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1.
J Dairy Sci ; 101(4): 3021-3035, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29428753

RESUMO

Fish oil (FO) alters ruminal biohydrogenation causing trans fatty acid (FA) intermediates to accumulate, but the effects of 18-carbon polyunsaturated FA supply on ruminal long-chain FA metabolism and microbial communities in cattle fed FO are not well established. Four cows fitted with rumen cannula were used in a 4 × 4 Latin square with 21-d experimental periods to evaluate the effects of FO alone or in combination with plant oils high in 18:2n-6 or 18:3n-3 on rumen microbial ecology and flow of FA at the omasum. Treatments comprised a basal grass silage-based diet containing no additional oil (control) or supplements of FO (200 g/d) or FO (200 g/d) plus 500 g/d of sunflower oil (SFO) or linseed oil (LFO). Flow of FA was determined using the omasal sampling technique. The relative abundance of key biohydrogenating bacteria was assessed by quantitative PCR on 16S rRNA genes in omasal digesta. Fish oil-supplemented treatments increased the amounts of trans-18:1, trans-18:2, and 20- to 22-carbon polyunsaturated FA escaping the rumen. Relative to the control, oil supplements had no effect on the amount of 18:0 leaving the rumen, but LFO decreased the flow of 18:0 at the omasum compared with SFO. Both SFO and LFO increased trans-18:1 relative to FO, whereas LFO resulted in the highest trans-18:2 and 20- to 22-carbon FA flow. Supplements of FO plus plant oils shifted biohydrogenation toward trans-10 18:1 formation. Compared with FO alone, the ruminal metabolism of 22:6n-3 in the rumen of lactating cows is more extensive on diets containing higher amounts of 18-carbon polyunsaturated FA. However, the biohydrogenation of 22:5n-3 was less extensive in LFO than SFO, but showed no difference between FO and diets containing plant oils. Ruminal outflow of 20:5n-3 was not altered when plant oils were added to FO. Alterations in the amount of intermediates at the omasum or ruminal biohydrogenation pathways were not accompanied by major changes in analyzed bacterial populations. In conclusion, dietary supplements of FO alone or in combination with plant oils increase the amount of biohydrogenation intermediates containing 1 or more trans double bonds escaping the rumen, which may have implications for host metabolism and the nutritional quality of ruminant foods.


Assuntos
Bovinos/metabolismo , Bovinos/microbiologia , Óleos de Peixe/metabolismo , Microbioma Gastrointestinal/efeitos dos fármacos , Óleo de Semente do Linho/metabolismo , Metabolismo dos Lipídeos , Óleo de Girassol/metabolismo , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal/efeitos dos fármacos , Animais , Dieta/veterinária , Suplementos Nutricionais/análise , Ácidos Graxos/análise , Feminino , Óleos de Peixe/administração & dosagem , Lactação , Óleo de Semente do Linho/administração & dosagem , Metabolismo dos Lipídeos/efeitos dos fármacos , Omaso/metabolismo , Rúmen/efeitos dos fármacos , Rúmen/metabolismo , Rúmen/microbiologia , Óleo de Girassol/administração & dosagem
2.
Phys Rev Lett ; 114(6): 065502, 2015 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-25723227

RESUMO

A basic tenet of material science is that the flow stress of a metal increases as its grain size decreases, an effect described by the Hall-Petch relation. This relation is used extensively in material design to optimize the hardness, durability, survivability, and ductility of structural metals. This Letter reports experimental results in a new regime of high pressures and strain rates that challenge this basic tenet of mechanical metallurgy. We report measurements of the plastic flow of the model body-centered-cubic metal tantalum made under conditions of high pressure (>100 GPa) and strain rate (∼10(7) s(-1)) achieved by using the Omega laser. Under these unique plastic deformation ("flow") conditions, the effect of grain size is found to be negligible for grain sizes >0.25 µm sizes. A multiscale model of the plastic flow suggests that pressure and strain rate hardening dominate over the grain-size effects. Theoretical estimates, based on grain compatibility and geometrically necessary dislocations, corroborate this conclusion.


