RESUMEN

BACKGROUND: This study evaluated cognitive workload in soldiers undertaking a long duration march wearing different loads. METHODS: Military participants (n=12 men and n=10 women) performed four 3-hour loaded marches (12.25 km at 4.9 km/hour) wearing either 21 kg, 26 kg, 33 kg or 43 kg. During the march, accuracy and response time were measured using the verbal working memory n-back test (0, 1, 2 and 3) and two bespoke Go/No Go tests (visual/auditory) to assess inhibition of a pre-potent response. RESULTS: The physical demands of the march increased with load and march duration but remained at moderate intensity. N-back test accuracy ranged from 74% to 98% in men and 62% to 98% in women. Reduced accuracy was observed as load and time increased. Accuracy during the visual Go/No Go test also reduced with load, accuracy ranged from 69% to 89% in men and 65% to 90% in women. No differences due to load or time were observed during completion of the auditory Go/No Go task; accuracy ranged from 93% to 97% in men and 77% to 95% in women. A number of participants were unable to complete the march due to discomfort. Reports of discomfort were more frequent in women, which may have contributed to the greater reductions in accuracy observed. CONCLUSION: These data provide further evidence that cognitive performance of military personnel can be affected during long duration loaded marching. Women reported discomfort from equipment more frequently than men, which may make them more susceptible to declines in cognitive performance. These findings highlight important considerations for equipment procurement.

Asunto(s)

Personal Militar , Masculino , Humanos , Femenino , Personal Militar/psicología , Caminata/fisiología , Soporte de Peso/fisiología , Factores de Tiempo , Cognición/fisiología

RESUMEN

It has long been claimed that non-wetsuit cold water swimming (CWS) benefits health (1), and anecdotally cold-water swimmers claimed to suffer fewer and milder infections, though this was not directly measured. A boost to immunity is biologically plausible: stress hormones are released during cold-water immersion (2), and short-term stress may ready the immune system for injury or infection (3). However, very few studies have investigated immune system markers and/or actual illness in habitual cold-water swimmers.

Asunto(s)

Infecciones del Sistema Respiratorio , Natación , Frío , Humanos , Agua

RESUMEN

OBJECTIVE: The pathogenesis of polycystic ovary syndrome (PCOS), a common endocrine disease and metabolic disturbance, is still unknown. The aim of the study was to investigate whether patients with PCOS display increased expression of inflammatory markers in adipose tissue. PATIENTS AND METHODS: Two groups of women were investigated, those diagnosed with PCOS (n = 8) and age and BMI-matched normal women (n = 12). Their age was between 20-45 years and all subjects were apparently healthy and did not take any medications. Adipose tissue levels of mRNA of inflammatory markers were determined by use of real-time PCR. RESULTS: There were no differences between obese patients and obese PCOS in levels of adipocytokines. CONCLUSIONS: There were no effects of PCOS on the expression of any of the adipocytokines genes measured in subcutaneous adipose tissue.

Asunto(s)

Tejido Adiposo/metabolismo , Inflamación , Obesidad/metabolismo , Síndrome del Ovario Poliquístico/genética , Índice de Masa Corporal , Femenino , Expresión Génica , Humanos , Resistencia a la Insulina , Grasa Subcutánea/metabolismo

RESUMEN

The upper body trunk musculature is key in supporting breathing, propulsion, and stabilization during front crawl swimming. The aim of this study was to determine if the latissimus dorsi, pectoralis major, and serratus anterior contributed to the development of inspiratory muscle fatigue observed following front crawl swimming. Fourteen trained swimmers completed a 200-m front crawl swim at 90% of race pace. Maximal inspiratory and expiratory mouth pressures (PImax and PEmax) were assessed before (baseline) and after each swim, and electromyography was recorded from the three muscles. Post-swim PImax fell by 11% (P < 0.001, d = 0.57) and the median frequency (MDF: a measure of fatigue) of the latissimus dorsi, pectoralis major, and serratus anterior fell to 90% (P = 0.001, d = 1.57), 87% (P = 0.001, r = -0.60) and 89% (P = 0.018, d = 1.04) of baseline, respectively. The fall in serratus anterior MDF was correlated with breathing frequency (r = 0.675, P = 0.008) and stroke rate (r = 0.639, P = 0.014). The results suggest that the occurrence of inspiratory muscle fatigue was partly caused by fatigue of these muscles, and that breathing frequency and stroke rate particularly affect the serratus anterior.

