to placenta-fetus pairs is a consequence of placental infection. In addition, the occurrence of viral-induced maternal illness is associated with additive risk to placental and fetal health not explained by an increased rate of placental or fetal infection.
Placenta 2000 Nov
PMID:Picornavirus infection in early murine gestation: significance of maternal illness. 1109 34