In vitro activity of dicationic compounds against a North American foxhound isolate of Leishmania infantum     

Rosypal AC  Hall JE  Bakunova S  Patrick DA  Bakunov S  Stephens CE  Kumar A  Boykin DW  Tidwell RR 《Veterinary parasitology》2007,145(3-4):207-216

Canine leishmaniasis caused by Leishmania infantum is enzootic in the North American foxhound population. Currently available chemotherapy for canine leishmaniasis is not completely effective and relapses are common in treated dogs. Pentamidine and related aromatic diamidines possess broad spectrum antiprotozoal activity. The in vitro antileishmanial activities of 35 aromatic cationic molecules were determined, using pentamidine as the reference drug. The compounds were examined for activity against promastigotes of L. infantum isolated from a foxhound from Virginia. The compounds most active against Leishmania parasites were reversed amidines. Compound 9, a reversed amidine, exhibited the highest activity against L. infantum, with a 50% inhibitory concentration (IC(50)) of 0.0042 microM compared with 14.2 microM for pentamidine. Antileishmanial activities of nine compounds were at least 1000-fold higher relative to the reference drug. Results from this study indicate that several pentamidine-related compounds warrant further investigation as possible new agents for the treatment of canine leishmaniasis.  相似文献   

Surgical correction of brachycephalic syndrome in dogs: 62 cases (1991-2004)     

Riecks TW  Birchard SJ  Stephens JA 《Journal of the American Veterinary Medical Association》2007,230(9):1324-1328

OBJECTIVE: To assess results of surgical correction of brachycephalic syndrome (including stenotic nares, elongated soft palate, and everted laryngeal saccules) in dogs and determine whether dogs with hypoplastic trachea have a less favorable long-term outcome. DESIGN: Retrospective case series. ANIMALS: 62 dogs with brachycephalic syndrome. PROCEDURES: Medical records from 1991 to 2004 were reviewed for information regarding signalment, clinical signs, diagnosis, surgery, and long-term outcome. Surgical outcome was rated by owners as excellent, good, fair, or poor. Common abnormalities, treatments, and long-term outcomes among the 62 dogs were assessed. RESULTS: Predominantly affected breeds included English Bulldog, Pug, and Boston Terrier. Elongated soft palate was the most common abnormality (54/62 [87.1%] dogs); the most common combination of abnormalities was elongated soft palate, stenotic nares, and everted saccules (16/62 [25.8%] dogs). The English Bulldog was the most common breed for all abnormalities, including elongated soft palate (27/54 [50%] dogs), stenotic nares (14/36 [38.9%] dogs), everted saccules (20/36 [55.6%] dogs), hypoplastic trachea (7/13 [53.9%] dogs), and laryngeal collapse (2/5 [40%]). No dogs had everted saccules alone. Outcome did not differ between dogs under-going staphylectomy by use of laser or scissor resection. Follow-up information was obtained for 34 dogs; 16 (47.1%) had an excellent outcome, and 16 (47.1%) had a good outcome. Overall treatment success rate was 94.2%, and overall mortality rate was 3.2%. CONCLUSIONS AND CLINICAL RELEVANCE: Surgical treatment of brachycephalic syndrome in dogs appeared to be associated with a favorable long-term outcome, regardless of age, breed, specific diagnoses, or number and combinations of diagnoses.  相似文献   

Cotton remains from archeological sites in central coastal peru     

Stephens SG  Moseley ME 《Science (New York, N.Y.)》1973,180(4082):186-188

Cotton remains from four archeological sites in central coastal Peru, representing a time sequence from about 2500 to 1000 B.C., were compared with similar materials obtained from living wild and cultivated forms of Gossypium barbadense L. The comparison revealed that the archeological cotton samples were primitive forms of Gossypium barbadense, differing little from present-day wild forms of the same species. Although not the earliest cottons recorded for the New World, they appear to represent the earliest stages of cotton domestication yet recorded.  相似文献   

The Seismic Structure of the Sun     

DO Gough  AG Kosovichev  J Toomre  E Anderson  HM Antia  S Basu  B Chaboyer  SM Chitre  J Christensen-Dalsgaard  WA Dziembowski  A Eff-Darwich  JR Elliott  PM Giles  PR Goode  JA Guzik  JW Harvey  F Hill  JW Leibacher  MJPFG Monteiro  O Richard  T Sekii  H Shibahashi  M Takata  MJ Thompson  S Vauclair  SV Vorontsov 《Science (New York, N.Y.)》1996,272(5266):1296-1300

Global Oscillation Network Group data reveal that the internal structure of the sun can be well represented by a calibrated standard model. However, immediately beneath the convection zone and at the edge of the energy-generating core, the sound-speed variation is somewhat smoother in the sun than it is in the model. This could be a consequence of chemical inhomogeneity that is too severe in the model, perhaps owing to inaccurate modeling of gravitational settling or to neglected macroscopic motion that may be present in the sun. Accurate knowledge of the sun's structure enables inferences to be made about the physics that controls the sun; for example, through the opacity, the equation of state, or wave motion. Those inferences can then be used elsewhere in astrophysics.  相似文献   