Asunto(s)

Fatiga Muscular , Músculos Pectorales/fisiología , Músculos Respiratorios/fisiología , Músculos Superficiales de la Espalda/fisiología , Natación/fisiología , Adolescente , Adulto , Electromiografía , Espiración/fisiología , Femenino , Humanos , Inhalación/fisiología , Masculino , Presión , Frecuencia Respiratoria , Adulto Joven

RESUMEN

Piglet neonatal mortality rates are high (~20%), so nutritional strategies to reduce this are highly desirable. Maternal fat substitution (FS) may promote the preweaning survival of piglets by improving their energy status. Therefore, the aim of the present study was to investigate the effects of FS throughout pregnancy on offspring viability, together with the gene expression of stress-related markers in the liver. Sixteen pregnant sows were randomly allocated to one of two isocaloric diets, control (C) or FS in the form of palm oil, fed from 0 to 110 days gestation. Glucose tolerance was examined on Day 108. Median and low birthweight offspring were allocated to tissue sampling at either 7 days or 6 months postnatal age. In response to a glucose tolerance test, FS sows exhibited a raised glucose area under the curve with no change in basal glucose. Average piglet mortality (up to Day 28) was increased fourfold in the FS group, with surviving median-sized piglets exhibiting significantly lower fatty acid binding protein 1 (FABP1) expression at 7 days. There were no effects on the abundance of any other stress- or metabolic-related genes examined. Thus, this study demonstrates that maternal FS throughout gestation causes maternal glucose intolerance that may be linked to the observed increase in piglet mortality. However, the surviving offspring do not exhibit any detectable differences in postnatal growth or hepatic gene profile in later life.

Asunto(s)

Fenómenos Fisiológicos Nutricionales de los Animales/fisiología , Dieta , Expresión Génica , Hígado/metabolismo , Fenómenos Fisiologicos Nutricionales Maternos/fisiología , Aceites de Plantas/administración & dosificación , Alimentación Animal/análisis , Animales , Animales Recién Nacidos , Proteínas de Unión a Ácidos Grasos/genética , Proteínas de Unión a Ácidos Grasos/metabolismo , Femenino , Intolerancia a la Glucosa/genética , Intolerancia a la Glucosa/metabolismo , Aceite de Palma , Embarazo , Porcinos

RESUMEN

OBJECTIVE: The purposes of this study were to examine the literature on the proportion of medical students and residents who experience the death of a patient by suicide and to identify curricula with data on outcomes that assist medical students or residents in preparing for or managing the psychological stress in dealing with those suicides. METHODS: The authors searched PubMed, Scopus, Google Scholar, and ScienceDirect databases using search terms patient suicide, trainee, medical student, and resident. They conducted a separate search to identify relevant curricula using the same terms in combination with coping, teaching, programs, and education. RESULTS: Eight studies met inclusion criteria, all of which concerned psychiatry residents alone. We found no studies that determined the prevalence of the experience of death of a patient by suicide among medical students or residents in specialties other than psychiatry. The prevalences were 31, 33, 43, 47, 54, 61, 68, and 69 %. All studies were cross-sectional, and none collected data prospectively. Limitations of these data included single-site studies, lack of clarity of the specific question asked, low response rates, and uncertain reporting periods. The authors found two curricula with outcome data that assisted medical trainees in managing the psychologically distressing consequences of the death of a patient. CONCLUSION: Although the data are limited, psychiatry residents commonly experience the death of a patient by suicide. There is a paucity of data on this topic concerning the experiences of medical students and of residents in other specialties.

Asunto(s)

Internado y Residencia/estadística & datos numéricos , Estudiantes de Medicina/estadística & datos numéricos , Suicidio/estadística & datos numéricos , Humanos , Prevalencia , Estudiantes de Medicina/psicología

RESUMEN

BACKGROUND: Infectious complications remain a serious threat to patients with multiple trauma. Susceptibility and response to infection is, in part, heritable. The lectin pathway plays a major role in innate immunity. The aim of this study was to assess whether single nucleotide polymorphisms (SNPs) in three key genes within the lectin pathway affect susceptibility to infectious complications in severely injured patients. METHODS: A prospective cohort of severely injured patients admitted to a level I trauma centre between January 2008 and April 2011 were genotyped for SNPs in MBL2 (mannose-binding lectin 2), MASP2 (MBL-associated serine protease 2) and FCN2 (ficolin 2). Association of genotype with prevalence of positive culture findings and infection was tested by χ(2) and logistic regression analysis. RESULTS: A total of 219 patients were included, of whom 112 (51·1 per cent) developed a positive culture from sputum, wounds, blood or urine. A systemic inflammatory response syndrome (SIRS) developed in 139 patients (63·5 per cent), sepsis in 79 (36·1 per cent) and septic shock in 37 (16·9 per cent). Patients with a MBL2 exon 1 variant allele were more prone to positive wound cultures (odds ratio (OR) 2·51, 95 per cent confidence interval 1·12 to 5·62; P = 0·025). A MASP2 Y371D DD genotype predisposed to SIRS (OR 4·78, 1·06 to 21·59; P = 0·042) and septic shock (OR 2·53, 1·12 to 4·33; P = 0·003). A FCN2 A258S AS genotype predisposed to positive wound cultures (OR 3·37, 1·45 to 7·85; P = 0·005) and septic shock (OR 2·18, 1·30 to 4·78; P = 0·011). CONCLUSION: Severely injured patients with SNPs in MBL2, MASP2 Y371D and FCN2 A258S of the lectin pathway of complement activation are significantly more susceptible to positive culture findings, and to infectious complications, SIRS and septic shock than patients with a wildtype genotype.

