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1.
Rev Sci Instrum ; 95(1)2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-38236087

RESUMO

We present the development of an experimental platform that can collect four frames of x-ray diffraction data along a single line of sight during laser-driven, dynamic-compression experiments at the National Ignition Facility. The platform is comprised of a diagnostic imager built around ultrafast sensors with a 2-ns integration time, a custom target assembly that serves also to shield the imager, and a 10-ns duration, quasi-monochromatic x-ray source produced by laser-generated plasma. We demonstrate the performance with diffraction data for Pb ramp compressed to 150 GPa and illuminated by a Ge x-ray source that produces ∼7 × 1011, 10.25-keV photons/ns at the 400 µm diameter sample.

3.
Nature ; 589(7843): 532-535, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33505034

RESUMO

Carbon is the fourth-most prevalent element in the Universe and essential for all known life. In the elemental form it is found in multiple allotropes, including graphite, diamond and fullerenes, and it has long been predicted that even more structures can exist at pressures greater than those at Earth's core1-3. Several phases have been predicted to exist in the multi-terapascal regime, which is important for accurate modelling of the interiors of carbon-rich exoplanets4,5. By compressing solid carbon to 2 terapascals (20 million atmospheres; more than five times the pressure at Earth's core) using ramp-shaped laser pulses and simultaneously measuring nanosecond-duration time-resolved X-ray diffraction, we found that solid carbon retains the diamond structure far beyond its regime of predicted stability. The results confirm predictions that the strength of the tetrahedral molecular orbital bonds in diamond persists under enormous pressure, resulting in large energy barriers that hinder conversion to more-stable high-pressure allotropes1,2, just as graphite formation from metastable diamond is kinetically hindered at atmospheric pressure. This work nearly doubles the highest pressure at which X-ray diffraction has been recorded on any material.

4.
Animal ; 12(6): 1165-1173, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29065940

RESUMO

The effect of a calcium (Ca) and phosphorus (P) depletion and repletion strategy was studied in four consecutive feeding phases of 28 days each. In all, 60 castrated male pigs (14±1.6 kg initial BW) received 60% (low (L) diet; depletion) or 100% (control (C) diet; repletion) of their Ca and digestible P requirements according to six feeding sequences (CCCC, CCCL, CLCC, CCLC, LCLC and LLLL; subsequent letters indicate the diet received in phases 1, 2, 3 and 4, respectively). Pigs bone mineral content in whole-body (BMCb) and lumbar vertebrae L2 to L4 (BMCv) was measured in every feeding phase by dual-energy X-ray absorptiometry. Growth performance was slightly (<10%) affected by depletion, however, dietary treatments did not affect overall growth. Compared with control pigs, depletion reduced BMCb (34%, 38%, 33% and 22%) and BMCv (46%, 54%, 38% and 26%) in phases 1 to 4, respectively. Depletion increased however digestible P retention efficiency from the second to the fourth phases allowing LLLL pigs to present no differences in BMCb and BMCv gain compared with CCCC pigs in phase 4. Growth performance in repleted compared with control pigs was lower in phase 2, was no different in phase 3 and was lower in CLCC pigs in phase 4. Repletion increased body P and Ca retention efficiency when compared with control pigs (respectively, 8% and 10% for LC v. CC, P<0.01; 8% and 10% for CLC v. CCC, P<0.10; 18% and 25% for CLCC, CCLC, LCLC v. CCCC, P<0.001). Moreover, BMCv gain was higher in CLC pigs (P<0.001) and gains of body P, Ca, BMCb and BMCv in phase 4 were also higher in repleted than in CCCC pigs (respectively, 14%, 20%, 20% and 52%; P⩽0.02). Repletion reduced body P, Ca, BMCb and BMCv masses in phase 2 but no differences were found in phase 4 compared with control pigs. Lumbar vertebrae L2 to L4 bone mineral content was more sensitive to depletion and repletion sequences than BMCb especially in the first phase probably due to a higher proportion of metabolically active trabecular bone in vertebrae than in the whole skeleton. Dietary Ca was, however, oversupply in L compared with C diets (3.1 v. 2.5 Ca:digestible P ratio, respectively) suggesting that P has probably driven the regulations. Phosphorus and Ca depletion and repletion increases dietary P utilization efficiency and can help to reduce dietary P supply, but the underlying mechanisms need elucidation before its practical application.


