Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 61
Filtrar
Mais filtros

País/Região como assunto
País de afiliação
Intervalo de ano de publicação
1.
J Dairy Sci ; 106(11): 7341-7351, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37641291

RESUMO

Restricting milk or milk replacer (MR) fed to dairy calves to 10% of body weight at 12.5% total solids (TS) concentration is a common feeding strategy that promotes early weaning and lowers total feed costs for raising young calves. However, this strategy has been associated with inferior performance and compromised welfare. Because a restricted liquid nutrition plan limits calf growth due to limited supply of nutrients, research on increased supply of nutrients from liquid has shown improved growth, health, and welfare of calves. Nutrient supply may be increased by feeding larger amounts of milk or MR averaging 12.5% TS, or by increasing TS above the usual 12.5% TS by increasing MR TS concentration alone (TS+), or by increasing TS concentration and volume simultaneously (TSV+). The objective of this review is to discuss liquid nutrition plans with greater TS concentration in MR or in milk diets, considering the effects of such strategies on performance and digestive tract development before weaning and the future performance of dairy calves. This review will focus on liquid nutrition plans that are based on increased TS concentration (i.e., TS+ or TSV+); therefore, enhanced liquid nutrition plans based only on increased volumes will not be the discussed. Improved growth rates have been observed in calves fed TSV+ programs. However, reduced starter intake preweaning can also have negative effects on dry matter intake, average daily gain, and digestibility postweaning. Feeding a TS+ program may reduce impairment of starter intake and therefore have positive effects on performance, nutrient digestibility, and health. When considering an accelerated nutrition plan with TS+ or TSV+, it is important to consider osmolality of the liquid diet. Further studies are necessary to confirm this hypothesis and the cost-benefit of alternative liquid nutrition plans, as well as the optimal TS concentration of milk or MR fed to dairy calves.

2.
J Dairy Sci ; 101(1): 201-221, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29103715

RESUMO

The objectives of this experiment were to evaluate the effect of feeding a culture of Saccharomyces cerevisiae on rumen metabolism and digestibility when cows are fed diets varying in starch content. Four lactating Holstein cows were assigned to a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Treatments were low starch (LS; 23% of diet DM) and no yeast culture (YC; LS-control), LS and 15 g of YC/d (LS-YC), high starch (HS; 29% of diet DM) and no YC (HS-control), and HS and 15 g of YC/d (HS-YC). Periods lasted 28 d, with the last 9 d for data collection. Days 20 to 24 were used to determine production, nutrient flow, and digestibility. On d 25, 3 kg of corn grain DM was placed in the rumen 1 h before the morning feeding, and yields of milk and milk components were measured after the challenge. Blood was sampled -1, 3, 7, and 11 h relative to the morning feeding on d 24 and 25. Rumen pH was measured continuously on d 24 and 25. Rumen papillae were collected on d 24 and 28 to quantify mRNA expression of select genes. Supplementing YC increased yields of milk (26.3 vs. 29.6 kg/d), energy-corrected milk (ECM; 26.5 vs. 30.3 kg/d), fat (0.94 vs. 1.08 kg/d), true protein (0.84 vs. 0.96 kg/d), and ECM/dry matter intake (1.15 vs. 1.30) compared with the control but did not affect dry matter intake (22.6 vs. 22.9 kg/d). Cows fed HS had increased milk true protein percentage (3.18 vs. 3.31%) and yield (0.87 vs. 0.94 kg/d) compared with cows fed LS. Feeding HS-YC increased the proportion of dietary N incorporated into milk true protein from 24.9% in the other 3 treatments to 29.6%. Feeding HS increased the concentration of propionate (21.7 vs. 32.3 mM) and reduced that of NH3-N (8.3 vs. 6.7 mg/dL) in rumen fluid compared with the control, and combining HS with YC in HS-YC tended to increase microbial N synthesis compared with LS-YC (275 vs. 322 g/d). Supplementing YC to cows fed HS reduced plasma haptoglobin and rumen lactate concentrations, increased mean rumen pH, reduced the time with pH <6.0, and prevented the decrease in rumen neutral detergent fiber digestion caused by HS. Cows fed HS had less total-tract digestion of organic matter (73.9 vs. 72.4%) because of reduced acid detergent fiber (57.6 vs. 51.7%) and neutral detergent fiber (60.9 vs. 56.7%) digestibility. Production performance after the challenge was similar to that before the challenge, and YC improved yield of ECM. After the challenge, supplementing YC tended to reduce rumen lactate concentration compared with the control and reduced haptoglobin in cows fed HS. Feeding HS but not YC increased expression in rumen papillae of genes for receptors (FFAR2 and FFAR3) and transporter (SLC16A3) of short-chain fatty acids but did not affect genes involved in transport of Na+/H+ or water or in inflammatory response. Supplementing YC to dairy cows improved lactation performance in diets containing low or high starch, and mechanisms might be partially attributed to improvements in rumen pH, digestion of fiber, microbial N synthesis, and reduction in acute phase response.


