Country‐wide analysis of large wood as a driver of fish abundance in Swedish streams: Which species benefit and where?

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An index of human alteration of lake shore morphology

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Post-mortem findings of gastric ulcers in Swedish horses up to one year of age: a retrospective study 1924-1996

Necropsy records from 702 horses, less than one year old, that were subjected to necropsy between 1924 and 1996 were used to estimate the prevalence of gastric ulceration in younger horses and to evaluate some potential risk factors that may contribute to the development of gastric ulceration. Information concerning breed, gender, age, season of death, clinical signs of colic, medical treatment, parasitism and documentation of diseases in different organs were recorded, as well as size, number and anatomical distribution of ulcers. Gastric ulcers were found in 96 of 702 young horses (14%) and gastritis in another 64 animals (9%). The cutaneous region adjacent to margo plicatus (51%), and the corpus region were commonly affected (46%). The investigation clearly demonstrates that gastric ulceration has affected young Swedish horses to a similar degree during most of the 20th century. A significant (p < or = 0.05) association between gastric ulcers and the signs of colic, parasitism and a concomitant intestinal, liver, and oesophageal involvement was found. No breed or sex predilection with gastric ulcers was obtained. The risk of gastric ulcers was highest during the fall (odds ratio 3.52) and lowest during the summer (odds ratio 0.45). The seasonal variation could not be explained by concomitant findings of Gasterophilus larvae. By using a multivariate logistic regression analysis, only season significantly influenced the risk of gastric ulceration.     

Local,landscape and regional factors structuring benthic macroinvertebrate assemblages in Swedish streams

A total of 694 streams were sampled for benthic macroinvertebrates in the autumn of 1995 as part of the Swedish national stream survey. After removal of sites considered as impacted, data from 428 streams as well as a large number of environmental variables were used to determine the relative importance of local, landscape, and large scale factors in explaining the variability in species composition of benthic stream macroinvertebrates. The environmental variables were divided into seven explanatory variable groups: local physical, local chemical, catchment land use/cover, catchment bedrock geology, Quaternary geology in catchment, regional factors (such as ecoregion) and spatial position. Partial Canonical Correspondence Analysis was used to partition the total explained variance in the species data into these variable groups. The pure (or unique) effects of the seven variable groups accounted for 69.1%, and combinations of variable groups (interaction terms) the remaining 30.9% of the total explained variability. Local scale variables such as in-stream substratum, vegetation in and near the stream (riparian zone), and some chemical variables were most strongly associated with the among-site variability. Local physical (24.4%) and local chemical (20.4%) variables explained the largest part of the among-site variability of community assemblages. These results are of importance when planning conservation and management measurements, implementing large-scale biomonitoring programs, and predicting how human alterations will affect running water ecosystems.This revised version was published online in May 2005 with corrections to the Cover Date.     

Identification and pathogenicity of Fusarium species associated with pokkah boeng of sugarcane in Brazil

Brazil is the world’s biggest producer of sugarcane (Saccharum spp. hybrids). Pokkah boeng is an important fungal disease in this crop caused by members of the Fusarium fujikuroi species complex (FFSC) and characterized by deformation of the aerial part of the plant and stem rot. While the occurrence of symptoms has been reported in plantations in Brazil, no official reports of the disease exist. In this study, species of the FFSC were identified that are associated with sugarcane plants with symptoms of pokkah boeng in Brazil. This was achieved using two-loci molecular phylogeny, sexual compatibility and analysis of morphological markers. The ability of strains to cause disease in plants of sugarcane, maize, sorghum and millet was also evaluated. The 39 isolates studied were identified as F. sacchari, F. proliferatum and another, still unknown, phylogenetic lineage that is sister to F. andiyazi. Crossing field isolates of F. sacchari and F. proliferatum with their respective tester strains produced fertile perithecia and viable ascospores. All three species induced symptoms of pokkah boeng on inoculated sugarcane plants and caused stem rot in maize, sorghum and millet. Symptoms on sugarcane are chlorosis and necrosis of leaves, punctured lesions, twisted leaves, reduction of the total leaf area, death of the top of the plant and stalk rot. The findings confirmed the aetiology of the disease in Brazil, generated basic knowledge for the development of strategies for diagnosis and monitoring of the disease and support breeding programmes for selecting resistant germplasm.     