Assuntos
Ração Animal , Composição Corporal , Cálcio da Dieta , Fósforo , Suínos , Fenômenos Fisiológicos da Nutrição Animal , Animais , Cálcio , Dieta , Masculino , Fósforo na Dieta , Suínos/crescimento & desenvolvimento
5.
Ann Oncol ; 27(10): 1848-54, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27456297

RESUMO

Over the past three decades, oral human papillomavirus (HPV) has been associated with an increase in the incidence of oropharyngeal squamous cell carcinoma (OPSCC) in several countries. Specialist oncologists in head and neck cancer are observing a wider range of demographics, sexual behaviours, and survival outcomes with their patients. Additionally, there are fewer smokers, consumers of alcohol, or people of lower socioeconomic status than in previous decades. In order to support patients, the European Head and Neck Society's Make Sense Campaign aims to promote best practice in the management of head and neck cancer through the delivery of counselling, psychological assessment, support with the patient experience following HPV-related cancer diagnosis, sexual impact (in terms of communication, behaviour and prevention), facilitating access to educational resources about HPV in head and neck squamous cell carcinoma and OPSCC, and early referral if necessary. New concerns about psychosocial distress and unmet psychosocial needs following diagnosis, therefore, exist throughout the disease and treatment periods. Oncologists treating patients with HPV-related head and neck cancer must integrate new parameters focused on infection risk transmission and sexual topics. The development and dissemination of best practice guidelines through The European Head and Neck Cancer Society Make Sense Campaign will help healthcare professionals to be more confident and resourceful in supporting patients with HPV-related head and neck cancer.


Assuntos
Neoplasias de Cabeça e Pescoço/psicologia , Neoplasias de Cabeça e Pescoço/virologia , Infecções por Papillomavirus/psicologia , Guias de Prática Clínica como Assunto , Gerenciamento Clínico , Guias como Assunto , Neoplasias de Cabeça e Pescoço/epidemiologia , Humanos , Papillomaviridae/patogenicidade , Infecções por Papillomavirus/epidemiologia , Infecções por Papillomavirus/virologia , Fatores de Risco
6.
J Anim Sci ; 94(1): 255-66, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26812332

RESUMO

The effect of Lys restriction followed by a repletion period on the performance of growing pigs was studied during 3 feeding phases, each lasting 28 d. A total of 47 castrated male pigs (G Performer 8.0 × Fertilis 25 pigs; Genetiporc Inc., Saint-Bernard, QC, Canada; initial BW of 26.7 ± 2.7 kg) were given each d 70% or 100% of their Lys requirements according to 1 of the following 5 sequences: 70-70-70, 70-70-100, 70-100-70, 70-100-100, or 100-100-100 (for each sequence, numbers indicate the Lys supply percentage in phase 1, 2, and 3, respectively). Individual Lys requirements were estimated daily on the basis of each pig's actual BW and feed intake and BW gain patterns obtained by regression using each pig's historical data. At the end of phase 1, the pigs given 100% of their Lys requirements had higher ADFI ( = 0.01), ADG ( < 0.01), and average daily protein deposition ( < 0.01) than did the pigs given 70% of their requirements. Similar results were observed during phases 2 and 3. At the end of phase 2, the pigs in the 70-100 sequence did not display any compensatory response, given that their ADFI, ADG, and average daily protein deposition did not differ from those of the pigs in the 100-100 sequence. Similar results were observed during phase 3. Although no compensatory growth was observed during the growing phases, the fact that the pigs in the 70-100-100 treatment were able to catch up in terms of BW and body protein mass to the pigs in the 100-100-100 sequence could indicate that a small degree of compensation did occur; these research results cannot ascertain that any compensatory growth occurred.


