RESUMEN
BACKGROUND: Acute exercise has been shown to induce nutritional adaptations in obese and lean inactive youth but it remains unclear whether youth with a high level of physical activity experience such exercise-induced energy intake and appetite modifications. METHODS: 14 (15- to 16-year-old) male elite rugby players completed sessions on three separate occasions: (1) a control session (CON); (2) an exercise session (EX) and; (3) a rugby session (RUGBY). The energy induced by the rugby and exercise sessions was matched (Polar Team2 pro technology), and participants' energy intake, food preferences (ad libitum buffet meals) and appetite feelings (Visual Analogue Scales) were assessed throughout the experimental days. RESULTS: The energy intake during lunch and snack time was not different between conditions. Dinner time energy intake was significantly increased after RUBGY compared to CON with respectively 969 ± 145 kcal and 777 ± 183 kcal (p < 0.05). The energy intake at dinner time was significantly increased during EX (1185 ± 199 kcal) compared to both CON (p < 0.001) and RUGBY (p < 0.01). None of the appetite feelings investigated were modified between sessions. CONCLUSION: Adolescent elite rugby players regulate their energy intake differently depending on the nature of their training; independently of the energy expended. This demonstrates the need for energetic and nutritional education to optimize their physical fitness and performance.
Asunto(s)
Apetito/fisiología , Ingestión de Energía/fisiología , Metabolismo Energético/fisiología , Ejercicio Físico/fisiología , Conducta Alimentaria , Fútbol Americano/fisiología , Adolescente , Humanos , Masculino , Comidas , Consumo de Oxígeno , Aptitud Física , Fenómenos Fisiológicos en la Nutrición DeportivaRESUMEN
The objectives of the current study were (1) to determine the gain in prognostic accuracy of preoperative l-lactate concentration (LAC) measured on farm on cows with right displaced abomasum (RDA) or abomasal volvulus (AV) for predicting negative outcome; and (2) to suggest clinically relevant thresholds for such use. A cohort of 102 cows with on-farm surgical diagnostic of RDA or AV was obtained from June 2009 through December 2011. Blood was drawn from coccygeal vessels before surgery and plasma LAC was immediately measured by using a portable clinical analyzer. Dairy producers were interviewed by phone 30 d following surgery and the outcome was determined: a positive outcome if the owner was satisfied of the overall evolution 30 d postoperatively, and a negative outcome if the cow was culled, died, or if the owner reported being unsatisfied 30 d postoperatively. The area under the curve of the receiver operating characteristic curve for LAC was 0.92 and was significantly greater than the area under the curve of the receiver operating characteristic curve of heart rate (HR; 0.77), indicating that LAC, in general, performed better than HR to predict a negative outcome. Furthermore, the ability to predict a negative outcome was significantly improved when LAC measurement was considered in addition to the already available HR data (area under the curve: 0.93 and 95% confidence interval: 0.87, 0.99). Important inflection points of the misclassification cost term function were noted at thresholds of 2 and 6 mmol/L, suggesting the potential utility of these cut-points. The 2 and 6 mmol/L thresholds had a sensitivity, specificity, positive predictive value, and negative predictive value for predicting a negative outcome of 76.2, 82.7, 53.3, and 93.1%, and of 28.6, 97.5, 75, and 84%, respectively. In terms of clinical interpretation, LAC ≤2 mmol/L appeared to be a good indicator of positive outcome and could be used to support a surgical treatment decision. The treatment decision for cows with LAC between 2 and 6 mmol/L, however, would depend on the economic context and the owner's attitude to risk in regard to potential return on its investment. Finally, performing a surgical correction on commercial cows with RDA or AV and a LAC ≥6 mmol/L appeared to be unjustified and these animals should be culled based on their high probability of negative outcome.
