RESUMO
Black auroras are small-scale features embedded in the diffuse background aurora, typically occurring post-substorm after magnetic midnight and with an eastward drift imposed. Black auroras show a significant reduction in optical brightness compared to the surrounding diffuse aurora, and can appear as slow-moving arcs or rapidly-moving patches and arc segments. We report, for the first time, an even more elusive small-scale optical structure that has always been observed occurring paired with [Formula: see text] 10% of black aurora patches. A patch or arc segment of enhanced luminosity, distinctly brighter than the diffuse background, which we name the anti-black aurora, may appear adjacent to the black aurora. The anti-black aurora is of similar shape and size, and always moves in parallel to the drifting black aurora, although it may suddenly switch sides for no apparent reason. The paired phenomenon always drifts with the same average speed in an easterly direction. From the first dual-wavelength (427.8 nm and 844.6 nm) optical observations of the phenomenon recorded on 12 March 2016 outside Tromsø Norway, we show that the anti-black and black auroras have a higher and lower mean energy, respectively, of the precipitating electrons compared to the diffuse background.
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Chemical pollution was monitored and assessed along the Swedish west coast. 62 of 172 analyzed organic chemicals were detected in the water phase of at least one of five monitored sites. A Concentration Addition based screening-level risk assessment indicates that all sites are put at risk from chemical contamination, with total risk quotients between 2 and 9. Only at one site did none of the individual chemicals exceeded its corresponding environmental threshold (PNEC, EQS). The monitoring data thus demonstrate a widespread blanket of diffuse pollution, with no clear trends among sites. Further issues critical for the environmental chemical risk assessment include the challenges to achieve sufficiently low levels of detection, especially for hormones and cypermethrin (a pyrethroid insecticide), the appropriate consideration of non-detects and the limited availability of reliable PNECs and EQS values.
Assuntos
Monitoramento Ambiental , Poluentes Químicos da Água/análise , Meio Ambiente , Compostos Orgânicos , SuéciaRESUMO
The objective of the study was to investigate whether specific single nucleotide polymorphisms (SNPs) with influence on drug transport, biotransformation and repair mechanisms are associated with treatment outcome and toxicity in metastatic colorectal cancer (mCRC). We genotyped blood samples from 519 mCRC patients treated with first-line 5-fluorouracil and oxaliplatin +/- cetuximab for 17 SNPs in 10 genes involved in membrane transport (ABCC1 and ABCC2), drug biotransformation (GSTP1 and AGXT) and DNA repair (ERCC1, ERCC2, XRCC1, XRCC3, XPG and MSH6). The AGXT-rs34116584 and the ERCC2-rs238406 polymorphisms were significantly associated with progression-free survival (P=0.002 and P=0.001, respectively). Associations between 18 toxicity variables and SNPs were identified, although none were significant after Bonferroni correction for multiple comparisons. The study identified SNPs of potential use as markers of clinical outcome in oxaliplatin-treated mCRC patients. If validated in other studies, they could improve the selection of therapy in mCRC.
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Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Biomarcadores Tumorais/genética , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Fluoruracila/uso terapêutico , Compostos Organoplatínicos/uso terapêutico , Variantes Farmacogenômicos/genética , Polimorfismo de Nucleotídeo Único , Transaminases/genética , Proteína Grupo D do Xeroderma Pigmentoso/genética , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Ensaios Clínicos Fase III como Assunto , Neoplasias Colorretais/mortalidade , Neoplasias Colorretais/patologia , Intervalo Livre de Doença , Feminino , Fluoruracila/efeitos adversos , Estudos de Associação Genética , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Proteína 2 Associada à Farmacorresistência Múltipla , Metástase Neoplásica , Compostos Organoplatínicos/efeitos adversos , Oxaliplatina , Fenótipo , Ensaios Clínicos Controlados Aleatórios como Assunto , Estudos Retrospectivos , Fatores de Risco , Países Escandinavos e Nórdicos , Fatores de Tempo , Resultado do Tratamento , Adulto JovemRESUMO
This study aimed to compare the response of performance-matched black and white runners during maximal and sub-maximal running in normoxic and hypoxic conditions. 14 well-trained runners (8 black, 6 white) performed 2 incremental maximal exercise tests and 2 fatigue resistance tests at 21% O2 (normoxia) or 14% O2 (hypoxia). Respiratory parameters, heart rate (HR), lactate concentration ([La(-)]) as well as arterial saturation (SpO2) were measured. Enzyme activities and myosin heavy chain content (MHC) were also measured. White runners reached a significantly greater peak treadmill speed and a higher HRmax than black runners in hypoxia (p<0.05). Additionally, White runners achieved a greater time to fatigue than black runners (p<0.05), with black runners displaying a greater decline in performance in hypoxia compared to normoxia (20.3% vs. 13.4%, black vs. white, respectively). However, black runners presented lower [La(-)] and higher SpO2 than white runners in hypoxia (p<0.05). Black runners had a higher proportion of MHC IIa and higher lactate dehydrogenase activity (p<0.05). The greater performance impairment observed in black runners in hypoxia suggests a greater performance sensitivity to this condition, despite the maintenance of physiological variables such as SpO2 and [La (-) ] within a smaller range than white runners.
