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1.
Article in English | MEDLINE | ID: mdl-34089890

ABSTRACT

Evidence from mammals and aves alludes to a possibly conserved seasonal photoperiod induced neuroendocrine cascade which stimulates subsequent sexual maturation however our understanding of this mechanism in teleosts is lacking. Unlike all teleosts studied to date, the Atlantic cod (Gadus morhua) is a short day breeder with the reduction in day-length from the summer solstice stimulating gametogenesis. Cod specific orthologues of eya3, tshß and dio2 were identified and their expression was monitored in the brain and pituitary of cod held under either stimulated or inhibited photoperiod conditions. While no differential expression was apparent in brain dio2 & tshß and pituitary tshß, there was significant temporal variation in expression of pituitary eya3 under the SNP treatment, with expression level elevating in association with active gametogenesis. Under the LL treatment, sexual maturation was inhibited and there was a corresponding suppression of eya3 expression. In a second study the impact of size/energetic status on the initiation of sexual maturation was investigated. In the feed restricted population maturation was significantly suppressed (5% sexually mature) compared to the ab libitum fed stock (95% sexually mature) with there being a concomitant significant suppression in pituitary eya3 expression. Overall, these results suggest that pituitary eya3 has the potential to act as an integrator of both environmental and energetic regulation of sexual maturation of cod. Being the first account of eya3 induction in a short day breeding teleost, the conserved association with stimulation of reproduction and not seasonal state indicates that the upstream drivers which initiate the pathway differ among vertebrates according to their breeding strategies, but the pathway itself and its role in the reproductive cascade appears to be conserved across the vertebrate clade.


Subject(s)
Animal Nutritional Physiological Phenomena , Gadus morhua/physiology , Neurosecretory Systems , Photoperiod , Sexual Maturation , Animals , Circadian Rhythm/physiology , Female , Gene Expression Profiling , Gene Expression Regulation , Male , Phylogeny , Pituitary Gland/metabolism , Reproduction/physiology , Seasons , Time Factors , Vertebrates
2.
Sci Rep ; 9(1): 15179, 2019 10 23.
Article in English | MEDLINE | ID: mdl-31645599

ABSTRACT

Understanding how temperature affects the relative phenology of predators and prey is necessary to predict climate change impacts and recruitment variation. This study examines the role of temperature in the phenology of a key forage fish, the lesser sandeel (Ammodytes marinus, Raitt) and its copepod prey. Using time-series of temperature, fish larval and copepod abundance from a Scottish coastal monitoring site, the study quantifies how thermal relationships affect the match between hatching in sandeel and egg production of its copepod prey. While sandeel hatch time was found to be related to the rate of seasonal temperature decline during the autumn and winter through effects on gonad and egg development, variation in copepod timing mostly responded to February temperature. These two temperature relationships defined the degree of trophic mismatch which in turn explained variation in local sandeel recruitment. Projected warming scenarios indicated an increasing probability of phenological decoupling and concomitant decline in sandeel recruitment. This study sheds light on the mechanisms by which future warming could increase the trophic mismatch between predator and prey, and demonstrates the need to identify the temperature-sensitive stages in predator-prey phenology for predicting future responses to climate change.

3.
J Fish Biol ; 91(1): 362-367, 2017 Jul.
Article in English | MEDLINE | ID: mdl-28691400

ABSTRACT

Ovarian development was examined in relation to size and temperature in late pre-spawning Ammodytes marinus over 5 years. Oocyte diameter was positively related to length indicating that larger females spawned earlier. Age and temperature, whilst accounting for the effect of length, were not found to affect oocyte development, although the thermal range examined was only 1·3° C.


Subject(s)
Body Size/physiology , Fishes/anatomy & histology , Fishes/physiology , Reproduction/physiology , Animals , Female , Likelihood Functions , Linear Models , North Sea , Oocytes/growth & development , Oocytes/ultrastructure , Oogenesis/physiology , Scotland , Statistics, Nonparametric , Temperature , Time Factors
4.
Vet Microbiol ; 164(3-4): 399-404, 2013 Jun 28.
Article in English | MEDLINE | ID: mdl-23523172