Assuntos
Ração Animal/análise , Lisina/farmacologia , Suínos/fisiologia , Fenômenos Fisiológicos da Nutrição Animal , Animais , Composição Corporal , Relação Dose-Resposta a Droga , Lisina/administração & dosagem , Masculino , Necessidades Nutricionais , Aumento de Peso/efeitos dos fármacos , Aumento de Peso/fisiologia
7.
Br J Pharmacol ; 172(19): 4757-71, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26178144

RESUMO

BACKGROUND AND PURPOSE: There is current interest in vitamin D as a potential anti-inflammatory treatment for chronic inflammatory lung disease, including cystic fibrosis (CF). Vitamin D transcriptionally up-regulates the anti-inflammatory gene DUSP1, which partly controls production of the inflammatory chemokine IL-8. IL-8 is overabundant in CF airways, potentially due to hyperinflammatory responses of CF macrophages. We tested the ability of vitamin D metabolites to down-regulate IL-8 production in CF macrophages. EXPERIMENTAL APPROACH: CF and healthy monocyte-derived macrophages (MDM) were treated with two vitamin D metabolites, 25-hydroxyvitamin D3 (25OHD3 ) and 1,25-dihydroxyvitamin D3 (1,25(OH)2 D3 ), or paricalcitol, synthetic analogue of 1,25(OH)2 D3 . 25OHD3 was tested at doses of 25-150 nM, whereas 1,25(OH)2 D3 and paricalcitol at doses of up to 100 nM. IL-8 was stimulated by bacterial virulence factors. As potential anti-inflammatory mechanism of vitamin D metabolites, we assessed up-regulation of DUSP1. KEY RESULTS: MDM from patients with CF and some healthy donors showed excessive production of stimulated IL-8, highlighting their hyperinflammatory phenotype. Vitamin D metabolites down-regulated stimulated IL-8 only in those hyperinflammatory MDM, and only when used at high doses (>100 nM for 25OHD3 , or >1 nM for 1,25(OH)2 D3 and paricalcitol). The magnitude of IL-8 down-regulation by vitamin D metabolites or paricalcitol was moderate (∼30% vs. >70% by low-dose dexamethasone). Transcriptional up-regulation of DUSP1 by vitamin D metabolites was seen in all tested MDM, regardless of IL-8 down-regulation. CONCLUSIONS AND IMPLICATIONS: Vitamin D metabolites and their analogues moderately down-regulate IL-8 in hyperinflammatory macrophages, including those from CF. This down-regulation appears to go through DUSP1-independent mechanisms.


Assuntos
Calcifediol/farmacologia , Fibrose Cística/metabolismo , Ergocalciferóis/farmacologia , Interleucina-8/metabolismo , Macrófagos/efeitos dos fármacos , Vitamina D/análogos & derivados , 25-Hidroxivitamina D3 1-alfa-Hidroxilase/genética , Adulto , Calcifediol/sangue , Células Cultivadas , Regulação para Baixo , Fosfatase 1 de Especificidade Dupla/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Macrófagos/metabolismo , Receptores de Calcitriol/genética , Regulação para Cima , Vitamina D/farmacologia , Vitamina D3 24-Hidroxilase/genética , Adulto Jovem
8.
Animal ; 9(4): 561-8, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25483208

RESUMO

The implementation of precision feeding in growing-finishing facilities requires accurate estimates of the animals' nutrient requirements. The objectives of the current study was to validate a method for estimating the real-time individual standardized ileal digestible (SID) lysine (Lys) requirements of growing-finishing pigs and the ability of this method to estimate the Lys requirements of pigs with different feed intake and growth patterns. Seventy-five pigs from a terminal cross and 72 pigs from a maternal cross were used in two 28-day experimental phases beginning at 25.8 (±2.5) and 73.3 (±5.2) kg BW, respectively. Treatments were randomly assigned to pigs within each experimental phase according to a 2×4 factorial design in which the two genetic lines and four dietary SID Lys levels (70%, 85%, 100% and 115% of the requirements estimated by the factorial method developed for precision feeding) were the main factors. Individual pigs' Lys requirements were estimated daily using a factorial approach based on their feed intake, BW and weight gain patterns. From 25 to 50 kg BW, this method slightly underestimated the pigs' SID Lys requirements, given that maximum protein deposition and weight gain were achieved at 115% of SID Lys requirements. However, the best gain-to-feed ratio (G : F) was obtained at a level of 85% or more of the estimated Lys requirement. From 70 to 100 kg, the method adequately estimated the pigs' individual requirements, given that maximum performance was achieved at 100% of Lys requirements. Terminal line pigs ate more (P=0.04) during the first experimental phase and tended to eat more (P=0.10) during the second phase than the maternal line pigs but both genetic lines had similar ADG and protein deposition rates during the two phases. The factorial method used in this study to estimate individual daily SID Lys requirements was able to accommodate the small genetic differences in feed intake, and it was concluded that this method can be used in precision feeding systems without adjustments. However, the method's ability to accommodate large genetic differences in feed intake and protein deposition patterns needs to be studied further.