Assuntos
Bovinos , Dieta/veterinária , Carboidratos da Dieta/administração & dosagem , Suplementos Nutricionais , Digestão/efeitos dos fármacos , Rúmen/fisiologia , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Ácidos Graxos Voláteis/análise , Feminino , Fermentação , Lactação/fisiologia , Leite/química , Proteínas do Leite/análise
3.
J Dairy Sci ; 101(1): 186-200, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29103717

RESUMO

The objectives were to evaluate the effects of a culture of Saccharomyces cerevisiae (YC) on lactation performance of cows fed diets differing in starch content. Fifty-six Holstein cows at 42 d postpartum were blocked by parity and milk production and randomly assigned to 1 of 4 treatments, low starch (23% diet DM) and no YC (LS-control), low starch and 15 g/d of YC (LS-YC), high starch (29% diet DM) and no YC (HS-control), and high starch and 15 g/d of YC (HS-YC). The experiment lasted 14 wk. Blood was sampled twice weekly during the first 5 wk in the experiment. Feeding behavior was evaluated in 2 consecutive days when cows were 33 d in the experiment. On d 92 in the experiment, cows were challenged with 3 kg of corn grain DM immediately before the morning feeding. Blood was sampled in the first 12 h after the challenge. Rumen fluid was collected 5 h after the challenge, and pH, ammonia N, short-chain fatty acids, and lactate concentrations were quantified. Lactation performance was measured daily before and after the challenge. Supplementation with YC increased yields of 3.5% fat-corrected milk and energy-corrected milk by 2.2 and 2.0 kg/d, and the increments were observed in both low- and high-starch diets. Feeding HS tended to decrease milk fat content (LS = 3.88 vs. HS = 3.73%), but increased concentration (LS = 2.87 vs. HS = 3.00%) and yield (LS = 1.11 vs. HS = 1.20 kg/d) of milk true protein. Feeding YC increased yields of fat and true protein in milk by 100 and 60 g/d. Energy balance, body weight, and feed efficiency did not differ with treatments. Feeding HS reduced eating time (LS = 177 vs. HS = 159 min/12 h) and intermeal interval (LS = 103 vs. HS = 82 min), but tended to increase eating rate (LS = 139 vs. HS = 150 g/min). Interactions were detected between level of starch and YC for ruminating time, meal duration, and meal size because within LS, feeding YC increased ruminating time 23 min/12 h, but reduced meal duration 6 min/meal and meal size 0.7 kg/meal. Concentrations of glucose in plasma increased (LS = 62.1 vs. HS = 63.8 mg/dL), whereas those of urea N decreased (LS = 10.1 vs. HS = 9.4 mg/dL) with feeding HS compared with LS in the first 5 wk in the experiment, and the same responses were observed after the challenge with corn grain. After the challenge, rumen pH was less and short-chain fatty acid concentrations were greater in cows fed HS compared with those fed LS; however, supplementing YC to high-starch diets increased rumen pH (HS-control = 5.72 vs. HS-YC = 6.12) and reduced concentrations of lactate in rumen fluid (HS-control = 7.72 vs. HS-YC = 1.33 mM) and haptoglobin in plasma 28%. Feeding YC improved lactation performance irrespective of the level of dietary starch and reduced the risk of subacute rumen acidosis induced by a grain challenge when cows were fed a high-starch ration.


Assuntos
Bovinos/metabolismo , Suplementos Nutricionais/análise , Saccharomyces cerevisiae/metabolismo , Amido/metabolismo , Animais , Peso Corporal , Bovinos/crescimento & desenvolvimento , Dieta/veterinária , Carboidratos da Dieta/metabolismo , Metabolismo Energético/fisiologia , Ácidos Graxos Voláteis/análise , Comportamento Alimentar , Feminino , Lactação , Leite/química , Período Pós-Parto/metabolismo , Gravidez , Rúmen/metabolismo , Amido/análise
4.
J Dairy Sci ; 101(6): 5060-5068, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29525309

RESUMO

The aims of this study were (1) to assess if there is phenotypical divergence for feed efficiency (FE) during the preweaning phase; (2) if FE is correlated with heat production (HP) measured by the face mask method or (3) by surface skin temperature via thermography, and (4) whether these methods are applicable to preweaned calves. Holstein × Gyr heifer calves (n = 36, birth body weight = 32.4 ± 6.6 kg) were enrolled and on trial between 4 and 12 wk of age and were classified into 2 residual feed intake (RFI) and residual body weight gain (RG) groups: high efficiency (HE; RFI, n = 10; and RG, n = 9) and low efficiency (LE; RFI, n = 10; and RG, n = 8). Calves were fed milk (6 L/d) and solid feed (95% starter and 5% chopped Tifton 85 hay, as fed). Growth was monitored weekly and feed intake (milk and solid feed) daily, during the whole period. Gas exchanges (O2 consumption and production of CO2 and CH4) were obtained using a face mask at 45 ± 5 d of age and HP was estimated. Maximum temperatures were measured at 7 sites with an infrared camera at 62 ± 7 d of age. There was divergence in RFI and RG. Respectively, HE and LE calves had RFI of -0.14 and 0.13 kg/d, and RG of 0.05 and -0.07 kg/d. Dry matter intake was 15% lower in HE-RFI compared with LE-RFI, but no differences were observed in average daily weight gain. Within the RG test, no differences were observed in dry matter intake or average daily gain. The HE-RFI calves consumed less O2 (L/d) and produced less CO2 (L/d). Heart rate and HP were lower for HE-RFI calves compared with LE-RFI. Residual feed intake was correlated with HP (r = 0.48), O2 consumption (r = 0.48), CO2 production (r = 0.48), and heart rate (r = 0.40). No differences were observed in HP and gas exchanges between RG groups. Methane production was null in both groups. Eye temperature measured by thermography was 0.5°C greater in HE-RG than LE-RG calves. Differences in skin temperature between HE and LE calves were not observed at the other sites. These results support the hypothesis that calves are divergent for RFI, RG, and FE during preweaning and divergence tests are applicable during this phase. The face mask method described here is a useful tool for estimating differences in HP among phenotypically divergent RFI calves. Eye temperature measured by infrared thermography may have potential to screen phenotypically divergent RG calves.