Asunto(s)

Infecciones Bacterianas/genética , Lectinas/genética , Lectina de Unión a Manosa/genética , Serina Proteasas Asociadas a la Proteína de Unión a la Manosa/genética , Polimorfismo de Nucleótido Simple/genética , Heridas y Lesiones/genética , Adulto , Activación de Complemento/genética , Femenino , Genotipo , Humanos , Inmunidad Innata/genética , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Factores de Riesgo , Sepsis/genética , Choque Séptico/genética , Síndrome de Respuesta Inflamatoria Sistémica/genética , Ficolinas

RESUMEN

DNA damage of exposed tumour tissue leading to cell death is one of the detrimental effects of ionising radiation that is exploited, with beneficial consequences, for radiotherapy. The pattern of the discrete energy depositions during passage of the ionising track of radiation defines the spatial distribution of lesions induced in DNA with a fraction of the DNA damage sites containing clusters of lesions, formed over a few nanometres, against a background of endogenously induced individual lesions. These clustered DNA damage sites, which may be considered as a signature of ionising radiation, underlie the deleterious biological consequences of ionising radiation. The concepts developed rely in part on the fact that ionising radiation creates significant levels of clustered DNA damage, including complex double-strand breaks (DSB), to kill tumour cells as clustered damage sites are difficult to repair. This reduced repairability of clustered DNA damage using specific repair pathways is exploitable in radiotherapy for the treatment of cancer. We discuss some potential strategies to enhance radiosensitivity by targeting the repair pathways of radiation-induced clustered damage and complex DNA DSB, through inhibition of specific proteins that are not required in the repair pathways for endogenous damage. The variety and severity of DNA damage from ionising radiation is also influenced by the tumour microenvironment, being especially sensitive to the oxygen status of the cells. For instance, nitric oxide is known to influence the types of damage induced by radiation under hypoxic conditions. A potential strategy based on bioreductive activation of pro-drugs to release nitric oxide is discussed as an approach to deliver nitric oxide to hypoxic tumours during radiotherapy. The ultimate aim of this review is to stimulate thinking on how knowledge of the complexity of radiation-induced DNA damage may contribute to the development of adjuncts to radiotherapy.

Asunto(s)

Daño del ADN , ADN de Neoplasias/efectos de la radiación , Neoplasias/genética , Neoplasias/radioterapia , Humanos , Radioterapia/métodos

RESUMEN

Expression of the brown adipocyte-specific gene, uncoupling protein 1 (UCP1), is increased by both PPARγ stimulation and cAMP activation through their ability to stimulate the expression of the PPAR coactivator PGC1α. In HIB1B brown preadipocytes, combination of the PPARγ agonist, rosiglitazone, and the cAMP stimulator forskolin synergistically increased UCP1 mRNA expression, but PGC1α expression was only increased additively by the two drugs. The PPARγ antagonist, GW9662, and the PKA inhibitor, H89, both inhibited UCP1 expression stimulated by rosiglitazone and forskolin but PGC1α expression was not altered to the same extent. Reporter studies demonstrated that combined rosiglitazone and forskolin synergistically activated transcription from a full length 3.1 kbp UCP1 luciferase promoter construct, but the response was only additive and much reduced when a minimal 260 bp proximal UCP1 promoter was examined. Rosiglitazone and forskolin in combination were able to synergistically stimulate promoters comprising of tandem repeats of either PPREs or CREs. We conclude that rosiglitazone and forskolin act together to synergistically activate the UCP1 promoter directly rather than by increasing PGC1α expression and by a mechanism involving cross-talk between the signalling systems regulating the CRE and PPRE on the promoters.

