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1.
Phys Rev Lett ; 130(21): 212701, 2023 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-37295108

RESUMO

The rate of the final step in the astrophysical αp process, the ^{34}Ar(α,p)^{37}K reaction, suffers from large uncertainties due to a lack of experimental data, despite having a considerable impact on the observable light curves of x-ray bursts and the composition of the ashes of hydrogen and helium burning on accreting neutron stars. We present the first direct measurement constraining the ^{34}Ar(α,p)^{37}K reaction cross section, using the Jet Experiments in Nuclear Structure and Astrophysics gas jet target. The combined cross section for the ^{34}Ar,Cl(α,p)^{37}K,Ar reaction is found to agree well with Hauser-Feshbach predictions. The ^{34}Ar(α,2p)^{36}Ar cross section, which can be exclusively attributed to the ^{34}Ar beam component, also agrees to within the typical uncertainties quoted for statistical models. This indicates the applicability of the statistical model for predicting astrophysical (α,p) reaction rates in this part of the αp process, in contrast to earlier findings from indirect reaction studies indicating orders-of-magnitude discrepancies. This removes a significant uncertainty in models of hydrogen and helium burning on accreting neutron stars.


Assuntos
Hélio , Hidrogênio , Modelos Estatísticos , Nêutrons
2.
Phys Rev Lett ; 128(18): 182701, 2022 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-35594108

RESUMO

The ^{30}P(p,γ)^{31}S reaction plays an important role in understanding the nucleosynthesis of A≥30 nuclides in oxygen-neon novae. The Gaseous Detector with Germanium Tagging was used to measure ^{31}Cl ß-delayed proton decay through the key J^{π}=3/2^{+}, 260-keV resonance. The intensity I_{ßp}^{260}=8.3_{-0.9}^{+1.2}×10^{-6} represents the weakest ß-delayed, charged-particle emission ever measured below 400 keV, resulting in a proton branching ratio of Γ_{p}/Γ=2.5_{-0.3}^{+0.4}×10^{-4}. By combining this measurement with shell-model calculations for Γ_{γ} and past work on other resonances, the total ^{30}P(p,γ)^{31}S rate has been determined with reduced uncertainty. The new rate has been used in hydrodynamic simulations to model the composition of nova ejecta, leading to a concrete prediction of ^{30}Si:^{28}Si excesses in presolar nova grains and the calibration of nuclear thermometers.

3.
Phys Rev Lett ; 129(15): 152501, 2022 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-36269970

RESUMO

Absolute cross sections for the addition of s- and d-wave neutrons to ^{14}C and ^{14}N have been determined simultaneously via the (d,p) reaction at 10 MeV/u. The difference between the neutron and proton separation energies, ΔS, is around -20 MeV for the ^{14}C+n system and +8 MeV for ^{14}N+n. The population of the 1s_{1/2} and 0d_{5/2} orbitals for both systems is reduced by a factor of approximately 0.5 compared with the independent single-particle model, or about 0.6 when compared with the shell model. This finding strongly contrasts with results deduced from intermediate-energy knockout reactions between similar nuclei on targets of ^{9}Be and ^{12}C. The simultaneous technique used removes many systematic uncertainties.

4.
Phys Rev Lett ; 126(4): 042701, 2021 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-33576674

RESUMO

Proton capture on the excited isomeric state of ^{26}Al strongly influences the abundance of ^{26}Mg ejected in explosive astronomical events and, as such, plays a critical role in determining the initial content of radiogenic ^{26}Al in presolar grains. This reaction also affects the temperature range for thermal equilibrium between the ground and isomeric levels. We present a novel technique, which exploits the isospin symmetry of the nuclear force, to address the long-standing challenge of determining proton-capture rates on excited nuclear levels. Such a technique has in-built tests that strongly support its veracity and, for the first time, we have experimentally constrained the strengths of resonances that dominate the astrophysical ^{26m}Al(p,γ)^{27}Si reaction. These constraints demonstrate that the rate is at least a factor ∼8 lower than previously expected, indicating an increase in the stellar production of ^{26}Mg and a possible need to reinvestigate sensitivity studies involving the thermal equilibration of ^{26}Al.