Assuntos
Ciências da Nutrição Animal/métodos , Lisina/metabolismo , Suínos/fisiologia , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Necessidades Nutricionais , Distribuição Aleatória , Aumento de Peso
9.
Ann Oncol ; 25(11): 2115-2124, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24608199

RESUMO

Squamous cell carcinoma of the head and neck (SCCHN) is considered a worldwide health care problem. The majority of patients have a history of alcohol abuse and high-level tobacco consumption; however, SCCHN is also associated with exposure to viruses including human papillomavirus (HPV) and Epstein-Barr virus. A major problem facing SCCHN patients is that their disease is often diagnosed at an advanced stage where treatment options may not be curative, or can have severe post-treatment consequences. Confronted with their diagnosis and treatment options, the patient can express a range of emotional reactions which may lead to maladaptive coping. During the SCCHN patient journey, there are a number of stages where emotional support could be offered. A point of contact should be allocated to help patients navigate these stages and deliver practical emotive support (such as encouraging attendance at hospital appointments, compliance with lifestyle modifications and treatment adherence), and to identify if or when more advanced emotive support, in the form of a mental health professional, might be needed. This role might be carried out by a representative within the multidisciplinary health care team (e.g. a nurse). While optimal care is provided by specialist health care professionals, each with specific roles and responsibilities during the patient journey, all are important in screening for emotional distress and providing referral to the mental health team. This article reviews the key points for delivering emotional support to SCCHN patients at each stage of their care. Emotional problems cannot be ignored in SCCHN patients if optimal outcomes are to be achieved, particularly as therapeutic options extend overall survival for many patients. Health care professionals must be able to implement efficient screening for psychological distress to support patient's compliance to their care and treatment. They must also be able to recognize when to refer patients at risk for pharmacological and/or psychotherapeutic interventions.


Assuntos
Carcinoma de Células Escamosas/psicologia , Gerenciamento Clínico , Neoplasias de Cabeça e Pescoço/psicologia , Equipe de Assistência ao Paciente , Carcinoma de Células Escamosas/patologia , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Carcinoma de Células Escamosas de Cabeça e Pescoço , População Branca
11.
Surg Oncol ; 21(1): 15-21, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20708925

RESUMO

During the last six years the European School of Oncology (ESO) opened an undergraduate programme for European medical students, aiming to further improve their oncology knowledge and clinical skills. In this endeavour a 5-day course is organized every summer at the University of Ioannina, Greece, where distinguished European oncologists introduce preselected medical students to cancer medicine. The programme includes teaching of several oncological topic regarding diagnosis and treatment of the most common tumours; interactive case presentations and discussions were also incorporated. An overall of 229 medical students, mostly from European medical schools, have been taking part to this intensive summer course, from 2004 to 2009. This article presents the detailed educational programme, the evaluation results and the outcome of the last six ESO courses; an assessment of the oncological curricula available across European faculties is also presented.