ABSTRACT

Escherichia coli (E. coli) is the most commonly isolated infectious agent causing pyometra in bitches. Many E. coli strains isolated from the uteri of infected dogs carry several adhesin genes (fimH, papGIII and sfa). The objective of this study was to investigate the role of each adhesin gene product, acting alone or expressed in combination, in the bacterial binding to canine endometrium. E. coli strain P3, which was isolated from a uterus of a bitch naturally affected with pyometra, was shown by PCR to carry all three known fimbrial adhesin genes fimH, papGIII and sfa. Knockout (KO) mutants of this wildtype (P3-wt) strain were generated using insertional inactivation. Adhesion assays on anoestrous uteri of three post-pubertal bitches were undertaken. Overall, the number of bacteria adhering to canine endometrial biopsies was comparable between strains and no significant difference in the number of bound bacteria was found between the P3-wt strain and the single or double KO-strains. However, the triple knockout strain displayed less binding to the canine endometrium compared with the P3-wt strain. This study shows that a pathogenic E. coli strain (P3) isolated from the uterus of a bitch with pyometra was able to fully compensate for the loss of two of its three known adhesin genes. It was necessary to inactivate all three known adhesin genes in order to see a significant decrease in binding to canine endometrium.


Subject(s)
Dog Diseases/microbiology , Endometrium/microbiology , Escherichia coli Infections/veterinary , Escherichia coli/metabolism , Fimbriae, Bacterial/metabolism , Adhesins, Escherichia coli/genetics , Adhesins, Escherichia coli/metabolism , Animals , Bacterial Adhesion/genetics , Bacterial Adhesion/immunology , Dogs , Endometrium/metabolism , Escherichia coli/genetics , Escherichia coli Infections/microbiology , Female , Fimbriae, Bacterial/genetics , Gene Knockout Techniques
5.
J Fish Biol ; 82(3): 741-63, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23464542

ABSTRACT

The application of data storage tags bears the potential for a quantum leap in the research on fish migrations, because not only first-capture and recapture positions are known, but at least theoretically, the migration path during the period at large can be reconstructed. Position, however, cannot be measured directly but has to be estimated using the available data on light, temperature, pressure and salinity. The reconstructed locations based on advanced estimation techniques have been termed geolocations. Examples are discussed which illustrate the applicability of geolocations in individual path descriptions, separation of reproductively isolated populations, timing and areas of spawning, tidal transport and use of protected areas. The examples are based on archival tag data from the North Sea, the Baltic Sea, the Barents Sea and Faroese and Icelandic Waters. Besides presenting the state-of-the-art geolocations for cod Gadus morhua in the north-east Atlantic Ocean, the major aim of this review is to raise awareness of gaps in knowledge and to identify ideas for new research.


Subject(s)
Animal Identification Systems/trends , Animal Migration , Ecology/trends , Gadus morhua , Animals , Atlantic Ocean
6.
Comp Immunol Microbiol Infect Dis ; 35(5): 461-7, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22554919

ABSTRACT

Pyometra is a potentially life-threatening condition in bitches and is often caused by Escherichia coli infection. Both pathogenic and non-pathogenic E. coli strains commonly carry the genes for type 1 fimbriae that mediate bacterial adhesion onto host epithelium. To investigate whether the type 1 fimbrial adhesin, FimH, facilitates the binding of uropathogenic E. coli to canine endometrium, the fimH gene was insertionally inactivated in a pathogenic E. coli strain. The ability of E. coli to bind to canine endometrial epithelial cells was determined in vitro using canine uterine biopsies. Binding of the fimH mutant was only 0.3% of that of the wild type. Complementation of the mutation restored the phenotype to that of the parent. This study has developed an in vitro model that allows quantitative and qualitative assessment of bacterial binding to canine endometrium and has demonstrated that the fimH gene plays a role in adherence of pathogenic E. coli to canine endometrium.


Subject(s)
Adhesins, Escherichia coli/metabolism , Dogs/microbiology , Endometrium/microbiology , Escherichia coli Infections/veterinary , Fimbriae Proteins/metabolism , Pyometra/veterinary , Uropathogenic Escherichia coli/pathogenicity , Adhesins, Escherichia coli/genetics , Animals , Bacterial Adhesion , Bacterial Load , Biopsy , Dog Diseases/microbiology , Endometrium/pathology , Escherichia coli Infections/microbiology , Female , Fimbriae Proteins/genetics , Gene Knockout Techniques , Gene Silencing , Genes, Bacterial , Genetic Complementation Test , Hysterectomy , Mutation , Pyometra/microbiology , Uropathogenic Escherichia coli/genetics , Virulence Factors/genetics , Virulence Factors/metabolism
7.
Reprod Domest Anim ; 47 Suppl 6: 331-4, 2012 Dec.
Article in English | MEDLINE | ID: mdl-23279531