5.
Gynecol Oncol ; 159(3): 692-698, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33077258

RESUMO

BACKGROUND: We investigated the safety and efficacy of a combination of the oral tyrosine kinase inhibitor, nintedanib (BIBF 1120) with oral cyclophosphamide in patients with relapsed ovarian cancer. PATIENTS AND METHODS: Patients with relapsed ovarian, fallopian tube or primary peritoneal cancer received oral cyclophosphamide (100 mg o.d.) and were randomised (1,1) to also have either oral nintedanib or placebo. The primary endpoint was overall survival (OS). Secondary endpoints included progression free survival (PFS), response rate, toxicity, and quality of life. RESULTS: 117 patients were randomised, 3 did not start trial treatment, median age 64 years. Forty-five (39%) had received ≥5 lines chemotherapy. 30% had received prior bevacizumab. The median OS was 6.8 (nintedanib) versus 6.4 (placebo) months (hazard ratio 1.08; 95% confidence interval 0.72-1.62; P = 0.72). The 6-month PFS rate was 29.6% versus 22.8% (P = 0.57). Grade 3/4 adverse events occurred in 64% (nintedanib) versus 54% (placebo) of patients (P = 0.28); the most frequent G3/4 toxicities were lymphopenia (18.6% nintedanib versus 16.4% placebo), diarrhoea (13.6% versus 0%), neutropenia (11.9% versus 0%), fatigue (10.2% versus 9.1%), and vomiting (10.2% versus 7.3%). Patients who had received prior bevacizumab treatment had 52 days less time on treatment (P < 0.01). 26 patients (23%) took oral cyclophosphamide for ≥6 months. There were no differences in quality of life between treatment arms. CONCLUSIONS: This is the largest reported cohort of patients with relapsed ovarian cancer treated with oral cyclophosphamide. Nintedanib did not improve outcomes when added to oral cyclophosphamide. Although not significant, more patients than expected remained on treatment for ≥6 months. This may reflect a higher proportion of patients with more indolent disease or the higher dose of cyclophosphamide used. CLINICAL TRIAL REGISTRATION: Clinicaltrials.govNCT01610869.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Ciclofosfamida/efeitos adversos , Neoplasias das Tubas Uterinas/tratamento farmacológico , Indóis/efeitos adversos , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Peritoneais/tratamento farmacológico , Administração Metronômica , Administração Oral , Idoso , Inibidores da Angiogênese/administração & dosagem , Inibidores da Angiogênese/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Ciclofosfamida/administração & dosagem , Neoplasias das Tubas Uterinas/diagnóstico , Neoplasias das Tubas Uterinas/mortalidade , Neoplasias das Tubas Uterinas/patologia , Feminino , Humanos , Indóis/administração & dosagem , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Neoplasias Ovarianas/diagnóstico , Neoplasias Ovarianas/mortalidade , Neoplasias Ovarianas/patologia , Neoplasias Peritoneais/diagnóstico , Neoplasias Peritoneais/mortalidade , Neoplasias Peritoneais/patologia , Intervalo Livre de Progressão , Qualidade de Vida
6.
Phys Rev Lett ; 122(5): 052701, 2019 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-30822026

RESUMO

Detection of nuclear-decay γ rays provides a sensitive thermometer of nova nucleosynthesis. The most intense γ-ray flux is thought to be annihilation radiation from the ß^{+} decay of ^{18}F, which is destroyed prior to decay by the ^{18}F(p,α)^{15}O reaction. Estimates of ^{18}F production had been uncertain, however, because key near-threshold levels in the compound nucleus, ^{19}Ne, had yet to be identified. We report the first measurement of the ^{19}F(^{3}He,tγ)^{19}Ne reaction, in which the placement of two long-sought 3/2^{+} levels is suggested via triton-γ-γ coincidences. The precise determination of their resonance energies reduces the upper limit of the rate by a factor of 1.5-17 at nova temperatures and reduces the average uncertainty on the nova detection probability by a factor of 2.1.