Assuntos
Educação de Graduação em Medicina/métodos , Oncologia/educação , Adulto , Currículo , Educação de Graduação em Medicina/organização & administração , Avaliação Educacional , Escolaridade , Docentes de Medicina , Feminino , Grécia , Humanos , Masculino , Avaliação de Programas e Projetos de Saúde , Critérios de Admissão Escolar , Faculdades de Medicina , Ensino/organização & administração , Adulto Jovem
13.
J Anim Sci ; 89(11): 3596-611, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21680789

RESUMO

Environmental effects of excess P from manure and the soaring price of phosphates are major issues in pig production. To optimize P utilization, it is crucial to improve our capacity to predict the amount of P absorbed, while taking into account the main factors of variation. Mathematical modeling can represent the complexity of the processes and interactions in determining the digestive utilization of P in growing pigs. This paper describes and evaluates a model developed to simulate the fate of the dietary forms of P in the digestive tract of growing pigs, with particular emphasis on the effect of dietary Ca and exogenous phytase on P digestive utilization. The model consists of 3 compartments associated with specific anatomical sections: stomach, proximal small intestine, and distal small intestine. The main metabolic processes occurring in these sections are, respectively, P solubilization/insolubilization and phytate P hydrolysis, and P absorption and P insolubilization. Model parameters governing these flows were derived from in vitro and in vivo literature data. The sensitivity analysis revealed that the model was stable within a large range of model parameter values (±1.5 SD). The model was able to predict the efficacy of Aspergillus niger microbial phytase in accordance with literature values, as well as the decreased efficacy of plant phytase compared with microbial phytase. The prediction capabilities of the model were assessed by comparing actual and simulated P and Ca apparent total-tract digestibility (ATTD) based on published pig data not used for model development. Prediction of P digestibility across 66 experiments and 281 observations was adequate [P ATTD observed = 0.24 (SE, 0.943) + 0.98 (SE, 0.0196) × P ATTD predicted; R(2), 0.90; disturbance error (ED), 96.5%], whereas prediction of Ca digestibility across 47 experiments and 193 observations was less accurate (Ca ATTD observed = 11.1 + 0.75 × Ca ATTD predicted; R(2), 0.78; ED, 20.4%). A lack of agreement between experimental and simulated Ca digestibility was found. This model is, therefore, useful in evaluating P digestibility for different feedstuffs and feeding strategies. It can also be used to provide insight for improving dietary P utilization, especially from plant sources, by quantifying the effect of the mean sources of variation affecting P utilization.


Assuntos
Trato Gastrointestinal/metabolismo , Modelos Biológicos , Fósforo na Dieta/metabolismo , Suínos/metabolismo , 6-Fitase/metabolismo , Animais , Cálcio da Dieta/metabolismo , Simulação por Computador
14.
Ann Oncol ; 22(10): 2191-200, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21606209

RESUMO

BACKGROUND: Radiation dermatitis developing in patients receiving cetuximab concomitantly with radiotherapy for locally advanced squamous cell carcinoma of the head and neck (LA SCCHN) is now recognized to have different pathophysiological and clinical characteristics to the radiation dermatitis associated with radiotherapy or concomitant chemotherapy and radiotherapy. Current grading tools were not designed to grade this type of radiation dermatitis; their use may lead to misclassification of reactions and inappropriate management strategies, potentially compromising cancer treatment. PATIENTS AND METHODS: An advisory board of seven leading European specialists (three medical oncologists, three radiation oncologists and a dermatologist) with extensive experience of the use of cetuximab plus radiotherapy produced consensus guidelines for the grading and management of radiation dermatitis in patients receiving cetuximab plus radiotherapy. RESULTS: Modifications to the current, commonly used National Cancer Institute-Common Terminology Criteria for Adverse Events version 4.3 for grading radiation dermatitis were proposed. Updated management guidelines, building on previously published guidelines from 2008, were also proposed. CONCLUSIONS: The proposed revisions to the grading system and updated management guidelines described here represent important developments toward the more appropriate grading and effective management of radiation dermatitis in patients receiving cetuximab plus radiotherapy for LA SCCHN.