Vertebrectomy, bone allograft fusion, and antitumor vaccination for the treatment of vertebral fibrosarcoma in a dog

OBJECTIVE: To describe the surgical technique of vertebrectomy with bone allograft fusion and the use of antitumor vaccine for the treatment of a primary vertebral neoplasm in a dog. STUDY DESIGN: Case Report. ANIMALS OR SAMPLE POPULATION: A 3 year old 32 kg female spayed mixed breed dog with progressive paraplegia. METHODS: Myelography was performed to identify an L5 lytic lesion with spinal cord compression. A dorsal laminectomy was performed to decompress the spinal cord and obtain biopsies. Pathologic fracture of the vertebral body two days later was treated with L5 vertebrectomy, cortical allograft implantation, and bilateral plating from L4 to L6. Tumor samples were used to create an autologous cytokine-gene-engineered tumor cell vaccine. Recheck radiographs and neurologic examinations were obtained 1, 2, 7, and 13 months after surgery. RESULTS: The histopathologic diagnosis was fibrosarcoma. Although slight osteopenia of the allograft was noted thirteen months after surgery, the allograft and plate fixation remained stable. The patient tolerated the antitumor vaccination protocol well. Two years after the procedures the dog was able to ambulate normally but remained urinary and fecal incontinent. CONCLUSIONS AND CLINICAL RELEVANCE: Vertebrectomy and cortical allograft implantation with plating permitted this patient to return to a functional lifestyle with its owners.     

Effects of lipopolysaccharide and phenylbutazone on gastric contents in the horse

REASONS FOR PERFORMING STUDY: Endotoxaemia causes a disruption of gastrointestinal motility in the horse but there is no information on its effects on gastric secretion. Lipopolysaccharide (LPS) administration is known to affect gastric secretion in other species. HYPOTHESIS: That LPS, a toxic component of Gram-negative bacteria, would reduce gastric acid secretion and that pretreatment with phenylbutazone (PBZ) would block the effects of LPS. METHODS: The effects of LPS and PBZ on gastric contents were investigated in fasted, mature horses, with permanent gastric cannulae. Horses were pretreated with either saline or PBZ 15 mins before a 60 min infusion of either LPS or saline. Gastric contents were collected at 15 min intervals for 3 h, beginning 15 mins after the start of the LPS or saline infusion. RESULTS: Lipopolysaccharide significantly decreased gastric acid output, [K+] and potassium output and increased [Na+] and sodium output. Phenylbutazone did not affect basal gastric acid secretion but decreased LPS-induced changes in the secreted volume, [Na+] and sodium output. CONCLUSIONS: This study provides evidence that LPS affects gastric acid secretion in the horse and that these LPS-induced changes are mediated, in part, by prostaglandins. POTENTIAL RELEVANCE: Lipopolysaccharide administration can induce changes in the composition of gastric contents in the horse but further work is needed to determine the source of these changes.     

Postmortem findings of gastric ulcers in Swedish horses older than age one year: a retrospective study of 3715 horses (1924-1996)

The present study was performed to estimate retrospectively the prevalence of gastric ulceration in necropsied Swedish horses and to evaluate some potential risk factors. Horses (n = 3715) older than age one year and necropsied 1924-1996 were included. Information about breed, gender, age, season of death, clinical signs of colic, Gasterophilus larvae and documentation of diseases in different organs was recorded. Data on size, number and anatomical distribution of gastric ulcers were also obtained. The cold-blooded horses and the Standardbreds were the 2 most dominating breeds in our material. Gastric ulcers/erosions were seen in 633 (17%) of the horses. The highest prevalence was found in Thoroughbreds (19%) and Standardbreds (19%), whereas only 7% of the cold-blooded horses were affected. The cutaneous region along the margo plicatus was the most commonly affected area (52%). Multiple ulcers were seen in 62% of the horses with gastric ulcers and concurrent ulcers in the oesophagus were reported in 6%. In the bivariate analysis, significant associations were found between gastric ulcers and signs of colic (P<0.001) and gender (P<0.001), as well as between concomitant bowel (P<0.001), liver (P<0.05) and oesophageal (P<0.01) lesions. Using a multivariate logistic regression model, only year of necropsy and breed were found significantly to influence the risk of gastric ulceration by decreasing the Log Likelihood test value. The present study shows clearly that gastric ulceration has been present in Swedish horses throughout the 20th century, which also may be the situation worldwide.