7.
Br J Surg ; 99(9): 1254-61, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22829411

RESUMO

BACKGROUND: Although cholecystectomy is the standard therapy for acute cholecystitis (AC), operative morbidity in the elderly may be high owing to medical co-morbidities and decreased physiological reserve. Outcomes of AC in the elderly have not been fully defined with regard to operative and long-term non-operative management. METHODS: Patients aged 65 years or over admitted to a tertiary care centre with a diagnosis of AC between January 2000 and December 2009 were reviewed retrospectively. Patient data, operative and postoperative details were obtained. To determine cholecystectomy rates in the non-operative group, medical records were reviewed, and patients and families were interviewed. RESULTS: A total of 290 patients underwent cholecystectomy during the index admission, of whom 59 (20·3 per cent) required conversion to open operation. Fifty-eight of these patients experienced 98 complications, including acute respiratory failure (27), pneumonia (18), myocardial infarction (16) and sepsis (15). Some 185 patients had non-operative treatment, of whom 67 underwent percutaneous cholecystostomy. Forty-four patients subsequently had elective cholecystectomy, with a complication rate of 23 per cent. One hundred and twenty-six patients were discharged without a plan for cholecystectomy; the rate of recurrent AC was 4 per cent among the two-thirds of patients followed to within 15 months of death. No deaths or major complications occurred among those with recurrent AC. CONCLUSION: Despite selection of the best elderly candidates for cholecystectomy, postoperative morbidity was significant. Medical management, with interval cholecystectomy only for recurrent AC, may be appropriate in selected patients.


Assuntos
Antibacterianos/administração & dosagem , Colecistectomia Laparoscópica/estatística & dados numéricos , Colecistite Aguda/tratamento farmacológico , Idoso , Antibacterianos/uso terapêutico , Colecistite Aguda/cirurgia , Feminino , Humanos , Infusões Parenterais , Masculino , Complicações Pós-Operatórias/etiologia , Recidiva , Estudos Retrospectivos , Fatores de Risco , Resultado do Tratamento
9.
J Appl Microbiol ; 108(5): 1744-50, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-19886890

RESUMO

AIMS: The isolation of lytic bacteriophage of Vibrio harveyi with potential for phage therapy of bacterial pathogens of phyllosoma larvae from the tropical rock lobster Panulirus ornatus. METHODS AND RESULTS: Water samples from discharge channels and grow-out ponds of a prawn farm in northeastern Australia were enriched for 24 h in a broth containing four V. harveyi strains. The bacteriophage-enriched filtrates were spotted onto bacterial lawns demonstrating that the bacteriophage host range for the samples included strains of V. harveyi, Vibrio campbellii, Vibrio rotiferianus, Vibrio parahaemolyticus and Vibrio proteolyticus. Bacteriophage were isolated from eight enriched samples through triple plaque purification. The host range of purified phage included V. harveyi, V. campbellii, V. rotiferianus and V. parahaemolyticus. Transmission electron microscope examination revealed that six purified phage belonged to the family Siphoviridae, whilst two belonged to the family Myoviridae. The Myoviridae appeared to induce bacteriocin production in a limited number of host bacterial strains, suggesting that they were lysogenic rather than lytic. A purified Siphoviridae phage could delay the entry of a broth culture of V. harveyi strain 12 into exponential growth, but could not prevent the overall growth of the bacterial strain. CONCLUSIONS: Bacteriophage with lytic activity against V. harveyi were isolated from prawn farm samples. Purified phage of the family Siphoviridae had a clear lytic ability and no apparent transducing properties, indicating they are appropriate for phage therapy. Phage resistance is potentially a major constraint to the use of phage therapy in aquaculture as bacteria are not completely eliminated. SIGNIFICANCE AND IMPACT OF THE STUDY: Phage therapy is emerging as a potential antibacterial agent that can be used to control pathogenic bacteria in aquaculture systems. The development of phage therapy for aquaculture requires initial isolation and determination of the bacteriophage host range, with subsequent creation of suitable phage cocktails.