Assuntos
Bovinos/fisiologia , Termogênese , Ração Animal/análise , Animais , Temperatura Corporal , Dieta/veterinária , Ingestão de Alimentos/fisiologia , Feminino , Frequência Cardíaca , Masculino , Leite/metabolismo , Termografia , Desmame , Aumento de Peso
5.
J Dairy Sci ; 101(1): 767-773, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29103720

RESUMO

The aim of this study was to determine the effect of increasing total solids (TS) in the liquid diet during the preweaning phase on mammary gland development in dairy heifers. The increase in TS was obtained with the addition of milk replacer powder to whole milk. Crossbreed Holstein-Gyr heifers (n = 60) were distributed in 4 treatments with different TS concentrations: 13.5% (n = 15), 16.1% (n = 15), 18.2% (n = 15), and 20.4% (n = 15). The liquid diets were provided from 5 to 55 d of age. From 56 to 59 d of age, the total amount of liquid feed was reduced by half. Heifers were weaned at 60 d and monitored until 90 d of age. Ultrasound mammary gland evaluations were performed weekly between 5 to 11 wk of age, using a B-mode ultrasound equipped with microconvex transducer at a frequency of 6 MHz. In those same weeks, the manual palpation of mammary parenchyma (PAR) was performed. Increased TS concentration of liquid diet during the preweaning period increased body weight of heifers, but did not alter PAR growth and the deposition of adipose tissue in the mammary gland evaluated by ultrasonography. The oval-shaped structure of PAR was altered after 2 mo of age. In the evaluated period, PAR growth was isometric with respect to the body growth rate. Palpation scoring of PAR had a strong correlation with the ultrasound evaluation of the PAR.


Assuntos
Ração Animal/análise , Bovinos/crescimento & desenvolvimento , Glândulas Mamárias Animais/crescimento & desenvolvimento , Leite/metabolismo , Tecido Adiposo/diagnóstico por imagem , Tecido Adiposo/crescimento & desenvolvimento , Animais , Peso Corporal , Bovinos/metabolismo , Dieta/veterinária , Feminino , Glândulas Mamárias Animais/diagnóstico por imagem , Glândulas Mamárias Animais/metabolismo , Leite/química , Tamanho do Órgão , Tecido Parenquimatoso/diagnóstico por imagem , Tecido Parenquimatoso/crescimento & desenvolvimento , Ultrassonografia , Desmame
6.
J Dairy Sci ; 100(11): 8967-8976, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28888607

RESUMO

The aim of this study was to evaluate the effects of increasing the total solids (TS) content of liquid feed, by adding increasing amounts of milk replacer powder to whole milk, on age at puberty and postweaning performance, glucose metabolism, and mammary fat pad of dairy heifers. Crossbreed Holstein × Gyr heifers (n = 58) were distributed into 4 different treatments during the preweaning period. Treatments consisted of liquid feeds with TS content of 12.5 (actual TS = 13.5 ± 0.53%; n = 15), 15.0 (actual TS = 16.1 ± 0.03%; n = 15), 17.5 (actual TS = 18.2 ± 0.14%; n = 13), or 20.0% (actual TS = 20.4 ± 0.24%; n = 15), which were provided up to 59 d old. From 60 to 89 d old, the animals received the same starter offered during the preweaning period in addition to corn silage ad libitum starting at 70 d old. From 90 to 104 d old, the animals were adapted to a total mixed ration. At 105 d old, the animals were distributed in 4 paddocks equipped with electronic feed and water bins and were fed the same total mixed ration ad libitum. A period of adaptation to the electronic feed bins occurred from 105 to 119 d old. Feed and water intake and body weight and body frame development were assessed until puberty. Mammary gland evaluations were performed monthly by ultrasonography from 120 d of age until puberty onset. Puberty onset was determined as plasma progesterone concentration greater than 1 ng/mL in 2 consecutive samples collected 7 d apart. The date of puberty onset was recorded as the collection day of the first of these samples. A glucose tolerance test was performed at 280 d of age. The increased TS content of the liquid feed fed during the preweaning period did not affect dry matter intake, performance, age at puberty, glucose metabolism, or mammary gland fat pad at later stages of rearing process. Conversely, hip width and heart girth increased linearly up to 150 and 240 d of age, respectively, as a result of the increased TS concentration of the liquid feed during the preweaning period.