RESUMEN

To provide a tool for research on regulating adipocyte differentiation, tetracycline inducible (Tet on) lentiviral expression vectors under the control of an adipose-specific promoter were constructed. The lowest basal expression in the absence of doxycycline and most efficient dose-dependent, doxycycline-induced transient overexpression was observed using vectors constructed with a combination of Tetracycline Responsive Element (TRE) and reverse tetracycline-controlled TransActivator advanced (rtTAadv), transfected in white (3T3-L1) and brown (HIB-1B) preadipocytes cell lines. The results demonstrate that doxycycline adipogenic inducible expression can be achieved using a pLenti TRE / rtTA adv under the control of the truncated aP2 promoter in HIB-1B preadipocytes.

Asunto(s)

Adipogénesis , Doxiciclina/farmacología , Vectores Genéticos/genética , Lentivirus/genética , Células 3T3-L1 , Adipocitos Marrones/citología , Adipocitos Marrones/efectos de los fármacos , Adipocitos Marrones/metabolismo , Animales , Doxiciclina/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Ratones , Plásmidos/genética , Plásmidos/metabolismo , Regiones Promotoras Genéticas , Tetraciclina , Transactivadores/genética , Transactivadores/metabolismo , Transcripción Genética , Transfección

RESUMEN

The consequences of sub-optimal nutrition through alterations in the macronutrient content of the maternal diet will not simply be reflected in altered neonatal body composition and increased mortality, but are likely to continue into adulthood and confer greater risk of metabolic disease. One mechanism linking manipulations of the maternal environment to an increased risk of later disease is enhanced fetal exposure to glucocorticoids (GC). Tissue sensitivity to cortisol is regulated, in part, by the GC receptor and 11ß-hydroxysteroid dehydrogenase (11ß-HSD) types 1 and 2. Several studies have shown the effects of maternal undernutrition, particularly low-protein diets, on the programming of GC action in the offspring; however, dietary excess is far more characteristic of the diets consumed by contemporary pregnant women. This study investigated the programming effects of moderate protein supplementation in pigs throughout pregnancy. We have demonstrated an up-regulation of genes involved in GC sensitivity, such as GC receptor and 11ß-HSD, in the liver, but have yet to detect any other significant changes in these piglets, with no differences observed in body weight or composition. This increase in GC sensitivity was similar to the programming effects observed following maternal protein restriction or global undernutrition during pregnancy.

Asunto(s)

Dieta , Proteínas en la Dieta/farmacología , Desarrollo Fetal/efectos de los fármacos , Glucocorticoides/metabolismo , Complicaciones del Embarazo , Fenómenos Fisiologicos de la Nutrición Prenatal , Desnutrición Proteico-Calórica/complicaciones , Animales , Suplementos Dietéticos , Femenino , Desarrollo Fetal/fisiología , Hidroxiesteroide Deshidrogenasas/metabolismo , Hígado/metabolismo , Enfermedades Metabólicas/etiología , Embarazo , Efectos Tardíos de la Exposición Prenatal , Receptores de Glucocorticoides/metabolismo , Porcinos , Regulación hacia Arriba

RESUMEN

AIMS/HYPOTHESIS: Increasing the expression of the brown adipose tissue-specific gene uncoupling protein-1 (Ucp1) is a potential target for treating obesity. We investigated the role of DNA methylation and histone modification in Ucp1 expression in adipose cell lines and ex vivo murine adipose tissues. METHODS: Methylation state of the Ucp1 enhancer was studied using bisulphite mapping in murine adipose cell lines, and tissue taken from cold-stressed mice, coupled with functional assays of the effects of methylation and demethylation of the Ucp1 promoter on gene expression and nuclear protein binding. RESULTS: We show that demethylation of the Ucp1 promoter by 5-aza-deoxycytidine increases Ucp1 expression while methylation of Ucp1 promoter-reporter constructs decreases expression. Brown adipose tissue-specific Ucp1 expression is associated with decreased CpG dinucleotide methylation of the Ucp1 enhancer. The lowest CpG dinucleotide methylation state was found in two cyclic AMP response elements (CRE3, CRE2) in the Ucp1 promoter and methylation of the CpG in CRE2, but not CRE3 decreased nuclear protein binding. Chromatin immunoprecipitation assays revealed the presence of the silencing DiMethH3K9 modification on the Ucp1 enhancer in white adipose tissue and the appearance of the active TriMethH3K4 mark at the Ucp1 promoter in brown adipose tissue in response to a cold environment. CONCLUSIONS/INTERPRETATION: The results demonstrate that CpG dinucleotide methylation of the Ucp1 enhancer exhibits tissue-specific patterns in murine tissue and cell lines and suggest that adipose tissue-specific Ucp1 expression involves demethylation of CpG dinucleotides found in regulatory CREs in the Ucp1 enhancer, as well as modification of histone tails.