ABSTRACT

Pyometra, a prevalent infectious uterine disease that affects intact middle-aged bitches, is typically associated with Escherichia coli. Our hypotheses were (i) that bacterial adhesion to canine endometrium differs between different stages of the oestrous cycle and (ii) that the adhesin FimH facilitates this adhesion. Twelve post-pubertal, ovariectomized greyhound bitches were treated with exogenous hormones to simulate different stages of the oestrous cycle. Tissue samples from each uterus were incubated with a pathogenic E. coli strain carrying the fimH gene, but no other adhesin genes (P4-wt)--or an E. coli strain in which fimH was insertionally inactivated (P4-∆fimH::kan)--or with phosphate-buffered saline as a negative control. After washing, tissue samples were homogenized for quantification of adherent bacteria. The differences in binding to canine endometrium at different stages of the oestrous cycle were not significant. However, the mean difference in binding of the P4-wt and the P4-∆fimH::kan across all stages of the simulated oestrous cycle was significant (p < 0.001 by paired t-test on geometric means). Individual differences in numbers of P4-wt bacteria bound between dogs might suggest genetic variations or epigenetic differences in FimH receptor expression by the endometrium, unrelated to the stage of the oestrous cycle.


Subject(s)
Dog Diseases/microbiology , Dogs , Endometrium/microbiology , Escherichia coli/metabolism , Estrous Cycle/physiology , Adhesins, Escherichia coli/genetics , Adhesins, Escherichia coli/metabolism , Animals , Bacterial Adhesion , Endometrium/metabolism , Escherichia coli/genetics , Escherichia coli Infections/microbiology , Escherichia coli Infections/veterinary , Female , Fimbriae Proteins/genetics , Fimbriae Proteins/metabolism , Gene Expression Regulation, Bacterial/physiology , Pyometra/microbiology , Pyometra/veterinary
8.
J Fish Biol ; 77(6): 1252-67, 2010 Oct.
Article in English | MEDLINE | ID: mdl-21039503

ABSTRACT

The timing of maturation in haddock Melanogrammus aeglefinus was examined using changes in gonad development, follicle stimulating hormone ß (FSH-ß) transcript expression profile, growth and condition of 1 year old females held under a common environment between the summer and winter solstices. The circumnuclear ring, cortical alveolus and vitellogenic oocyte stages were first observed in August, October and November, respectively. FSH-ß transcript levels did not change significantly until September but increased markedly thereafter in maturing fish. A combined analysis of the mean oocyte diameter of the leading cohort, histological staging and FSH-ß transcript profile provided evidence of a commitment to maturation by October or November. Contrary to that previously proposed for gadoid species, histological analysis of field-caught immature M. aeglefinus during the spawning season indicated that cortical alveolar, rather than circumnuclear ring, stage oocytes provided definitive evidence of maturation. A decrease in relative liver size following the summer solstice suggested a possible link between energy status and maturation.


Subject(s)
Follicle Stimulating Hormone, beta Subunit/metabolism , Gadiformes/growth & development , Oocytes/growth & development , Ovary/growth & development , Animals , Female , Follicle Stimulating Hormone, beta Subunit/genetics , Gadiformes/genetics , Gene Expression Profiling
9.
J Fish Biol ; 74(3): 715-21, 2009 Feb.
Article in English | MEDLINE | ID: mdl-20735592

ABSTRACT

Internally implanted data storage tags (DST) recording hydrostatic pressure (depth) and temperature in Atlantic cod Gadus morhua were used to track the behaviour of nine individuals during fishing operations. Gadus morhua showed identifiable and characteristic behavioural responses to different capture processes. In a unique observation, one fish survived being discarded and upon return to the seabed exhibited a cessation of activity comparable to observations on stressed fish under laboratory conditions.