Assuntos
Ração Animal , Bovinos , Glucose/metabolismo , Leite , Tecido Adiposo/metabolismo , Ração Animal/análise , Animais , Peso Corporal , Metabolismo dos Carboidratos , Indústria de Laticínios , Dieta/veterinária , Feminino , Leite/metabolismo , Reprodução , Silagem , Desmame , Zea mays
7.
J Dairy Sci ; 99(10): 8018-8027, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27474984

RESUMO

The aim of this study was to evaluate the effects on feed intake, heifer performance, and health of increasing the total solids (TS) content of liquid feed (whole milk) by adding increasing amounts of milk replacer powder during the pre- and postweaning periods. Crossbred Holstein-Gyr heifers (n=60) were assigned to 1 of 4 treatments (n=15 per group), which consisted of different TS concentrations: 12.5, 15.0, 17.5, and 20.0% of liquid feed. Heifers received 6 L of liquid feed per day, divided into 2 equal meals (0800 and 1600h) and provided in buckets, from 5 to 55d of age. From 56 to 59d of age, the total amount of liquid feed was reduced by half, maintaining only morning feedings. Heifers were weaned at 60d and monitored until 90d of age. Water and starter were provided ad libitum during the entire experiment. Corn silage was included in the diet during the postweaning period (70d of age). Feed intake and health scores were evaluated daily. Body weight and body frame development were recorded weekly. Starting at 14d, ruminal pH was measured every other week. Laboratory analysis determined that the actual TS contents of the liquid feed were 13.5, 16.1, 18.2, and 20.4%, for the proposed 12.5, 15.0, 17.5, and 20.0% TS treatments, respectively. The osmolality of liquid feed treatments was 265 to 533mOsm/L. Intake of liquid feed was similar among treatments from 4wk of age. During the preweaning period, starter intake, fecal score, and days with diarrhea were similar among treatments. Ruminal pH at weaning averaged 6.2 and was similar among treatments. Increasing concentrations of TS in the liquid feed were associated with linear increases in average daily gain, final body weight, and growth performance, but linear decreases in feed efficiency. During the postweaning period, intake of starter, corn silage, and water were similar among treatments, as well as average daily gain and feed efficiency. Final body weight and growth performance during the postweaning period also increased linearly with concentration of TS in liquid feed. Increasing the concentration of TS in liquid feed up to 20.4% increased performance and body frame development in dairy heifers during the pre- and postweaning periods and had no effects on solid feed intake or health.


Assuntos
Ração Animal , Leite/química , Animais , Peso Corporal , Bovinos , Dieta/veterinária , Feminino , Desmame
8.
J Dairy Sci ; 99(11): 8746-8758, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27592428

RESUMO

The aim of this study was to evaluate the effects on feed intake, calf performance, feed efficiency, fecal score, passage rate, apparent nutrient digestibility, development of rumen and other organs, and body composition of increasing the total solids content of liquid feed (whole milk) by adding increasing amounts of milk replacer powder during the preweaning period. Crossbred Holstein-Gyr calves (n=32) were assigned to 1 of 4 treatments (n=8 per group), which consisted of different total solids concentrations: 12.5, 15.0, 17.5, and 20.0% of liquid feed. Calves received 6 L of liquid per day, divided into 2 equal meals (0800 and 1600 h) and provided in buckets, from 5 to 55d of age. Starter and water were provided ad libitum during the entire experiment. At 56d of age, animals were killed. Laboratory analysis determined that the actual total solids contents of the liquid feed were 13.5, 16.1, 18.2, and 20.4%, for the proposed 12.5, 15.0, 17.5, and 20.0% total solids treatments, respectively. The osmolality of liquid feed treatments was 265 to 533 mOsm/L. Fecal score was similar among treatments, except for wk 2 and 7. Intake of liquid feed was similar among treatments from 6wk of age. During wk 4, 5, and 6, we detected a linear decrease in starter intake. After wk 7, we observed greater starter intake for calves fed approximately 16.1% total solids. Water intake, feed efficiency, and withers height were similar among treatments. Increasing concentrations of total solids in liquid feed quadratically affected average daily gain, final body weight, and empty body weight. We observed a greater average daily gain for calves fed approximately 20.4% total solids. Passage rate, nutrient digestibility, development of pre-stomachs and intestine, and body composition were similar among treatments. Increasing the concentration of total solids in liquid feed up to 20.4% reduced starter intake between 4 and 6wk of life, but increased average daily gain. It did not affect passage rate, nutrient digestibility, ruminal and organ development, or body composition in calves during the preweaning period, indicating that this strategy may be a viable alternative for feeding without increasing the total volume of liquid feed provided to dairy calves.


