Pleistocene extinction of genyornis newtoni: human impact on australian megafauna

More than 85 percent of Australian terrestrial genera with a body mass exceeding 44 kilograms became extinct in the Late Pleistocene. Although most were marsupials, the list includes the large, flightless mihirung Genyornis newtoni. More than 700 dates onGenyornis eggshells from three different climate regions document the continuous presence of Genyornis from more than 100,000 years ago until their sudden disappearance 50,000 years ago, about the same time that humans arrived in Australia. Simultaneous extinction of Genyornis at all sites during an interval of modest climate change implies that human impact, not climate, was responsible.     

Ancillary tests for assessment of the reproductive system.

Ancillary tests applied to the male reproductive system include semen evaluation, ultrasonography, and testicular biopsy. Venereal disease testing and karyotyping are conducted on both male and female animals. The ancillary tests conducted on the female ruminant include culture, biopsy, cytology, and lavage; oviduct patency; and progesterone analysis. The application and interpretation of these tests as adjuncts to the physical examination of the reproductive system are discussed.     

The genetic basis of singlet oxygen-induced stress responses of Arabidopsis thaliana

Plants under oxidative stress suffer from damages that have been interpreted as unavoidable consequences of injuries inflicted upon plants by toxic levels of reactive oxygen species (ROS). However, this paradigm needs to be modified. Inactivation of a single gene, EXECUTER1, is sufficient to abrogate stress responses of Arabidopsis thaliana caused by the release of singlet oxygen: External conditions under which these stress responses are observed and the amounts of ROS that accumulate in plants exposed to these environmental conditions do not directly cause damages. Instead, seedling lethality and growth inhibition of mature plants result from genetic programs that are activated after the release of singlet oxygen has been perceived by the plant.     

Pharmacokinetics and endometrial tissue concentrations of enrofloxacin and the metabolite ciprofloxacin after i.v. administration of enrofloxacin to mares

Enrofloxacin was administered i.v. to five adult mares at a dose of 5 mg/kg. After administration, blood and endometrial biopsy samples were collected at regular intervals for 24 h. The plasma and tissue samples were analyzed for enrofloxacin and the metabolite ciprofloxacin by high-pressure liquid chromatography. In plasma, enrofloxacin had a terminal half-life (t(1/2)), volume of distribution (area method), and systemic clearance of 6.7 +/- 2.9 h, 1.9 +/- 0.4 L/kg, and 3.7 +/- 1.4 mL/kg/min, respectively. Ciprofloxacin had a maximum plasma concentration (Cmax) of 0.28 +/- 0.09 microg/mL. In endometrial tissue, the enrofloxacin Cmax was 1.7 +/- 0.5 microg/g, and the t(1/2) was 7.8 +/- 3.7 h. Ciprofloxacin Cmax in tissues was 0.15 +/- 0.04 microg/g and the t(1/2) was 5.2 +/- 2.0 h. The tissue:plasma enrofloxacin concentration ratios (w/w:w/v) were 0.175 +/- 0.08 and 0.47 +/- 0.06 for Cmax and AUC, respectively. For ciprofloxacin, these values were 0.55 +/- 0.13 and 0.58 +/- 0.31, respectively. We concluded that plasma concentrations achieved after 5 mg/kg i.v. are high enough to meet surrogate markers for antibacterial activity (Cmax:MIC ratio, and AUC:MIC ratio) considered effective for most susceptible gram-negative bacteria. Endometrial tissue concentrations taken from the mares after dosing showed that enrofloxacin and ciprofloxacin both penetrate this tissue adequately after systemic administration and would attain concentrations high enough in the tissue fluids to treat infections of the endometrium caused by susceptible bacteria.     

The effect of nerve growth factor and antibodies to nerve growth factor on ethylnitrosourea-induced neoplastic proliferation in rat trigeminal nerves

Sprague-Dawley (CD) rats were injected intravenously with ethylnitrosourea at a dose of 20 mg/kg on day 20 of gestation. This exposure resulted in early neoplastic proliferation or development of a neurinoma of the trigeminal nerve in 58% of the offspring at 90 days of age. Implantation of osmotic microinfusion pumps containing 2.5S nerve growth factor prior to ethylnitrosourea administration significantly reduced the incidence of early neoplastic proliferation. Postnatal implantation of microinfusion pumps containing 2.5S nerve growth factor also resulted in a significant but less pronounced reduction of early neoplastic proliferation. Immunoglobulin G directed against nerve growth factor (anti-nerve growth factor) did not influence the incidence of early neoplastic proliferation when administered via microinfusion pumps implanted on day 15 postnatally. These findings suggest that nerve growth factor has a protective effect on the developing nervous system against ethylnitrosourea-induced carcinogenesis.     

Effect of transport on feeder calves

One hundred fifty feeder steers (mean body weight, 195 kg) were assigned to 1 of 3 transport groups and were deprived of feed and water (fasted) for 24 hours. Additionally, calves were transported on a commercial livestock trailer for 0 (control-fasted only), 12 (short haul), or 24 (long haul) hours. Blood samples were obtained from the jugular vein before calves were loaded on the transport vehicle and immediately after calves of the long-haul group returned to the research feedlot. Complete blood counts were performed and 32 mineral, enzyme, and biochemical constituents were measured. Calf morbidity, mortality, and average daily weight gain were evaluated during the next 56 days. Duration of transport did not affect average daily gain; however, calves of the short-haul group had significantly (P less than 0.05) higher morbidity and mortality than did those of the control and long-haul groups. In all groups, results of differential leukocyte counts were indicative of stress response. Significant (P less than 0.05) linear contrasts were observed between duration of transport and erythrocyte, leukocyte, segmented neutrophil, lymphocyte, and eosinophil counts and results of serum enzyme (alanine transaminase, hydroxybutyrate dehydrogenase, total lactate dehydrogenase [LD], and LD-1, LD-3, and LD-4 isoenzymes), iron, urea nitrogen, beta-globulin, glucose, and urea nitrogen-to-creatinine ratio determinations. Significant (P less than 0.05) quadratic contrasts were observed between duration of transport and serum unsaturated iron binding capacity, total iron binding capacity, and LD-5 percentage. Calf source had a significant (P less than 0.05) effect on almost all variables tested.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effects of hemolyzed blood on pulmonary and systemic arterial pressure and heart rate of the dog.

The injection of hemolyzed blood into the venous system of the dog produced a rise in the pulmonary arterial pressure and a fall in the systemic arterial pressure. There were variable changes in the heart rate. Comparison with serotonin injections indicated that the above responses were produced by factors other than serotonin.