Assuntos
Modelos Teóricos , Tantálio/química , Teste de Materiais/métodos , Metais/química , Tamanho da Partícula
3.
J Dairy Sci ; 96(4): 2428-2447, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23375967

RESUMO

The effect of forage conservation method on ruminal lipid metabolism and microbial ecology was examined in 2 complementary experiments in cows. Treatments comprised fresh chopped grass, barn-dried hay, or untreated (UTS) or formic acid-treated silage (FAS) prepared from the same grass sward. Preparation of conserved forages coincided with the collection of samples from cows offered fresh grass. In the first experiment, 5 multiparous Finnish Ayrshire cows (229 d in milk) were used to compare the effects of feeding diets based on grass followed by hay during 2 consecutive 14-d periods separated by a 5-d transition during which extensively wilted grass was fed. In the second experiment, 5 multiparous Finnish Ayrshire cows (53 d in milk) were assigned to 1 of 2 blocks and allocated treatments according to a replicated 3×3 Latin square design with 14-d periods to compare the effects of hay, UTS, and FAS. Cows received 7 or 9 kg/d of the same concentrate in experiments 1 and 2, respectively. Conservation of grass by drying, but not ensiling, decreased forage fatty acid content primarily due to losses of 18:2n-6 and 18:3n-3. Compared with grass, feeding hay had no effect on dry matter intake (DMI), rumen pH, or fermentation characteristics, other than increasing ammonia content, but lowered whole-tract organic matter and fiber digestibility (experiment 1). Relative to hay, silage increased DMI, rumen volatile fatty acid (VFA) concentrations, and molar proportions of butyrate, and decreased molar acetate proportions (experiment 2). Compared with UTS, FAS increased DMI, had no effect on rumen ammonia or VFA concentrations, but tended to lower rumen pH and the molar ratio of lipogenic to glucogenic VFA. Conservation method had no substantial effect on ruminal or whole-tract digestibility coefficients. Compared with fresh grass and silages, hay decreased lipolysis and biohydrogenation (BH) of dietary unsaturates in the rumen, resulting in similar flows of 18:2n-6 and 18:3n-3, but lower amounts of trans-11 18:1 and Δ11,13 18:2 at the omasum. The extent of silage fermentation had minimal influence on ruminal lipid metabolism. Treatments were not associated with changes in the relative abundance of specific bacteria known to be capable of BH or rumen protozoal numbers. In conclusion, conservation method altered forage lipids, the extent of lipolysis and BH in the rumen, and the flow of fatty acids at the omasum, in the absence of substantial changes in ruminal Butyrivibrio populations.


Assuntos
Bovinos/metabolismo , Dieta/veterinária , Metabolismo dos Lipídeos , Rúmen/microbiologia , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Carga Bacteriana , Butyrivibrio , Bovinos/microbiologia , Digestão , Ácidos Graxos , Ácidos Graxos Voláteis/análise , Feminino , Fermentação , Concentração de Íons de Hidrogênio , Lactação , Lipólise , Poaceae , Rúmen/química , Rúmen/parasitologia , Silagem
4.
Rev Sci Instrum ; 93(4): 043006, 2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35489905

RESUMO

A plasma mirror platform was developed for the OMEGA-EP facility to redirect beams, thus enabling more flexible experimental configurations as well as a platform that can be used in the future to improve laser contrast. The plasma mirror reflected a short pulse focusing beam at 22.5° angle of incidence onto a 12.5 µm thick Cu foil, generating Bremsstrahlung and kα x rays, and accelerating ions and relativistic electrons. By measuring these secondary sources, the plasma mirror key performance metrics of integrated reflectivity and optical quality are inferred. It is shown that for a 5 ± 2 ps, 310 J laser pulse, the plasma mirror integrated reflectivity was 62 ± 13% at an operating fluence of 1670 J cm-2, and that the resultant short pulse driven particle acceleration and x-ray generation indicate that the on target intensity was 3.1 × 1018 W cm-2, which is indicative of a good post-plasma mirror interaction beam optical quality. By deriving the plasma mirror performance metrics from the secondary source scalings, it was simultaneously demonstrated that the plasma mirror is ready for adoption in short pulse particle acceleration and high energy photon generation experiments using the OMEGA-EP system.

5.
Animal ; 16(3): 100462, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35180682

RESUMO

High levels of supplementation with cereal increases production rates in cattle but can increase incidence of disease, ranging from mild indigestion to acute ruminal acidosis and death. Therefore, there is motivation to determine biological markers which can be used to identify whether animals have been, or are being fed, sufficient or excessive cereals. This study aimed to describe light microscopic findings from animals being fed diverse dietary cereal proportions and to test the performance of a novel rumen epithelial scoring system. Rumen wall tissue samples were obtained from the abattoir from 195 cattle from 11 Scottish farms and processed for histological examination. Light microscopic examination was used to characterise ruminal epithelial response to dietary challenge. Secondary objectives included describing the distribution of immune-related cells in bovine ruminal epithelium and assessing the use of a modified Elastin Martius Scarlet Blue stain (EMSB) for histological examination of the rumen epithelium. Cells staining positive for cluster of differentiation 3 were distributed mainly in the lower layers of the stratum basale and were found in higher densities in animals offered lower cereal proportion diets. Cells staining positive for major histocompatibility complex class 2 (MHCII) were most common in perivascular locations and in the junction between the lower stratum basale and the propria-submucosa. The density of MHCII positive staining cells was higher in animals on lower cereal diets. The level of supplementation with cereal was also associated with the thickness of the stratum corneum (SCT) and stratum granulosum (SGT), the integrity of the stratum corneum and sloughing of cornified cells. There were no advantages in using EMSB stain over haematoxylin and eosin (H&E) in this scoring system. We concluded that a scoring system that included only SCT, SGT and a measure of the loss of appearance of intercellular space allowed differentiation of groups of animals according to the level of cereal supplementation.


