The biliary accumulation of corticosteroids in rainbow trout,Oncorhynchus mykiss,during acute and chronic stress     

T. G. Pottinger  T. A. Moran  P. A. Cranwell 《Fish physiology and biochemistry》1992,10(1):55-66

The accumulation of immunoreactive corticosteroids in the bile of rainbow trout during stress was monitored by radioimmunoassay and GUMS. Although plasma cortisol levels were elevated by confinement for 1 hour, biliary levels of free and conjugated steroids in the bile were unaffected. However, after 24 hours confinement, in addition to elevated plasma cortisol levels, free and conjugated steroids in the bile were also significantly higher than in control, unstressed fish. The time-course of change in plasma and biliary corticosteroid levels was determined in rainbow trout subject to 96 hours confinement stress. Free steroid levels in the bile of stressed fish were elevated within 2 hours of the onset of stress, while levels of conjugated steroids were significantly elevated within 4 hours of the onset of confinement. Analysis of bile from stressed fish, by GC/MS, established the major conjugated steroids present to be tetrahydrocortisone (230 g ml^–1 bile), tetrahydrocortisol (75 g ml^–1), cortisone (33.5 g ml^–1), cortisol (25 g ml^–1) and -cortolone (5 g ml^–1). The data are discussed with reference to the role of cortisone and conjugating enzymes in the clearance of cortisol, and further data are presented to suggest that the analysis of biliary steroid content may provide a suitable means of identifying stressed fish under conditions in which an additional sampling stress is unavoidable.  相似文献   

Reproductive behaviour and early development in yellowtail kingfish (Seriola lalandi Valenciennes 1833)     

Damian Moran  Cea K. Smith  Carolyn W. Poortenaar 《Aquaculture (Amsterdam, Netherlands)》2007,262(1):95-104

The spawning behaviour of wild caught brood stock as well as early egg and larval development were studied in yellowtail kingfish (Seriola lalandi). Spawning occurred naturally in the austral spring/summer (November-February) when the seawater temperature was above 17 °C. Courtship behaviour involved one male and female, and consisted of a high-speed pursuit punctuated by stalling, nipping and touching. This lasted for approximately 0.5-1.5 h until, immediately prior to spawning, the male would nip at the female gonoduct, presumably to induce spawning. At this stage, in 50% of spawns, a second male would become involved. The release of gametes involved frenzied circling behaviour near the bottom of the tank and lasted approximately 22 s. Spawning occurred in the early daylight hours at the start of the spawning season, but shifted to around dusk in the latter part. Spawned eggs were positively buoyant, had a high fertilisation rate (> 99%), ranged 1.33-1.50 mm in diameter with a single oil droplet 0.30-0.33 mm diameter, and developed in a similar manner to that described in congenerics. Egg viability within the floating fraction was visually determined to be 74% ± 17% over the entire reproductive season. Indistinct cell margins and asymmetrical cleavage were the most common blastomere deformities observed. Egg and oil droplet volume were found to decrease by 15-20% over the spawning season, though no relationship was found between visually assessed egg viability and date. Egg incubation trials between 16 and 24 °C indicated that temperature accelerated the time to hatch by a Q₁₀ of 5.0. While larvae were found to hatch at a smaller length with a larger yolk sac and oil droplet at warmer incubation temperatures, there was little difference in the maximum larval length reached at the onset of first feeding among the rearing temperatures used. It is proposed that the reason for this was that higher incubation temperatures accelerated the hatching process faster than the rate of tissue deposition. The findings from this study are discussed in terms of the biological significance and implications for the larviculture of this species.  相似文献   

Spectral Properties of Near-Earth Asteroids: Evidence for Sources of Ordinary Chondrite Meteorites     

RP Binzel  SJ Bus  TH Burbine  JM Sunshine 《Science (New York, N.Y.)》1996,273(5277):946-948