Asunto(s)
Abomaso/patología , Enfermedades de los Bovinos/diagnóstico , Lactatos/sangre , Gastropatías/diagnóstico , Gastropatías/veterinaria , Animales , Bovinos , Enfermedades de los Bovinos/sangre , Enfermedades de los Bovinos/patología , Femenino , Pronóstico , Sensibilidad y Especificidad , Gastropatías/patologíaRESUMEN
We report results of RIC AHSCT in four adolescents with aggressive refractory HL. They all received three or four lines of therapy prior to RIC-AHSCT including autografts. At the time of RIC, they were in partial response except for one patient who had progressive chemoresistant disease. The conditioning regimen consisted of fludarabin, busulfan and ATG. They all had a matched related donor. The median follow-up was 12-16-month post-allograft. All patient transplants engrafted rapidly. The median time of hospitalization was 35 days. The median time to neutrophil recovery (>or=500/muL) was 19 days. All the patients were in complete donor chimerism at day 60. Four patients developed skin (grade Asunto(s)
Busulfano/uso terapéutico
, Trasplante de Células Madre Hematopoyéticas/métodos
, Enfermedad de Hodgkin/cirugía
, Agonistas Mieloablativos/uso terapéutico
, Vidarabina/análogos & derivados
, Adolescente
, Antineoplásicos/uso terapéutico
, Quimioterapia Combinada
, Femenino
, Estudios de Seguimiento
, Enfermedad de Hodgkin/diagnóstico
, Enfermedad de Hodgkin/tratamiento farmacológico
, Humanos
, Masculino
, Tomografía de Emisión de Positrones
, Índice de Severidad de la Enfermedad
, Factores de Tiempo
, Trasplante Homólogo
, Resultado del Tratamiento
, Vidarabina/uso terapéutico
RESUMEN
BACKGROUND: Obesity is increasing worldwide, reaching alarming proportions. Eating habits have changed over time and nowadays children and adolescents' environment favours the adoption of unhealthy eating behaviours leading to metabolic impairment. OBJECTIVE: To explore the impact of eating risk factors and their cumulative effect on anthropometric characteristics in French primary school children. METHODS: A total of 278 healthy French children (7.50 ± 0.67 years old) and their legal representatives agreed to take part in this study. Parents were asked to fill in an eating habits clinical questionnaire with questions about skipping breakfast, snacking between meals, eating in front of the TV and sugar-sweetened beverage consumption. On the basis of the answers, children were classified into four categories as a function of the number of eating risk factors they presented. Body mass index (BMI), the sum of four skinfolds (Σ4 skinfolds: tricipital, bicipital, sub-scapular and supra-iliac) and waist circumference (WC) were measured. BMI was transformed into z-BMI for each child. RESULTS: ANOVA and unpaired t-test provided significantly higher z-BMI, Σ4 skinfolds and WC in children who were used to skipping breakfast, snacking, watching TV while eating and consuming sugar-sweetened beverages. The more children accumulated eating risk factors, the higher were their z-BMI, Σ4 skinfolds and WC (MANOVA: P < 0.001). CONCLUSIONS: Eating habits appear to be associated with anthropometric characteristics in French primary school children. Anthropometric values (z-BMI, Σ4 skinfolds and WC) increased with the number of eating risk factors they presented.
Asunto(s)
Ingestión de Energía/fisiología , Conducta Alimentaria/psicología , Obesidad/etiología , Antropometría , Índice de Masa Corporal , Peso Corporal , Niño , Femenino , Francia , Humanos , Masculino , Encuestas Nutricionales , Factores de Riesgo , Instituciones Académicas , Encuestas y Cuestionarios , Factores de TiempoRESUMEN
Several (but not all) Plasmodium berghei chromosomes bear in the subtelomeric position a cluster of 2.3-kilobase (kb) tandem repeats. The 2.3-kb unit contains 160 base pairs of telomeric sequence. The resulting subtelomeric structure is one in which stretches of telomeric sequences are periodically spaced by a 2.1-kb reiterated sequence. This periodic organization of internal telomeric sequences might be related to chromosome-size polymorphisms involving the loss or addition of subtelomeric 2.3-kb units.
