MRI characteristics of cerebral microbleeds in four dogs

Cerebral microbleeds in people are small foci of hemosiderin-containing macrophages in normal brain parenchyma. They are the remnant of previous hemorrhage and occur with greater frequency in older individuals. Our purpose was to describe the magnetic resonance (MR) appearance of cerebral microbleeds in four dogs. These lesions appeared as round, hypointense foci measuring ≤4 mm on T2*-gradient-recalled echo images. They were less conspicuous or absent on T2-weighting, being iso- or hypointense, and uniformly invisible on T1-weighted images. No contrast enhancement was seen in any of the cerebral microbleeds. Necropsy-derived histopathologic analysis of one brain confirmed these lesions to be chronic cerebrocortical infarcts containing hemosiderin. The MR changes seen in dogs were analogous to what has been described in people and will be helpful in distinguishing cerebral microbleeds from other brain lesions.     

Treatment with aspirin or clopidogrel does not affect equine platelet expression of P selectin or platelet-neutrophil aggregates

Inflammation-induced P-selectin (CD62P) expression on platelets and endothelial cells facilitates interactions among platelets and polymorphonuclear leukocytes (PMN), and can also promote coagulation. The effects of clopidogrel and aspirin (ASA) on equine platelet CD62P expression were investigated. Six horses were treated in a cross-over design with clopidogrel (2mg/kg PO q 24) or ASA (5mg/kg PO q 24h) for 5 days. Platelets collected at 24, 72, 96, 120, and 168h after the initiation of therapy were stimulated using 0.1μg/mL thrombin, followed by flow cytometric analysis using anti-CD41/61 and anti-equine CD62P antibodies. Platelet-PMN aggregates were also enumerated. Baseline CD62P positive platelet numbers were not different between groups (mean±SD): 4254±1785 (clopidogrel) and 3600±1780 (ASA, P=0. 435). Although expression tended to decrease, there were no significant changes in CD62P+platelets after treatment with either drug (clopidogrel P=0.139, ASA P=0.161). There was also no difference in platelet-PMN aggregates during or after treatment with ASA (P=0.513) or clopidogrel (P=0.543). Due to small numbers of horses, this study may have been underpowered to detect a true decrease in expression, and differences between therapies may have been more pronounced if this study had evaluated horses with systemic inflammation.     

Impact of oil palm plantations on the structure of the agroforestry mosaic of La Gamba, southern Costa Rica: potential implications for biodiversity

Human activities often cause changes and homogenization in landscape structure. To investigate the impact of changing cultivation systems on structural and functional aspects of a tropical agroforestry system, we developed satellite based land cover maps of the La Gamba area in southwestern Costa Rica and refined them by mapping fine-scale linear landscape elements. Performing a landscape pattern analysis, we compared eight sections of the study area by landscape metrics. Furthermore we performed a Morphological spatial pattern analysis (MSPA) for hypothetical non-forest, forest generalist and forest specialist species, and compared the current situation to a possible future scenario with double the area covered by oil palm plantations after a virtual conversion of other agricultural patches. The heterogeneous rural sections clearly differed from the homogeneous forests and especially pasture-dominated rural sections included many diverse, small and elongated patches, many linear landscape elements but few big plantations. According to the scenario with double the area covered by oil palm plantations, non-forest species lost large parts of their habitat, while forest species mainly lost corridors. The protection of natural landscape elements that support wildlife movement between forest areas is of major importance, particularly as the globally increasing cultivation of oil palm is significantly altering many tropical land mosaics, including the countryside of La Gamba. We propose the establishment of eight least cost path corridor routes in the study area to make the agricultural area pervious for wildlife.     

Neospora caninum: in vivo and in vitro treatment with artemisone

Neosporosis caused by Neospora caninum has global economic, clinical, and epidemiological impacts, mainly in the cattle industry. Currently, there is no useful drug for treatment of neosporosis. This publication is the first to describe the significant benefits that artemisone has on Neospora infections both in vitro and in vivo. Artemisone is a new semi-synthetic 10-alkylamino artemisinin that is superior to other artemisinin derivatives in terms of its significantly higher antimalarial activity, its tolerance in vivo, lack of detectable neurotoxic potential, improved in vivo pharmacokinetics and metabolic stability. Low micromolar concentrations of artemisone inhibited in vitro Neospora development. Prophylactic and post-infection treatment profoundly reduced the number of infected cells and parasites per cell. In the in vivo gerbil model, a non-toxic dose prevented typical cerebral symptoms, in most animals. There were no signs of clinical symptoms and brain PCR was negative. Most treated gerbils produced high specific antibody titer and were protected against a challenge. Overall, artemisone could be considered as a future drug for neosporosis.     