Subject(s)
Behavior, Animal , Gadus morhua/physiology , Stress, Physiological , Animals
10.
MAGMA ; 21(1-2): 121-30, 2008 Mar.
Article in English | MEDLINE | ID: mdl-18259791

ABSTRACT

METHOD: This paper presents methods of measuring the longitudinal relaxation time using inversion recovery turbo spin echo (IR-TSE) and magnetization-prepared rapid gradient echo (MPRAGE) sequences, comparing and optimizing these sequences, reporting T1 values for water protons measured from brain tissue at 1.5, 3, and 7 T. T1 was measured in cortical grey matter and white matter using the IR-TSE, MPRAGE, and inversion recovery echo planar imaging (IR-EPI) pulse sequences. RESULTS: In four subjects the T1 of white and grey matter were found to be 646+/-32 and 1,197+/-134 ms at 1.5 T, 838+/-50 and 1,607+/-112 ms at 3T, and 1,126+/-97, and 1,939+/-149 ms at 7 T with the MPRAGE sequence. The T1 of the putamen was found to be 1,084+/-63 ms at 1.5 T, 1,332+/-68 ms at 3T, and 1,644+/-167 ms at 7 T. The T1 of the caudate head was found to be 1,109+/- 66 ms at 1.5 T, 1,395+/-49 ms at 3T, and 1,684+/-76 ms at 7 T. DISCUSSION: There was a trend for the IR-TSE sequence to underestimate T1 in vivo. The sequence parameters for the IR-TSE and MPRAGE sequences were also optimized in terms of the signal-to-noise ratio (SNR) in the fitted T1. The optimal sequence for IR-TSE in terms of SNR in the fitted T1 was found to have five readouts at TIs of 120, 260, 563, 1,221, 2,647, 5,736 ms and TR of 7 s. The optimal pulse sequence for MPRAGE with readout flip angle = 8 degrees was found to have five readouts at TIs of 160, 398, 988, 2,455, and 6,102 ms and a TR of 9 s. Further optimization including the readout flip angle suggests that the flip angle should be increased, beyond levels that are acceptable in terms of power deposition and point-spread function.


Subject(s)
Echo-Planar Imaging/methods , Image Processing, Computer-Assisted/methods , Magnetic Resonance Imaging/methods , Adult , Algorithms , Brain/pathology , Calibration , Female , Humans , Magnetics , Male , Models, Statistical , Protons , Reproducibility of Results , Water/chemistry
11.
Arch Virol ; 152(6): 1075-86, 2007.
Article in English | MEDLINE | ID: mdl-17334907

ABSTRACT

We describe an outbreak of gastroenteritis in which the nucleic acid of three distinct noroviruses was amplified from the same fecal sample. To enable the separate amplification of each virus, an inclusion/exclusion RT-PCR primer design strategy was developed. This paired a virus-specific exclusion primer (designed with the exact sequence of one virus in a region displaying low conservation among the three viruses) with a virus-nonspecific inclusion primer (designed in a conserved region). Thus, in each reaction the exclusion primer provided specificity for a single virus, and the inclusion primer increased the sensitivity and allowed hybridization in a region of unknown sequence. Analysis of the partial genomic sequences of the three viruses (3.6-3.8 kb) indicated that each virus belonged to a separate genogroup II cluster, and each displayed evidence of a potential recombination event when the sequences were compared with other published norovirus sequences. Our results, which show a mixed norovirus infection in a single individual, confirm the need to be aware of the possibility of mixed norovirus infections, and of the possibility of genomic recombination causing anomalies in phylogenetic analyses in such instances.


Subject(s)
Caliciviridae Infections/epidemiology , Caliciviridae Infections/virology , Gastroenteritis/epidemiology , Gastroenteritis/virology , Norovirus/genetics , Norovirus/isolation & purification , Ostreidae/virology , Recombination, Genetic , Animals , Base Sequence , DNA Primers/genetics , DNA, Viral/genetics , Disease Outbreaks , Food Microbiology , Genome, Viral , Humans , Male , Molecular Sequence Data , Norovirus/classification , Phylogeny , Reverse Transcriptase Polymerase Chain Reaction , Victoria/epidemiology
12.
Int J Clin Pract ; 60(8): 967-75, 2006 Aug.
Article in English | MEDLINE | ID: mdl-16780568