Assuntos
Anticorpos Monoclonais/efeitos adversos , Antineoplásicos/efeitos adversos , Carcinoma de Células Escamosas/terapia , Neoplasias de Cabeça e Pescoço/terapia , Radioterapia (Especialidade)/normas , Radiodermite/etiologia , Radiodermite/patologia , Anticorpos Monoclonais Humanizados , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/radioterapia , Cetuximab , Terapia Combinada/efeitos adversos , Receptores ErbB/antagonistas & inibidores , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/radioterapia , Humanos , Guias de Prática Clínica como Assunto , Radiodermite/fisiopatologia , Radiodermite/terapia , Radioterapia/efeitos adversos , Carcinoma de Células Escamosas de Cabeça e Pescoço
15.
Br J Cancer ; 103(8): 1173-81, 2010 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-20842129

RESUMO

BACKGROUND: The EORTC 24971/TAX 323, a phase III study of 358 patients with unresectable locoregionally advanced squamous cell carcinoma of the head and neck, showed an improved progression-free and overall survival (OS) with less toxicity when docetaxel (T) was added to cisplatin and 5-fluorouracil (PF) for induction and given before radiotherapy (RT). The impact of the addition of docetaxel on patients' health-related quality of life (HRQOL) and symptoms was investigated. METHODS: HRQOL was assessed at baseline, at end of cycle 2, and 4, 6, and 9 months after completion of RT using the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire C30 (QLQ-C30) and the EORTC QLQ Head and Neck Cancer-Specific Module (EORTC QLQ-H&N35). The primary HRQOL scale was global HRQOL per protocol. RESULTS: Compliance to HRQOL assessments was 97% at baseline, but dropped to 54% by 6 months. Data were analysed up to 6 months. There was a trend towards improved global HRQOL during the treatment period. At 6 months after the end of RT, global HRQOL was higher in the TPF arm than in the PF arm, but the low compliance does not allow to draw definitive conclusions. Swallowing and coughing problems decreased more in the TPF arm than in the PF arm at the end of cycle 2, but to a limited extent. CONCLUSION: Induction chemotherapy with TPF before RT not only improves survival and reduces toxicity compared with PF but also seems to improve global HRQOL in a more sustainable manner.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma de Células Escamosas/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Qualidade de Vida , Taxoides/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Carcinoma de Células Escamosas/mortalidade , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/fisiopatologia , Cisplatino/administração & dosagem , Cisplatino/efeitos adversos , Cisplatino/uso terapêutico , Progressão da Doença , Docetaxel , Fluoruracila/administração & dosagem , Fluoruracila/efeitos adversos , Fluoruracila/uso terapêutico , Neoplasias de Cabeça e Pescoço/mortalidade , Neoplasias de Cabeça e Pescoço/patologia , Neoplasias de Cabeça e Pescoço/fisiopatologia , Nível de Saúde , Humanos , Taxoides/efeitos adversos , Taxoides/uso terapêutico , Fatores de Tempo , Resultado do Tratamento
16.
Phys Rev Lett ; 104(13): 135504, 2010 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-20481894

RESUMO

Experimental results showing significant reductions from classical in the Rayleigh-Taylor instability growth rate due to high pressure effective lattice viscosity are presented. Using a laser created ramped drive, vanadium samples are compressed and accelerated quasi-isentropically at approximately 1 Mbar peak pressures, while maintaining the sample in the solid state. Comparisons with simulations and theory indicate that the high pressure, high strain rate conditions trigger a phonon drag mechanism, resulting in the observed high effective lattice viscosity and strong stabilization of the Rayleigh-Taylor instability.