Assuntos
Bacteriófagos/fisiologia , Vibrio/virologia , Animais , Aquicultura , Austrália , Bacteriófagos/isolamento & purificação , Bacteriófagos/ultraestrutura , Especificidade de Hospedeiro , Myoviridae/fisiologia , Myoviridae/ultraestrutura
10.
J Appl Microbiol ; 105(2): 340-50, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18298531

RESUMO

AIMS: This study aimed to determine the bacterial community associated with wild-caught, mid-stage larvae of spiny lobsters (Palinuridae) in their native oligotrophic marine environment, and to compare their diversity and composition with communities associated with aquaculture-reared larvae of the tropical rock lobster Panulirus ornatus. METHODS AND RESULTS: Bacterial clone libraries constructed from wild P. ornatus (two libraries) and Panulirus penicillatus (one library) larvae (phyllosoma) revealed a dominance of alpha-proteobacterial sequences, with Sulfitobacter spp.-affiliated sequences dominating both P. ornatus libraries and constituting a major portion of the P. penicillatus library. Vibrio-related sequences were rarely detected from wild phyllosoma clone libraries in contrast to similar studies of aquaculture-reared animals. Scanning electron microscopy analysis revealed low levels of bacterial colonization on the external carapace of wild phyllosoma, again in contrast to aquaculture-reared animals, which are often colonized with filamentous bacteria (mainly Thiothrix sp.) that compromise their health. Fluorescence in situ hybridization of sectioned wild phyllosoma tissue displayed low overall abundance of bacteria within the tissue and on external surfaces, with alpha-, beta-, and gamma-Proteobacteria being confirmed as members of this bacterial community. CONCLUSIONS: The consistency in predominant clone sequences retrieved from the three libraries indicated a conserved microbiota associated with wild phyllosoma. In addition, the observed differences in the microbial composition and load of reared and wild phyllosoma are indicative of the different environments in which the animals live. SIGNIFICANCE AND IMPACT OF THE STUDY: Bacterial disease during early larval stages is a major constraint currently hindering the development of an aquaculture industry for the ornate rock lobster P. ornatus. Knowledge of the microbial community associated with wild animals will be advantageous for the identification of bacteria that may promote animal health.


Assuntos
Bactérias/isolamento & purificação , Palinuridae/microbiologia , Microbiologia da Água , Animais , Aquicultura , Austrália , Bactérias/ultraestrutura , Biodiversidade , Biblioteca Gênica , Hibridização in Situ Fluorescente/métodos , Larva/microbiologia , Microscopia Eletrônica de Varredura , Sondas de Oligonucleotídeos/genética , Palinuridae/ultraestrutura , Filogenia , RNA Ribossômico 16S/genética , Água do Mar
11.
Heliyon ; 4(9): e00804, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30258994

