Search Results - (Author, Cooperation:R. Virtanen)

2011-07-19

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Animals ; Biodiversity ; *Ecosystem ; *Extinction, Biological ; Feeding Behavior ; *Food Chain ; Humans ; Introduced Species ; Population Dynamics ; Predatory Behavior

1600-0714

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

The possible involvement of Cytomegalovirus (CMV) and Helicobacter pylori (HP) in oral mucosal ulcers is suggested by their role in the development of ulceration at other mucosal sites of the gastrointestinal tract. A series of 29 incisional biopsies from 29 consecutive and apparently immunocompetent patients attending the clinic for oral ulceration were examined by routine histopathology as well as by in situ hybridisation (ISH) with biotinylated CMV and HP DNA probes. In 14/29 biopsies, Giemsa staining disclosed spiral bacteria. Six (20.7%) of these 14 Giemsa-positive samples showed HP DNA on ISH and 3 ulcers (10.3%) contained CMV DNA. In none of the specimens were CMV and HP detected simultaneously. Two of the ulcers containing CMV DNA were found on the labial mucosa and one on the posterior palatal mucosa, whereas all HP DNA-positive ulcers were located on the buccal mucosa. The results indicate that CMV and HP DNA can be found in separate oral mucosal ulcers in apparently immunocompetent adults.

Electronic Resource

1600-0714

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Oral ulcers are common in AIDS patients, with a wide spectrum of underlying causes, including different viruses. In the present study, the presence of cytomegalovirus (CMV), Epstein-Barr virus (EBV) and human herpesvirus-8 (HHV-8) DNA was analysed in 21 biopsies from oral ulcers of 17 male homosexual AIDS patients. The methods used were in situ hybridization (ISH) and the polymerase chain reaction (PCR) with subsequent non-radioactive Southern blot hybridization to confirm the specificity of PCR products. With ISH, 4 biopsies were CMV DNA-positive and 11 contained EBV-DNA. Using PCR, an additional 4 CMV-and 7 EBV-positive samples were detected, and HHV-8 DNA was present in three oral ulcers. Six of the patients (35%) had oral ulcers co-infected by two or three viruses. The overall figures for patients with the detectable EBV-, CMV-, and HHV-8 DNA were 82% (14/17), 35% (6/17) and 18% (3/17), respectively. This is the first study to show the frequent presence of EBV-DNA in oral ulcers of AIDS patients. Because ISH-positivity signifies active virus replication, these results implicate an etiological role of EBV in AIDS-associated oral ulcers. The causal role of HHV-8 has to be considered as well, because this virus was detected in three such ulcers, which were not associated with Kaposi's sarcoma. To conclude, three common members of the herpesvirus family (CMV, EBV, HHV-8) were detected in all but three ulcers in AIDS patients, warranting the inclusion of these viral analyses in the diagnosis of ulcerative lesions of the oral mucosa in all immunosuppressed individuals.

Electronic Resource

0003-2670

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

0003-2670

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

0003-2670

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

0003-2670

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

1432-2056

Springer Online Journal Archives 1860-2000

Biology

Abstract  Vegetation on Bear Island, Jan Mayen and Spitsbergen was investigated along altitudinal and topographic gradients in order to describe the main patterns in plant community distributions and compare them with those on the mainland. In a numerical classification the communities were distinctly differentiated; however, physiognomically similar Racomitrium and Sanionia communities dominated in most habitats on Bear Island and Jan Mayen. On Spitsbergen, moss-dominated communities prevailed in depression sites. High-altitude sites were occupied either by moss-dominated communities or by variable assemblages of fragmented moss cover and scattered vascular plants. Dwarf shrub and grass heaths that were common on the mainland did not occur on grazer-free Bear Island and Jan Mayen, and were confined to the lowest altitudes on Spitsbergen. The lack of grazers on Bear Island and Jan Mayen accounts in part for the differences in vegetation between the mainland and the islands.

Electronic Resource

0035-1466

Linguistics and Literary Studies

Notes et Documents

1573-5052

pH ; Acidity ; Community ; Diversity ; Grassland ; Long-term effect ; Nutrients ; Transient dynamics

Springer Online Journal Archives 1860-2000

Biology

Abstract The relationships between bryophyte biomass and species richness and soil pH, nutrient applications and vascular plant biomass and species richness were analyzed for the Park Grass Experiment (Rothamsted, UK). The study examined the abundance of bryophytes in relation to long-term fertilizer and lime application and to fertilizer treatments recently being ceased on some plots. The probability of bryophytes being present on a plot increased with increasing soil pH, and on plots at soil pH 3.3–4.5, the lowest values in this experiment, there were virtually no mosses present. Total bryophyte biomass decreased with increasing vascular plant biomass and vascular plant richness. Both bryophyte biomass and species richness showed a curvilinear response to soil pH. Bryophyte biomass was markedly increased on plots where nitrogen (N) fertilization had recently been ceased. The abundance of the common bryophyte species showed individualistic responses to treatments. N had a negative effect on the abundance of Brachythecium rutabulum. Increasing soil pH, and the application of phosphorus (P) and potassium (K) fertilizer together, had a positive effect on Eurhynchium praelongum. This species was also negatively affected by N, but tolerated larger amounts of it (100–150 kg ha−1 N) than B. rutabulum. An ephemeral moss, Bryum subapiculatum, had a unimodal response to soil pH but showed no response to N, P, K or other explanatory variables.

Electronic Resource