Animal mortality

About: Animal mortality is a research topic. Over the lifetime, 526 publications have been published within this topic receiving 14887 citations.

Solid tumour models for the assessment of different treatment modalities: VII: single vs fractionated doses of 5-fluorouracil on two solid tumours and their hosts.

Abstract: The effects of one large single dose of 5-fluorouracil (FU) have been compared to the same amount given in divided doses daily over a 3- or 5-day period. Comparison of the effects of single vs fractionated dosage was made on 2 types of experimental solid tumour with different growth, cell kinetic, histological and metastasizing properties. The tumour response was essentially the same for both the single and fractionated dose schedules. There were marked increases in animal mortality from drug toxicity following fractionated doses of FU compared to one large single dose. Mortality in animals with Tumour 3924A increased from 10% following one large single dose to 60% for animals given daily fractionated doses for 3 days, and 80% for animals given daily fractionated doses for 5 days. Total marrow reserve was measured by the total DNA content of tibial marrow. The nadir of 6 days for loss of total tibial marrow DNA following one large dose of FU was increased to 9 days for both fractionated schedules of FU. The 3-day delay in recovery of the marrow prevented recovery within the time frame necessary for animal survival. The inference from these experimental cancer-treatment studies is that daily fractions of chemotherapeutic agents such as FU result in increased morbidity and mortality, without benefit in the control of the solid tumour. The results question the advisability of the clinical practice of initially giving small daily “loading doses” of proliferation-dependent agents such as FU. These results emphasize the need for more precise information on the temporal relationship between the response and recovery of the host and the response and recovery of the solid tumour. They also emphasize the need for a better clinical understanding of the time sequence of solid-tumour recovery in relation to the time sequence of marrow recovery.

Spatial Pattern of Illegal Activities and the Impact on Wildlife Populations in Protected Areas in the Serengeti Ecosystem

Abstract: Illegal activities in protected areas (PAs) are a major conservation problem linked to biodiversity loss. However, the scale of the problem at a global and local scale is unclear. There is a lack of understanding of the factors driving illegal activities and how law enforcement is targeted to reduce the impact of illegal activities. These information gaps limit the improvement of conservation, making tackling the problem difficult. I use an analytical approach, quantitative field surveys and field experiments in the Serengeti ecosystem to improve our understanding of this problem and how it could be reduced in protected areas. At a global scale, I found that illegal activities are present in more PAs than previously thought. Population of large wild mammals are more likely to decline in less-strict PAs in countries with limited conservation resources and where illegal hunting is conducted for commercial benefits rather than for subsistence. The probability of the mammal decline increases in countries where land use change is driven by illegal plant exploitation. At a local scale, in the Serengeti ecosystem, illegal activities are wide-spread, suggesting the problem is bigger than previously perceived. These are driven by poaching decisions made at various scales influenced by local habitats and environmental characteristics. I estimate there could be 137000 wire snares set at any one point across the Serengeti ecosystem, resulting in killing of approximately 14% of the animal population available each year. Despite this, I found current anti-poaching strategies ineffective at detecting and removing wire snares, increasing the risks of animal mortality and potential population declines, and fuelling the illegal wildlife trade. Any comprehensive strategy towards curbing poaching and other illegal activities in PAs must improve the deterrent effects of law- enforcement patrols through increasing conservation resources and improving their ability to detect and remove existing threats.

Serum lipid abnormalities in a chemical/viral mouse model for reye's syndrome

Abstract: Neonatal mice given nontoxic dermal applications of an industrial surfactant, Toximul MP8 (Tox), and subsequently infected with sublethal doses of mouse-adapted human Influenza B (Lee) virus (FluB) develop many of the biochemical features of Reye's Syndrome (RS). To determine whether these also include abnormal circulating lipid, we examined serum lipid profiles in the mouse model throughout the treatment course using Iatroscan-TH10. Following 10 days of exposure to surfactant, serum phospholipid and cholesterol levels were significantly reduced relative to control animals. These reductions were transient; however, four days following virus administration, significant differences in serum lipid were again evident. These abnormalities coincided and correlated with increased animal mortality. Animals that received combined Tox + virus treatment had significant decreases in serum total lipids relative to control animals, a reflection of a reduction in all lipid classes, including phospholipid, cholesterol, neutral glycerides (triglycerides plus diglycerides) and free fatty acids. Phospholipid (specifically phosphatidylcholine and lysophosphatidylcholine) and free fatty acid levels in the Tox + virus group were also significantly lower than those in animals that received virus alone. This study has demonstrated that suckling mice given chemical/viral treatment have the serum hypopanlipidemia but not the freefattyacidemia that are characteristic of RS.

Prokaryotic responses to a warm temperature anomaly in northeast subarctic Pacific waters.

Abstract: Recent studies on marine heat waves describe water temperature anomalies causing changes in food web structure, bloom dynamics, biodiversity loss, and increased plant and animal mortality. However, little information is available on how water temperature anomalies impact prokaryotes (bacteria and archaea) inhabiting ocean waters. This is a nontrivial omission given their integral roles in driving major biogeochemical fluxes that influence ocean productivity and the climate system. Here we present a time-resolved study on the impact of a large-scale warm water surface anomaly in the northeast subarctic Pacific Ocean, colloquially known as the Blob, on prokaryotic community compositions. Multivariate statistical analyses identified significant depth- and season-dependent trends that were accentuated during the Blob. Moreover, network and indicator analyses identified shifts in specific prokaryotic assemblages from typically particle-associated before the Blob to taxa considered free-living and chemoautotrophic during the Blob, with potential implications for primary production and organic carbon conversion and export. Traving et al. use small subunit ribosomal RNA gene sequencing to examine spatial and temporal trends in bacterial and archaeal community structure during a large marine warm water surface anomaly, the Blob. Their findings suggest that community structure shifted during the Blob, with taxa considered free-living and chemoautotrophic prevailing under these unusual conditions.