Assuntos
Acidose , Doenças dos Bovinos , Acidose/veterinária , Ração Animal/análise , Animais , Bovinos , Doenças dos Bovinos/etiologia , Dieta/veterinária , Grão Comestível , Epitélio , Concentração de Íons de Hidrogênio , Rúmen/fisiologia
6.
Phys Rev Lett ; 106(8): 085003, 2011 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-21405579

RESUMO

The first soft x-ray radiation flux measurements from hohlraums using both a 96 and a 192 beam configuration at the National Ignition Facility have shown high x-ray conversion efficiencies of ∼85%-90%. These experiments employed gold vacuum hohlraums, 6.4 mm long and 3.55 mm in diameter, heated with laser energies between 150-635 kJ. The hohlraums reached radiation temperatures of up to 340 eV. These hohlraums for the first time reached coronal plasma conditions sufficient for two-electron processes and coronal heat conduction to be important for determining the radiation drive.

7.
Br Poult Sci ; 51(4): 461-87, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20924841

RESUMO

1. Plants and their biologically active chemical constituents, sometimes called secondary metabolites or bioactives, present numerous opportunities for the improvement of livestock production by inclusion in the diet. 2. Many such plant derived materials have well established therapeutic values in man; however, their potential as feed additives in animal production, particularly of poultry, remains largely unexploited. 3. There is increasing evidence indicating that they can be efficient in controlling diseases, and plant bioactives may also influence production parameters such as feed efficiency and product quality. 4. It has been reported that they may even replicate some of the effects of antibiotic growth promoters, which were banned from use in Europe from 2006. 5. This review assesses the status of plant bioactives in poultry production and their mode of action on avian physiology, particularly in the digestive tract.


Assuntos
Ração Animal , Aditivos Alimentares/farmacologia , Plantas/química , Aves Domésticas/fisiologia , Fenômenos Fisiológicos da Nutrição Animal , Animais , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Aditivos Alimentares/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Aves Domésticas/imunologia , Aves Domésticas/microbiologia , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/prevenção & controle
8.
Animal ; 14(7): 1447-1460, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31875798

RESUMO

Sub-acute ruminal acidosis (SARA) can reduce the production efficiency and impair the welfare of cattle, potentially in all production systems. The aim of this study was to characterise measurable postmortem observations from divergently managed intensive beef finishing farms with high rates of concentrate feeding. At the time of slaughter, we obtained samples from 19 to 20 animals on each of 6 beef finishing units (119 animals in total) with diverse feeding practices, which had been subjectively classified as being high risk (three farms) or low risk (three farms) for SARA on the basis of the proportions of barley, silage and straw in the ration. We measured the concentrations of histamine, lipopolysaccharide (LPS), lactate and other short-chain fatty acids (SCFAs) in ruminal fluid, LPS and SCFA in caecal fluid. We also took samples of the ventral blind sac of the rumen for histopathology, immunohistopathology and gene expression. Subjective assessments were made of the presence of lesions on the ruminal wall, the colour of the lining of the ruminal wall and the shape of the ruminal papillae. Almost all variables differed significantly and substantially among farms. Very few pathological changes were detected in any of the rumens examined. The animals on the high-risk diets had lower concentrations of SCFA and higher concentrations of lactate and LPS in the ruminal fluid. Higher LPS concentrations were found in the caecum than the rumen but were not related to the risk status of the farm. The diameters of the stratum granulosum, stratum corneum and of the vasculature of the papillae, and the expression of the gene TLR4 in the ruminal epithelium were all increased on the high-risk farms. The expression of IFN-γ and IL-1ß and the counts of cluster of differentiation 3 positive and major histocompatibility complex class two positive cells were lower on the high-risk farms. High among-farm variation and the unbalanced design inherent in this type of study in the field prevented confident assignment of variation in the dependent variables to individual dietary components; however, the CP percentage of the total mixed ration DM was the factor that was most consistently associated with the variables of interest. Despite the strong effect of farm on the measured variables, there was wide inter-animal variation.