17.
J Anim Sci ; 88(5): 1706-17, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20118415

RESUMO

The present study was conducted to assess the effect of 2 dietary Ca concentrations on P and Ca digestive and metabolic utilization in weanling pigs fed diets providing practical concentrations of P, with or without phytase. The responses of pigs fed diets adequate or moderately deficient in Ca and P postweaning were compared. A total of 60 pigs weaned at 28 d of age were used. Two groups of 30 pigs with differing mineral status resulted from a 10-d depletion period, during which the animals received depletion diets (DD) that consisted of corn-soybean meal with either 1.42% Ca and 0.80% P (DD+) or 0.67% Ca and 0.43% P (DD-), designed to achieve the same Ca:digestible P ratio. At the end of the depletion period, a plasma sample was taken from each pig and 12 pigs (6 from each group) were slaughtered for bone assessment to establish the baseline mineral status. The animals fed the DD- diet had signs of P deficiency with reduced plasma P (13%; P < 0.01) and femur ash concentration (8%; P < 0.05), and increased plasma Ca (9%; P < 0.05) and alkaline phosphatase activity (31%; P < 0.01). For the subsequent 25-d period, the remaining 24 pigs from each group were fed 1 of 4 repletion diets: 1) 0.56% P, 1.06% Ca; 2) 0.56% P, 0.67% Ca; 3) diet 1 + 1,000 phytase units (FTU) of Natuphos phytase/kg; and 4) diet 2 + 1,000 FTU of Natuphos phytase/kg. Total feces and urine were collected from d 5 to 11, and a blood sample was taken from each pig at d 11 and 25. The initial moderate P deficiency (DD-) stimulated Ca absorption (5%; P < 0.01), irrespective of the repletion diet, and stimulated P absorption (5%; DD x phytase, P < 0.05), only when the diets contained phytase. At the end of the repletion period, because of these compensatory phenomena, the depleted pigs achieved full recovery of femur DM and ash weight when they received phytase, whereas ash concentration tended to remain reduced by 3% (P = 0.08). Phosphorus digestibility was improved in the diets supplemented with phytase (73.0 vs. 56.0%; P < 0.001), whereas an increase in dietary Ca decreased P digestibility (65.6 vs. 63.4%; P < 0.05). Those 2 effects were independent, indicating that dietary Ca reduced equally P digestibility with and without phytase and did not influence the efficiency of phytase in releasing P in the digestive tract. In pigs fed diets with phytase, however, the reduction of Ca (Ca:P from 1.9 to 1.3) increased urinary P losses 5-fold. Those extra losses were due to a lack of Ca for skeleton ash deposition, resulting in a 4% reduction in femur ash concentration. In the end, reducing the dietary Ca:P from 1.9 to 1.3 in a practical diet containing 0.56% P did not improve the efficiency of phytase in releasing P. Moreover, the reduction in dietary Ca (Ca:P) caused an imbalance between Ca and P that impaired bone mineralization.


Assuntos
6-Fitase/farmacologia , Cálcio da Dieta/farmacologia , Cálcio/metabolismo , Fósforo/metabolismo , 6-Fitase/administração & dosagem , Animais , Densidade Óssea/efeitos dos fármacos , Suplementos Nutricionais , Relação Dose-Resposta a Droga , Feminino , Masculino , Minerais , Suínos , Desmame
18.
Animal ; 4(11): 1844-53, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22445145

RESUMO

Pollution relative to phosphorus excretion in poultry manure as well as the soaring prices of phosphate, a non-renewable resource, remain of major importance. Thus, a good understanding of bird response regarding dietary phosphorus (P) is a prerequisite to optimise the utilisation of this essential element in broiler diets. A database built from 15 experiments with 203 treatments was used to predict the response of 21-day-old broilers to dietary non-phytate P (NPP), taking into account the main factors of variation, calcium (Ca) and microbial phytase derived from Aspergillus niger, in terms of average daily feed intake (ADFI), average daily gain (ADG), gain to feed (G:F) and tibia ash concentration. All criteria evolve linearly (P < 0.001) and quadratically (P < 0.001) with dietary NPP concentration. Dietary Ca affected the intercept and linear component for ADG (P < 0.01), G:F (P < 0.05) and tibia ash concentration (P < 0.001), whereas for ADFI, it affected only the intercept (P < 0.01). Microbial phytase addition impacted on the intercept, the linear and the quadratic coefficient for ADFI (P < 0.01), ADG (P < 0.001) and G:F (P < 0.05), and on the intercept and the linear component (P < 0.001) for tibia ash concentration. An evaluation of these models was then performed on a database built from 28 experiments and 255 treatments that were not used to perform the models. Results showed that ADFI, ADG and Tibia ash concentration were predicted fairly well (slope and intercept did not deviate from 0 to 1, respectively), whereas this was not the case for G:F. The increase in dietary Ca concentration aggravated P deficiency for all criteria while phytase addition had a positive effect. The more P deficiency was marked, the more the bird response to ADFI, ADG, G:F and tibia ash concentration was exacerbated. It must also be considered that even if the decrease in dietary Ca may improve P utilisation, it could in turn become limiting for bone mineralisation. In conclusion, this meta-analysis provides ways to reduce dietary P in broiler diets without impairing performance, taking into account dietary Ca and microbial phytase.