RESUMO

BACKGROUND: Chemoradiation (CRT) or short-course radiotherapy (SCRT) are standard treatments for locally advanced rectal cancer (LARC). We evaluated the efficacy/safety of two neoadjuvant chemotherapy (NACT) regimens as an alternative prior to total mesorectal excision (TME). METHODS/DESIGN: This multi-centre, phase II trial in patients with magnetic resonance imaging (MRI) defined high-risk LARC (>cT3b, cN2+ or extramural venous invasion) randomised patients (1:1) to FOLFOX + Bevacizumab (Arm 1) or FOLFOXIRI + bevacizumab (Arm 2) every 14 days for 6 cycles prior to surgery. Patients were withdrawn if positron emission tomography (PET) standardised uptake value (SUV) after 3 cycles failed to decrease by >30% or increased compared to baseline. Primary endpoint was pathological complete response rate (pCR). Secondary endpoints included adverse events (AE) and toxicity. Neoadjuvant rectal (NAR) scores based on "T" and "N" downstaging were calculated. FINDINGS: Twenty patients aged 18-75 years were randomised. The trial stopped early because of poor accrual. Seventeen patients completed all 6 cycles of NACT. One stopped due to myocardial infarction, 1 poor response on PET (both received CRT) and 1 committed suicide. 11 patients had G3 AE, 1 G4 AE (neutropenia), and 1 G5 (suicide). pCR (the primary endpoint) was 0/10 for Arm 1 and 2/10 for Arm 2 i.e. 2/20 (10%) overall. Median NAR score was 14·9 with 5 (28%), 7 (39%), and 6 (33%) having low, intermediate, or high scores. Surgical morbidity was acceptable (1/18 wound infection, no anastomotic leak/pelvic sepsis/fistulae). The 24-month progression-free survival rate was 75% (95% CI: 60%-85%). INTERPRETATION: The primary endpoint (pCR rate) was not met. However, FOLFOXIRI and bevacizumab achieved promising pCR rates, low NAR scores and was well-tolerated. This regimen is suitable for testing as the novel arm against current standards of SCRT and/or CRT in a future trial.

12.
Sci Rep ; 7(1): 6000, 2017 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-28729681

RESUMO

The giant triton snail (Charonia tritonis) is one of the few natural predators of the adult Crown-of-Thorns starfish (COTS), a corallivore that has been damaging to many reefs in the Indo-Pacific. Charonia species have large salivary glands (SGs) that are suspected to produce either a venom and/or sulphuric acid which can immobilize their prey and neutralize the intrinsic toxic properties of COTS. To date, there is little information on the types of toxins produced by tritons. In this paper, the predatory behaviour of the C. tritonis is described. Then, the C. tritonis SG, which itself is made up of an anterior lobe (AL) and posterior lobe (PL), was analyzed using an integrated transcriptomics and proteomics approach, to identify putative toxin- and feeding-related proteins. A de novo transcriptome database and in silico protein analysis predicts that ~3800 proteins have features consistent with being secreted. A gland-specific proteomics analysis confirmed the presence of numerous SG-AL and SG-PL proteins, including those with similarity to cysteine-rich venom proteins. Sulfuric acid biosynthesis enzymes were identified, specific to the SG-PL. Our analysis of the C. tritonis SG (AL and PL) has provided a deeper insight into the biomolecular toolkit used for predation and feeding by C. tritonis.


Assuntos
Genômica/métodos , Comportamento Predatório , Glândulas Salivares/metabolismo , Caramujos/genética , Estrelas-do-Mar/fisiologia , Sequência de Aminoácidos , Animais , Proteínas/química , Proteínas/genética , Proteômica , Glândulas Salivares/anatomia & histologia , Ácidos Sulfúricos/metabolismo , Transcriptoma
13.
Peptides ; 98: 3-14, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28082215

RESUMO

Neuropeptides represent a diverse class of signaling molecules originating from neural tissues. These chemical modulators orchestrate complex physiological events including those associated with growth and reproduction. De novo transcriptome sequencing of a cerebral ganglion library of the endangered giant triton snail (Charonia tritonis) was undertaken in an effort to identify key neuropeptides that control or influence its physiology. The giant triton snail is considered a primary predator of the corallivore Acanthaster planci (Crown-of-Thorns Starfish) that is responsible for a significant loss in coral cover on reefs in the Indo-Pacific. The transcriptome library was assembled into contigs, and then bioinformatic analysis was used to identify a repertoire of 38 giant triton snail neuropeptide precursor genes, and various isoforms, that encode conserved molluscan neuropeptides. C. tritonis neuropeptides show overall precursor organisation consistent with those of other molluscs. These include those neuropeptides associated with mollusc reproduction such as the APGWamide, buccalin, conopressin, gonadotropin-releasing hormone (GnRH), NKY and egg-laying hormone. These data provide a foundation for further studies targeted towards the functional characterisation of neuropeptides to further understand aspects of the biology of the giant triton snail, such as elucidating its reproductive neuroendocrine pathway to allow the development of knowledge based captive breeding programs.