ABSTRACT

Of the current options available to treat erectile dysfunction, oral phosphodiesterase type 5 (PDE5) inhibitors are the recommended first-line treatment. This review compares the three currently licensed PDE5 inhibitors: sildenafil citrate (sildenafil), vardenafil HCl (vardenafil) and tadalafil. All three drugs have similar efficacy and toxicity profiles. Sildenafil and vardenafil have similar molecular structures, but tadalafil is structurally different, which is reflected in its pharmacokinetic profile. With regard to the onset of action, achievement of an erection that leads to successful intercourse has been reported for 35% of patients treated with sildenafil within 14 min, 21% of patients treated with vardenafil within 10 min and 16% of patients treated with tadalafil within 16 min. Sildenafil and vardenafil both have half-lives of approximately 4 h but the half-life of tadalafil is 17.5 h. Another difference between the PDE5 inhibitors is that food, especially fatty food, affects the pharmacokinetic profiles of sildenafil and vardenafil, but not that of tadalafil. These pharmacokinetic differences among the PDE5 inhibitors may underlie patient preference, an important and emerging aspect of ED therapy.


Subject(s)
Erectile Dysfunction/drug therapy , Phosphodiesterase Inhibitors/therapeutic use , Administration, Oral , Cost-Benefit Analysis , Double-Blind Method , Humans , Male , Multicenter Studies as Topic , Patient Satisfaction , Phosphodiesterase Inhibitors/chemistry , Phosphodiesterase Inhibitors/pharmacokinetics , Randomized Controlled Trials as Topic , Treatment Failure
13.
Theriogenology ; 66(6-7): 1530-6, 2006 Oct.
Article in English | MEDLINE | ID: mdl-16620926

ABSTRACT

The objective of this study was to develop a reliable model for the study of the cystic endometrial hyperplasia and pyometra complex (CEH/P) in the bitch. Greyhound bitches (n = 15) were ovariectomised and allocated into three groups (Group 1, n = 5; Group 2, n = 5; Group 3, n = 10, including 5 used from Group 1). Simulated proestrus, estrus and diestrus were induced by treatment with estradiol benzoate and megestrol acetate. The duration of cervical opening during estrus was determined by the intra-vaginal infusion of radio-opaque medium and subsequent radiography of the uterus (Group 1). One milliliter of a culture of Escherichia coli (with five uro-pathogenic virulence factors as identified by PCR: pap, sfa, hlyA, cnf1 and fim) was inoculated intra-vaginally daily throughout the simulated estrus (Group 2). One milliliter of the culture (n = 6) or sterile Luria-Bertani broth (n = 4) was introduced directly into the uterus on simulated diestrus Days 8 or 12 (Group 3). Necropsies were performed 12 and 7-14 days after the inoculation (Groups 2 and 3). The cervix remained open throughout the duration of simulated estrus (5-6 days) in four out of five bitches, and for a shorter duration (3 days of a 6-day estrus period) in one bitch (Group 1). CEH/P was induced by inoculation of bacteria into the uterus (10/10 bitches) but not into the vagina (0/5 bitches), (P = 0.003). A model for the study of CEH/P has been validated.


Subject(s)
Dog Diseases/microbiology , Dog Diseases/pathology , Endometrial Hyperplasia/veterinary , Escherichia coli Infections/veterinary , Escherichia coli/growth & development , Uterine Diseases/pathology , Uterine Diseases/veterinary , Animals , Cervix Uteri/physiology , Colony Count, Microbial , Contrast Media , Dogs , Endometrial Hyperplasia/diagnostic imaging , Endometrial Hyperplasia/microbiology , Endometrial Hyperplasia/pathology , Escherichia coli Infections/microbiology , Escherichia coli Infections/pathology , Estrous Cycle/drug effects , Estrous Cycle/physiology , Female , Ovariectomy/veterinary , Progesterone/blood , Radiography , Uterine Diseases/microbiology , Vaginal Smears
14.
Theriogenology ; 66(6-7): 1513-7, 2006 Oct.
Article in English | MEDLINE | ID: mdl-16488001