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População Negra , Hipóxia/fisiopatologia , Resistência Física/fisiologia , Corrida/fisiologia , População Branca , Adulto , Antropometria , Teste de Esforço , Fadiga/fisiopatologia , Frequência Cardíaca , Humanos , Ácido Láctico/sangue , Masculino , Músculo Esquelético/enzimologia , Cadeias Pesadas de Miosina/metabolismo , Oxigênio/sangue , Consumo de Oxigênio/fisiologia , Respiração , Adulto JovemRESUMO
The aim of this study was to, from a holistic perspective, describe the effects of a forage-only feeding system and a conventional training program on young Standardbred horses and compare data with similar observations from the literature. Sixteen Standardbred colts fed a forage-only diet for 4 months from breaking (August to December) and with the goal to vigorously trot 5 to 7 km at a speed of 5.6 m/s (3 min/km) were studied. The horses were fed grass haylage (56 to 61% dry matter (DM), 2.80 to 3.02 Mcal DE/kg DM and 130 to 152 g CP/kg DM) ad libitum, 1 kg of a lucerne product and minerals. The amount of training and number of training sessions were documented daily, and feed intake and body development were measured once every month. Heart rate (HR) was measured during and after a standardized exercise test in October and December. In December, a postexercise venous blood sample was collected and analyzed for plasma lactate concentration. Muscle biopsies (m. gluteus medius) were taken and analyzed for glycogen and fiber composition. Health was assessed in October and November by an independent veterinarian using a standardized health scoring protocol. BW and height at withers increased from 402 to 453 kg (root mean square error (RMSE) 6) and from 148.7 to 154.1 cm (RMSE 0.7), respectively, and the body condition score was 4.9 (RMSE 0.2) at the end of the study. Muscle glycogen content was 532 mmol/kg dry weight (s.d. 56). There was a significant decrease in postexercise HR (81 v. 73 bpm, RMSE 8), and the individual amount of training was negatively correlated with HR during and after exercise. Health scores were high and similar at both assessments (8.4 and 8.4 (RMSE 1.0) out of 10; P > 0.05), and the number of lost training days per month due to health problems was <0.9, with the exception of November (5.3 days). It is concluded that yearlings in training fed high-energy forage ad libitum can reach a conventional training goal and grow at least as well as earlier observations on yearlings of other light breeds.
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Dieta/veterinária , Cavalos/crescimento & desenvolvimento , Cavalos/fisiologia , Condicionamento Físico Animal/fisiologia , Poaceae/química , Silagem/análise , Envelhecimento , Fenômenos Fisiológicos da Nutrição Animal , Animais , Ingestão de Alimentos , Frequência Cardíaca , Ácido Láctico/sangue , Masculino , Músculo EsqueléticoRESUMO
Several factors determine overall outcome and possible local recurrence after curative surgery for rectal carcinoma. Surgical performance is usually believed to be the most pertinent factor, followed by adjuvant oncological treatment and tumor histopathology. However, chromosomal instability is common in colorectal cancer and tumor clones are assumed to differ in aggressiveness and potential of causing local recurrence. The aim of this study was, therefore, to evaluate if genetic alterations in primary rectal carcinoma are predictive of local recurrences. A large clinical database with linked bio-bank allowed for careful matching of two patient groups (R0) resected for rectal carcinoma. One group had developed early, isolated local recurrences and the other group seemed cured after 93 months follow-up. DNA from the primary tumors was analysed with array-CGH (comparative genomic hybridization) including 55,000 genomic probes. DNA from all primary tumors in both groups displayed previously reported and well-recognised DNA aberrations in colorectal carcinoma. Significant copy number gains were confirmed in the 4q31.1-31.22 region in DNA from tumors with subsequent local recurrence. Twenty-two affected genes in this region code for products with high relevance in tumor biology (p53 regulation, cell cycle activity, transcription). DNA from rectal carcinoma displayed well-known aberrations as described for colon carcinoma with no obvious prediction of local rectal recurrence. Gains in the 4q31.1-31.22 DNA region are highly potential for local recurrence despite R0 resection to be confirmed in larger patient materials.