Although ordinary chondrite (OC) meteorites dominate observed falls, the identification of near-Earth and main-belt asteroid sources has remained elusive. Telescopic measurements of 35 near-Earth asteroids ( approximately3 kilometers in diameter) revealed six that have visible wavelength spectra similar to laboratory spectra of OC meteorites. Near-Earth asteroids were found to have spectral properties that span the range between the previously separated domains of OC meteorites and the most common (S class) asteroids, suggesting a link. This range of spectral properties could arise through a diversity of mineralogies and regolith particle sizes, as well as through a time-dependent surface weathering process.  相似文献   

Fine-Scale Doppler Radar Observations of Tornadoes     

J Wurman  JM Straka  EN Rasmussen 《Science (New York, N.Y.)》1996,272(5269):1774-1777

Observations obtained with a mobile pencil-beam Doppler radar revealed many previously unresolved structures within tornadic storms and tornadoes and helped verify various aspects of conceptual models. Radar data from the parent circulations indicate the existence of spiral reflectivity bands, intense radial wind shear zones, and multiple larger-scale velocity maxima. Tornado structures observed include debris shields, clear axial (eye) regions, multiple reflectivity bands surrounding the center of the eye, and occasional reflectivity protrusions into the eye. Velocity and reflectivity data from tornado-scale circulations show evidence of axial downdrafts.  相似文献   

Evaluation of tumescent local anesthesia in cats undergoing unilateral mastectomy     

Clarissa MR. Moreira  Renato LS. Oliveira  Gilberto A. Costa  Katia B. Corgozinho  Stelio PL. Luna  Heloisa JM. Souza 《Veterinary anaesthesia and analgesia》2021,48(1):134-141

ObjectiveTo evaluate the analgesic efficacy and safety of tumescent local anesthesia (TLA) in cats undergoing unilateral mastectomy.Study designProspective clinical trial.AnimalsA total of 12 ovariohysterectomized female cats.MethodsAll animals were premedicated with pethidine (4 mg kg^–1) intramuscularly (IM), followed by induction of anesthesia with propofol (5 mg kg^–1) intravenously and maintenance with isoflurane in oxygen. A refrigerated TLA solution (15 mL kg^–1, 8 °C) was injected using a Klein cannula. The solution was composed of 0.5 mL of epinephrine (1 mg mL^–1) and 40 mL of 2% lidocaine added to 210 mL lactated Ringer’s solution (final lidocaine concentration 0.32%). Heart and respiratory rates, systolic arterial blood pressure, temperature and oxygen saturation were measured during anesthesia. Blood samples were collected from the jugular vein for measurement of plasma lidocaine concentration using high performance liquid chromatography. Postoperative pain scores were evaluated hourly for 6 hours. Analgesic rescue was performed with tramadol (2 mg kg^–1) IM and meloxicam (0.15 mg kg^–1) subcutaneously.ResultsPlasma lidocaine concentration peaked at 90 minutes after injection of TLA, but no concentration considered toxic for the species was measured. The median postoperative analgesia time was 6 hours after injection of TLA.ConclusionsThis study found that TLA prevented sympathetic response to noxious stimuli during anesthesia and provided satisfactory postoperative analgesia in cats submitted to total unilateral mastectomy, with no apparent signs of toxicity.Clinical relevanceTLA can prevent sympathetic stimulation resulting from noxious stimuli during anesthesia, promoting good intraoperative conditions, proving to be a viable addition to analgesia in cats submitted to a total unilateral mastectomy.  相似文献   

Health and production effects of killed vaccines against Mannheimia haemolytica,bovine viral diarrhoea virus and bovine herpesvirus 1, in locally backgrounded feedlot cattle     

PMV Cusack  EL Bergman  KE Hay  JM Morton 《Australian veterinary journal》2021,99(1-2):24-31

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Comparative functional genomics of the fission yeasts     