Asunto(s)
Cromosomas/ultraestructura , Plasmodium berghei/genética , Secuencias Repetitivas de Ácidos Nucleicos , Animales , Secuencia de Bases , Mapeo Cromosómico , Electroforesis en Gel de Agar , Datos de Secuencia Molecular , Mapeo RestrictivoRESUMEN
During prolonged in vivo mitotic multiplication of a Plasmodium berghei ANKA clone (8417HP), parasites that contained an enlarged version of chromosome 4 were observed. Restriction mapping and hybridization results demonstrated that the extra DNA present in the enlarged chromosome consists of 2.3-kb tandem repeats, known to be normally located in subtelomeric position at several chromosomal ends but absent in the original chromosome. The inserted 2.3-kb units appeared to interrupt one of the original telomeres and to create an internal (approximately 1-kb-long) telomeric sequence.
Asunto(s)
Elementos Transponibles de ADN , Plasmodium berghei/genética , Polimorfismo Genético , Animales , Secuencia de Bases , Clonación Molecular , Datos de Secuencia Molecular , Sondas de Oligonucleótidos , Mapeo RestrictivoRESUMEN
BACKGROUND: The signalment, clinicopathologic, bacteriological, histopathological, ultrasonographic characteristics, and the treatment and outcomes of adult cattle with cholangiohepatitis are poorly defined. ANIMALS: Thirteen Holstein cows with cholangiohepatitis. METHODS: Retrospective study of medical records of cattle admitted to the CHUV and the AVC between 1992 and 2012 and 2000 and 2012, respectively, for cattle older than 3 months of age with a histopathological diagnosis of cholangiohepatitis. Cholangiohepatitis was defined as the presence of portal inflammation surrounding or infiltrating bile ducts, with or without epithelial damage, and extending into the adjacent lobules. RESULTS: At the time of diagnosis of cholangiohepatitis, cows had decreased appetite (n = 7) or were anorectic (n = 6), had fever (n = 5), and had tachycardia (n = 8). Icterus was detected in 5 cows. Yellow discoloration was identified on the skin of the udder (n = 3), conjunctiva (n = 2), and vulva (n = 1). There was leukocytosis (n = 6), neutrophilia (n = 9), and hyperfibrinogenemia (n = 8). Alteration in the serum biochemistry profile included hyperglobulinemia (n = 8), hypoalbuminemia (n = 10), increased activity of GGT (n = 12), AST (n = 8), and ALP (n = 10), and hyperbilirubinemia (n = 10). Histopathological diagnosis included mild, subacute, nonsuppurative cholangiohepatitis (n = 4), mild suppurative cholangiohepatitis (n = 4), mild mixed (neutrophilic and lymphocytic) cholangiohepatitis (n = 3), and moderate, chronic, nonsuppurative cholangiohepatitis (n = 1). Six cows were discharged from the hospital, and 7 were euthanized. CONCLUSIONS AND CLINICAL IMPORTANCE: Cholangiohepatitis is a rare condition in adult cattle. Antemortem diagnosis can be challenging because clinical signs are unspecific.