Assuntos
Hordeum , Rúmen , Ração Animal/análise , Animais , Bovinos , Ceco , Dieta/veterinária , Fermentação , Expressão Gênica , Hordeum/genética , Concentração de Íons de Hidrogênio , Rúmen/metabolismo , Silagem/análise
9.
J Hosp Infect ; 104(2): 214-235, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31715282

RESUMO

Mycobacterial infection-related morbidity and mortality in patients following cardiopulmonary bypass surgery is high and there is a growing need for a consensus-based expert opinion to provide international guidance for diagnosing, preventing and treating in these patients. In this document the International Society for Cardiovascular Infectious Diseases (ISCVID) covers aspects of prevention (field of hospital epidemiology), clinical management (infectious disease specialists, cardiac surgeons, ophthalmologists, others), laboratory diagnostics (microbiologists, molecular diagnostics), device management (perfusionists, cardiac surgeons) and public health aspects.


Assuntos
Infecção Hospitalar , Infecções por Mycobacterium não Tuberculosas , Mycobacterium , Antibacterianos/uso terapêutico , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Procedimentos Cirúrgicos Cardíacos/métodos , Cardiologia , Ponte Cardiopulmonar , Doenças Transmissíveis , Infecção Hospitalar/diagnóstico , Infecção Hospitalar/tratamento farmacológico , Infecção Hospitalar/microbiologia , Infecção Hospitalar/prevenção & controle , Contaminação de Equipamentos , Humanos , Mycobacterium/isolamento & purificação , Infecções por Mycobacterium não Tuberculosas/diagnóstico , Infecções por Mycobacterium não Tuberculosas/tratamento farmacológico , Infecções por Mycobacterium não Tuberculosas/prevenção & controle , Fatores de Risco , Sociedades Médicas , Reino Unido
10.
J Appl Microbiol ; 104(6): 1617-23, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18194251

RESUMO

AIMS: The recent EU ban of growth-promoting antibiotics in animal production was based on fears concerning antibiotic resistance being transmitted to human pathogens. This paper explores the adaptation mechanism of a common ruminal bacterium, Prevotella bryantii, to one of the banned compounds, flavomycin (flavophospholipol). METHODS AND RESULTS: Growth in the presence of flavomycin (2 and 20 microg ml(-1)) was characterized by a concentration-dependent increase in the length of the lag phase, which decreased after previous flavomycin exposure. From growth patterns on solid medium, decreased sensitivity appeared to be due to a whole-population adaptation. Proteomic analysis indicated upregulation of three native proteins occurred following flavomycin adaptation. Further analysis of two of these proteins resulted in no database matches, suggesting that they may be species-specific. Flavomycin adaptation also resulted in co-adaptation to bacitracin and vancomycin. CONCLUSIONS: Adaptation of P. bryantii to flavomycin, which also resulted in co-adaptation to bacitracin and vancomycin, may involve an increased availability of undecaprenyl pyrophosphate. SIGNIFICANCE AND IMPACT OF THE STUDY: The use of flavomycin, and similar growth-promoting antibiotics, in animal production may prompt adaptive responses in ruminal bacteria which can significantly change their antibiotic sensitivity.


Assuntos
Antibacterianos/farmacologia , Bambermicinas/farmacologia , Bovinos/microbiologia , Prevotella/fisiologia , Rúmen/microbiologia , Adaptação Fisiológica , Animais , Bacitracina/farmacologia , Proteínas de Bactérias/análise , Proteínas de Bactérias/metabolismo , Relação Dose-Resposta a Droga , Farmacorresistência Bacteriana/fisiologia , Eletroforese em Gel Bidimensional , Testes de Sensibilidade Microbiana , Prevotella/efeitos dos fármacos , Regulação para Cima , Vancomicina/farmacologia
11.
Animal ; 11(10): 1762-1771, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28222832