Assuntos
Ração Animal , Leite , Animais , Composição Corporal , Bovinos , Dieta/veterinária , Desmame
9.
BMC Cancer ; 15: 807, 2015 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-26503030

RESUMO

BACKGROUND: Malignant melanoma is an aggressive type of skin cancer, and despite recent advances in treatment, the survival rate of the metastatic form remains low. Nifuroxazide analogues are drugs based on the substitution of the nitrofuran group by benzofuroxan, in view of the pharmacophore similarity of the nitro group, improving bioavailability, with higher intrinsic activity and less toxicity. Benzofuroxan activity involves the intracellular production of free-radical species. In the present work, we evaluated the antitumor effects of different benzofuroxan derivatives in a murine melanoma model. METHODS: B16F10-Nex2 melanoma cells were used to investigate the antitumor effects of Benzofuroxan derivatives in vitro and in a syngeneic melanoma model in C57Bl/6 mice. Cytotoxicity, morphological changes and reactive oxygen species (ROS) were assessed by a diphenyltetrasolium reagent, optical and fluorescence microscopy, respectively. Annexin-V binding and mitochondrial integrity were analyzed by flow cytometry. Western blotting and colorimetry identified cell signaling proteins. RESULTS: Benzofuroxan N-Br and N-I derivatives were active against murine and human tumor cell lines, exerting significant protection against metastatic melanoma in a syngeneic model. N-Br and N-I induce apoptosis in melanoma cells, evidenced by specific morphological changes, DNA condensation and degradation, and phosphatidylserine translocation in the plasma membrane. The intrinsic mitochondrial pathway in B16F10-Nex2 cells is suggested owing to reduced outer membrane potential in mitochondria, followed by caspase -9, -3 activation and cleavage of PARP. The cytotoxicity of N-Br and N-I in B16F10-Nex2 cells is mediated by the generation of ROS, inhibited by pre-incubation of the cells with N-acetylcysteine (NAC). The induction of ROS by N-Br and N-I resulted in the inhibition of AKT activation, an important molecule related to tumor cell survival, followed by upregulation of BIM. CONCLUSION: We conclude that N-Br and N-I are promising agents aiming at cancer treatment. They may be useful in melanoma therapy as inducers of intrinsic apoptosis and by exerting significant antitumor activity against metastatic melanoma, as presently shown in syngeneic mice.


Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Apoptose/efeitos dos fármacos , Benzoxazóis/química , Benzoxazóis/uso terapêutico , Melanoma Experimental/metabolismo , Proteínas de Membrana/metabolismo , Proteína Oncogênica v-akt/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Apoptose/fisiologia , Proteínas Reguladoras de Apoptose/antagonistas & inibidores , Proteína 11 Semelhante a Bcl-2 , Benzoxazóis/farmacologia , Linhagem Celular Tumoral , Células HeLa , Humanos , Masculino , Melanoma Experimental/tratamento farmacológico , Proteínas de Membrana/antagonistas & inibidores , Camundongos , Camundongos Endogâmicos C57BL , Proteína Oncogênica v-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia
10.
Braz J Med Biol Res ; 57: e13102, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38451607

RESUMO

The present study investigated the reliability and sensitivity of a wearable near-infrared spectroscopy (wNIRS) device in moderate and heavy exercise intensity domains. On three separate days, eleven males performed an incremental test to exhaustion, and in the following visits, four submaximal constant-load bouts (i.e., test and retest) were performed in the moderate-intensity domain (100 and 130 W) and heavy-intensity domain (160 and 190 W). The local tissue oxygen saturation index (SmO2) and pulmonary oxygen uptake (V̇O2) were measured continuously. The absolute SmO2 and V̇O2 values and the change (Δ) from the 3rd to 6th min of exercise were calculated. There was good reliability for SmO2 measurements, as indicated by the high intraclass correlation coefficient analysis (ICC ≥0.84 for all) and low coefficient of variation between the two trials (CV ≤4.1% for all). Steady-state responses were observed for SmO2 and V̇O2 from the 3rd to the 6th min in the two moderate-intensity bouts (P>0.05), whereas SmO2 decreased and V̇O2 increased from the 3rd to the 6th min in the two heavy-intensity bouts (P<0.05). Together, these findings suggested that the SmO2 measured with a wNIRS device is reliable and sensitive to track local metabolic changes provoked by slight increments in exercise intensity.


Assuntos
Espectroscopia de Luz Próxima ao Infravermelho , Dispositivos Eletrônicos Vestíveis , Masculino , Humanos , Reprodutibilidade dos Testes , Terapia por Exercício , Exercício Físico
11.
Braz J Med Biol Res ; 55: e11901, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35239783

RESUMO

We examined whether endurance performance and neuromuscular fatigue would be affected by caffeine ingestion during closed- and open-loop exercises. Nine cyclists performed a closed-loop (4,000-m cycling time trial) and an open-loop exercise (work rate fixed at mean power of the closed-loop trial) 60 min after ingesting caffeine (CAF, 5 mg/kg) or placebo (PLA, cellulose). Central and peripheral fatigue was quantified via pre- to post-exercise decrease in quadriceps voluntary activation and potentiated twitch force, respectively. Test sensitivity for detecting caffeine-induced improvements in exercise performance was calculated as the mean change in time divided by the error of measurement. Caffeine ingestion reduced the time of the closed-loop trial (PLA: 375.1±14.5 s vs CAF: 368.2±14.9 s, P=0.024) and increased exercise tolerance during the open-loop trial (PLA: 418.2±99.5 s vs CAF: 552.5±106.5 s, P=0.001), with similar calculated sensitivity indices (1.5, 90%CI: 0.7-2.9 vs 2.8, 90%CI: 1.9-5.1). The reduction in voluntary activation was more pronounced (P=0.019) in open- (-6.8±8.3%) than in closed-loop exercises (-1.9±4.4%), but there was no difference between open- and closed-loop exercises for the potentiated twitch force reduction (-25.6±12.8 vs -26.6±12.0%, P>0.05). Caffeine had no effect on central and peripheral fatigue development in either mode of exercise. In conclusion, caffeine improved endurance performance in both modes of exercise without influence on post-exercise central and peripheral fatigue, with the open-loop exercise imposing a greater challenge to central fatigue tolerance.