Asunto(s)

Tejido Adiposo Pardo/metabolismo , Tejido Adiposo Blanco/metabolismo , Ensamble y Desensamble de Cromatina/genética , Islas de CpG/genética , Metilación de ADN/genética , Canales Iónicos/genética , Proteínas Mitocondriales/genética , Animales , Línea Celular , Células Cultivadas , Inmunoprecipitación de Cromatina , Frío , Femenino , Silenciador del Gen , Histonas/genética , Histonas/metabolismo , Canales Iónicos/metabolismo , Ratones , Ratones Endogámicos C57BL , Proteínas Mitocondriales/metabolismo , Regiones Promotoras Genéticas/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Proteína Desacopladora 1

RESUMEN

BACKGROUND: A specific inspiratory muscle 'warm-up' (IWU) prior to assessment of maximal inspiratory mouth pressure (PI(max)) may reduce the number of measurements required to obtain reproducible, representative estimates of PI(max). The influence of inspiratory muscle training (IMT) upon this phenomenon is unknown. OBJECTIVE: Compare the impact of an IWU on the between- and within-day reliability of PI(max) before and after IMT. METHOD: Eight participants were assessed on 4 separate occasions: 2 trials preceded IMT and 2 followed it. At each assessment, the highest of 3 initial efforts was recorded as the pre-IWU value (PI). The highest of 9 subsequent efforts that followed 2 sets of 30 breaths at 40% PI was recorded as PI(max). Following 4 weeks of IMT, the trials were repeated. RESULTS: IWU increased PI by 11-17% (p < or = 0.01), irrespective of IMT status. After IWU, 5-6 efforts were required to determine PI(max), irrespective of IMT status. PI(max) was similar between the 2 trials before IMT and the 2 trials after IMT (p > or = 0.05), and was 21% higher after IMT (p < or = 0.01). The coefficient of variation was excellent before and after IWU, both before (1.9 and 0.6%, respectively) and after IMT (1.1 and 0.3%, respectively). Limits of agreement and sample sizes for effect sizes < or =10% were substantially smaller after IWU in all trials. CONCLUSIONS: (1) IWU enhances the between-day reliability of PI(max) measurement, and this is unaffected by IMT, and (2) judgements regarding acceptability in relation to PI(max) reliability should be made in relation to analytical goals and we present data to facilitate this.

Asunto(s)

Inhalación , Músculos Respiratorios/fisiología , Adulto , Femenino , Humanos , Masculino , Presión , Reproducibilidad de los Resultados , Pruebas de Función Respiratoria , Adulto Joven

RESUMEN

Effects of increased ammonia and/or arginine absorption across the portal-drained viscera (PDV) on net splanchnic (PDV and liver) metabolism of nitrogenous compounds and urinary N excretion were investigated in six catheterized Hereford x Angus steers (501 +/- 1 kg BW) fed a 75% alfalfa:25% (as-fed basis) corn-soybean meal diet (0.523 MJ of ME/[kg BW(0.75).d]) every 2 h without (27.0 g of N/kg of dietary DM) and with 20 g of urea/kg of dietary DM (35.7 g of N/kg of dietary DM) in a split-plot design. Net splanchnic flux measurements were obtained immediately before beginning and ending a 72-h mesenteric vein infusion of L-arginine (15 mmol/h). For 3 d before and during arginine infusion, daily urine voided was measured and analyzed for N composition. Feeding urea increased PDV absorption (P < 0.01) and hepatic removal (P < 0.01) of ammonia N, accounting for 80% of increased hepatic urea N output (P < 0.01). Numerical increases in net hepatic removal of AA N could account for the remaining portion of increased hepatic urea N output. Arginine infusion increased hepatic arginine removal (P < 0.01) and hepatic urea N output (P < 0.03) and switched hepatic ornithine flux from net uptake to net output (P < 0.01), but numerical changes in net hepatic removal of ammonia and AA N could not account fully for the increase in hepatic urea N output. Increases in urine N excretion equaled quantities of N fed as urea or infused as arginine. Estimated salivary urea N excretion was not changed by either treatment. Urea cycle regulation occurs via a complex interaction of mechanisms and requires N sources other than ammonia, but the effect of increased ammonia absorption on hepatic catabolism of individual AA in the present study was not significant.