RESUMO

This study was undertaken to further develop our understanding of the links between breed, diet and the rumen microbial community and determine their effect on production characteristics and methane (CH4) emissions from beef cattle. The experiment was of a 2×2 factorial design, comprising two breeds (crossbred Charolais (CHX); purebred Luing (LU)) and two diets (concentrate-straw or silage-based). In total, 80 steers were used and balanced for sire within each breed, farm of origin and BW across diets. The diets (fed as total mixed rations) consisted of (g/kg dry matter (DM)) forage to concentrate ratios of either 500 : 500 (Mixed) or 79 : 921 (Concentrate). Steers were adapted to the diets over a 4-week period and performance and feed efficiency were then measured over a 56-day test period. Directly after the 56-day test, CH4 and carbon dioxide (CO2) emissions were measured (six steers/week) over a 13-week period. Compared with LU steers, CHX steers had greater average daily gain (ADG; P<0.05) and significantly (P<0.001) lower residual feed intake. Crossbred Charolais steers had superior conformation and fatness scores (P<0.001) than LU steers. Although steers consumed, on a DM basis, more Concentrate than Mixed diet (P<0.01), there were no differences between diets in either ADG or feed efficiency during the 56-day test. At slaughter, however, Concentrate-fed steers were heavier (P<0.05) and had greater carcass weights than Mixed-fed steers (P<0.001). Breed of steer did not influence CH4 production, but it was substantially lower when the Concentrate rather than Mixed diet was fed (P<0.001). Rumen fluid from Concentrate-fed steers contained greater proportions of propionic acid (P<0.001) and lower proportions of acetic acid (P<0.001), fewer archaea (P<0.01) and protozoa (P=0.09), but more Clostridium Cluster XIVa (P<0.01) and Bacteroides plus Prevotella (P<0.001) than Mixed-fed steers. When the CH4 to CO2 molar ratio was considered as a proxy method for CH4 production (g/kg DM intake), only weak relationships were found within diets. In conclusion, although feeding Concentrate and Mixed diets produced substantial differences in CH4 emissions and rumen characteristics, differences in performance were influenced more markedly by breed.


Assuntos
Bovinos/fisiologia , Metano/metabolismo , Carne Vermelha/normas , Rúmen/metabolismo , Silagem/análise , Ácido Acético/análise , Animais , Cruzamento , Bovinos/classificação , Bovinos/crescimento & desenvolvimento , Dieta/veterinária , Masculino , Propionatos/análise , Rúmen/química , Rúmen/microbiologia , Rúmen/parasitologia
12.
Nat Commun ; 8(1): 1118, 2017 10 24.
Artigo em Inglês | MEDLINE | ID: mdl-29061963

RESUMO

Mesenchymal cells expressing platelet-derived growth factor receptor beta (PDGFRß) are known to be important in fibrosis of organs such as the liver and kidney. Here we show that PDGFRß+ cells contribute to skeletal muscle and cardiac fibrosis via a mechanism that depends on αv integrins. Mice in which αv integrin is depleted in PDGFRß+ cells are protected from cardiotoxin and laceration-induced skeletal muscle fibrosis and angiotensin II-induced cardiac fibrosis. In addition, a small-molecule inhibitor of αv integrins attenuates fibrosis, even when pre-established, in both skeletal and cardiac muscle, and improves skeletal muscle function. αv integrin blockade also reduces TGFß activation in primary human skeletal muscle and cardiac PDGFRß+ cells, suggesting that αv integrin inhibitors may be effective for the treatment and prevention of a broad range of muscle fibroses.


Assuntos
Integrina alfaV/metabolismo , Músculo Esquelético/patologia , Miocárdio/patologia , Receptor beta de Fator de Crescimento Derivado de Plaquetas/genética , Animais , Apoptose , Movimento Celular , Células Cultivadas , Colágeno/metabolismo , Fibrose , Genótipo , Humanos , Masculino , Células-Tronco Mesenquimais/citologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Receptor beta de Fator de Crescimento Derivado de Plaquetas/metabolismo , Proteínas Recombinantes/metabolismo
13.
J Med Microbiol ; 55(Pt 5): 495-504, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16585634

RESUMO

Clostridium perfringens gas gangrene is a fulminant necrotizing infection in which inflammatory cells are notably absent from infected tissues but are often massed within adjacent vessels. It has been shown that C. perfringens phospholipase C (PLC) stimulates formation of large intravascular platelet/leukocyte complexes and that PLC-induced activation of platelet gpIIbIIIa plays a major role. In vivo, such aggregates contribute to microvascular thrombosis and ischaemic necrosis of tissue. However, the effects of adherent platelets on neutrophil diapedesis have not been established. The present work investigated (1) the contribution of platelet P-selectin (CD62P) to PLC-induced cellular complex formation and (2) the effects of platelet adhesion on neutrophil diapedesis. The effects of anti-gpIIbIIIa and anti-CD62P strategies on PLC-induced complex formation were measured by flow cytometry and followed by light microscopy. Both platelet gpIIbIIIa and CD62P contributed to the formation of platelet/leukocyte complexes. Specifically, gpIIbIIIa mediated the formation of large platelet/platelet aggregates that were tethered to the leukocyte principally via CD62P. Neutrophil diapedesis, quantified by a transendothelial cell migration assay and visualized by electron microscopy, was significantly reduced (>60%) by the adherence of large platelet aggregates. It was concluded that the absence of a tissue inflammatory response in C. perfringens gas gangrene is due, in part, to impaired neutrophil mobility caused by large aggregates of adherent platelets induced by PLC. Further, an adjunctive immunotherapeutic strategy targeting both gpIIbIIIa and CD62P may improve the tissue inflammatory response, prevent vascular occlusion, maintain tissue viability, and reduce the need for radical amputation in patients with clostridial gas gangrene.