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Instabilidade Cromossômica/genética , Hibridização Genômica Comparativa , Recidiva Local de Neoplasia/genética , Neoplasias Retais/genética , Cromossomos Humanos Par 4/genética , Variações do Número de Cópias de DNA/genética , Feminino , Genoma Humano , Humanos , Masculino , Recidiva Local de Neoplasia/patologia , Estadiamento de Neoplasias , Neoplasias Retais/patologiaRESUMO
AIM: Local recurrence is an important endpoint of rectal cancer treatment, but details of this form of treatment failure are less well described. The aim of this study was to acquire deeper knowledge of local recurrence regarding symptoms, diagnostic work-up, clinical management, health-care utilization and outcome. METHOD: Of 671 patients with rectal cancer, 57 were diagnosed with local recurrence within 5 years after surgery. Their records were analysed. RESULTS: At diagnosis of local recurrence 49 (86%) of 57 patients were symptomatic and 40 (70%) were diagnosed between scheduled follow-up visits. The predominant symptom was pain. Forty-five of the 57 (79%) had a palpable tumour. Most were deemed incurable at presentation and 10 (18%) were operated on with curative intent. Five years after the initial rectal cancer surgery, two patients were alive, with one free of disease. Despite the need for multiple interventions, including surgery, only four out of 40 patients were classified as being well-palliated in the terminal stage. CONCLUSION: Follow-up after rectal cancer surgery by annual clinical examination is not sufficient to detect local recurrence when it is asymptomatic. Local recurrence of rectal cancer is often associated with intractable symptoms. These patients require frequent interventions and can rarely be cured if diagnosed at an advanced stage. Strategies for early detection of local recurrence and the management thereof require improvement.
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Adenocarcinoma/cirurgia , Hemorragia Gastrointestinal/etiologia , Recidiva Local de Neoplasia/diagnóstico , Recidiva Local de Neoplasia/terapia , Cuidados Paliativos , Neoplasias Retais/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Anemia/etiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/complicações , Dor/etiologia , Estudos Retrospectivos , Análise de Sobrevida , Fatores de Tempo , Resultado do TratamentoRESUMO
REASONS FOR PERFORMING STUDY: The trotting speed of Norwegian-Swedish Coldblooded Trotters (NSCTs) is, although inferior to Standardbred speeds, gradually increasing. This development is mainly attributed to breeding progresses. Characteristics of the middle gluteal muscle have recently been described in a small number of these horses but the actual spread in muscle parameters within the population is unknown. OBJECTIVES: To describe the characteristics of the middle gluteal muscle and their naturally occurring variability in young NSCT horses and investigate possible association with body size, individual breeding index and early training. METHODS: Biopsies of the middle gluteal muscle of 144 NSCT horses born in 2005 were collected at age 17-24 months. The horses were randomly selected by stratified sampling with gender and paternal progeny as stratification factors. The muscle samples were analysed for fibre type composition, fibre type areas, capillary supply and the activity of the key metabolic enzymes citrate synthase, 3-OH-acyl-CoA-dehydrogenase and lactate dehydrogenase. Correlation analysis including muscle parameters and body size, individual breeding index and early training was performed. RESULTS: Large interindividual differences were identified in muscle characteristics. Male horses had higher percentages of type IIA fibres and lower percentages of type IIX fibres than age-matched females. Fibre type areas followed the order type IIX>IIAX>IIA>I, while the capillary supply per fibre type area increased in the opposite order. No gender-related differences were found in fibre type areas or capillary supply. Height was correlated to the relative area of type I fibres. Early training was associated with increased oxidative capacity and increased percentage of type IIA fibres. The lowest breeding index was found in untrained horses. CONCLUSIONS: Muscle characteristics differ among young NSCT horses, but the innate oxidative capacity seems to be lower than in Standardbreds of comparable age. Early training may influence on these parameters.