ABSTRACT

UNLABELLED: The objectives of this study were to confirm: (i) whether progestin treatment suppressed GnRH agonist-induced estrus in anestrous greyhound bitches; and (ii) the site of progestin action (i.e. pituitary, ovary). All bitches received a deslorelin implant on Day 0 and blood samples were taken from -1 h to +6 h. Five bitches were treated with megestrol acetate (2 mg/kg orally once daily) from -7 d to +6 d (Group 1) and 10 bitches were untreated controls (Group 2). Proestrous or estrous signs were observed in 4 of 5 bitches in Group 1, and 4 of 10 bitches in Group 2 (P = 0.28). The plasma LH responses (area under the curve from 0 to 6h after implantation) were higher (P = 0.008) in Group 2 than in Group 1. Plasma LH responses were similar (P = 0.59) in bitches showing signs of proestrus or estrus (responders) and in non-responders. The plasma estradiol responses (calculated as for LH response) were greater in Group 1 than in Group 2 (P = 0.048), and in responders than in non-responders (P = 0.02). IN CONCLUSION: (i) progestin treatment (a) did not suppress the incidence of bitches showing deslorelin-induced proestrus or estrus, and (b) was associated with a reduced pituitary responsiveness and an increased ovarian responsiveness to deslorelin treatment; (ii) the occurrence of proestrous or estrous signs reflected increased ovarian responsiveness to induced gonadotrophin secretion and not increased pituitary responsiveness to deslorelin.


Subject(s)
Anestrus/physiology , Dogs/physiology , Estradiol/blood , Luteinizing Hormone/blood , Progestins/pharmacology , Triptorelin Pamoate/analogs & derivatives , Anestrus/drug effects , Animals , Dogs/blood , Drug Implants , Estrus/drug effects , Estrus/physiology , Female , Megestrol Acetate/pharmacology , Progesterone/blood , Triptorelin Pamoate/administration & dosage , Triptorelin Pamoate/antagonists & inhibitors , Triptorelin Pamoate/pharmacology
15.
Theriogenology ; 66(6-7): 1545-9, 2006 Oct.
Article in English | MEDLINE | ID: mdl-16473400

ABSTRACT

The relationships between changes in plasma progesterone concentrations, degeneration of the luminal epithelium, the occurrence of apoptosis of endometrial cells and endometrial leucocyte populations in the bitch were determined. Mature bitches (n = 15) were euthanized and necropsied when in diestrus (Days 7-75, n = 12) or in anestrus (Days 10, 32 and 53). Degeneration of the luminal epithelium was observed in bitches in late diestrus (Days 38-75, n = 5) when plasma progesterone concentrations were decreasing and in anestrus (Days 10 and 32, n = 2) when plasma progesterone concentrations were < 0.5 ng/mL. Endometrial leucocyte populations increased after degeneration of the luminal epithelium (around Day 42 of diestrus). Apoptosis was mainly observed in the basal glandular epithelial cells and endothelial cells of blood capillaries in all except anestrous bitches. Very few apoptotic cells were found in the superficial glandular epithelial cells and stromal cells. Higher apoptotic indices were detected in the basal glandular epithelium on Days 12-42 of diestrus than at other stages. Therefore, apoptosis of glandular basal epithelial cells occurred mainly in early diestrus, degeneration of cells of the luminal epithelium occurred from mid-diestrus to early anestrus, and the increase in leucocyte numbers may have been a consequence and not a cause of luminal epithelial degeneration.


Subject(s)
Apoptosis/physiology , Dogs/physiology , Endometrium/cytology , Endometrium/physiology , Anestrus/physiology , Animals , Diestrus/physiology , Dogs/blood , Epithelial Cells/cytology , Epithelial Cells/physiology , Female , Histocytochemistry/veterinary , In Situ Nick-End Labeling/veterinary , Leukocyte Count/veterinary , Progesterone/blood
16.
Theriogenology ; 66(6-7): 1537-44, 2006 Oct.
Article in English | MEDLINE | ID: mdl-16472854

ABSTRACT

Cystic endometrial hyperplasia (CEH) was induced in the left uterine horns of 14 mature ovariectomised greyhound bitches with an intra-luminal silk suture (uterine irritant) and treatment with estradiol benzoate and megestrol acetate (to simulate stages of a normal canine estrous cycle). Right uterine horns served as suture-free controls. From Day 30 of simulated diestrus, bitches received treatments of suture removal (n = 4), progestagen withdrawal (n = 5) or both (n = 5). Necropsies were performed 3 or 9 weeks later. At 3 weeks, severe cystic endometrial hyperplasia was present in all (6/6) left horns and in no (0/6) right horns. At 9 weeks, the left horns in 5/6 of bitches subjected to progestagen-withdrawal had recovered (in varying degrees) from cystic endometrial hyperplasia, whereas no recovery was evident in the left horns of bitches (n = 2) that continued to receive progestagen. This study demonstrated that: (i) cystic endometrial hyperplasia was reversible upon withdrawal of progestagen; (ii) progestagen maintained cystic endometrial hyperplasia in the presence or absence of irritant; and (iii) persistent endometrial irritation in the absence of progestagen may not maintain cystic endometrial hyperplasia.