Assuntos
Neuropeptídeos/genética , Caramujos/crescimento & desenvolvimento , Caramujos/genética , Transcriptoma/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Simulação por Computador , Gânglios dos Invertebrados/metabolismo , Estudos de Associação Genética , Hormônios de Invertebrado/genética , Reprodução , Estrelas-do-Mar
14.
J Vet Diagn Invest ; 18(1): 76-80, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16566260

RESUMO

Epizootic bovine abortion (EBA), a tick-transmitted disease of pregnant cattle grazing foothill pastures, is a major cause of reproductive failure in California and adjacent states. Affected fetuses develop a chronic disease, resulting in late-term abortion or premature calving. Despite investigations spanning 50 years, to the authors' knowledge, the etiologic agent of EBA has not yet been isolated from affected fetuses or the tick vector. The diagnosis of EBA is based on gross and microscopic lesions. Recently, documentation that the etiologic agent is susceptible to antibiotics and identification of a unique 16S deltaproteobacterial rDNA gene sequence in 90% of thymus tissues from aborted fetuses have supported the role of a bacterial infection as the cause of EBA. To determine whether bacteria could be detected in the tissues, histochemical staining and immunohistochemical procedures were used on formalin-fixed, paraffin-embedded tissues. Use of a modified Steiner silver stain revealed small numbers of intracytoplasmic bacterial rods in 37 of 42 thymic samples from EBA-affected fetuses. Improved detection was achieved by use of immunohistochemical staining with serum from EBA-affected fetuses that resulted in detection of numerous bacterial rods in the cytoplasm of histiocytic cells in the thymus from all 42 EBA-affected fetuses. Immunohistochemical examination of additional tissues from 21 field and experimental EBA cases revealed positively stained intracytoplasmic bacterial rods in many organs with inflammatory lesions. Use of the modified Steiner stain and immunohistochemical staining of tissues from negative-control fetuses failed to reveal organisms. To the authors' knowledge, this is the first report to document morphologic evidence of a bacterium associated with the lesions of EBA.


Assuntos
Aborto Animal/patologia , Doenças dos Bovinos/patologia , Infecções por Bactérias Gram-Positivas/veterinária , Bacilos Gram-Positivos/isolamento & purificação , Histocitoquímica/veterinária , Imuno-Histoquímica/veterinária , Aborto Animal/microbiologia , Animais , Bovinos , Doenças dos Bovinos/microbiologia , Doenças dos Bovinos/transmissão , Deltaproteobacteria/isolamento & purificação , Feminino , Feto/microbiologia , Infecções por Bactérias Gram-Positivas/complicações , Infecções por Bactérias Gram-Positivas/transmissão , Histocitoquímica/métodos , Imuno-Histoquímica/métodos , Gravidez , Estudos Retrospectivos , Timo/embriologia , Timo/microbiologia , Infestações por Carrapato/complicações , Infestações por Carrapato/veterinária
15.
Phys Rev E ; 93(1): 013122, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26871169

RESUMO

We present a strong relationship between the microstructural characteristics of, and the fluid velocity fields confined to, three-dimensional random porous materials. The relationship is revealed through simultaneously extracting correlation functions R_{uu}(r) of the spatial (Eulerian) velocity fields and microstructural two-point correlation functions S_{2}(r) of the random porous heterogeneous materials. This demonstrates that the effective physical transport properties depend on the characteristics of complex pore structure owing to the relationship between R_{uu}(r) and S_{2}(r) revealed in this study. Further, the mean excess plot was used to investigate the right tail of the streamwise velocity component that was found to obey light-tail distributions. Based on the mean excess plot, a generalized Pareto distribution can be used to approximate the positive streamwise velocity distribution.