Asunto(s)
Enfermedades de los Bovinos/patología , Colangitis/veterinaria , Animales , Conductos Biliares/patología , Biopsia/veterinaria , Bovinos , Enfermedades de los Bovinos/diagnóstico , Enfermedades de los Bovinos/diagnóstico por imagen , Enfermedades de los Bovinos/terapia , Colangitis/diagnóstico , Colangitis/patología , Colangitis/terapia , Femenino , Hígado/patología , Estudios Retrospectivos , Ultrasonografía/veterinariaRESUMEN
UNLABELLED: Thrombotic thrombocytopenic purpura (TTP), when accompanied by regenerative anaemia with schizocytosis, thrombopenia and neurological manifestations, is a disease whose main characteristic is the absence of the von Willebrand factor (vWF) cleaving protease. The two types of TTP are distinguishable by the presence or absence of antiprotease inhibitors, which are, respectively, either acquired or constitutional. The acquired autoimmune form is most frequently observed in adults. OBSERVATION: An adolescent with a previous history of moderate, isolated thrombopenia first showed symptoms of TTP at the age of 14. Positive antiprotease inhibitors in combination with a degeneration of protease activity confirmed the diagnosis of acquired autoimmune TTP. A treatment consisting of daily plasma exchange led to rapid improvement; however, a failed attempt to space out plasma exchanges necessitated the introduction of 4 weekly injections of Rituximab beginning on day 40, which was successful. Indeed, since the second injection of Rituximab on day 51, the number of platelets stabilized at a normal level, thereby allowing for the complete cessation of plasma exchange. At this writing - day 89 - the patient remains in persistent remission. CONCLUSION: Given the different therapeutic and prognostic implications of the 2 types of TTP in child patients, it is mandatory to end at an accurate biological diagnosis: whereas the constitutional form is effectively treated with plasma injections, the acquired form, while initially requiring plasma exchange, often necessitates the use of immunosuppressors during acute or relapse phase. The present study concerns a paediatric case of acquired TTP treated successfully with Rituximab during an acute dependant phase.
Asunto(s)
Púrpura Trombocitopénica Idiopática , Púrpura Trombocitopénica Trombótica , Inducción de Remisión , Adolescente , Factores de Edad , Anticuerpos Monoclonales/administración & dosificación , Anticuerpos Monoclonales/uso terapéutico , Anticuerpos Monoclonales de Origen Murino , Humanos , Factores Inmunológicos/administración & dosificación , Factores Inmunológicos/uso terapéutico , Masculino , Intercambio Plasmático , Púrpura Trombocitopénica Idiopática/diagnóstico , Púrpura Trombocitopénica Idiopática/tratamiento farmacológico , Púrpura Trombocitopénica Idiopática/terapia , Púrpura Trombocitopénica Trombótica/diagnóstico , Púrpura Trombocitopénica Trombótica/tratamiento farmacológico , Púrpura Trombocitopénica Trombótica/terapia , Rituximab , Factores de Tiempo , Resultado del TratamientoRESUMEN
Euglycemic-hyperinsulinemic clamps were performed on 4- and 12-wk-old anesthetized lean and obese Zucker rats. During the clamp studies, total glucose production and utilization were assessed with a 3-[3H]glucose perfusion, whereas local glucose utilization was determined by measuring 2-deoxy-1-[3H]glucose 6-phosphate accumulation in various tissues. In the basal state, 4 wk-old obese rats were hyperinsulinemic (159 +/- 8 vs. 82 +/- 9 microU/ml), whereas glucose turnover rate was similar to that observed in lean rats (14.9 +/- 1.9 vs. 12.5 +/- 1.9 mg X min-1 X kg-1). Glucose utilization was identical in skeletal muscles, whereas it was increased in white adipose tissue of obese rats (22 +/- 4 vs. 8 +/- 2 ng X min-1 X mg-1). At plasma insulin level of 500 microU/ml, glucose production was totally suppressed in both groups, whereas overall glucose utilization was slightly less in 4-wk-old obese than in lean rats. This was due to a reduced stimulation of glucose utilization in skeletal muscles and brown adipose tissue. In contrast, glucose utilization in periovarian white adipose tissue was similarly increased in lean and obese rats. For a maximal insulin concentration (1500 microU/ml), all the differences were abolished between lean and obese young Zucker rats. In older (12-wk-old) obese rats, glucose utilization in various tissues was markedly reduced at maximal insulin level compared with that observed in age-matched lean animals.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Tejido Adiposo Pardo/metabolismo , Tejido Adiposo/metabolismo , Resistencia a la Insulina , Músculos/metabolismo , Obesidad/metabolismo , Tejido Adiposo/efectos de los fármacos , Tejido Adiposo Pardo/efectos de los fármacos , Animales , Femenino , Glucosa/metabolismo , Insulina/sangre , Insulina/farmacología , Hígado/efectos de los fármacos , Hígado/metabolismo , Músculos/efectos de los fármacos , Ratas , Ratas ZuckerRESUMEN
Using as probes the subfragments of the telomeric sequence previously cloned by us from Plasmodium berghei DNA, we identified and cloned a 2.3 kb repeat, largely overlapping the original telomeric insert. Restriction mapping indicated that cloned inserts (2.3 kb in length) represented circularly permutated versions of a rather well conserved repeated element, at least in part organized in tandem. The 2.3 kb repeat family with a copy number of about 300 occupies about 4% of the whole genome. The copies are unevenly distributed among the chromosome-sized molecules revealed by pulsed field gradient electrophoresis. Complete sequence determination of the 2.3 kb element revealed that telomere-related motifs are present with a characteristic pattern in a set of tandem repeats, 27 bp long. The perfect conservation of these motifs as well as the pattern of chromosomal distribution suggest that we are dealing with a specialised structure subject to selective mechanisms of amplification and maintenance.