Subject(s)
Dog Diseases/pathology , Endometrial Hyperplasia/pathology , Endometrial Hyperplasia/veterinary , Estradiol/analogs & derivatives , Megestrol Acetate/pharmacology , Progestins/pharmacology , Animals , Dogs , Endometrial Hyperplasia/etiology , Estradiol/pharmacology , Estrous Cycle/physiology , Female , Histocytochemistry/veterinary , Irritants , Ovariectomy/veterinary , Silk , Sutures
17.
Arch Virol ; 150(3): 521-32, 2005 Mar.
Article in English | MEDLINE | ID: mdl-15526144

ABSTRACT

Hendra virus is one of two virus species within the newly-formed genus Henipavirus, subfamily Paramxyovirinae. It is a designated select agent with potential biosecurity threat to both human and animal health. Quantitative real-time PCR was used to measure viral RNA synthesis in Vero cells infected by Hendra virus, and to examine the inhibitory effect of ribavirin. It was also used to determine the points of attenuation during transcription of the six viral genes N, P, M, F, G and L by targeting amplicons located towards the 3' end of each gene. Major increases in viral RNA and virus yield occurred between 4 to 8 h and 8 to 10 h post infection, respectively. The effect of ribavirin was examined at a range of concentrations up to 400 microm. At 50 microm, RNA synthesis was reduced 9 fold, and virus yield 58 fold. As expected for a member of the order Mononegavirales, a gradient of transcription was observed in Hendra virus-infected cells. There was significant attenuation at the M-F and G-L junctions, more closely resembling Sendai virus (genus Respirovirus) than measles virus (genus Morbillivirus).


Subject(s)
Antiviral Agents/pharmacology , Hendra Virus/physiology , RNA, Viral/biosynthesis , Ribavirin/pharmacology , Animals , Chlorocebus aethiops , Dose-Response Relationship, Drug , Gene Amplification , Hendra Virus/drug effects , Polymerase Chain Reaction , RNA, Viral/analysis , Vero Cells , Virus Replication
18.
Arch Virol Suppl ; (18): 122-31, 2004.
Article in English | MEDLINE | ID: mdl-15119767

ABSTRACT

Hendra virus (HENV) and Nipah virus (NIPV) are classified in the new genus Henipavirus, within the subfamily Paramyxovirinae, family Paramyxoviridae. The genetic and biological characteristics that differentiate henipaviruses from other members of the subfamily are summarized. Although they do not display neuraminidase and hemagglutination activities and in that regard resemble viruses in the genus Morbillivirus, several recent observations highlight similarities between henipaviruses and respiroviruses (genus Respirovirus) in structure and replication strategy. First, three-dimensional modeling studies suggest that the external globular head domain of the HENV G protein resembles that of respiroviruses rather than morbilliviruses. Second, the pattern of transcriptional attenuation in HENV-infected cells resembles that observed with Sendai virus, a respirovirus, and differs from that found in cells infected with measles virus, a morbillivirus. Henipaviruses have a broad host range in vitro and in vivo, indicating wide distribution of cellular receptor molecules. The extensive host range has been confirmed in a quantitative in vitro cell-fusion assay using recombinant vaccinia viruses expressing the attachment and fusion proteins of HENV and NIPV. Cell lines of diverse origin and which are permissive in the in vitro cell fusion assay have been identified and the pattern of relative susceptibilities is the same for both HENV and NIPV, implying that both viruses use the same cell receptor. Protease treatment of permissive cells destroys their ability to fuse with cells expressing viral envelope glycoproteins. Virus overlay protein binding assay (VOPBA) and radio-immune precipitation assays confirm that both HENV and NIPV bind to membrane proteins in the 35-50 kD range. Treatment of cell membrane proteins with N-glycosidase eliminates HeV binding activity in VOPBA whereas treatment with neuraminidase has no effect on binding. Thus preliminary evidence suggests that NIPV and HENV bind to the same glycoprotein receptor via a non-sialic acid-dependant mechanism.