16.
J Endocrinol ; 117(1): 75-84, 1988 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-3128623

RESUMO

Antisera raised against domestic fowl transthyretin (thyroxine-binding prealbumin) and quail albumin were used to identify thyroxine-binding proteins in the plasma of White storks (Ciconia ciconia) and to measure seasonal changes in these proteins. Three plasma proteins were shown to bind thyroxine (T4). They were albumin, transthyretin and a protein with an electrophoretic mobility on non-denaturing polyacrylamide gel electrophoresis intermediate between albumin and transthyretin. There was no thyroxine-binding globulin. The plasma concentrations of transthyretin and albumin were measured in male and female storks exposed to the photoperiodic and climatic conditions experienced during an annual cycle at 46 degrees N, 11 degrees E. The storks were in four age groups, fledglings and 1-, 2- and 3-year-old birds. A strong correlation (P less than 0.001) was found between daylength and the concentration of transthyretin during the period from February to August in the 1-, 2- and 3-year-old male and female storks, with peak values of 150-210 mg/l in May, June and July coinciding with the annual moult. Between September and January the concentration of plasma transthyretin was low, ranging between 80 and 100 mg/l. The concentration of plasma albumin was not correlated with seasonal changes in daylength and did not change during moult. It is suggested that seasonally high concentrations of plasma transthyretin may have a physiological role in moult.


Assuntos
Aves/fisiologia , Plumas/fisiologia , Pré-Albumina/metabolismo , Proteínas de Ligação a Tiroxina/metabolismo , Tiroxina/sangue , Animais , Transporte Biológico , Clima , Feminino , Luz , Masculino , Estações do Ano , Fatores de Tempo
17.
J Endocrinol ; 146(1): 71-9, 1995 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-7561623

RESUMO

The present study addresses the role of prolactin as a regulator of migratory fattening in European quail (Coturnix coturnix). Plasma prolactin levels in captive birds undergoing migratory fattening in an outdoor aviary and in the laboratory were measured by radioimmunoassay with an antibody raised against recombinant-derived chicken prolactin. No strong association between prolactin and migratory fattening was apparent, and prolactin levels were more closely related to daylength, with the highest concentrations being reached on long days. Plasma prolactin profiles were similar in intact and castrated male quail. Prolactin was secreted in a daily rhythm, with the highest concentrations occurring early in the photophase. However, when birds were food-restricted for 50 days during a migratory phase, there was no difference in fat deposition between birds food-deprived for the first half of the daily photophase compared with those deprived for the second half. Fattening was reduced in the food-restricted birds relative to ad libitum-fed controls, but there was no difference in plasma prolactin levels between the groups. Injections of ovine prolactin (4 mg/kg) significantly increased food intake and body mass of birds maintained on long days, but there were no differences in fattening between birds injected in the morning compared with those injected in the afternoon. Collectively, these results do not support a major role for prolactin in the regulation of migratory fat deposition in European quail.


Assuntos
Adaptação Fisiológica , Tecido Adiposo/fisiologia , Coturnix/metabolismo , Prolactina/fisiologia , Animais , Feminino , Masculino , Fotoperíodo , Prolactina/sangue , Estações do Ano
18.
Toxicology ; 159(3): 159-69, 2001 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-11223171