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Cruzamento , Cavalos/genética , Cavalos/fisiologia , Músculo Esquelético/fisiologia , Envelhecimento , Animais , Tamanho Corporal , Feminino , Masculino , Caracteres SexuaisRESUMO
AIM: The aim was to assess the feasibility of preoperative chemotherapy and possible tumour response using Pemetrexed (Alimta) in rectal cancer. METHOD: The study was a prospective, non-randomized, single-centre phase I/II feasibility trial. 37 patients with resectable rectal cancer were recruited and given three 3-week cycles of preoperative Pemetrexed therapy. Tumour size and stage were assessed by MRI scans before and after chemotherapy. Treatment tolerability and response such as changes in tumour size and symptoms were assessed. RESULTS: All patients completed the chemotherapy. Whilst mild side effects were frequent (grade 1, 34/37), the risk of severe effects was limited (grade 3 or 4, 4/37). Overall, there was a significant reduction in tumour size (p < 0.001). By RECIST criteria, one patient had tumour progression, 23/36 had stable disease and 12 patients had a response of up to 65%. There was also a significant decrease in the number of pre-treatment symptoms (p < 0.018) including reduction of bleeding and diarrhoea/constipation. CONCLUSION: Preoperative (Neoadjuvant) treatment with Pemetrexed was feasible in studied patients. Serious side effects were limited and a radiological tumour response or stable disease was seen in a majority of patients.
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Adenocarcinoma/tratamento farmacológico , Antimetabólitos Antineoplásicos/uso terapêutico , Glutamatos/uso terapêutico , Guanina/análogos & derivados , Terapia Neoadjuvante , Recidiva Local de Neoplasia , Neoplasias Retais/tratamento farmacológico , Adenocarcinoma/patologia , Adenocarcinoma/cirurgia , Idoso , Antimetabólitos Antineoplásicos/efeitos adversos , Quimioterapia Adjuvante , Distribuição de Qui-Quadrado , Estudos de Viabilidade , Feminino , Glutamatos/efeitos adversos , Guanina/efeitos adversos , Guanina/uso terapêutico , Humanos , Tempo de Internação , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Pemetrexede , Neoplasias Retais/patologia , Neoplasias Retais/cirurgia , Resultado do Tratamento , Carga Tumoral/efeitos dos fármacosRESUMO
The aim of this study is to evaluate possible benefits of hyperbaric oxygen (HBO) therapy in the treatment of deep postoperative infections in six high risk paediatric patients with neuromuscular spine deformity. The study involved review of medical records including radiology, office visits, and telephone contacts for six patients, referred for postoperative HBO therapy in 2003-2005. Infection control and healing without removal of implants or major revision surgery with a minimum of 2-year follow-up after index surgery were considered to represent success. All infections were resolved. Median time for wound healing, normalisation of blood tests and antibiotic weaning were 3 months. Radiological bony fusion, intact implants without any signs of radiolucent zones were seen in all cases at a mean follow-up of 54 months (37-72). Side effects of HBO treatment were minor. HBO is a safe and potentially useful adjuvance in the treatment of early deep postoperative infections in complex situations with spinal implants in high risk paediatric patients.