Asunto(s)
ADN/análisis , Genes , Plasmodium berghei/genética , Secuencias Repetitivas de Ácidos Nucleicos , Animales , Secuencia de Bases , Mapeo Cromosómico , Clonación Molecular , Enzimas de Restricción del ADN , Electroforesis en Gel de Agar , Hibridación de Ácido Nucleico , Homología de Secuencia de Ácido NucleicoRESUMEN
The average length and the interspersion pattern of repetitive DNA sequences in the Plasmodium berghei genome have been studied by electron microscopy. Within the limitations posed by the relatively high genome complexity, analysis of partially renatured total DNA indicates that repetitive sequences do not occupy preferential positions along the genome, but are widely dispersed (one in approx. 8000 base pairs of unique DNA). Structures appearing as loops flanked by inverted repeats are present. Analysis of the repetitive fraction purified by hydroxyapatite chromatography shows that the average length of rapidly reassociating repetitive structures is around 800 base pairs with 90% of the length distribution between 400 and 1400 base pairs. Suitable extraction methods, preserving circularity of extrachromosomal DNA components, allow the detection of molecules which can be identified as mitochondrial DNA, 10.5 +/- 0.4 microns long.
Asunto(s)
ADN/análisis , Plasmodium berghei/genética , Animales , Secuencia de Bases , Cromatografía/métodos , Durapatita , Hidroxiapatitas , Microscopía Electrónica , Mitocondrias/análisisRESUMEN
The basic element of the 2.3 kb repetitive family, present in approximately 300 copies in the Plasmodium berghei genome, contains a bent DNA region. Indications of this given by anomalies in electrophoretic behaviour were confirmed by computational analysis of sequence data.
Asunto(s)
Plasmodium berghei/genética , Animales , Secuencia de Bases , ADN/genética , Datos de Secuencia Molecular , Secuencias Repetitivas de Ácidos NucleicosRESUMEN
A strain of Plasmodium berghei (NK 65) was followed during syringe transmission in mice for over 120 passages after the last complete cycle, while the following parameters were monitored: (a) capacity to infect mosquitoes, inducing oocyst formation; (b) presence in the peripheral blood of morphologically identifiable gametocytes; (c) presence of a repetitive component in the DNA extracted from intraerythrocytic population. The suggestion of a possible role of this component in gametogenesis came from an earlier work (Dore, E., Birago, C., Frontali, C. and Battaglia, P.A. (1980) Mol. Biochem. Parasitol. 1, 199-208). Present results confirm the correlation between proportion of repetitive DNA and infectivity towards mosquitoes with a correlation coefficient r = 0.92-0.07+0.04. A parallel decrease of the two quantities is observed in the course of syringe transmission. A limited number of cloned lines, derived from strain NK 65 at different times during syringe transmission, shared the infectivity properties of the parent strain at the moment of cloning, thus confirming that in the infective stage single asexual parasites from the schizogonic cycle are able to originate the whole cycle. The above arguments and results suggest that differentiation into active gametocytes involves amplification of a portion of the genome.