RESUMO

Verotoxin-producing Escherichia coli (VTEC) produce one or two toxins known as VT1 and VT2. These toxins have been associated with several human illnesses. Dairy cattle harboring VTEC represent a potential health hazard because they enter the food chain as ground beef. The objective of this study was to assess the occurrence of VTEC in dairy heifers. A total of 91 fecal samples were rectally collected during four periods (spring, summer, fall, and winter of 1999) from 23 heifers. A random sample (n=530) of potential VTEC isolates were tested for verotoxicity and were screened by the polymerase chain reaction (PCR) for presence or absence of VT1 and/or VT2 genes. Thirteen isolates from two heifers (from the winter collection) were verotoxic and were confirmed as E. coli. VTEC were only detected during winter with an occurrence rate of 9.5%. Using PCR, five isolates had the VT1 gene while the remaining eight had the VT2 gene. The sequence and expression of VT1 and VT2 genes were confirmed. No E. coli O157:H7 was detected, but serotyping revealed that the five VT1-positive isolates were O26:NM (a non-motile strain of O26). The remaining eight isolates were untypeable. Identification of VTEC-positive cattle before slaughter is a critical step in any on-farm strategy to minimize the risk of beef contamination with such pathogens.


Assuntos
Doenças dos Bovinos/microbiologia , Infecções por Escherichia coli/veterinária , Escherichia coli O157/isolamento & purificação , Toxina Shiga I/biossíntese , Toxina Shiga II/biossíntese , Animais , Bovinos , Chlorocebus aethiops , Primers do DNA/química , DNA Bacteriano/análise , Infecções por Escherichia coli/diagnóstico , Infecções por Escherichia coli/microbiologia , Escherichia coli O157/classificação , Escherichia coli O157/genética , Escherichia coli O157/metabolismo , Fezes/microbiologia , Feminino , Nevada , Reação em Cadeia da Polimerase , Sorotipagem , Toxina Shiga I/genética , Toxina Shiga II/genética , Células Vero/citologia , Células Vero/efeitos dos fármacos
19.
Physiol Behav ; 50(2): 311-6, 1991 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-1745674

RESUMO

Plasma levels of prolactin were measured during the onset of incubation in ducks. A rapid rise in prolactin levels from a mean of 5.7 to 33.1 ng/ml occurred during the formation of the final 20% of the clutch; during which the females increased their nest-box occupancy from 9.9 to 22.2 hours per day. A pronounced decrease in plasma progesterone levels, but not estradiol, occurred in females in the days immediately preceding the onset of incubation and termination of egg laying. A similar decrease in plasma LH occurred. Plasma corticosterone levels also decreased during the transition from egg laying to incubation. In male ducks, who play no role in incubation, LH remained constant until well into incubation when it decreased. Changes in plasma levels of prolactin are discussed in relation to tactile stimulation from the clutch and nutritional stress.


Assuntos
Patos/fisiologia , Hormônios Esteroides Gonadais/fisiologia , Comportamento de Nidação/fisiologia , Oviposição/fisiologia , Comportamento Sexual Animal/fisiologia , Animais , Peso Corporal/fisiologia , Mapeamento Encefálico , Corticosterona/fisiologia , Feminino , Prolactina/fisiologia
20.
Chem Biol Interact ; 32(1-2): 111-23, 1980 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-6253088

RESUMO

The metabolism of benzo[a]pyrene (BP) by cell cultures and cell-free extracts of the monkey kidney cell line CV-1 was studied in uninfected and Simian virus 40 (SV40) infected cells. Metabolites formed were separated by high-pressure liquid chromatography (HPLC) and quantified by liquid scintillation techniques. The profiles metabolites formed by uninfected and SV40 infected cells were similar except that SV40 infected cell cultures metabolized BP at an increased rate relative to uninfected cells. In addition, SV40 infected cell cultures and cell-free extracts produced an unknown compound which eluted between the 3-hydroxybenzo[a]pyrene and BP fractions. This material does not have a retention time characteristic of any of the known metabolites of BP. Labelled BP and/or its metabolites were bound to the viral DNA and histone components of intracellular viral minichromosomes as well as the viral DNA and proteins of mature virions.


Assuntos
Benzopirenos/metabolismo , Transformação Celular Neoplásica , Transformação Celular Viral , Vírus 40 dos Símios , Animais , Linhagem Celular , Chlorocebus aethiops , DNA Viral/metabolismo , Rim , Proteínas Virais/metabolismo , Replicação Viral
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