Asunto(s)

Bovinos/metabolismo , Dieta/veterinaria , Hígado/metabolismo , Compuestos de Nitrógeno/metabolismo , Urea/farmacología , Vísceras/metabolismo , Aminoácidos/sangre , Amoníaco/metabolismo , Amoníaco/orina , Alimentación Animal/análisis , Animales , Arginina/administración & dosificación , Arginina/metabolismo , Peso Corporal , Hematócrito/veterinaria , Hígado/efectos de los fármacos , Masculino , Medicago sativa/metabolismo , Nitrógeno/orina , Compuestos de Nitrógeno/sangre , Vena Porta/fisiología , Distribución Aleatoria , Urea/administración & dosificación , Orina/química , Orina/fisiología , Vísceras/efectos de los fármacos

RESUMEN

Effects of increased ammonia and/or arginine absorption on net splanchnic (portal-drained viscera [PDV] plus liver) metabolism of nonnitrogenous nutrients and hormones in cattle were examined. Six Hereford x Angus steers (501 +/- 1 kg BW) prepared with vascular catheters for measurements of net flux across the splanchnic bed were fed a 75% alfalfa:25% (as-fed basis) corn and soybean meal diet (0.523 MJ of ME/[kg BW(0.75).d]) every 2 h without (27.0 g of N/kg of DM) and with 20 g of urea/kg of DM (35.7 g of N/kg of DM) in a split-plot design. Net flux measurements were made immediately before and after a 72-h mesenteric vein infusion of L-arginine (15 mmol/h). There were no treatment effects on PDV or hepatic O2 consumption. Dietary urea had no effect on splanchnic metabolism of glucose or L-lactate, but arginine infusion decreased net hepatic removal of L-lactate when urea was fed (P < 0.01). Net PDV appearance of n-butyrate was increased by arginine infusion (P < 0.07), and both dietary urea (P < 0.09) and arginine infusion (P < 0.05) increased net hepatic removal of n-butyrate. Dietary urea also increased total splanchnic acetate output (P < 0.06), tended to increase arterial glucagon concentration (P < 0.11), and decreased arterial ST concentration (P < 0.03). Arginine infusion increased arterial concentration (P < 0.07) and net PDV release (P < 0.10) and tended to increase hepatic removal (P < 0.11) of insulin, as well as arterial concentration (P < 0.01) and total splanchnic output (P < 0.01) of glucagon. Despite changes in splanchnic N metabolism, increased ammonia and arginine absorption had little measurable effect on splanchnic metabolism of glucose and other nonnitrogenous components of splanchnic energy metabolism.

Asunto(s)

Amoníaco/farmacocinética , Arginina/farmacocinética , Bovinos/metabolismo , Hígado/metabolismo , Urea/farmacología , Vísceras/metabolismo , Ácido 3-Hidroxibutírico/sangre , Absorción , Animales , Arginina/administración & dosificación , Arginina/metabolismo , Glucemia/análisis , Ácidos Grasos Volátiles/sangre , Glucagón/metabolismo , Infusiones Intravenosas/veterinaria , Insulina/metabolismo , Hígado/irrigación sanguínea , Hígado/efectos de los fármacos , Masculino , Oxígeno/sangre , Vena Porta , Distribución Aleatoria , Flujo Sanguíneo Regional/efectos de los fármacos , Urea/administración & dosificación

RESUMEN

Diet-induced changes in the polyunsaturated fatty acid (PUFA) content of immune cells influences the immune phenotype that develops following infection. The aim of this study was to examine the effect of manipulating dietary PUFA supply on tissue fatty acids composition and immunity to a mixed infection with an abomasal and an intestinal nematode parasite in calves. Calves (n=24) were allocated into two treatment groups and fed 25 g/day of either fish oil (n-3 group) or a binary mixture of palm/rapeseed oil (normal group) as a supplement in milk replacer. Within each treatment group eight calves were infected with 2000 L3 Ostertagia ostertagi and Cooperia oncophora, three times per week for 8 weeks, the remaining calves were pair-fed uninfected controls. Faecal egg counts (FEC) were carried out twice weekly. At slaughter, the whole gut was removed intact for worm counts and tissue samples were taken for fatty acid analysis. Samples of abomasum, duodenum and mid-gut were also collected for immunohistological analysis. FEC were not significantly influenced by oil supplement but tended to remain higher in the palm/rapeseed oil-fed group (normal infected). The number of intestinal immature worms was significantly (p<0.05) higher in the n-3 group. Mucosal mast cell (MMC) and eosinophil numbers were significantly increased (p<0.05) by infection and were significantly lower (p<0.05) in the intestinal tissue of the fish oil supplemented and infected group (n-3 infected group). These results suggest that feeding an n-3 PUFA-rich supplement (fish oil) can influence cellular mediators of immunity to nematode infection. This is the first report of the establishment of patency and the subsequent development of immunity to a mixed infection with O. ostertagi and C. oncophora in calves undergoing early rumen development. The trend in the FEC, MMC and eosinophil numbers in the n-3 group suggests that decreasing the dietary n-6/n-3 PUFA ratio may be a worthwhile immunonutritional strategy for potentiating the immune response to nematode parasite infection in the calf.