19.
J Dairy Sci ; 92(7): 3233-43, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19528600

RESUMO

In the transition from the pre- to postcalving state, the demands on the cow increase from support of gestation to high rates of milk production. This extra demand is met partly by increased intake but may also involve altered metabolism of major nutrients. Six multiparous Holstein cows were used to monitor changes in net fluxes of nutrients across the portal-drained viscera and liver (splanchnic tissues) between late gestation and early lactation. Blood samples were obtained simultaneously from the portal, hepatic, and subcutaneous abdominal veins and the caudal aorta 18 d before expected calving and 21 or 42 d after calving. On the day of blood sampling and the 3 d preceding sampling, cows were fed every 2 h. The precalving (1.63 Mcal of net energy for lactation/kg and 1,326 g of metabolizable protein/d) and postcalving (1.72 Mcal of net energy for lactation/kg and 2,136 g of metabolizable protein/d) diets were based on corn silage, alfalfa hay, and corn grain. Dry matter intake increased postcalving. Net splanchnic release of glucose increased postpartum because of tendencies for both increased portal absorption and net liver release. Increased removal of lactate, rather than AA, contributed to the additional hepatic gluconeogenesis. Although portal absorption of AA increased with intake at the onset of lactation, hepatic removal of total AA-N tended to decline. This clearly indicates that liver removal of AA is not linked to portal absorption. Furthermore, net liver removal relative to total liver inflow even decreased for Gly, His, Met, Phe, and Tyr. Together, these data indicate that in early lactation, metabolic priority is given to direct AA toward milk protein production rather than gluconeogenesis, in cows fed a corn-based ration.


Assuntos
Bovinos/fisiologia , Metabolismo Energético , Lactação/fisiologia , Fígado/metabolismo , Sistema Porta/metabolismo , Aminoácidos/sangue , Aminoácidos/metabolismo , Animais , Glicemia/análise , Bovinos/metabolismo , Ingestão de Alimentos , Feminino , Ácido Láctico/sangue , Nitrogênio/sangue , Nitrogênio/metabolismo , Gravidez
20.
Parasitology ; 136(5): 469-85, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19265565

RESUMO

SUMMARY: Infection of the snail, Biomphalaria glabrata, by the free-swimming miracidial stage of the human blood fluke, Schistosoma mansoni, and its subsequent development to the parasitic sporocyst stage is critical to establishment of viable infections and continued human transmission. We performed a genome-wide expression analysis of the S. mansoni miracidia and developing sporocyst using Long Serial Analysis of Gene Expression (LongSAGE). Five cDNA libraries were constructed from miracidia and in vitro cultured 6- and 20-day-old sporocysts maintained in sporocyst medium (SM) or in SM conditioned by previous cultivation with cells of the B. glabrata embryonic (Bge) cell line. We generated 21 440 SAGE tags and mapped 13 381 to the S. mansoni gene predictions (v4.0e) either by estimating theoretical 3' UTR lengths or using existing 3' EST sequence data. Overall, 432 transcripts were found to be differentially expressed amongst all 5 libraries. In total, 172 tags were differentially expressed between miracidia and 6-day conditioned sporocysts and 152 were differentially expressed between miracidia and 6-day unconditioned sporocysts. In addition, 53 and 45 tags, respectively, were differentially expressed in 6-day and 20-day cultured sporocysts, due to the effects of exposure to Bge cell-conditioned medium.


Assuntos
Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Helminto/metabolismo , Schistosoma mansoni/crescimento & desenvolvimento , Animais , Sequência de Bases , Biomphalaria/parasitologia , DNA de Helmintos/análise , Biblioteca Gênica , Proteínas de Helminto/genética , Interações Hospedeiro-Parasita , Larva/genética , Larva/crescimento & desenvolvimento , Larva/metabolismo , Dados de Sequência Molecular , Oocistos/crescimento & desenvolvimento , Oocistos/metabolismo , Schistosoma mansoni/genética , Schistosoma mansoni/metabolismo , Análise de Sequência de DNA
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