Asunto(s)
Aedes/parasitología , ADN/genética , Malaria/parasitología , Plasmodium berghei/genética , Animales , Cinética , Ratones , Ratones Endogámicos ICR , Renaturación de Ácido Nucleico , Ratas , Ratas Endogámicas , Secuencias Repetitivas de Ácidos NucleicosRESUMEN
Previous results, relating mosquito infectivity to percentage of repetitive DNA in the genome of Plasmodia, are re-examined in the light of the finding that a parasite line used in the previous studies and classified as Plasmodium berghei NK65, was a mixed infection, where the major component appeared to be Plasmodium yoelii. This conclusion was reached through cloning and isoenzyme typing of different clones. Isoenzyme typing alone is not sufficiently sensitive to reveal contamination amounting to less than 20% in a mixture. Attention is drawn to the risk inherent in work with uncloned lines, where the proportions of species or sub-species present may vary according to line history and gametocyte viability.
Asunto(s)
Culicidae/parasitología , ADN/análisis , Plasmodium/clasificación , Animales , Glucosa-6-Fosfato Isomerasa/análisis , Isoenzimas/análisis , Malaria/parasitología , Malaria/veterinaria , Ratones , Plasmodium/enzimología , Plasmodium/genética , Plasmodium/fisiología , Secuencias Repetitivas de Ácidos Nucleicos , Enfermedades de los Roedores/parasitologíaRESUMEN
The telomeric sequence cloned from Plasmodium berghei (see M. Ponzi et al. (1985) EMBO J. 4, 2991-2995) was tested for species specificity. A telomeric and a subtelomeric fragment of the cloned insert served as separate, labelled probes on pulsed field gradient electrophoretical patterns and on genomic digests from the rodent malarias Plasmodium yoelii, Plasmodium chabaudi and from the human malaria Plasmodium falciparum. Results indicate that the subtelomeric fragment, abundantly represented in two chromosomes of P. berghei, is not present in the other DNA tested, while the telomeric fragment is present in every chromosome-sized molecule in all the species tested. The telomeric location in the other genomes of the sequences homologous to the P. berghei telomeric probe is confirmed by experiments with Bal 31 exonuclease. In all cases, the TaqI site appears to delimit the common telomeric portion.
Asunto(s)
ADN/análisis , Plasmodium berghei/genética , Plasmodium falciparum/genética , Plasmodium/genética , Animales , Mapeo Cromosómico , Enzimas de Restricción del ADN , Electroforesis en Gel de Agar , Genes , Hibridación de Ácido Nucleico , Homología de Secuencia de Ácido Nucleico , Especificidad de la EspecieRESUMEN
Superposition of two unrelated processes, namely terminal reticulocyte differentiation and synchronous plasmodial development, takes place in experimental infections of Plasmodium berghei. The first process is shown to be responsible for the appearance of some discrete restriction bands of host origin when DNA is extracted from leucocyte-free blood containing synchronous parasites at early stages of infection. These discrete DNA fragments cross-hybridize with host cell mitochondrial DNA. Purification steps are suggested to reduce this effect, which might be relevant also in the case of other plasmodial species exhibiting preference for reticulocytes as host cell.
Asunto(s)
ADN Mitocondrial/análisis , Plasmodium berghei/genética , Reticulocitos/análisis , Animales , Southern Blotting , Clonación Molecular , Leucocitos/parasitología , Malaria/diagnóstico , Ratas , Mapeo RestrictivoRESUMEN
Extensive chromosome size polymorphism arises in Plasmodium berghei during in vivo mitotic multiplication. Size differences between homologous chromosomes involve rearrangements occurring in the subtelomeric portions while internal chromosomal regions do not contribute significantly to chromosome size polymorphism. Differences in the copy number of a 2.3-kb subtelomeric repeated unit are shown to correlate with size variations, and in at least one case to account completely for the size difference between two variants of the same chromosome.