Assuntos
Plaquetas/fisiologia , Clostridium perfringens/enzimologia , Neutrófilos/fisiologia , Fosfolipases Tipo C/metabolismo , Inibição de Migração Celular , Movimento Celular , Clostridium perfringens/patogenicidade , Citometria de Fluxo , Gangrena Gasosa/microbiologia , Gangrena Gasosa/patologia , Humanos , Microscopia Eletrônica , Modelos Biológicos , Selectina-P/metabolismo , Agregação Plaquetária , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/metabolismo
14.
Animal ; 10(9): 1439-47, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26965186

RESUMO

Studies on microbial biohydrogenation of fatty acids in the rumen are of importance as this process lowers the availability of nutritionally beneficial unsaturated fatty acids for incorporation into meat and milk but also might result in the accumulation of biologically active intermediates. The impact was studied of adsorption of 22:6n-3 (DHA) to particulate material on its disappearance during 24 h in vitro batch incubations with rumen inoculum. Four adsorbants were used in two doses (1 and 5 mg/ml of mucin, gum arabic, bentonite or silicic acid). In addition, the distribution of 22:6n-3 in the pellet and supernatant of diluted rumen fluid was measured. Bentonite and silicic acid did not alter the distribution of 22:6n-3 between pellet and supernatant nor increased the disappearance of 22:6n-3 during the incubation. Both mucin and gum arabic increased the recovery of 22:6n-3 in the supernatant, indicating that these compounds lowered the adsorption of the fatty acid to ruminal particles. This was associated with an increased disappearance of 22:6n-3, when initial 22:6n-3 was 0.06 or 0.10 mg/ml, and an increased formation of 22:0, when initial 22:6n-3 was 0.02 mg/ml, during the 24 h batch culture experiment. Addition of gum arabic to pure cultures of Butyrivibrio fibrisolvens or Butyrivibrio proteoclasticus did not negate the inhibitory effect of 22:6n-3 on growth. As both mucin and gum arabic provide fermentable substrate for ruminal bacteria, an additional experiment was performed in which mucin and gum arabic were replaced by equal amounts of starch, cellulose or xylan. No differences in disappearance of 22:6n-3 were observed, suggesting that the stimulatory effect of mucin and gum arabic on disappearance of 22:6n-3 most probably is not due to provision of an alternative site of adsorption but related to stimulation of bacterial growth. A relatively high proportion of 22:6n-3 can be reduced to 22:0 provided the initial concentration is low.


Assuntos
Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Ácidos Graxos não Esterificados/metabolismo , Carneiro Doméstico/metabolismo , Carneiro Doméstico/microbiologia , Adsorção , Animais , Butyrivibrio/crescimento & desenvolvimento , Butyrivibrio/metabolismo , Microbioma Gastrointestinal/efeitos dos fármacos , Goma Arábica/metabolismo , Hidrogenação , Rúmen/metabolismo , Rúmen/microbiologia
15.
Bone Joint Res ; 5(2): 61-5, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26883967

RESUMO

OBJECTIVES: Temperature is known to influence muscle physiology, with the velocity of shortening, relaxation and propagation all increasing with temperature. Scant data are available, however, regarding thermal influences on energy required to induce muscle damage. METHODS: Gastrocnemius and soleus muscles were harvested from 36 male rat limbs and exposed to increasing impact energy in a mechanical test rig. Muscle temperature was varied in 5°C increments, from 17°C to 42°C (to encompass the in vivo range). The energy causing non-recoverable deformation was recorded for each temperature. A measure of tissue elasticity was determined via accelerometer data, smoothed by low-pass fifth order Butterworth filter (10 kHz). Data were analysed using one-way analysis of variance (ANOVA) and significance was accepted at p = 0.05. RESULTS: The energy required to induce muscle failure was significantly lower at muscle temperatures of 17°C to 32°C compared with muscle at core temperature, i.e., 37°C (p < 0.01). During low-energy impacts there were no differences in muscle elasticity between cold and warm muscles (p = 0.18). Differences in elasticity were, however, seen at higher impact energies (p < 0.02). CONCLUSION: Our findings are of particular clinical relevance, as when muscle temperature drops below 32°C, less energy is required to cause muscle tears. Muscle temperatures of 32°C are reported in ambient conditions, suggesting that it would be beneficial, particularly in colder environments, to ensure that peripheral muscle temperature is raised close to core levels prior to high-velocity exercise. Thus, this work stresses the importance of not only ensuring that the muscle groups are well stretched, but also that all muscle groups are warmed to core temperature in pre-exercise routines.Cite this article: Professor A. H. R. W. Simpson. Increased risk of muscle tears below physiological temperature ranges. Bone Joint Res 2016;5:61-65. doi: 10.1302/2046-3758.52.2000484.