Assuntos
Ciclismo , Cafeína , Método Duplo-Cego , Exercício Físico/fisiologia , Terapia por Exercício , Humanos , Músculo Quadríceps
12.
Braz J Med Biol Res ; 54(5): e10693, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33729393

RESUMO

The present study compared the effects of a footwear designed to enhance energy return (thermoplastic polyurethane, TPU) vs minimalist shoes on running economy (RE) and endurance performance. In this counterbalanced and crossover design study, 11 recreational male runners performed two submaximal constant-speed running tests and two 3-km time-trials with the two shoe models. Oxygen uptake was measured during submaximal constant-speed running tests in order to determine the RE at 12 km/h and oxygen cost of running (CTO2) at individual average speed sustained during the 3-km running time-trials wearing either of the two shoes. Our results revealed that RE was improved (2.4%) with TPU shoes compared with minimalist shoes (P=0.01). However, there was no significant difference for CTO2 (P=0.61) and running performance (P=0.52) comparing the TPU (710±60 s) and the minimalist (718±63 s) shoe models. These novel findings demonstrate that shoes with enhanced mechanical energy return (i.e. TPU) produced a lower energy cost of running at low (i.e., 12 km/h) but not at high speeds (i.e., average speed sustained during the 3-km running time-trial, ∼15 km/h), ultimately resulting in similar running performance compared to the minimalist shoe.


Assuntos
Corrida , Fenômenos Biomecânicos , Estudos Cross-Over , Masculino , Consumo de Oxigênio , Sapatos
13.
Amino Acids ; 39(4): 979-89, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20373119

RESUMO

Forty-five years ago, a paper published by Mertz et al. (Science 145:279-280, 1964) initiated a revolution in the history of plant protein quality and affected dramatically the study of cereal crop storage proteins. The observation of the high lysine content of the endosperm of the opaque-2 (o2) maize mutant was a key factor in bringing about a new concept in the production of cereal seeds with a high nutritional value. It has been a long and very interesting road with astonishing results over these 45 years. We are now probably about to see the release of commercially engineered high-lysine maize lines. We have decided to pinpoint some key contributions to the science behind high-lysine plants and concentrated on the research done on maize, which is possibly the most complete and simple example to illustrate the advances achieved. However, studies on other plant species such as barley and model species such as tobacco are totally relevant and will be briefly addressed.


Assuntos
Lisina/metabolismo , Proteínas de Armazenamento de Sementes/biossíntese , Zea mays/genética , Zea mays/metabolismo , Ácido Aspártico/metabolismo , Produtos Agrícolas , Grão Comestível , Hordeum/metabolismo , Redes e Vias Metabólicas , Valor Nutritivo , Plantas Geneticamente Modificadas , Sementes/genética , Sementes/metabolismo
14.
Acta Paediatr ; 99(8): 1218-23, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20298493

RESUMO

BACKGROUND: Age, developmental stage and gender are risk factors for paediatric non-alcoholic fatty liver disease (NAFLD). AIMS: The aim of this study was to identify differences in clinical or laboratory variables between sexes in adolescents with NAFLD. METHODOLOGY: Ninety obese adolescents including 36 males and 54 females were evaluated. Inclusion criteria for this study were a Body Mass Index above the 95th percentile, as set forth by the National Center for Health Statistics, and an age of 10-19 years. A clinical and laboratory evaluation was conducted for all adolescents. RESULTS: The variables that were found to be predictive of NAFLD in adolescence were visceral fat, Aminotransferase, Gamma-Glutamyl Transferase, triglyderides, cholesterol and LDL-cholesterol. We also observed that cholesterol and LDL-cholesterol variables were influenced by gender, i.e. there was a significant statistical difference in the values of these variables between male and female adolescents. With regard to cholesterol serum concentrations, the risk was 6.99 times greater for females, compared with 1.2 times for males; and for LDL-cholesterol serum concentrations the risk was 8.15 times greater for females, compared with and 1.26 times for males. CONCLUSION: Female adolescents with NAFLD showed a significantly different metabolic behaviour than males.