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Infecções Bacterianas/terapia , Coluna Vertebral/cirurgia , Infecção da Ferida Cirúrgica/terapia , Adolescente , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Oxigenoterapia Hiperbárica , Lactente , Masculino , Resultado do Tratamento , CicatrizaçãoRESUMO
High-intensity interval training (HIIT) forms an important component of endurance athletes' training, but little is known on intramuscular metabolic and fiber type adaptations. This study investigated physiological and skeletal muscle adaptations in endurance runners subjected to 6 weeks HIIT. Eighteen well-trained endurance athletes were subjected to 6 weeks HIIT. Maximal and submaximal exercise tests and muscle biopsies were performed before and after training. Results indicated that peak treadmill speed (PTS) increased (21.0 ± 0.8 vs 22.1 ± 1.2 km/h, P<0.001) and plasma lactate decreased at 64% and 80% PTS (P<0.05) after HIIT. Cross-sectional area of type II fibers tended to have decreased (P=0.06). No changes were observed in maximal oxygen consumption, muscle fiber type, capillary supply, citrate synthase and 3-hydroxyacetyl CoA dehydrogenase activities. Lactate dehydrogenase (LDH) activity increased in homogenate (P<0.05) and type IIa fiber pools (9.3%, P<0.05). The change in the latter correlated with an absolute interval training speed (r=0.65; P<0.05). In conclusion, HIIT in trained endurance runners causes no adaptations in muscle oxidative capacity but increased LDH activity, especially in type IIa fibers and in relation to absolute HIIT speed.
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Adaptação Fisiológica/fisiologia , Fibras Musculares de Contração Rápida/metabolismo , Esforço Físico/fisiologia , Corrida/fisiologia , Biópsia , Teste de Esforço , Humanos , Fibras Musculares de Contração Rápida/fisiologia , Consumo de Oxigênio/fisiologia , Resistência Física/fisiologia , Músculo QuadrícepsRESUMO
REASONS FOR PERFORMING STUDY: Muscular changes caused by training are breed-specific and studies on the Norwegian-Swedish Coldblooded Trotter (NSCT) are limited. Knowledge about lactate-transporters in muscle in this light draught breed used for harness racing is lacking. OBJECTIVES: To identify muscular changes associated with training in young NSCTs and investigate muscular distribution of the monocarboxylate transporter 1 (MCT1) and its ancillary protein CD147, which facilitate lactate transport across membranes. METHODS: Nine horses were followed from the start of their training period until the end of their 3-year-old season. A biopsy sample of the middle gluteal muscle was collected on 4 occasions. On the last 3 sampling occasions, individual V(La4)-values (the speed corresponding to a blood lactate concentration of 4 mmol/l) were determined in an incremental exercise test on a high-speed treadmill. One horse was excluded due to lameness. Histochemical and immunohistochemical analyses were performed on all muscle samples to determine fibre types (I, IIA, IIAX, IIX), oxidative capacity (NADH) and the expression of MCT1 and CD147. The activity of selected metabolic enzymes in the muscle before and after training was determined. RESULTS: The percentage of type IIX fibres decreased with training while the percentage of type IIAX fibres increased. The activity of citrate synthase and 3-OH-acyl-CoA-dehydrogenase increased with training. The expression of MCT1 was lower in membranes and cytoplasm of type IIX fibres compared to all other fibre types both before and after training. The antibody against CD147 stained membranes and cytoplasm of all fibres. The first V(La4)-value was lower than the last 2 in all horses. CONCLUSIONS: Muscular changes with training of NSCTs were similar to those reported in Standardbreds, indicating fibre type transitions and increased oxidative capacity. Expression of MCT1 differed among fibre types and was related to the oxidative capacity of the fibres.
Assuntos
Cavalos/genética , Cavalos/fisiologia , Transportadores de Ácidos Monocarboxílicos/metabolismo , Fibras Musculares Esqueléticas/fisiologia , Condicionamento Físico Animal/fisiologia , Envelhecimento/fisiologia , Animais , Feminino , Regulação da Expressão Gênica/fisiologia , Masculino , Transportadores de Ácidos Monocarboxílicos/genéticaRESUMO
REASONS FOR PERFORMING STUDY: A higher forage allowance to athletic horses might be an alternative to increase health and the gut fluid reservoir. However, more forage might increase bodyweight (bwt) and could therefore be a limitation during competition. OBJECTIVES: To investigate the effect of a forage-only diet (FD) compared to a 50:50 (dry matter basis) forage:oats diet (OD) on bwt, plasma protein concentration and some metabolic plasma parameters during 12 h of feed deprivation. METHODS: Twelve adult Standardbred horses in training were used. The 2 diets were fed in 2 experimental periods of 3 weeks each in a crossover design. The last day of each period the horses were fasted for 12 h. The horses were weighed and their water intake measured every day during the trial and every hour during the 12 h feed deprivation. During feed deprivation total plasma protein (TPP), insulin, nonesterified fatty acids (NEFA), urea, glucose and acetate concentrations were analysed. RESULTS: Bwt and water intake was higher on FD compared to OD. Bwt loss was higher during feed deprivation on FD compared to OD. TPP was lower before and during the last 8 h of feed deprivation on FD compared to OD. Plasma insulin was lower on FD than on OD at feeding and for 5 h during feed deprivation. Plasma NEFA and urea increased on both diets during feed deprivation. Plasma glucose was not affected by diet or feed deprivation. CONCLUSION: High energy forage diets could be an alternative to high grain diets for athletic horses. The small increase in bwt on FD diminished with feed deprivation and the low TPP concentration indicate a greater potential to use an internal fluid compartment to maintain plasma volume.