Subject(s)
Henipavirus Infections/virology , Henipavirus/genetics , Receptors, Virus/physiology , Diagnosis, Differential , Henipavirus/classification , Henipavirus/pathogenicity , Henipavirus/physiology , Henipavirus Infections/diagnosis , Humans , Transcription, Genetic
19.
Public Health ; 118(3): 230-3, 2004 Apr.
Article in English | MEDLINE | ID: mdl-15003413

ABSTRACT

Noroviruses are a major cause of both sporadic and epidemic gastroenteritis in humans, but the mechanisms by which norovirus circulates within the community are poorly understood. In this study, we examined the hypothesis that asymptomatic people act as a reservoir for norovirus. Faecal specimens from 399 asymptomatic individuals were tested for norovirus by reverse transcription polymerase chain reaction (RT-PCR) methodology, and no norovirus was detected. The failure to detect norovirus was not apparently due to the test sample being resistant to norovirus infection, nor to the presence of PCR inhibitors in the test sample. The findings suggest that, if norovirus is carried by asymptomatic people, the carriage rate is very low; the upper bound (95% confidence interval, binomial distribution) of the carriage rate was only 0.8%. Thus, it is unlikely that asymptomatic people are an important reservoir for norovirus.


Subject(s)
Caliciviridae Infections/diagnosis , Gastroenteritis/diagnosis , Norovirus/isolation & purification , Adolescent , Adult , Australia , Caliciviridae Infections/virology , Child , Child, Preschool , Feces/virology , Female , Gastroenteritis/virology , Health Services Research , Humans , Infant , Male , Middle Aged , Public Health
20.
Anim Reprod Sci ; 76(3-4): 177-93, 2003 Apr 15.
Article in English | MEDLINE | ID: mdl-12586491

ABSTRACT

Ovarian follicular development and concentrations of gonadotrophin and steroid hormones were studied in non-lactating Holstein cows following administration of progesterone (P(4)) or oestradiol benzoate (ODB) at the start of treatment with an intravaginal progesterone releasing insert (IVP(4)) in a 2 by 2 factorial experiment. Cows were treated at random stages of the oestrous cycle with an IVP(4) device (Day 0) and either no other treatment (n=8), 200 mg of P(4) IM (n=9), 2.0 mg of ODB IM (n=8) or both P(4) and ODB (n=9). Seven days later devices were removed and PGF(2alpha) was administered. Twenty-four hours later 1.0mg of ODB was administered IM. Oestrus was detected in 97.1% and ovulation in 64.7% (effect of treatment, P=0.41) of cows within 96 h of removing inserts. In the cows that ovulated, day of emergence of the ovulatory follicle was delayed (P<0.01) and more precise (P<0.05) in cows treated with ODB compared to the cows treated with P(4). Interval from wave emergence to ovulation and the diameter of the ovulatory follicle was less (P<0.05) in cows treated with ODB compared to cows treated with P(4). Combined treatment with P(4) and ODB at the time of starting treatment with an IVP(4) device did not significantly change the pattern of ovarian follicular development compared to treatment with ODB alone. Concentrations of LH and FSH in plasma were less in cows treated with ODB between Days 0 and 4 (P<0.05) while treatment with P(4) increased concentrations of FSH in plasma between Days 0 and 4 (P<0.05). When anovulatory cows were compared to ovulatory cows, diameters of follicles (P<0.001) and growth rate of follicles (P<0.01) were less in anovulatory cows between Days 7 and 9, while concentrations of FSH in plasma were greater (P<0.01), concentrations of LH similar (P>0.90) and concentrations of oestradiol were less (P=0.01) in the anovulatory cows between Days 4 and 10. Our findings support a hypothesis that ovarian follicular development following administration of P(4) or ODB at the start of treatment with an IVP(4) device differs. Anovulatory oestrus may have been associated with reduced maturity and/or later emergence of ovarian follicles.


Subject(s)
Cattle/physiology , Estradiol/administration & dosage , Hormones/blood , Ovarian Follicle/drug effects , Ovarian Follicle/physiology , Progesterone/administration & dosage , Administration, Intravaginal , Animals , Estradiol/blood , Estrus , Estrus Synchronization , Female , Follicle Stimulating Hormone/blood , Luteinizing Hormone/blood , Ovarian Follicle/diagnostic imaging , Ovulation , Progesterone/blood , Ultrasonography
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