Assuntos
Fígado Gorduroso/epidemiologia , Fígado Gorduroso/metabolismo , Obesidade/complicações , Fatores Sexuais , Adolescente , Antropometria , Composição Corporal , Brasil/epidemiologia , Criança , Colesterol/sangue , Fígado Gorduroso/diagnóstico por imagem , Feminino , Humanos , Masculino , Obesidade/metabolismo , Valor Preditivo dos Testes , Prevalência , Fatores de Risco , Ultrassonografia , Adulto Jovem
15.
Fungal Biol ; 124(12): 1039-1051, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33213784

RESUMO

The fungal pathogen Sporisorium scitamineum causes sugarcane smut disease. We have previously shown that resistant sugarcane plants induce ROS, coinciding with a delay in fungal colonization. Here, we investigated whether the fungus modifies the enzymatic antioxidant system in vitro and when colonizing sugarcane tissues in response to ROS. In vitro, the exposure to ROS did not affect cell integrity, and a combination of superoxide dismutases (SOD) and catalases (CAT) were active. In vitro, the fungus did not alter the expression of the transcriptional regulator Yap1 and the effector Pep1. The fungus activated distinct enzymes when colonizing plant tissues. Instead of CAT, S. scitamineum induced glutathione peroxidase (Gpx) expression only when colonizing smut-resistant plants. Yap1 had an earlier expression in both smut-susceptible and -resistant plants, with no apparent correlation with the expression of antioxidant genes sod, cat, gpx, or external redox imbalance. The expression of the effector pep1 was induced only in smut-resistant plants, potentially in response to ROS. These results collectively suggest that S. scitamineum copes with oxidative stress by inducing different mechanisms depending on the conditions (in vitro/in planta) and intensity of ROS. Moreover, the effector Pep1 is responsive to the stress imposed only by the sugarcane resistant genotype.


Assuntos
Basidiomycota , Doenças das Plantas/microbiologia , Espécies Reativas de Oxigênio , Saccharum , Basidiomycota/enzimologia , Basidiomycota/genética , Regulação da Expressão Gênica de Plantas , Espécies Reativas de Oxigênio/metabolismo , Saccharum/microbiologia
16.
Braz. j. med. biol. res ; 57: e13102, fev.2024. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1534066

RESUMO

The present study investigated the reliability and sensitivity of a wearable near-infrared spectroscopy (wNIRS) device in moderate and heavy exercise intensity domains. On three separate days, eleven males performed an incremental test to exhaustion, and in the following visits, four submaximal constant-load bouts (i.e., test and retest) were performed in the moderate-intensity domain (100 and 130 W) and heavy-intensity domain (160 and 190 W). The local tissue oxygen saturation index (SmO2) and pulmonary oxygen uptake (V̇O2) were measured continuously. The absolute SmO2 and V̇O2 values and the change (Δ) from the 3rd to 6th min of exercise were calculated. There was good reliability for SmO2 measurements, as indicated by the high intraclass correlation coefficient analysis (ICC ≥0.84 for all) and low coefficient of variation between the two trials (CV ≤4.1% for all). Steady-state responses were observed for SmO2 and V̇O2 from the 3rd to the 6th min in the two moderate-intensity bouts (P>0.05), whereas SmO2 decreased and V̇O2 increased from the 3rd to the 6th min in the two heavy-intensity bouts (P<0.05). Together, these findings suggested that the SmO2 measured with a wNIRS device is reliable and sensitive to track local metabolic changes provoked by slight increments in exercise intensity.

17.
Transplant Proc ; 50(10): 3513-3515, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30586838

RESUMO

PURPOSE: Biliary atresia (BA) is the main indication for pediatric liver transplantation. The aim of this study is to correlate aspects of histological examinations of diagnostic hepatic biopsies for BA with the patients' clinical progression and successful addition to the liver transplant waitlist. METHODS: This was a retrospective study of all 108 BA cases treated at the Federal University of São Paulo (1998-2015). Demographic and clinical data were correlated with histological findings. A logistic regression was used for outcome analysis, while the Kaplan-Meier method was applied for survival analysis. RESULTS: There were 108 patients with BA, 68.5% of whom underwent Kasai surgery. Patients added to the transplant waitlist tended to undergo Kasai surgery at a later time (P = .035). Periductal lymphocytic infiltrate was correlated with the addition to the transplant waitlist, with an odds ratio of 3.92 (P = .033). Patients who developed ascites after surgery were more frequently added to the transplant waitlist (P = .05). CONCLUSION: Patients added to the transplant waitlist underwent Kasai surgery later than other patients. Periductal lymphocytic infiltrate in the diagnostic hepatic biopsy and ascites after Kasai surgery were associated with an increased likelihood of addition to the transplant waitlist.


Assuntos
Atresia Biliar/imunologia , Atresia Biliar/patologia , Transplante de Fígado/métodos , Seleção de Pacientes , Listas de Espera , Ductos Biliares/imunologia , Ductos Biliares/patologia , Atresia Biliar/cirurgia , Biópsia , Pré-Escolar , Progressão da Doença , Feminino , Humanos , Lactente , Estimativa de Kaplan-Meier , Fígado/imunologia , Fígado/patologia , Modelos Logísticos , Linfócitos/imunologia , Masculino , Infiltração de Neutrófilos , Razão de Chances , Estudos Retrospectivos , Resultado do Tratamento
18.
Artigo em Inglês | MEDLINE | ID: mdl-17137817

RESUMO

Glycosaminoglycans from the ventral and dorsal integuments of the anuran Bufo ictericus were characterized based on biochemical and histochemical methods. Dermatan sulfate is the major metachromatic glycosaminoglycan found in these tissues, but small amount of heparan sulfate was also detected. The average molecular mass of the dermatan sulfate is approximately 20 kDa, similar to the glycosaminoglycan isolated from mammalian skin. In addition, the amphibian integument contains high amounts of hyaluronic acid, especially in the ventral area. We also observed that the glycosaminoglycans occur in the anuran integument as irregular deposits through the spongious dermis and in the mast cells, as revealed by histochemical analysis using Alcian blue, dimethylmethylene blue and toluidine blue stains. The concentration and composition of glycosaminoglycans found in the amphibian integument resemble those from mammalian skin except for the higher concentration of hyaluronic acid in the amphibian tissue. Possibly, this observation indicates that the function of the sulfated glycosaminoglycan in these tissues has been preserved during evolution, although the amphibian integument and the human skin have their own particular physiology.