Impact of livestock and settlement on the large mammalian wildlife of Bale Mountains National Park, southern Ethiopia     

Philip A. Stephens  Candy A. d''Sa  Claudio Sillero-Zubiri  Nigel Leader-Williams 《Biological conservation》2001,100(3):307-322

Large mammals, both wild and domestic, were censused in four study areas in Bale Mountains National Park (BMNP), southern Ethiopia, from April until August 1997, using established road counts, horse-back counts and systematic transects, a new approach to censusing large mammals in BMNP. Data collected since 1983 were also examined to indicate trends in mammalian abundance. Civil unrest following the government changeover in 1991 disrupted management of BMNP, leading to an increase in human settlement and livestock densities. The effect of these factors on BMNP's wildlife is assessed and discussed. Most large mammalian wildlife has declined since 1983 but signs of recovery for some species in recent years are positive. The fates of two charismatic endemics are emphasised. BMNP's current population of mountain nyala (Tragelaphus buxtoni, an endangered antelope) was estimated to be between 1100 and 1300. This is lower than estimates for the late 1980s, but shows an increase from very low levels recorded following social turmoil during the government changeover in 1991. Data on the Ethiopian wolf (Canis simensis, a critically endangered canid) also indicate positive trends in abundance, following severe declines between 1989 and 1992 due to rabies epizootics. Action to reduce human utilisation of parts of BMNP is urgently required to prevent further degradation of the environment and to safeguard the future of both the mountain nyala and Ethiopian wolf.  相似文献   

Where nothing stands still: quantifying nomadism in Australian arid-zone birds     

Gibson  Michelle R.  Runge  Claire A.  Stephens  Philip A.  Fuller  Richard A.  Willis  Stephen G. 《Landscape Ecology》2022,37(1):191-208

Landscape Ecology - Nomadism is a movement strategy in response to non-seasonal environmental variability. Knowledge of nomadic species movements is poor but is necessary to understand life...  相似文献   

Identification of a tractable model system and oxalic acid-dependent symptom development of the dollar spot pathogen Clarireedia jacksonii     

Renée A. Rioux  Cameron M. Stephens  Paul L. Koch  Mehdi Kabbage  James P. Kerns 《Plant pathology》2021,70(3):722-734

Clarireedia jacksonii causes dollar spot disease of cool-season turfgrasses in the United States and produces the phytotoxin oxalic acid. The role of oxalic acid in host–pathogen interactions of C. jacksonii is unknown and there are multiple challenges to studying these interactions in natural turfgrass hosts. Consequently, identification of model plants to study C. jacksonii–host interactions and the role of oxalic acid in pathogenesis is necessary. Controlled environment inoculation assays were used to evaluate pathogenesis of C. jacksonii in various model plants and investigate the role of oxalic acid in symptom development. Observations at microscopic and macroscopic levels demonstrated that infection progressed similarly in all monocots tested (creeping bentgrass, wheat, barley, rice, Brachypodium distachyon) but not in the dicot Arabidopsis thaliana. Plant oxalic acid content increased from near zero to around 0.2–0.4 mM following inoculation with C. jacksonii in creeping bentgrass, barley, and wheat. Conversely, oxalic acid content remained near zero in A. thaliana and was not well correlated with inoculation in rice and B. distachyon, both of which had higher endogenous oxalic acid levels than other monocots. Time-course oxalic acid quantification experiments with creeping bentgrass and B. distachyon further supported a link between symptom development and in planta oxalic acid content and identified 48 hr postinoculation as a critical time-point for investigating the role of oxalic acid in C. jacksonii pathogenesis. These studies demonstrate that various monocots can serve as tractable model systems for studying C. jacksonii–host interactions and that increases in oxalic acid content are associated with C. jacksonii symptom development.  相似文献   

A survey of beef cattle farmers in New Zealand,examining management practices of primiparous breeding heifers     

RE Hickson  WJ Anderson  PR Kenyon  N Lopez-Villalobos  ST Morris 《New Zealand veterinary journal》2013,61(4):176-183

AIM: To obtain an estimate of the incidence of assistance at calving in primiparous (first-calving) beef heifers and the prevalence of breeding heifers at 15 months of age in New Zealand in 2006,and to identify factors contributing to farmers' decisions regarding breeding strategies for heifers, using a survey of beef cattle farmers.

METHODS: A questionnaire was sent to farmers listed in a Massey University database and to members of selected breed societies, as well as published in an industry newspaper; 331 valid responses were received. Information was gathered on the age and number of primiparous heifers, number of heifers assisted, and the importance of various reasons for and against breeding heifers at 15 months of age. Respondents were also required to outline the criteria used for selecting bulls to join with heifers, and the strategies used to manage dystocia in primiparous heifers.