16.
Arch Intern Med ; 144(10): 2063-5, 1984 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-6486990

RESUMO

Disseminated disease due to rapidly growing mycobacteria is manifested by positive blood cultures and multiple skin and subcutaneous abscesses. A patient had T-cell lymphoma and disseminated disease; he also had neutropenia intermittently. Single-agent therapy with amikacin sulfate or cefoxitin sodium was not adequate during periods of neutropenia, and combination therapy was necessary to control the infection. Clinical response correlated with detectable serum inhibitory levels of the antimicrobial agents. Surprisingly, the organism was not killed by either amikacin or cefoxitin, a finding that correlated with the absence of serum bactericidal levels. This case suggests that granulocytes may play a role in the host's response to this organism, and determination of serum inhibitory and possible bactericidal levels may be useful in monitoring therapy.


Assuntos
Amicacina/uso terapêutico , Cefoxitina/uso terapêutico , Granulócitos/fisiologia , Canamicina/análogos & derivados , Infecções por Mycobacterium não Tuberculosas/tratamento farmacológico , Infecções por Mycobacterium/tratamento farmacológico , Mycobacterium/efeitos dos fármacos , Micobactérias não Tuberculosas/efeitos dos fármacos , Adulto , Resistência Microbiana a Medicamentos , Humanos , Linfoma/complicações , Masculino , Infecções por Mycobacterium não Tuberculosas/etiologia , Neutropenia/etiologia , Dermatopatias Infecciosas/tratamento farmacológico , Dermatopatias Infecciosas/etiologia
17.
Arch Intern Med ; 146(5): 890-3, 1986 May.
Artigo em Inglês | MEDLINE | ID: mdl-3963981

RESUMO

To determine the possible role of Branhamella (formerly Neisseria) catarrhalis as a respiratory pathogen, we screened quality sputa (defined by cellular criteria) that showed numerous gram-negative cocci on Gram's stain for the presence of B catarrhalis. In an eight-month period, 52 isolates of B catarrhalis were identified in adults attending a hospital for chest diseases. During this period B catarrhalis was the third most common potential pathogen isolated from sputa. Twenty-two patients (42%) had associated patchy bronchopneumonic or lobar infiltrates. All had negative blood cultures and a generally mild clinical course. The majority of strains (73%) of B catarrhalis produced beta-lactamase and were resistant to penicillin and ampicillin. Isolates (including beta-lactamase-producing strains) were susceptible to erythromycin, tetracycline, and trimethoprim-sulfamethoxazole. These studies demonstrate that in patients with chronic lung disease, the presence of B catarrhalis in sputum can be suspected on the basis of a Gram's stain and may be associated with the development of new pneumonic infiltrates. Since these organisms frequently produce beta-lactamase, empiric antimicrobial therapy should include agents other than the penicillins.


Assuntos
Pneumopatias Obstrutivas/etiologia , Neisseriaceae/crescimento & desenvolvimento , Pneumonia/etiologia , Infecções Respiratórias/microbiologia , Idoso , Infecções Bacterianas/microbiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Escarro/microbiologia
18.
Arch Intern Med ; 140(4): 559-60, 1980 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-6767460

RESUMO

A rapidly progressing panophthalmitis due to Bacillus cereus developed in three patients. Infection was associated with intravenous drug abuse in two patients and was traced to contaminated injection paraphernalia in one. In the third patient, infection was associated with a foreign-body injury to the eye. Anterior chamber aspiration revealed the organism on Gram's stain in one case and isolation of the bacteria in all three. Despite intravenous and intraocular antibiotic therapy, the infection progressed rapidly and resulted in enucleation in all cases. Bacillus cereus isolates were sensitive to clindamycin hydrochloride hydrate and aminoglycosides but resistant to penicillins and cephalosporins.


