Follicle Wave Growth in Cattle   总被引：1，自引：0，他引：1  

M Mihm  MA Crowe  PG Knight  EJ Austin 《Reproduction in domestic animals》2002,37(4):191-200

Ovarian follicle growth in cattle culminates in the selection of a single dominant follicle which attains the ability for final maturation and ovulation once or twice during the luteal phase and at the end of the oestrous cycle, as well as during other reproductive states. This review will describe in detail the first follicle wave of the cycle leading to selection of the first wave dominant follicle, indicating the specific gonadotrophin dependencies of cohort and dominant follicles, and relating follicle fate to steroidogenesis. As a differential gonadotrophin response of growing antral follicles during the follies‐stimulating hormone (FSH) decline may determine which follicle becomes selected, first wave follicles are also characterized in relation to intrafollicular growth factors, which may modify the gonadotrophin response, such as inhibins and members of the insulin‐like growth factor (IGF) family. Subsequently, the follicular control of the transient FSH rise and decline so crucial to dominant follicle selection will be discussed. It is concluded that successful hormonal manipulation of follicle wave growth and dominant follicle selection will depend on our detailed understanding of the gonadotrophin requirements of differentiating wave follicles.  相似文献   

Mechanical properties of excised calf lungs   总被引：1，自引：0，他引：1  

P Gustin  P Lekeux  F Lomba  C Clercx 《Research in veterinary science》1987,42(3):272-276

Five isolated calf lungs were suspended in an airtight box used as a ventilator. Lungs were ventilated from the outside at different levels of transpulmonary pressure (Ptp). The static pressure-volume curve characteristics of the lungs were measured. Static compliance (Cstat) was 1.9 +/- 0.37 litres kPa-1 or 25 +/- 5 per cent of total lung capacity kPa-1. At a Ptp of 0.7 kPa, dynamic compliance (Cdyn) and lung resistance (RL) were 1.1 +/- 0.1 litres kPa-1 and 0.126 +/- 0.02 kPa litres sec-1, respectively. Both an increase and a decrease of this level of Ptp induced an increase of RL and a decrease of Cdyn. The ratio Cdyn/Cstat averaged 57 +/- 0.8 per cent. It was concluded that in excised lungs, Cdyn is lower in the calf than in a number of other species and that pulmonary function values measured in vitro are optimum at values of Ptp close to values recorded in vivo in healthy cattle.  相似文献   

A mechanosensitive ion channel in the yeast plasma membrane   总被引：36，自引：0，他引：36  

M C Gustin  X L Zhou  B Martinac  C Kung 《Science (New York, N.Y.)》1988,242(4879):762-765

Mechanosensitive ion channels use mechanical energy to gate the dissipation of electrochemical gradients across cell membranes. This function is fundamental to physiological processes such as hearing and touch. In electrophysiological studies of ion channels in the plasma membrane of the yeast Saccharomyces cerevisiae, channels were observed that were activated by, and adapted to, stretching of the membrane. Adaptation of channel activity to mechanical stimuli was voltage-dependent. Because these mechanosensitive channels pass both cations and anions, they may play a role in turgor regulation in this walled organism.  相似文献   

An investigation of transovarial transmission of Akabane virus in Culicoides brevitarsis     

PG ALLINGHAM  HA STANDFAST 《Australian veterinary journal》1990,67(7):273-274

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The prevalence of lice (Bovicola ovis) infested sheep flocks in Western Australia (1987–1993)     

PW MORCOMBE  ND THOMSON  PG BUCKMAN 《Australian veterinary journal》1994,71(3):71-74

SUMMARY The proportion of wool bale brands with a positive test for sheep lice in baled wool decreased from 29.5% in 1987/88 to 23.2% in 1990/91 before increasing to 38.2% in 1992/93. Changes in the proportion of wool bale brands with a positive test for lice were highly correlated with changes in the Wool Market Price Indicator. The increase in the proportion of positive lice tests since 1990/91 was associated with an increase in failures to eradicate lice from flocks. These failures were partly a consequence of the reduced use of lousicidal treatments, the development of resistance to synthetic pyrethroid chemicals and an increase in the transmission of lice between flocks.  相似文献   

Internal parasites from pigs in South Australia     

MG O'CALLAGHAN  PG LANGSTON 《Australian veterinary journal》1990,67(11):416-416

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Enterotoxaemia in goats in Australia     

FA UZAL  WR KELLY  PG PARSONS 《Australian veterinary journal》1998,76(8):543-543

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Guidelines for treatment of lice in sheep with long wool based on a model of the development of wool damage     

PG Lucas  BJ Horton 《Australian veterinary journal》2014,92(1-2):8-14

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The Effect of Intravenous Administration of Web 2086 on PAF-Induced Platelet Aggregation in Healthy Friesian Calves     

Da Silva  M. Bastos  Gustin  P.  Herion  F.  Raskinet  R.  David  J.-L.  Gougnard  T.  Plomteux  G.  Desmecht  D.  Lekeux  P. 《Veterinary research communications》1997,21(7):521-531

The in vivo ability of the specific PAF-antagonist WEB 2086, a thienotriazolodiazepine, to inhibit platelet-activating factor (PAF) in cattle was investigated by in vitro determination of platelet aggregation curves. WEB 2086 was infused intravenously into a group of 5 healthy male Friesian calves in a dose of 3 mg/kg over 1 min. The resultant inhibition peaked between 30 min and 1 h after administration of WEB 2086. The inhibition was significantly reduced after 3 h and became non-significant after 6 h, but maximal pre-treatment aggregation had not been restored by 24 h after the injection of WEB 2086. These results confirm previous results obtained in vitro and suggest that WEB 2086 is a potent antagonist of PAF activity in calves. They also suggest that further clinical studies with WEB 2086 in cattle are desirable.  相似文献   

Mercury Emissions from Background and Altered Geologic Units Throughout Nevada     

Nacht  David M.  Gustin  Mae S. 《Water, air, and soil pollution》2004,151(1-4):179-193

To date there have only been a few studies that measured mercury emissions from background substrate worldwide, and only a small amount of mercury flux data, from background substrate, exists for the Western United States. Because of this, the database of mercury emissions from background units < 0.1 mg kg^-1 mercury) is incomplete. This study focused on the collection of in-situ mercury flux data from representative lithologic units in Nevada. Measured mercury fluxes from substrate with background mercury concentration throughout Nevada were low (mean 2.0 ± 4.1 ng m^-2 hr^-1), and ranged from –3.7 to 9.3 ng m^-2 hr^-1. The mean measured mercury flux is slightly higher than those measured from background substrate from various locations throughout the world. The mean mercury flux from in-situ mercury measurements from substrate located near altered geologic units across Nevada was 15.5 ± 24.2 ng m^-2 hr^-1. These mercury fluxes are higher than the values applied in published global models for naturally enriched geologic units.  相似文献