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Ração Animal/análise , Privação de Alimentos/fisiologia , Cavalos/fisiologia , Fenômenos Fisiológicos da Nutrição Animal , Animais , Avena , Dieta/veterinária , Feminino , Masculino , Condicionamento Físico Animal/fisiologia , Redução de PesoRESUMO
REASONS FOR PERFORMING STUDY: There is little information about the influence of crude protein (CP) intake on glycogen and free pool amino acid concentrations in the muscle of horses in training. High energy forage-only diets may be an alternative to concentrate rich diets and may provide high levels of CP. OBJECTIVE: To study the effect of feeding 2 forage-only diets, containing either high or moderate CP concentrations on glycogen and free pool amino acid concentrations in the muscle. MATERIALS AND METHODS: Two high energy forage-only diets based on high-energy grass forage were fed for 23 days in a crossover design to 6 Standardbred horses in racing condition. One forage diet provided a high (HP) CP (16.6%) intake and the other diet provided recommended intake (RP) of CP (12.5%). At Day 19 a standardised treadmill test was performed to mimic a race. Blood samples were taken before, during and after (up to 90 min) the treadmill test and muscle biopsies (m. gluteus) were taken before and after exercise and after 90 min. Amino acids were analysed with a HPLC-technique and glycogen with a fluorimetric method. RESULTS: A main effect of the HP diet was that muscle glycogen and leucine concentrations were higher compared to the RP diet. Branched chain amino acid concentrations in plasma remained higher during early recovery from exercise on the HP diet compared to the RP diet. Intense exercise caused a similar decrease in glycogen, aspartate and glutamate concentrations in muscle and increase in alanine concentration on both diets. CONCLUSION: Feeding a forage-only diet with a high CP intake increases glycogen and leucine concentrations in muscle of horses in training. This may be beneficial for muscle recovery following intensive exercise.
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Aminoácidos/metabolismo , Proteínas Alimentares/farmacologia , Glicogênio/sangue , Cavalos/metabolismo , Músculo Esquelético/metabolismo , Proteínas de Plantas/metabolismo , Aminoácidos/química , Fenômenos Fisiológicos da Nutrição Animal , Animais , Estudos Cross-Over , Dieta/veterinária , Proteínas Alimentares/análise , Masculino , Músculo Esquelético/química , Condicionamento Físico Animal/fisiologia , Proteínas de Plantas/química , Poaceae/química , Silagem/análiseRESUMO
REASONS FOR PERFORMING STUDY: Since nonsteroidal anti-inflammatory drugs, such as flunixin, on account of their anti-inflammatory and analgesic properties, are used in both racing and equestrian sport horses, the question has been raised as to whether these drugs affect the physiological responses to exercise and thus performance potential. OBJECTIVES: The aims of this investigation were to study the effects of flunixin on cardiorespiratory, metabolic and locomotor parameters in horses during intense treadmill exercise. METHODS: Six Standardbred trotters underwent an incremental treadmill exercise test to fatigue, without drug and then after administration of flunixin meglumine (1.1 mg/kg bwt i.m.). Heart rate (HR), oxygen uptake and stride length were measured and venous blood samples drawn repeatedly during the test. RESULTS: Heart rates were found to be significantly higher at submaximal speeds, while the velocity causing a HR of 200 beats/min was significantly decreased after treatment with flunixin. Maximal HR and plasma lactate concentration 5 min after exercise were unchanged after medication. Flunixin caused higher plasma lactate concentrations at all speeds and the lactate threshold was decreased, compared with baseline values. Oxygen uptake levelled off at the highest velocities and did not change after flunixin treatment. Stride length was increased after treatment, although not at the highest velocities. CONCLUSION: The increased HR and lactate responses to exercise after flunixin treatment indicate that it does influence physiological responses, but does not improve the performance potential of clinically healthy horses. However, the lengthened stride during submaximal exercise after medication could imply undetected subclinical lameness, masked in some of the horses, i.e. they have performed with a longer stride at the cost of a higher heart rate and an increased lactate concentration.