Asunto(s)
Cromosomas , Mitosis , Plasmodium berghei/genética , Polimorfismo de Longitud del Fragmento de Restricción , Secuencias Repetitivas de Ácidos Nucleicos , Animales , Southern Blotting , Citometría de Flujo , Cariotipificación , Hibridación de Ácido Nucleico , Plasmodium berghei/citologíaRESUMEN
Intravenous injection of 99mTc-labeled macroaggregated albumin (MAA) followed by lung and whole-body scintigraphy results in data from which magnitude of right-to-left shunting and distribution of pulmonary arterial blood flow can be calculated. This information is useful in assessing the functional capacity of a surgical systemic-pulmonic anastomosis. Malfunctioning anastomoses do not significantly reduce right-to-left shunting and may cause unilateral pulmonary hyperperfusion. However, preferential nuclide accumulation may occur in either lung, regardless of shunt function. Consequently, the degree of right-to-left shunting must be determined to fully assess a surgical anastomosis. This technique also allows for assessment of the reduction of right-to-left shunting after intracardiac repairs of congenital cardiac abnormalities.
Asunto(s)
Cardiopatías Congénitas/cirugía , Circulación Pulmonar , Cintigrafía , Preescolar , Conducto Arterioso Permeable/fisiopatología , Conducto Arterioso Permeable/cirugía , Estudios de Evaluación como Asunto , Femenino , Cardiopatías Congénitas/fisiopatología , Humanos , Lactante , Recién Nacido , Masculino , Cuidados Paliativos , Albúmina Sérica , Tecnecio , Tetralogía de Fallot/fisiopatología , Tetralogía de Fallot/cirugíaRESUMEN
The purpose of this study was to investigate the relationship between cycling peak power (CPP; flywheel inertia included) and the applied braking force (F(B)) on a friction-loaded cycle ergometer in male children, adolescents, and adults. A total of 520 male subjects aged 8-20 yr performed three brief maximal sprints against three F(B): 0.245, 0.491, and 0.736 N x kg(-1) body mass (BM) (corresponding applied loads: 25 [F(B)25], 50 [F(B)50], and 75 [F(B)75] g x kg(-1) BM). For each F(B), peak power (PP) was measured (PP25, PP50 and PP75). For each subject, the highest PP was defined as CPP. Results showed that PP was dependent on F(B). In young adults PP25 underestimated CPP by more than 10%, and consequently, F(B)25 seemed to be too low for this population. However, in children, PP75 underestimated CPP by about 20%. A F(B) of 0.736 N x kg(-1) BM was definitively too high for the pediatric population. Therefore, the optimal F(B), even corrected for BM, was lower in children than in adults. The influence of growth and maturation on the force-generating capacity of the leg muscles may explain this difference. In this study, however, it was shown that the difference between PP50 and CPP was independent of age for the whole population investigated. Consequently, when flywheel inertia is included, one cycling sprint with a F(B) of 0.495 N x kg(-1) BM (corresponding applied load: 50 g x kg(-1) BM) is a feasible method for testing both children, adolescents, or young adults.
Asunto(s)
Ciclismo/fisiología , Tolerancia al Ejercicio/fisiología , Adolescente , Adulto , Factores de Edad , Fenómenos Biomecánicos , Índice de Masa Corporal , Niño , Prueba de Esfuerzo , Humanos , Masculino , Soporte de PesoRESUMEN
Fluidized bed bioreactor with alginate beads may be an alternative to hollow fiber cartridge to host hepatocytes for bioartificial liver purposes. After the bioreactor design and the characterization of fluid mechanics, the present study was aimed at analyzing bi-directional mass transfers of calibrated species between external fluid and empty beads. Static (batch) and dynamic (fluidized bed bioreactor) experimental conditions were analyzed. A simple modelling approach permitted the definition of mass transfer coefficients. The motion of beads within the bioreactor clearly enhanced mass transfer kinetics, but did not alter the amount exchanged. The shear enhanced diffusion coefficient for VitB12 was 20 times higher in the fluidized bed bioreactor than under batch conditions, proving the efficiency of such a device.