Mechanical evaluation of pin and tension-band wire factors in an olecranon osteotomy model

OBJECTIVE: To evaluate the effect of altering pin and wire diameter, wire position and configuration, and osteotomy angle on applied load and absorbed strain energy in a pin and tension-band wire (PTBW) fixation model. STUDY DESIGN: In vitro mechanical study. SAMPLE POPULATION: Delrin models (n=96). METHODS: PTBW was applied to Delrin olecranon osteotomy models. A control configuration was defined and then altered, 1 variable (wire diameter, pin diameter, wire-hole position, wire configuration, osteotomy angle) at a time, to create 11 test configurations. Tensile force was applied and displacement at the caudal aspect of the osteotomy was measured. Fixation strength, in terms of tensile load and strain energy, was compared between control and each test configuration at 4 osteotomy displacements. RESULTS: Models with larger wire, pins, or combined figure-of-eight/lateral wires were stronger than control, whereas those with smaller wire, pins, or a solitary lateral wire were weaker. The superior strength of the larger wire was apparent for all assessed osteotomy displacement. CONCLUSIONS: PTBW fixation strength increases as implant diameter is increased, with wire diameter having greatest effect. Lateral wire configuration is weaker than figure-of-eight, but can be added to figure-of-eight configuration to increase strength. Wire-hole position and osteotomy angle have little effect on PTBW strength. CLINICAL RELEVANCE: Wire diameter is the key determinant of PTBW strength, whereas pin diameter is somewhat less critical. Wire passage through an additional hole proximally provides equivalent strength and may avoid soft-tissue entrapment and subsequent loosening.     

Relationship between haptoglobin, serum amyloid A, and clinical status in a survey of dairy herds during a 6-month period

BACKGROUND: Haptoglobin and serum amyloid A are major acute phase proteins in cattle. Dairy cattle often develop pathologic conditions in the peripartum period; acute phase proteins may be useful in their diagnosis. OBJECTIVES: The purpose of this study was to compare the accuracy of serum haptoglobin (Hp) and serum amyloid A (SAA) concentrations with clinical health status for diagnosing disease during the peripartum period in dairy cattle. METHODS: Dairy cows from 4 herds were evaluated every 15 days over a 6-month period. Health status was determined by thorough clinical examination. Haptoglobin and SAA concentrations were measured in serum using validated methods and the results were classified as positive or negative based on defined cutoff points. Disease prevalence, sensitivity, and specificity were compared using clinical examination as the gold standard. RESULTS: A total of 1896 samples from 158 cows were analyzed. Significant increases in mean Hp and SAA concentrations were observed in the week following parturition in both primiparous and multiparous cows, although high interindividual variability was observed. Both Hp and SAA had low sensitivity but higher specificity in determining disease status compared with clinical examination. Increased concentrations of Hp and SAA were found in <10% of samples from clinically healthy cows, except in the week after parturition. CONCLUSIONS: Haptoglobin and serum amyloid A should be used with caution as markers of inflammation in the week after calving. Poor sensitivity in other postpartum periods could be related to the higher incidence of chronic (vs acute) inflammation. Haptoglobin may be appropriate for routine screening, but further work needs to be done to assess its value as an indicator of herd health.     

Was historical cisco Coregonus artedi yield consistent with contemporary recruitment and abundance in Lake Superior?

Historically, cisco Coregonus artedi Lesueur was the predominant prey fish and target of commercial fisheries throughout Lake Superior, but most spawning stocks collapsed by the mid-1900s. Stocks partially recovered by the early 1990s, but contemporary abundance is considered to be below historical levels and driven by intermittent recruitment. Stochastic, age-structured simulation models were used to determine whether historical (pre-1955) cisco yield in Lake Superior was consistent with contemporary (1992–2015) abundance, life-history characteristics and recruitment dynamics. When compared to contemporary stocks, the findings suggest historical stocks had: (1) similar recruits per spawner at low spawning stock sizes; (2) lower rates of compensatory density dependence; (3) similar or lower recruitment variation depending on the area and (4) higher median adult and age-1 density. These findings are consistent with the hypothesis that eutrophication during the historical period supported greater recruitment and adult abundance and that re-oligotrophication during the contemporary period may be limiting full recovery.     

Reservoir fish assemblage structure across an aquatic ecotone: Can river-reservoir interfaces provide conservation and management opportunities?

River-reservoir interfaces have been described as aquatic ecotones and contain strong environmental gradients of depth, turbidity and trophic resource abundance. These transitional habitats have traditionally been excluded by riverine and reservoir management schemes despite their prevalence in modern riverscapes. By systematically sampling shoreline habitats along a river-reservoir interface gradient from riverine to lacustrine zones with trammel nets in 2018–2019, strong patterns were identified in total species captured and individuals captured in the San Juan River-Lake Powell inflow, USA. Changes in assemblage structure were driven mainly by increases in relative abundance of benthic omnivores towards the riverine zone, including imperiled razorback sucker, Xyrauchen texanus (Abbott), but also by increases in predatory species, such as striped bass, Morone saxatilis (Walbaum). Inter-annual variation in species distributions along the river-reservoir interface gradient was likely influenced by variation in reservoir water level that differed by nearly 12 m between years. River-reservoir interfaces provide high-quality feeding and potentially spawning areas for both benthic omnivores and piscivores, and these areas should be considered in management and conservation efforts for species using these habitats.