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Clonixina/análogos & derivados , Cavalos/sangue , Cavalos/fisiologia , Ácido Láctico/sangue , Locomoção/efeitos dos fármacos , Condicionamento Físico Animal/fisiologia , Animais , Anti-Inflamatórios não Esteroides/uso terapêutico , Clonixina/farmacologia , Teste de Esforço/veterinária , Feminino , MasculinoRESUMO
REASONS FOR PERFORMING STUDY: Flexor tendon injury may be due to flexor muscle fatigue, contributing to fetlock joint hyperextension and tendon damage. A water treadmill provides resistance training on flexor tendon muscles, which might reduce the risk of tendon injury. OBJECTIVE: To determine the effect of water treadmill training on the properties of the gluteal and superficial digital flexor (SDF) muscles and on cardiocirculatory response to a standardised exercise test. METHODS: Five healthy unfit horses were trained on a water treadmill for 5 days/week for 4 weeks, starting with 5 min/day increasing to 20 min/day. Before and after the water treadmill training, an incremental SET was performed on a land treadmill to determine velocity at a heart rate 200 beats/min (V(200)) and resting gluteal and SDF muscle biopsies were obtained for biochemical analyses. RESULTS: There was no measurable difference in resting concentrations of gluteal or SDF muscle glycogen, lactate, ATP or glucose-6-phosphate (G6P), or activities of citrate synthase (CS), 3-hydroxyacyl CoA dehydrogenase (HAD) and lactate dehydrogenase (LDH) after training and no change in V(200), Lactate, glycogen, G6P and ATP concentrations were 50% lower and type 1 fibres 30% higher in SDF compared to gluteal muscles. CS and HAD activities were similar between SDF and gluteal, while LDH was lower in the SDF muscle. CONCLUSIONS: A more strenuous water treadmill conditioning protocol may be needed to induce a training effect in gluteal and SDF muscle and heart rate response. The low substrate concentrations and oxidative capacity of SDF may predispose this muscle to catastrophic fatigue during maximal exercise.
Assuntos
Metabolismo Energético/fisiologia , Teste de Esforço/veterinária , Cavalos/fisiologia , Músculo Esquelético/metabolismo , Condicionamento Físico Animal/fisiologia , Água , Trifosfato de Adenosina/metabolismo , Animais , Feminino , Glucose-6-Fosfato/metabolismo , Glicogênio/metabolismo , Ácido Láctico/metabolismo , MasculinoRESUMO
REASONS FOR PERFORMING STUDY: Neuromuscular electrical stimulation (NMES) is used to increase or maintain muscle strength during rehabilitation. Human studies investigating different protocols show that some treatments induce changes in muscle characteristics. Despite the frequent use of NMES in horses, no studies have been published describing its efficacy. OBJECTIVES: To investigate the effects of a NMES protocol on equine fibre types and areas, glycogen concentrations and enzyme activities. METHODS: NMES was administrated to m. gluteus medius and m. longissimus dorsi, on one side of 6 healthy Standardbred horses. The contralateral side of each muscle served as a nonstimulated control. The horses were stimulated at 50 Hz a day, with 21-39 mA, for 45-60 min, 5 days a week for 4 weeks. Needle biopsies were obtained from the muscles on both sides before and after the experimental period. Muscle samples were analysed for fibre type proportions and area using histochemical methods and for glycogen and enzyme activities (citrate synthase, 3-OH-acyl CoA dehydrogenase, hexokinase and lactate dehydrogenase) using biochemical methods. Muscle contractions at the location and depth of the muscle biopsy were confirmed by diagnostic ultrasound. Nonparametric tests (Mann-Whitney, Wilcoxon sign-rank) were used for statistical analysis. RESULTS: No significant differences were observed in the percentage of types I, IIA or IIX fibres, fibre areas, glycogen levels or enzyme activities either when comparing stimulated and nonstimulated muscles before and after the NMES treatment, or when comparing the left and right muscle samples. CONCLUSIONS: The NMES treatment was well tolerated by the horses, but the present protocol did not induce significant muscle adaptations. Further studies are needed to describe the effect of more intense and/or prolonged NMES treatment protocols on muscles of healthy horses, and to describe if stimulation protocols induce positive changes in atrophied muscles.