RESULTS: Sixty-five (95% CI=58–71)% of respondents had only 2-year-old primiparous heifers in 2006, whilst a further 11 (95% CI=8–16)% had both 2- and 3-year-old primiparous heifers. The mean reported incidence of assisted calving was 7.0 (95% CI=6.4–7.5)% for 2-year-old primiparous heifers and 1.7 (95% CI=1.2–2.2)% for 3-year-old primiparous heifers. The reported incidence of assistance at calving within individual herdsranged from 0 to 100% for 2-year-old heifers. Respondents with bull-breeding herds most commonly observed their primiparous 2-year-old heifers twice daily, whilst respondents with commercial herds most commonly observed them once daily during calving. The most important reason for breeding heifers at 15 months of age was “increased profit”, whereas the most important reason for not breeding them at that age was “concern about rebreeding performance of 2-year-old heifers”. Estimated breeding value (EBV) for birth weight was the factor considered most frequently when selecting bulls to join with maiden heifers; age of bull and body shape of bull were the next most frequently considered factors. Selection of an appropriate bull was the most common strategy used to manage dystocia in 2-year-old beef heifers.

CONCLUSIONS: The majority of respondents calved their heifers at 2 years of age, and “increased profit” was the primary motivator. Concern about the rebreeding performance of 2-year-old heifers was the most important reason among the remainder of respondents for not breeding heifers at 15 months of age. Dystocia in 2-year-old heifers was “not a problem” or “a minorproblem” in most herds, but there was much variation amongst herds.  相似文献   

Prevalence and clonal diversity of Campylobacter jejuni from dairy farms and urban sources     

B Adhikari  JH Connolly  P Madie  PR Davies 《New Zealand veterinary journal》2013,61(6):378-383

AIM: To investigate the role of free-living animals such as spar- rows, rodents and flies as potential reservoirs of Campylobacter spp on a dairy farm, and to assess the genetic diversity among Campylobacter isolates from the farm and an urban source.

METHODS: A total of 290 samples (bovine, passerine and ro- dent faeces, and whole flies) were collected from a large com- mercial dairy farm in the Manawatu district in New Zealand, and from faeces from urban sparrows in a nearby city. Other samples collected from the dairy farm included five from silage, two from aprons worn by workers during milking, two from workers' boots and two from water in troughs in a paddock. Isolates of thermophilic Campylobacter spp were identified mor- phologically and phenotypically and further characterised mo- lecularly using pulsed-field gel electrophoresis (PFGE) and the restriction enzyme SmaI.

RESULTS: Campylobacter jejuni was the only Campylobacter species isolated from all samples. The highest prevalence was found in faeces from dairy cows (54%), followed by faeces from sparrows from the urban area (40%) and the farm (38%), and from rodents (11%) and whole flies (9%). Other samples from the farm environment such as silage, trough water, and work- ers' aprons and boots were also positive for C. jejuni. Of the 22 restriction patterns obtained, seven were common to more than one source.

CONCLUSIONS: Cattle, sparrows, rodents and flies are po- tential reservoirs of C. jejuni on dairy farms. Identical clones of C. jejuni carried by cattle, sparrows, flies and rodents prob- ably indicate a common source of infection. The high level of asymptomatic carriage of C. jejuni by healthy dairy cows could be sufficient to maintain infections within the dairy farm sur- roundings via environmental contamination.  相似文献   

The effect of individual liveweight and use of teaser rams prior to mating on the reproductive performance of ewe hoggets     

PR Kenyon  PCH Morel  ST Morris  DM West 《New Zealand veterinary journal》2013,61(5):340-343

AIM: To determine the effects of liveweight (LW) and use of teaser rams prior to mating on both the mating performance and pregnancy rate of ewe hoggets.

METHODS: Romney hoggets (n=841) were weighed and randomly assigned to one of two treatment groups; either exposed to seven harnessed, vasectomised (teaser) rams for 17 days prior to the breeding period (n=283); or not exposed to teaser rams (unteased, n=558). Harnessed Perendale rams were then introduced for two oestrous cycles. Using crayon marks, hoggets were identified as having been mated during the first 17 days only, during the second 17 days only, during both periods, or not mated. All mated hoggets were then scanned for pregnancy using ultrasound, 48 days after the end of the breeding period, and identified as being either non-pregnant, or as single-, twinor triplet-bearing.

RESULTS: Hoggets mated in either the first 17 days only or in both the first and second 17-day periods were heavier than those mated in the second period only (p<0.001). Those mated in the first or second 17-day period only, and those mated in both periods were all heavier prior to mating than those not mated at all (p<0.001). Twin-bearing hoggets were heavier than both their single-bearing and non-pregnant counterparts (p<0.001). A greater proportion of the teased hoggets were mated in the first 17 days only compared with unteased hoggets (62.6 vs 32.1%; p<0.001). In contrast, more of the unteased hoggets were marked in the second 17-day period only (p<0.001). A greater proportion of mated, unteased hoggets were found to be non-pregnant in comparison to their teased counterparts (17.8 vs 11.2%; p=0.02).

CONCLUSIONS: Heavier hoggets at breeding were more likely to be mated in the first 17 days of the breeding period and more likely to be twin-bearing. Use of teaser rams for 17 days prior to the breeding period increased the proportion of hoggets mated in the first 17 days, increased conception rates, and thus increased the proportion of pregnant hoggets. These results indicate that farmers should utilise teasers for 17 days prior to commencement of the breeding period and avoid mating hoggets that weigh below 36 kg.  相似文献