Rhind N  Chen Z  Yassour M  Thompson DA  Haas BJ  Habib N  Wapinski I  Roy S  Lin MF  Heiman DI  Young SK  Furuya K  Guo Y  Pidoux A  Chen HM  Robbertse B  Goldberg JM  Aoki K  Bayne EH  Berlin AM  Desjardins CA  Dobbs E  Dukaj L  Fan L  FitzGerald MG  French C  Gujja S  Hansen K  Keifenheim D  Levin JZ  Mosher RA  Müller CA  Pfiffner J  Priest M  Russ C  Smialowska A  Swoboda P  Sykes SM  Vaughn M  Vengrova S  Yoder R  Zeng Q  Allshire R  Baulcombe D  Birren BW  Brown W  Ekwall K  Kellis M  Leatherwood J  Levin H  Margalit H  Martienssen R 《Science (New York, N.Y.)》2011,332(6032):930-936

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Differential representation of perception and action in the frontal cortex     

Schwartz AB  Moran DW  Reina GA 《Science (New York, N.Y.)》2004,303(5656):380-383

A motor illusion was created to separate human subjects' perception of arm movement from their actual movement during figure drawing. Trajectories constructed from cortical activity recorded in monkeys performing the same task showed that the actual movement was represented in the primary motor cortex, whereas the visualized, presumably perceived, trajectories were found in the ventral premotor cortex. Perception and action representations can be differentially recognized in the brain and may be contained in separate structures.  相似文献   

Thermally Switchable Periodicities and Diffraction from Mesoscopically Ordered Materials     

JM Weissman  HB Sunkara  AS Tse  SA Asher 《Science (New York, N.Y.)》1996,274(5289):959-960

Two switchable, mesoscopically periodic materials were created by combining crystalline colloidal array (CCA) self-assembly with the temperature-induced volume phase transition of poly(N-isopropylacrylamide) (PNIPAM). Body-centered-cubic CCAs of hydrated, swollen PNIPAM particles Bragg-diffract infrared, visible, and ultraviolet light weakly, whereas arrays of compact shrunken particles diffract efficiently. A tunable diffracting array was also created by embedding a CCA of polystyrene spheres within a PNIPAM hydrogel that swells and contracts with temperature; thus the array lattice constant varies with temperature, and the diffracted wavelength was thermally tunable across the entire visible spectrum. These materials may find applications in many areas of optics and materials science.  相似文献   

Single layer centrifugation of fresh dromedary camel semen improves sperm quality and in vitro fertilization capacity compared with simple sperm washing          下载免费PDF全文

C Malo  EG Crichton  JM Morrell  BS Pukazhenthi  JA Skidmore 《Reproduction in domestic animals》2017,52(6):1097-1103

Single layer centrifugation (SLC) through a colloid is a tool for selecting viable mammalian spermatozoa but has not been used previously for fresh dromedary camel sperm. Semen from six camels (2 ejaculates/male) was diluted 1:5 (v:v) or 1:10 (v:v) in a Tris–citrate–fructose buffer for mechanical liquefaction by gentle pipetting. Following liquefaction, semen was processed either by SLC or by centrifugation without a colloid (control). Total and progressive motilities, CASA kinematics, vitality and acrosome integrity (eosin–nigrosin) and plasma membrane integrity (Hypo‐osmotic swelling test; HOST), and fertilizing ability in a heterologous assay (zona‐free goat oocytes) were evaluated. Both total (p = .003) and progressive motilities (p = .003) were higher in SLC‐processed than in control semen samples, irrespective of dilution. Positive HOST values increased when using colloid in 1:5 (p = .001) and 1:10 dilution (p = .010). Colloid‐selected sperm had higher penetration rates than controls (p < .001 and p = .02 for 1:5 and 1:10 dilutions, respectively). However, only the SLC sperm at 1:5 dilution showed higher percentages of pronuclear formation (p = .02) than controls. Dilution effect was only significant for total motility before in vitro fertilization, with higher values for the 1:5 dilution (p = .033). The recovery rates of motile sperm between dilutions were similar (26.1% vs 35.4%; p = .226). In conclusion, SLC is a promising tool for selecting functional dromedary camel sperm and warrants more research.  相似文献