Assuntos
Bacillus cereus , Infecções Bacterianas , Panoftalmite/etiologia , Adulto , Corpos Estranhos no Olho/complicações , Feminino , Humanos , Masculino , Transtornos Relacionados ao Uso de Substâncias/complicações
19.
Bone Joint Res ; 4(6): 99-104, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26062566

RESUMO

OBJECTIVES: There remains conflicting evidence regarding cortical bone strength following bisphosphonate therapy. As part of a study to assess the effects of bisphosphonate treatment on the healing of rat tibial fractures, the mechanical properties and radiological density of the uninjured contralateral tibia was assessed. METHODS: Skeletally mature aged rats were used. A total of 14 rats received 1µg/kg ibandronate (iban) daily and 17 rats received 1 ml 0.9% sodium chloride (control) daily. Stress at failure and toughness of the tibial diaphysis were calculated following four-point bending tests. RESULTS: Uninjured cortical bone in the iban group had a significantly greater mean (standard deviation (sd)), p < 0.001, stress at failure of 219.2 MPa (sd 45.99) compared with the control group (169.46 MPa (sd 43.32)) following only nine weeks of therapy. Despite this, the cortical bone toughness and work to failure was similar. There was no significant difference in radiological density or physical dimensions of the cortical bone. CONCLUSIONS: Iban therapy increases the stress at failure of uninjured cortical bone. This has relevance when normalising the strength of repair in a limb when comparing it with the unfractured limb. However, the 20% increase in stress at failure with iban therapy needs to be interpreted with caution as there was no corresponding increase in toughness or work to failure. Further research is required in this area, especially with the increasing clinical burden of low-energy diaphyseal femoral fractures following prolonged use of bisphosphonates. Cite this article: Bone Joint Res 2015;4:99-104.

20.
J Anim Sci ; 93(4): 1815-23, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26020202

RESUMO

The objectives of this study were to investigate the effects of (1) the addition of nitrate and (2) an increase in dietary oil on methane (CH4) and hydrogen (H2) emissions from 2 breeds (cross-bred Charolais and purebred Luing) of finishing beef cattle receiving 2 contrasting basal diets consisting (grams per kilogram DM) of 500:500 (Mixed) and 80:920 (Concentrate) forage to concentrate ratios. Within each basal diet there were 3 treatments: (i) control treatments (mixed-CTL and concentrate-CTL) contained rapeseed meal as the protein source, which was replaced with either (ii) calcium nitrate (mixed-NIT and concentrate-NIT) supplying 21.5 g nitrate/kg DM, or (iii) rapeseed cake (mixed-RSC and concentrate-RSC) to increase dietary oil from 27 (CTL) to 53 g/kg DM (RSC). Following adaption to diets, CH4 and H2 emissions were measured on 1 occasion from each of the 76 steers over a 13-wk period. Dry matter intakes tended (P = 0.051) to be greater for the concentrate diet than the mixed diet; however, when expressed as grams DMI per kilogram BW, there was no difference between diets (P = 0.41). Dry matter intakes for NIT or RSC did not differ from CTL. Steers fed a concentrate diet produced less CH4 and H2 than those fed a mixed diet (P < 0.001). Molar proportions of acetate (P < 0.001) and butyrate (P < 0.01) were lower and propionate (P < 0.001) and valerate (P < 0.05) higher in the rumen fluid from steers fed the concentrate diet. For the mixed diet, CH4 yield (grams per kilogram DMI) was decreased by 17% when nitrate was added (P < 0.01), while H2 yield increased by 160% (P < 0.001). The addition of RSC to the mixed diet decreased CH4 yield by 7.5% (P = 0.18). However, for the concentrate diet neither addition of nitrate (P = 0.65) nor increasing dietary oil content (P = 0.46) decreased CH4 yield compared to concentrate-CTL. Molar proportions of acetate were higher (P < 0.001) and those of propionate lower (P < 0.01) in rumen fluid from NIT treatments compared to respective CTL treatments. Overall, reductions in CH4 emissions from adding nitrate or increasing the oil content of the mixed diet were similar to those expected from previous reports. However, the lack of an effect of these mitigation strategies when used with high concentrate diets has not been previously reported. This study shows that the effect of CH4 mitigation strategies is basal diet-dependent.


Assuntos
Ração Animal/classificação , Compostos de Cálcio/farmacologia , Bovinos/metabolismo , Gorduras Insaturadas na Dieta/farmacologia , Suplementos Nutricionais , Metano/metabolismo , Nitratos/farmacologia , Rúmen/efeitos dos fármacos , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Brassica rapa , Compostos de Cálcio/administração & dosagem , Dieta/veterinária , Gorduras Insaturadas na Dieta/administração & dosagem , Grão Comestível , Efeito Estufa , Hidrogênio/metabolismo , Masculino , Nitratos/administração & dosagem , Nitratos/sangue , Rúmen/metabolismo
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