Asunto(s)

Enfermedades de los Bovinos/parasitología , Grasas Insaturadas en la Dieta/farmacología , Enfermedades Gastrointestinales/veterinaria , Ostertagia/crecimiento & desarrollo , Ostertagiasis/veterinaria , Trichostrongyloidea/crecimiento & desarrollo , Tricostrongiloidiasis/veterinaria , Animales , Bovinos , Enfermedades de los Bovinos/inmunología , Enfermedades de los Bovinos/metabolismo , Recuento de Células/veterinaria , Eosinófilos/inmunología , Eosinófilos/parasitología , Ácidos Grasos Monoinsaturados , Ácidos Grasos Omega-3/farmacología , Heces/parasitología , Enfermedades Gastrointestinales/inmunología , Enfermedades Gastrointestinales/metabolismo , Enfermedades Gastrointestinales/parasitología , Humanos , Mucosa Intestinal/citología , Mucosa Intestinal/inmunología , Mucosa Intestinal/parasitología , Intestinos/parasitología , Masculino , Mastocitos/inmunología , Mastocitos/parasitología , Ostertagiasis/inmunología , Ostertagiasis/metabolismo , Ostertagiasis/parasitología , Aceite de Palma , Recuento de Huevos de Parásitos/veterinaria , Aceites de Plantas/farmacología , Aceite de Brassica napus , Tricostrongiloidiasis/inmunología , Tricostrongiloidiasis/metabolismo , Tricostrongiloidiasis/parasitología

RESUMEN

The increase in fractional rate of protein synthesis (Ks) in the skeletal muscle of growing rats during the transition from fasted to fed state has been explained by the synergistic action of a rise in plasma insulin and branched-chain amino acids (BCAA). Since growing lambs also exhibit an increase in Ks with level of feed intake, the objective of the present study was to determine if this synergistic relationship between insulin and BCAA also occurs in ruminant animals. Six 30 kg fasted (72 h) lambs (8 months of age) received each of four treatments, which were based on continuous infusion into the jugular vein for 6 h of: (1) saline (155 mmol NaCl/l); (2) a mixture of BCAA (0.778 micromol leucine, 0.640 micromol isoleucine and 0.693 micromol valine/min.kg); (3) 18.7 micromol glucose/min.kg (to induce endogenous insulin secretion); (4) co-infusion of BCAA and glucose. Within each period all animals received the same isotope of phenylalanine (Phe) as follows: (1) L-[1-13C]Phe; (2) L-phenyl-[ring 2H5]-alanine; (3) L-[15N]Phe; (4) L-[ring 2,6-3H]Phe. Blood was sampled serially during infusions to measure plasma concentrations of insulin, glucose and amino acids, and plasma free Phe isotopic activity; biopsies were taken 6 h after the beginning of infusions to determine Ks in m. longissimus dorsi and vastus muscle. Compared with control (saline-infused) lambs, Ks was increased by an average of 40% at the end of glucose infusion, but this effect was not statistically significant in either of the muscles sampled. BCAA infusion, alone or in combination with glucose, also had no significant effect on Ks compared with control sheep. Ks was approximately 60% greater for vastus muscle than for m. longissimus dorsi (P<0.01), regardless of treatment. It is concluded that there are signals other than insulin and BCAA that are responsible for the feed-induced increase in Ks in muscle of growing ruminant animals.

Asunto(s)

Aminoácidos de Cadena Ramificada/administración & dosificación , Insulina/sangre , Proteínas Musculares/biosíntesis , Músculo Esquelético/metabolismo , Aminoácidos de Cadena Ramificada/análisis , Animales , Glucemia/análisis , Privación de Alimentos , Glucosa/administración & dosificación , Infusiones Intravenosas , Isoleucina/administración & dosificación , Isoleucina/análisis , Leucina/administración & dosificación , Leucina/análisis , Fenilalanina/administración & dosificación , Fenilalanina/análisis , Ovinos , Valina/administración & dosificación , Valina/análisis

