Biogeographical patterns and determinants of invasion by forest pathogens in Europe.

A large database of invasive forest pathogens (IFPs) was developed to investigate the patterns and determinants of invasion in Europe. Detailed taxonomic and biological information on the invasive species was combined with country-specific data on land use, climate, and the time since invasion to identify the determinants of invasiveness, and to differentiate the class of environments which share territorial and climate features associated with a susceptibility to invasion. IFPs increased exponentially in the last four decades. Until 1919, IFPs already present moved across Europe. Then, new IFPs were introduced mainly from North America, and recently from Asia. Hybrid pathogens also appeared. Countries with a wider range of environments, higher human impact or international trade hosted more IFPs. Rainfall influenced the diffusion rates. Environmental conditions of the new and original ranges and systematic and ecological attributes affected invasiveness. Further spread of established IFPs is expected in countries that have experienced commercial isolation in the recent past. Densely populated countries with high environmental diversity may be the weakest links in attempts to prevent new arrivals. Tight coordination of actions against new arrivals is needed. Eradication seems impossible, and prevention seems the only reliable measure, although this will be difficult in the face of global mobility.

Two coronaviruses isolated from central nervous system tissue of two multiple sclerosis patients.

Two coronaviruses were isolated from brain material obtained at autopsy from two multiple sclerosis patients. The viruses were neutralized by serum and spinal fluid from these patients. Although most of the population have antibody to these virus isolates, multiple sclerosis patients have slightly higher concentrations of serum antibody than controls. The results suggest that coronaviruses should be considered as one additional virus with a potential implication in the etiology of multiple sclerosis.

Pathogenesis of coronavirus SD in mice. I. Prominent demyelination in the absence of infectious virus production.

Following intracerebral inoculation of 3- to 4-week-old C57 B16/J mice with coronavirus SD, 23% exhibited neurologic signs within the first week. However, only 6% died. Within the first week after inoculation (AI), we noted a panencephalitis. Prominent demyelination detected in the spinal cord on day 6 continued through day 29 AI. Demyelinated lesions in the spinal cord were either subpial with few inflammatory cells except for macrophages or perivascular with prominent accumulation of lymphocytes, plasma cells, and macrophages. Beginning on day 6 AI, IgG was detected in the lesions. Although an infectious virus was detectable in the CNS only through day 12 AI, viral antigen expression continued through day 24. We concluded that coronavirus SD persists in a nonrecoverable form throughout the initial phase of demyelination, day 6 to day 24 AI.

Antigenic relationships of coronaviruses detectable by plaque neutralization, competitive enzyme linked immunoabsorbent assay, and immunoprecipitation.

The antigenic relationships of mouse coronaviruses JHM and A59, human viruses OC43 and 229E, and multiple sclerosis (MS) isolates SD and SK have been investigated by plaque neutralization, competitive enzyme linked immunoabsorbent assay, and immunoprecipitation. A59, SK, or SD plaques are neutralized by antiserum prepared against homologous as well as heterologous virus. Plaque neutralization also demonstrated weak reactivity between SD or SK and mouse virus JHM but no reactivity with human coronavirus 229E. An antiserum prepared against human virus OC43 neutralized viruses SD and SK but not mouse viruses A59 or JHM. In a competitive enzyme linked immunoabsorbent assay (cELISA) the binding of antiserum prepared against MS isolate SK to bound SK antigen was inhibited to a comparable degree using OC43, SD, or A59 viral antigens. Coronavirus 229E or uninfected cell antigens did not block the binding of anti-SK serum to bound antigen. However, a cELISA utilizing OC43 as bound antigen and competing an anti-OC43 serum suggests that virus OC43 may be more closely related to SK than A59. Specific viral polypeptides that share antigenic determinants have been identified by immunoprecipitation of S35 methionine labeled viral infected cell extracts. Polypeptides of similar molecular weight were precipitated from A59, SD, or SK infected cell extracts by SD, SK, OC43, or A59 antisera. Our data suggests that the mouse coronavirus A59, human coronavirus OC43, and MS isolates SD and SK contain antigenically related polypeptides of similar molecular weight.

Introduction to Distribution and Ecology of Sterile Conks of Inonotus obliquus.

Inonotus obliquus is a fungus that causes white heart rot on several broad-leaved species. This fungus forms typical charcoal-black, sterile conks (chaga) or cinder conks on infected stems of the birche (Betula spp). The dark brown pulp of the sterile conk is formed by a pure mycelial mass of fungus. Chaga are a folk remedy in Russia, reflecting the circumboreal distribution of I. obliquus in boreal forest ecosystems on Betula spp. and in meridional mountain forests on beech (Fagus spp.) in Russia, Scandinavia, Central Europe, and Eastern Europe. Distribution at lower latitudes in Western and Southern Europe, Northern America, Asia, Japan, and Korea is rare. Infected trees grow for many years without several symptoms of decline. The infection can penetrate through stem injuries with exterior sterile conks developing later. In the Czech Republic, cinder conk is found on birches inhabiting peat bogs and in mountain areas with a colder and more humid climate, although it is widespread in other broad leaved species over the Czech Republic. The most common hosts are B. pendula, B. pubescens, B. carpatica, and F. sylvatica. Less frequent hosts include Acer campestre, Acer pseudoplatanus, Alnus glutinosa, Alnus incana, Fraxinus excelsior, Quercus cerris, Q. petraea, Q. robur, Q. delachampii, and Ulmus sp.

Protective action of phenytoin in cerebral ischemia.

Thirty-six rabbits were subjected to 15-minute periods of stagnant cerebral hypoxia while blood flow to the rest of the body was preserved. After this ischemic interval the animals, divided into three groups, received either saline, phenytoin, 15 mg/kg IV, or thiopental 10 mg/kg IV and 10 mg/kg IM. Histologic examination of tissue sections of the brains, 72 hours after ischemia, indicated that phenytoin afforded significant protection (p less than 0.001) of neurons in the hippocampus and in the dentate nucleus when compared to saline, while the findings noted after thiopental were not statistically significant when compared to placebo. No statistically significant difference was noted between the two drugs. Neuron destruction was seen only in rabbits receiving either saline (92%) or thiopental (50%).