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Estimulação Elétrica , Cavalos/fisiologia , Fibras Musculares Esqueléticas/fisiologia , Animais , Feminino , Masculino , Contração Muscular , OxirreduçãoRESUMO
Monocarboxylate transporter 1 (MCT1) and its ancillary protein CD147 facilitate efflux of lactate from the muscle. Expression of MCT1 and CD147 were studied with immunohistochemistry in type I, IIA, IIAB and IIB fibres of equine gluteal muscle. Staining intensity of MCT1 in the cytoplasm as well as in the membranes of fibre types decreased in the order I=IIA>IIAB>IIB and correlated with the oxidative capacity. Capillaries were pronounced in the MCT1 staining. CD147 antibody stained plasma membranes of all fibre types evenly, whereas the staining in the cytoplasm followed that of MCT1. In the middle gluteal muscle the expression of MCT1 follows the oxidative capacity of muscle fibres, but the expression of CD147 in sarcolemma does not vary among fibre types. The use of horse specific MCT1 and CD147 antibodies can in future studies help to evaluate lactate efflux from different muscle fibre types.
Assuntos
Basigina/análise , Transportadores de Ácidos Monocarboxílicos/análise , Fibras Musculares Esqueléticas/química , Simportadores/análise , Animais , Basigina/imunologia , Basigina/metabolismo , Feminino , Cavalos , Masculino , Microscopia Eletrônica/veterinária , Transportadores de Ácidos Monocarboxílicos/química , Transportadores de Ácidos Monocarboxílicos/imunologia , Transportadores de Ácidos Monocarboxílicos/metabolismo , Fibras Musculares Esqueléticas/imunologia , Fibras Musculares Esqueléticas/metabolismo , NADH Tetrazólio Redutase , Sarcolema/química , Sarcolema/imunologia , Sarcolema/metabolismo , Simportadores/imunologia , Simportadores/metabolismoRESUMO
Experimental results are presented of pumping ionospheric plasma with a radio wave carrying orbital angular momentum (OAM), using the High Frequency Active Auroral Research Program (HAARP) facility in Alaska. Optical emissions from the pumped plasma turbulence exhibit the characteristic ring-shaped morphology when the pump beam carries OAM. Features of stimulated electromagnetic emissions (SEE) that are attributed to cascading Langmuir turbulence are well developed for a regular beam but are significantly weaker for a ring-shaped OAM beam in which case upper hybrid turbulence dominates the SEE.
RESUMO
Streptozotocin (STZ) given intravenously destroys pancreatic beta cells and is widely used in animal models to mimic type 1 diabetes. The effects of STZ on the clinical state of health and metabolism were studied in six high health certified domestic pigs weighing 19+/-1.3 kg at the start of the experiment. A single STZ dose of 150 mg/kg of body weight successfully induced hyperglycaemia and alterations in amino acid metabolism. Within 9 h after STZ administration, the blood glucose values fell from 5.4-7.5 mmol/L to 0.8-2.2 mmol/L. Hypoglycaemia was treated with 0.5 g glucose/kg body weight. In all pigs, hyperglycaemia was produced 24 h after STZ treatment, and 3 days after STZ injection, the glucose concentration was >25 mmol/L. Mean C-peptide concentration was 0.25+/-0.16 microg/L since 2 days after STZ injection until the end of the study. The serum concentration of the branched-chain amino acids (BCAA) increased four-fold, and alanine and taurine decreased by approximately 70% and 50%, respectively, after STZ treatment. All but one pig remained brisk and the physical examination was normal except for a retarded growth rate and a reduction of the skeletal muscle. At the end of the study, the pigs were moderately emaciated. Postmortem examination confirmed muscle wasting and a reduction of abdominal and subcutaneous fat. In conclusion, STZ-induced diabetes in pigs fulfils the requirements for a good animal model for type 1 diabetes with respect to clinical signs of the disease and alterations in the carbohydrate and amino acid metabolism.