RESUMEN

The objective of this work was to construct a dynamic model of hepatic amino acid metabolism in the lactating dairy cow that could be parameterized using net flow data from in vivo experiments. The model considers 22 amino acids, ammonia, urea, and 13 energetic metabolites, and was parameterized using a steady-state balance model and two in vivo, net flow experiments conducted with mid-lactation dairy cows. Extracellular flows were derived directly from the observed data. An optimization routine was used to derive nine intracellular flows. The resulting dynamic model was found to be stable across a range of inputs suggesting that it can be perturbed and applied to other physiological states. Although nitrogen was generally in balance, leucine was in slight deficit compared to predicted needs for export protein synthesis, suggesting that an alternative source of leucine (e.g. peptides) was utilized. Simulations of varying glucagon concentrations indicated that an additional 5 mol/d of glucose could be synthesized at the reference substrate concentrations and blood flows. The increased glucose production was supported by increased removal from blood of lactate, glutamate, aspartate, alanine, asparagine, and glutamine. As glucose output increased, ketone body and acetate release increased while CO(2) release declined. The pattern of amino acids appearing in hepatic vein blood was affected by changes in amino acid concentration in portal vein blood, portal blood flow rate and glucagon concentration, with methionine and phenylalanine being the most affected of essential amino acids. Experimental evidence is insufficient to determine whether essential amino acids are affected by varying gluconeogenic demands.

Asunto(s)

Aminoácidos/metabolismo , Bovinos/metabolismo , Lactancia/fisiología , Hígado/metabolismo , Animales , Femenino , Modelos Biológicos

RESUMEN

To determine whether serum supplementation influenced fatty acid content of bovine blastocysts and whether vitamin E addition to culture medium containing serum could improve development in vitro, cleaved eggs were cultured in synthetic oviduct fluid supplemented with bovine serum albumin (BSA, 0.4% w/v, fraction V) (SVBSA), fetal calf serum (FCS, 10% v/v) (SFCS) or FCS (10% v/v) plus 100 micro M vitamin E (SFCS + E). Blastocyst yields were recorded and fatty acid composition was determined by gas chromatography. Day 7 blastocysts were incubated with [2-(14)C] pyruvate for 3 h and then fixed for cell counts. Yields of good quality blastocysts were greatest from cleaved eggs cultured in serum-free conditions (P < 0.01). In the presence of serum, supplementation with vitamin E increased both total and good quality blastocyst yields (P < 0.01). Presence of serum increased fatty acid content (mean +/- SEM) of blastocysts (SVBSA v. SFCS = 57 +/- 2 v. 74 +/- 2 ng embryo(-1); P < 0.001). In contrast, pyruvate metabolism was greater in blastocysts produced without serum (27 +/- 3 v. 21 +/- 3 picomoles embryo(-1) 3h(-1); P < 0.01) but, on a per cell basis, no differences were detected. Addition of vitamin E to the serum-supplemented formulation did not alter either the fatty acid content (73 +/- 2 ng embryo(-1)) or pyruvate metabolism index (19 +/- 1 pmol embryo(-1) 3h(-1)) of SFCS + E blastocysts. Thus, despite lipid accumulation, supplementary vitamin E improved blastocyst yields in embryos exposed to serum.

Asunto(s)

Blastocisto/efectos de los fármacos , Medios de Cultivo/farmacología , Ácidos Grasos/análisis , Vitamina E/farmacología , Animales , Blastocisto/química , Blastocisto/metabolismo , Bovinos , Técnicas de Cultivo de Célula , Supervivencia Celular , Fase de Segmentación del Huevo/efectos de los fármacos , Fase de Segmentación del Huevo/metabolismo , Medios de Cultivo/química , Ácidos Grasos/metabolismo , Femenino , Ácido Pirúvico/análisis , Ácido Pirúvico/metabolismo , Suero/química , Vitamina E/análisis

RESUMEN

There is increasing evidence that at least one function of both the medial and the lateral olivocochlear efferent systems is to provide adjustment of the set point of activity in their postsynaptic target, the outer hair cells and afferent processes, respectively. New results, summarized in this review, suggest that both efferent systems can provide protection from noise through this mechanism. There are also intracellular pathways that can provide protection from noise-induced cellular damage in the cochlea. This review also summarizes new results on the pathways that regulate and react to levels of reactive oxygen species in the cochlea as well as the role of stress pathways for the heat shock proteins and for neurotrophic factors in protection, recovery and repair.

Asunto(s)

Estimulación Acústica , Cóclea/fisiología , Pérdida Auditiva Provocada por Ruido/prevención & control , Potenciales de Acción , Animales , Cóclea/anatomía & histología , Proteínas de Choque Térmico/metabolismo , Humanos , Estrés Oxidativo/fisiología , Especies Reactivas de Oxígeno/metabolismo