Assuntos
Bufonidae , Dermatan Sulfato/análise , Glicosaminoglicanos/análise , Pele/química , Animais , Dermatan Sulfato/química , Eletroforese em Gel de Poliacrilamida , Glicosaminoglicanos/química , Ácido Hialurônico/análise , Ácido Hialurônico/química , Masculino , Peso Molecular
19.
Cell Prolif ; 50(4)2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28618452

RESUMO

OBJECTIVES: The reprogramming of cancer cells into induced pluripotent stem cells or less aggressive cancer cells can provide a modern platform to study cancer-related genes and their interactions with cell environment before and after reprogramming. Herein, we aimed to investigate the reprogramming capacity of murine melanoma B16F10 cells. MATERIALS AND METHODS: The B16F10 was transfected using non-viral circular DNA plasmid containing the genes Sox-2, Oct4, Nanog, Lin28 and green fluorescent protein (GFP). These cells were characterized by immunofluorescence, analysis RT-PCR and cell cycle. RESULTS: Our results demonstrated for the first time that reprogramming of B16F10 may be induced using non-viral minicircle DNA containing the four reprogramming factors Oct4, Sox2, Lin 28, Nanog (OSLN) and the GFP reporter gene. The resulting clones are composed by epithelioid cells. These cells display characteristics of cancer stem cells, thus expressing pluripotent stem cell markers and dividing asymmetrically and symmetrically. Reprogrammed B16F10 cells did not form teratomas; however, they showed the suppression of tumourigenic abilities characterized by a reduced tumour size, when compared with parental B16F10 cell line. In contrast to parental cell line that showed accumulation of the cells in S phase of cell cycle, the cells of reprogrammed clones are accumulated in G1 phase. Long-term cultivation of reprogrammed B16F10 cells induces regression of their reprogramming. CONCLUSIONS: Our data imply that in result of reprogramming of B16F10 cells less aggressive Murine Melanoma Reprogrammed Cancer Cells may be obtained. These cells represent an interesting model to study mechanism of cells malignancy as well as provide a novel tool for anti-cancer drugs screening.


Assuntos
Reprogramação Celular , Vetores Genéticos/metabolismo , Melanoma Experimental/patologia , Animais , Linhagem Celular Tumoral , Pontos de Checagem da Fase G1 do Ciclo Celular , Vetores Genéticos/genética , Proteínas de Fluorescência Verde/genética , Melanoma Experimental/metabolismo , Camundongos , Microscopia de Fluorescência , Proteína Homeobox Nanog/genética , Fator 3 de Transcrição de Octâmero/genética , Células-Tronco Pluripotentes/citologia , Células-Tronco Pluripotentes/metabolismo , Proteínas de Ligação a RNA/genética , Fatores de Transcrição SOXB1/genética
20.
Braz. j. med. biol. res ; 55: e11901, 2022. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1364554

RESUMO

We examined whether endurance performance and neuromuscular fatigue would be affected by caffeine ingestion during closed- and open-loop exercises. Nine cyclists performed a closed-loop (4,000-m cycling time trial) and an open-loop exercise (work rate fixed at mean power of the closed-loop trial) 60 min after ingesting caffeine (CAF, 5 mg/kg) or placebo (PLA, cellulose). Central and peripheral fatigue was quantified via pre- to post-exercise decrease in quadriceps voluntary activation and potentiated twitch force, respectively. Test sensitivity for detecting caffeine-induced improvements in exercise performance was calculated as the mean change in time divided by the error of measurement. Caffeine ingestion reduced the time of the closed-loop trial (PLA: 375.1±14.5 s vs CAF: 368.2±14.9 s, P=0.024) and increased exercise tolerance during the open-loop trial (PLA: 418.2±99.5 s vs CAF: 552.5±106.5 s, P=0.001), with similar calculated sensitivity indices (1.5, 90%CI: 0.7-2.9 vs 2.8, 90%CI: 1.9-5.1). The reduction in voluntary activation was more pronounced (P=0.019) in open- (-6.8±8.3%) than in closed-loop exercises (-1.9±4.4%), but there was no difference between open- and closed-loop exercises for the potentiated twitch force reduction (-25.6±12.8 vs -26.6±12.0%, P>0.05). Caffeine had no effect on central and peripheral fatigue development in either mode of exercise. In conclusion, caffeine improved endurance performance in both modes of exercise without influence on post-exercise central and peripheral fatigue, with the open-loop exercise imposing a greater challenge to central fatigue tolerance.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA