RESUMO
OBJECTIVE: We hypothesized that a dietary combination of soy with either a probiotic (yoghurt) or a prebiotic (resistant starch) would result in enhanced lipid-lowering effects compared with a control soy diet, possibly via improvements in isoflavone bioavailability. SUBJECTS: Mildly hypercholesterolaemic subjects (men and post-menopausal women) older than 45 years were recruited via the local media. Thirty-six subjects commenced the study; five withdrew. RESULTS: Soy+probiotic significantly decreased total cholesterol (4.7+/-2.0%; P=0.038) and soy+prebiotic significantly decreased total and low-density lipoprotein cholesterol (5.5+/-1.6%; P=0.003 and 7.3+/-2.2%; P=0.005, respectively). The bioavailabilities of daidzein, genistein or equol were not affected by probiotic or prebiotic consumption or associated with lipid changes. CONCLUSION: Dietary combination of soy with either a probiotic or a prebiotic resulted in significant lipid lowering, not related to isoflavone bioavailability.
Assuntos
LDL-Colesterol/sangue , Colesterol/sangue , Hipercolesterolemia/dietoterapia , Isoflavonas/uso terapêutico , Probióticos/uso terapêutico , Alimentos de Soja , Idoso , Pão , HDL-Colesterol/sangue , Estudos Cross-Over , Dieta , Carboidratos da Dieta/uso terapêutico , Feminino , Genisteína/farmacocinética , Humanos , Hipercolesterolemia/sangue , Isoflavonas/farmacocinética , Masculino , Pessoa de Meia-Idade , Fitoestrógenos/farmacocinética , Amido/uso terapêutico , Triglicerídeos/sangue , Triticum , IogurteRESUMO
We examined the effects of cage size and testosterone (T) levels on basal and peak metabolic rates (BMR and PMR, respectively) and on pectoral and leg muscle masses of male house sparrows (Passer domesticus). Birds were housed either in small birdcages or in flight aviaries for at least 2 weeks prior to the initial metabolic evaluations. They were then implanted with either empty or T-filled silastic capsules and remeasured 5-6 weeks later. Birds treated with single T implants achieved breeding levels (4-6 ng/mL) and one group given double implants reached 10 ng/mL. There was no effect of T on BMR or PMR in any group studied, but there was an effect of caging. Caged birds showed significant reductions in PMR over the course of captivity, whereas PMR in aviary-housed birds were indistinguishable from their free-living counterparts. Testosterone treatment significantly increased leg muscle mass in caged birds, but had no effect on muscle mass in aviary-housed sparrows. We conclude that testosterone has no direct effect on sparrow metabolic rate or muscle mass, but may interact with cage conditions to produce indirect changes to these variables.
Assuntos
Metabolismo Basal/efeitos dos fármacos , Pardais/fisiologia , Testosterona/farmacologia , Animais , Peso Corporal/efeitos dos fármacos , Ritmo Circadiano/efeitos dos fármacos , Escuridão , Feminino , Membro Posterior/efeitos dos fármacos , Membro Posterior/fisiologia , Masculino , Músculos/efeitos dos fármacos , Músculos/fisiologia , Tamanho do Órgão/efeitos dos fármacos , Pardais/sangue , Testosterona/sangueRESUMO
Fipronil, a phenyl pyrazole pesticide, is aerially applied in eastern Australia to control locust outbreaks, usually as "Adonis 3UL Insecticide" (BASF), an ultra low (UL) volume formulation containing 0.3% active pesticide. We tested the toxicities of technical-grade fipronil, the Adonis 3UL formulation and its components in zebra finch, a native bird at risk of exposure in locust control regions. We estimated oral-dose LD50 by the Up-and-Down method. Under laboratory conditions, we identified unexpectedly high toxicities due exclusively to diacetone alcohol (DAA), a solvent making up 12.5% of the Adonis 3UL formulation. In contrast, finches were asymptomatic when exposed to 0.3% technical grade fipronil dissolved in a minimum amount of acetone. Depending upon the behaviour and persistence of DAA under field conditions, this formulation of Adonis 3UL may pose a far greater threat to the health of small birds and possibly other vertebrates than expected for fipronil alone.
Assuntos
Tentilhões , Pentanóis/toxicidade , Pentanonas/toxicidade , Pirazóis/toxicidade , Animais , Inseticidas/administração & dosagem , Inseticidas/química , Inseticidas/toxicidade , Dose Letal Mediana , Masculino , Pentanóis/administração & dosagem , Pentanóis/química , Pentanonas/administração & dosagem , Pentanonas/química , Pirazóis/administração & dosagem , Pirazóis/químicaRESUMO
Cooperative breeding systems are characterized by nonbreeding helpers that assist breeders in offspring care. However, the benefits to offspring of being fed by parents and helpers in cooperatively breeding birds can be difficult to detect. We offer experimental evidence that helper effects can be obscured by an undocumented maternal tactic. In superb fairy-wrens (Malurus cyaneus), mothers breeding in the presence of helpers lay smaller eggs of lower nutritional content that produce lighter chicks, as compared with those laying eggs in the absence of helpers. Helpers compensate fully for such reductions in investment and allow mothers to benefit through increased survival to the next breeding season. We suggest that failure to consider maternal egg-investment strategies can lead to underestimation of the force of selection acting on helping in avian cooperative breeders.
Assuntos
Comportamento Animal , Cruzamento , Comportamento Cooperativo , Comportamento de Ajuda , Passeriformes/fisiologia , Animais , Peso Corporal , Tamanho da Ninhada , Ovos , Ingestão de Energia , Feminino , Masculino , Oviposição , Passeriformes/crescimento & desenvolvimentoRESUMO
AIM: Physically active compared to inactive pre-menopausal women typically possess higher high-density lipoprotein (HDL) cholesterol and reduced plasma fibrinogen levels. The aim of this study was to compare resting blood lipid and fibrinogen levels of aerobically trained and untrained postmenopausal females. METHODS: Subjects were 13 aerobically trained (trained) and 26 untrained postmenopausal females (untrained) all on hormonal replacement therapy. Mean age of trained was 56 years (SD=3.6) and untrained was 58 years (SD=4.1). Testing involved blood sampling after an overnight fast. Plasma blood lipids were assessed through enzymatic methods, whereas plasma fibrinogen was measured through the Clauss method. RESULTS: Trained compared to untrained had significantly greater free fatty acid (51%, p<0.05) and apolipoprotein A levels (24%, p<0.05) and significantly lower fibrinogen (20%, p<0.05). Trained compared to untrained also possessed significantly lower total cholesterol/HDL cholesterol ratio (20%, p<0.05), total cholesterol/apolipoprotein A ratio (19%, p<0.05), apolipoprotein B/apolipoprotein A ratio (35%, p<0.05), and significantly higher HDL cholesterol (22%, p<0.05) although these differences were not significant after adjusting for body mass index (BMI). CONCLUSION: These results show that both a physically active lifestyle and a low BMI contribute to the improved lipid and fibrinogen levels of exercising postmenopausal women.
Assuntos
Ácidos Graxos não Esterificados/sangue , Fibrinogênio/análise , Lipoproteínas/sangue , Aptidão Física , Pós-Menopausa/sangue , Feminino , Humanos , Pessoa de Meia-IdadeRESUMO
Foods such as breads and breakfast cereals enriched with a combination of soy protein (soy grits and/or soy flour) and whole linseed are gaining popularity. Regular consumption of either whole grains or soy protein can lower risk factors for coronary heart disease. Furthermore, linseed is a rich source of the omega-3 fatty acid. alpha-linolenic acid (LNA), with purported cardiovascular benefits. The aim of this study was to determine the effect of daily consumption of soy and linseed containing foods and Canola (as an added source of LNA) on plasma lipid concentrations in 20 mildly hypercholesterolaemic postmenopausal women. Fasted blood samples were taken initially and after 3 and 8 weeks to assay plasma lipids and both plasma and erythrocyte membrane fatty acids. Urinary isoflavones were also measured. Data from 18 subjects were used for analysis. Plasma total, low-density lipoprotein (LDL) and non-high-density lipoprotein (HDL) cholesterol concentrations fell significantly (10, 12.5 and 12%, respectively) within 3 weeks. Although attenuated, there were still significant reductions in total and non-HDL cholesterol (5 and 6.5%, respectively) after 8 weeks of intervention. These reductions were associated with increases in urinary isoflavone excretion. This pilot study indicates that regular inclusion of foods containing soy and linseed in the diet may improve plasma lipids in subjects with hypercholesterolaemia.
Assuntos
Linho/metabolismo , Alimentos Fortificados , Glycine max/metabolismo , Hipercolesterolemia/dietoterapia , Lipídeos/sangue , Idoso , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Membrana Eritrocítica/química , Ácidos Graxos/sangue , Ácidos Graxos Ômega-3/uso terapêutico , Feminino , Linho/química , Humanos , Isoflavonas/urina , Pessoa de Meia-Idade , Projetos Piloto , Pós-Menopausa , Glycine max/químicaRESUMO
We studied a population of rufous whistlers, Pachycephala rufiventris, throughout a single breeding season in central New South Wales, Australia. We evaluated the relation between plasma testosterone (T) and reproductive behaviors using both simulated territorial intrusions (STIs) and subcutaneous T implants. We compared circulating T values to aggression levels of males (using STI) during pair bond and territory establishment and again during incubation. Although plasma T levels were significantly lower in the latter period, male responsiveness to STI, in terms of proximity to decoy, call rate, and number of attacks on the decoy, was indistinguishable between the two breeding stages. T levels of males exposed to STI were not different from the levels of unexposed free-living males at the same breeding stage. The effect of exogenous T on parental behavior was examined by comparing duration of incubation bouts of males and their mates prior to and after T treatment. T males significantly reduced the amount of time they incubated following implantation, whereas Control males maintained their incubation effort. After cessation of breeding activities, T males displayed significantly higher call rates due to increased use of the primary intersexual advertisement call in this species. The reduction of incubation behavior following T implantation emphasises the functional significance of the rapid decline in T in free-living males during incubation. The results from both experiments suggest that intersexual advertisement, rather than territorial aggression, may be dependent on high T levels in this species.
Assuntos
Aves/fisiologia , Hormônios Esteroides Gonadais/sangue , Territorialidade , Testosterona/sangue , Agressão/fisiologia , Animais , Hormônios Esteroides Gonadais/farmacologia , Masculino , Comportamento de Nidação/fisiologia , Comportamento Paterno , Testosterona/farmacologiaRESUMO
We examined the effect of corticosterone on plasma levels of reproductive hormones (testosterone, dihydrotestosterone, and luteinizing hormone) and territorial defense behavior in male tree sparrows, Spizella arborea. Birds receiving Silastic implants filled with corticosterone (B) had significantly higher plasma levels of B than control birds, which received empty implants, and exhibited pectoral muscle wastage and a decrease in body mass. We evaluated the hormonal and agonistic responses of the two implanted groups of birds using a simulated territorial intrusion (STI) 2 to 4 days after they were implanted. Corticosterone-treated and control birds did not differ in their circulating levels of reproductive hormones or in their behavioral responses to STI (latency to respond to intrusion, number of songs, and closest approach to a decoy and tape recording). Unlike previous studies of north temperate passerines, high physiological levels of exogenous B had no effect either on circulating levels of reproductive hormones or on territorial behaviors associated with breeding. Nonetheless, untreated tree sparrows do mount a robust adrenocortical response, having a two- to fourfold increase in plasma B levels during a 1-h period of capture. Thus, adrenocortical responsiveness is maintained in these birds, but elevated levels of glucocorticoids do not suppress reproductive hormones or associated behaviors. We believe that this hormonal and behavioral refractoriness to glucocorticoids-or uncoupling of the stress response from the reproductive axis-may be advantageous for species having extreme temporal constraints on their breeding schedules.
Assuntos
Agressão/efeitos dos fármacos , Corticosterona/farmacologia , Hormônios Esteroides Gonadais/sangue , Aves Canoras/fisiologia , Córtex Suprarrenal/metabolismo , Córtex Suprarrenal/fisiologia , Androgênios/sangue , Animais , Corticosterona/administração & dosagem , Implantes de Medicamento , Manobra Psicológica , Hormônio Luteinizante/sangue , Masculino , Radioimunoensaio , Estresse Psicológico/sangue , TerritorialidadeRESUMO
We tested the effects of naturally relevant environmental temperatures on long day-induced reproductive development in male and female white-crowned sparrows, Zonotrichia leucophrys gambelii. Transfer from short days (8L 16D) to long days (20L 4D) resulted in rapid testicular development and partial ovarian development as has been reported many times previously. Exposure of experimental groups to low (5 degrees), moderate (20 degrees), and high (30 degrees) temperature during photostimulation had only subtle effects on plasma levels of follicle-stimulating hormone and luteinizing hormone over time and no effects on the size of testes, cloacal protuberance, ovaries, or brood patch at Day 30 of treatment. Long days resulted in the well known increase in body mass and fat score, indicative of preparations for migration. In females, treatment with low temperature resulted in a reduction in the premigratory increase in fat and body mass when transferred to long days. This was accompanied by an increase in plasma levels of corticosterone during the early stages of photostimulation at low temperature. Temperature regimes had no effects on fattening or body mass in males, despite an early increase in plasma corticosterone at low temperature. Circulating levels of thyroxine (T4) and triiodothyronine (T3) increased to varying degrees following photostimulation. Temperature treatment had no effect on plasma levels of thyroid hormones in males, but low temperature did inhibit thyroid hormone secretion (particularly T4) in females. Although reproductive development appears to be resistant to naturally relevant temperature extremes in both sexes, low environmental temperature impaired preparations for migration in females but not males. This effect may be mediated through glucocorticosteroids and not thyroid hormones. Reasons for the sexual dimorphism in this response are unknown, but may be related to sexual selection for males to arrive on the breeding grounds ahead of females regardless of local weather conditions.
Assuntos
Tecido Adiposo/crescimento & desenvolvimento , Aves/fisiologia , Ovário/crescimento & desenvolvimento , Testículo/crescimento & desenvolvimento , Aumento de Peso/fisiologia , Tecido Adiposo/fisiologia , Animais , Cloaca/crescimento & desenvolvimento , Corticosterona/sangue , Feminino , Hormônio Foliculoestimulante/sangue , Hormônio Luteinizante/sangue , Masculino , Ovário/fisiologia , Estações do Ano , Temperatura , Testículo/fisiologia , Tiroxina/sangue , Tri-Iodotironina/sangueRESUMO
The Lapland longspur, Calcarius lapponicus, times its breeding season so that chicks hatch coincident with the brief period of food abundance in the high arctic. This synchronization requires that all reproductive activities occur in over a much shorter period than at lower latitudes. Because of the known influence of stress hormones on delaying breeding in temperate-zone birds and the detrimental effects of such delays in the arctic, we expected the performance of the hypothalamic-pituitary-adrenal (HPA) axis of arctic-breeding birds to show less sensitivity to environmental stress than their mid-latitude counterparts. We found that adrenocortical responsiveness to the standardized stress of capture and handling, measured by taking five serial blood samples for corticosterone during the course of a 1-hr period, was similar to many temperate passerines and was also similar both between male and female longspurs and between the migratory and reproductive phases. However, the profile of plasma corticosterone during capture stress was significantly damped in longspurs sampled as they began their postnuptial molt. In addition, we had the opportunity to examine endocrine responses to a natural environmental stress in 1989 during a 3-day snowstorm which concealed available food resources. During this storm longspurs formed progressively larger flocks each day, with females abandoning incubation duties by the third day. Birds captured during the storm showed highly significant increases in both the rate of plasma corticosterone increase during capture and the peak postcapture level compared with birds sampled before the storm. This increased adrenal potential suggests increased activity of the HPA axis in response to severe conditions and is reminiscent of the response to fasting. Although the storm occurred during incubation, and reproductive hormone levels had begun to decline, we measured significant reductions in luteinizing hormone in both males and a subset of females captured during the storm.
Assuntos
Córtex Suprarrenal/fisiologia , Aves/fisiologia , Clima Frio , Comportamento de Nidação/fisiologia , Oviposição/fisiologia , Alaska , Animais , Regiões Árticas , Nível de Alerta/fisiologia , Corticosterona/sangue , Jejum/fisiologia , Feminino , Sistema Hipotálamo-Hipofisário/fisiologia , Masculino , Fatores SexuaisRESUMO
We evaluated the adrenocortical response to acute stress in free-living Gambel's white-crowned sparrows (Zonotrichia leucophrys gambelii) using a standardized capture stress protocol in which five serial blood samples (70 microliters) were taken for measurement of plasma corticosterone (B) over the course of an hour of captivity (at 1, 5, 10, 30, and 60 min). In field-captured birds, male plasma B levels rose two to four times higher than those of females under capture stress during the breeding season, but were no different during winter (nonbreeding). We investigated the basis of this pattern by conducting dexamethasone (DEX) suppression tests on breeding and nonbreeding sparrows of both genders. This test involves pretreatment with subcutaneous DEX implants (a potent synthetic glucocorticoid) and challenge with intrajugular injections of either corticotropin (ACTH) or saline, followed by collection of a series of blood samples for evaluation of plasma B levels over a 2-hr period. ACTH injections in DEX-treated birds resulted in elevated B in both genders, with nonbreeding B profiles consistently lower than those of breeding birds. All DEX-treated, saline-injected birds, except breeding males, maintained low B levels for the entire 2-hr post-challenge period. This result indicates effective negative feedback by DEX on the hypothalamic-pituitary-adrenal axis, thus inhibiting endogenous B secretion. The apparent reduction in glucocorticoid feedback inhibition in breeding males may be related to an uncoupling of adrenal effects on reproductive behavior.
Assuntos
Córtex Suprarrenal/fisiologia , Hormônio Adrenocorticotrópico/farmacologia , Aves/fisiologia , Estações do Ano , Caracteres Sexuais , Córtex Suprarrenal/efeitos dos fármacos , Animais , Corticosterona/sangue , Dexametasona/farmacologia , Retroalimentação , Feminino , Cinética , Masculino , Estresse FisiológicoRESUMO
New cationic 99Tc/99Tc complexes formed with various symmetrical and asymmetrical vicinal dioximes of different carbon chain length (C5-C8) were synthesized by reduction of pertechnetate with BH4-, separated by HPLC and characterized by i.r./u.v./vis. spectroscopy, FAB mass spectrometry and electrophoresis. All complexes studied are trisdioximes containing boron as a constituent. Their lipophilicity, as assessed by the octanol/saline partition coefficient, ranges over almost four orders of magnitude. The myocardial uptake of the 99mTc complexes in mice proves to be lower than expected. The organ distributions are distinctly affected by the lipophilicity, the position of the dioxime group and the introduction of a terminal methoxy group.
Assuntos
Coração/diagnóstico por imagem , Oximas/síntese química , Tecnécio/química , Animais , Fenômenos Químicos , Físico-Química , Cromatografia Líquida de Alta Pressão , Marcação por Isótopo , Camundongos , Camundongos Endogâmicos , Estrutura Molecular , Oximas/química , Oximas/farmacocinética , Cintilografia , Espectrometria de Massas de Bombardeamento Rápido de Átomos , Distribuição TecidualRESUMO
Resting metabolic rates of Gambel's white-crowned sparrows (Zonotrichia leucophrys gambelii) and pine siskins (Carduelis pinus) were evaluated at thermoneutral temperatures before and after administration of corticosterone (B) at physiological doses. There was no effect of B on basal metabolic rate of either species, but nocturnal metabolic rate varied significantly less over the 3-h period of measurement in B-treated sparrows and siskins than in control birds. These results, coupled with observations of caged birds, suggest that corticosterone has no direct effect on avian resting metabolism but does reduce the responsiveness of birds to external stimuli and thus promotes nocturnal restfulness.
Assuntos
Aves/metabolismo , Corticosterona/farmacologia , Metabolismo/efeitos dos fármacos , Animais , Metabolismo Basal/efeitos dos fármacos , Ritmo Circadiano/efeitos dos fármacos , Escuridão , Consumo de Oxigênio/efeitos dos fármacos , Especificidade da EspécieRESUMO
Acetylcholinesterase (AChE) distribution in the dorsal lateral geniculate nucleus (LGd) of 3 polyprotodont and 3 diprotodont marsupials has been compared with the cytoarchitecture and, as appropriate, with retinal terminal bands (RTBs) as demonstrated by tracers injected into the vitreous body. In this series those polyprotodont marsupials showing only partial segregation of retinal input (Virginia opossum and Tasmanian devil), display the least cell laminar differentiation. In them AChE staining is mainly diffuse but stronger in areas of greatest retinal terminal overlap. Segregation of visual input increases progressively in the remaining polyprotodont (eastern quoll) and in the diprotodonts (Tasmanian bettong, Tasmanian potoroo and brush-tailed possum), culminating in the last-named, in which segregation is most complete. Related to this development varying numbers of cell laminae/sublaminae appear and retinal terminal laminae/sublaminae (bands) are revealed. AChE activity can be correlated with both specific cell laminae/sublaminae and retinal terminal laminae/sublaminae in these complex LGds. Greatest AChE staining in every case is related to laminae/RTBs located in the medial part of the lateral (alpha) segment of LGd. Cytoarchitecturally, the ventral lateral geniculate nucleus (LGv), unlike the heterogeneous LGd, is remarkably homogeneous in the series of animals studied and shows well-stained AChE patches relating to areas receiving significant retinal input.
Assuntos
Acetilcolinesterase/metabolismo , Corpos Geniculados/enzimologia , Marsupiais/metabolismo , Animais , Feminino , Histocitoquímica , Masculino , Especificidade da EspécieRESUMO
The synthesis and purification of two new ligands, 15-[bis(3,4-dimethyl arsino)phenyl] pentadecanoic acid (FA-DIARS) and [bis(16,17-dimethyl phosphino)] heptadecanoic acid (FA-DMPE) and the preparation of their corresponding 99Tc/99mTc complexes of the general formula [Tc(III)L2Cl2]+, wherein L is FA-DIARS or FA-DMPE are reported. After careful purification by preparative HPLC, the 99Tc complexes were characterized by spectroscopy, while the 99mTc complexes were used to determine the biodistribution in mice. The results of the organ distribution studies indicated a relatively high uptake in heart (5-7% dose/g). The complexes were, however, found to be very slowly cleared from the blood, probably due to strong binding to serum proteins. Further, the heart to liver and heart to lung ratios were unfavourable. Attempts to improve the efficacy by synthesizing complexes containing one fatty acid per molecule are also described.