38 research outputs found
Correlating corneal arcus with atherosclerosis in familial hypercholesterolemia
Abstract Background A relationship between corneal arcus and atherosclerosis has long been suspected but is controversial. The homozygous familial hypercholesterolemia patients in this study present a unique opportunity to assess this issue. They have both advanced atherosclerosis and corneal arcus. Methods This is a cross-sectional study of 17 patients homozygous for familial hypercholesterolemia presenting to the Clinical Center of the National Institutes of Health. Plasma lipoproteins, circumferential extent of arcus, thoracic aorta and coronary calcific atherosclerosis score, and Achilles tendon width were measured at the National Institutes of Health. Results Patients with corneal arcus had higher scores for calcific atherosclerosis (mean 2865 compared to 412), cholesterol-year score (mean 11830 mg-yr/dl compared to 5707 mg-yr/dl), and Achilles tendon width (mean 2.54 cm compared to 1.41 cm) than those without. Corneal arcus and Achilles tendon width were strongly correlated and predictive of each other. Although corneal arcus was correlated with calcific atherosclerosis (r = 0.67; p = 0.004), it was not as highly correlated as was the Achilles tendon width (r = 0.855; p Conclusion Corneal arcus reflects widespread tissue lipid deposition and is correlated with both calcific atherosclerosis and xanthomatosis in these patients. Patients with more severe arcus tend to have more severe calcific atherosclerosis. Corneal arcus is not as good an indicator of calcific atherosclerosis as Achilles tendon thickness, but its presence suggests increased atherosclerosis in these hypercholesterolemic patients.</p
Comparison of low temperature adaptation ability in three native and two hybrid strains of the rotifer Brachionus plicatilis species complex
The low temperature adaptation ability of five selected strains of the Brachionus plicatilis species complex, i.e., three native strains [ Japanese (NH1L), Australian, German] and two hybrid strains [♀NH1L and ♂Australian (N × A) and ♀NH1L and ♂German (N × G),was investigated in terms of life history traits, reproductive characteristics, and mobility under different thermal conditions (12 and 25 °C). The life history traits of these five strains included a longer lifespan, reproduction period and generation times at 12 °C than at 25 °C, combined with reduced lifetime egg and offspring production. At 12 °C, the intrinsic rate of natural increase was higher in NH1L and N × A strains. Reproductive characteristics determined at 12 °C by batch culture showed active population growth for NH1L and N × G strains, while no resting egg production was observed in all of the strains tested. The ratio of swimming rotifers at 12 °C was monitored every hour for 6 h (short term) and every day for 10 days (long term). In the short-term study there was a 81% ratio of swimming rotifers of the NH1L strain, while other strains exhibited low swimming ratios (75% swimming ratio from the initial day of the study. These results suggest that outcrossing of rotifer strains is useful to obtain live food resources for the larviculture of cold water fish
Effects of photoperiod and feeding frequency on performance of newly weaned Australian snapper Pagrus auratus
An experiment was done to investigate the interactive effects of photoperiod (12L:12D or 18L:6D) and feeding frequency on the growth of newly weaned Australian snapper (mean weight = 0.14 g fish- 1). Feeding frequency was investigated over 4 levels with 2 feeds delivered during the first half of the daylight period (2FE), 2 feeds during the latter half of the daylight period (2FL), 4 (4F) or 8 (8F) evenly spaced feeds per daylight period. Each treatment combination was replicated in 6 tanks and each tank was stocked with a biomass of 15 g tank- 1 (i.e. approximately 108 fish tank- 1). Snapper were fed a constant ration of 10% BW day- 1 for 32 days, which was adjusted during the experiment according to frequent weight check procedures. Fish that died were counted but not replaced. Photoperiod, feeding frequency and the interaction of these factors significantly affected the individual harvest weight and thermal growth coefficient (TGC) of snapper. Interactions were driven by an increase in the magnitude of individual weight and TGC in snapper fed the 4F and 8F treatments and reared under the 18L:6D photoperiod, compared to snapper fed at the same frequencies but reared under the 12L:12D regime. Weight gain and TGC were best in snapper reared under a 18L:6D photoperiod regime and fed 8 feeds day- 1, however, weight gain did not plateau, suggesting further increases in weight gain may be possible if feeding frequencies greater then 8F are employed. Survival and apparent feed conversion ratio (AFCR) were significantly affected by feeding frequency alone, with significant improvements in snapper fed more frequently and in snapper fed twice daily but later in the same photoperiod (2FE < 2FL < 4F < 8F). Size heterogeneity (measured by the coefficient of variation for individual harvest weight, CVhw) was affected by photoperiod, and decreased significantly in snapper reared under the 18L:6D regime. Size heterogeneity was also affected by feeding frequency, however, only the CVhw for snapper reared under the 8F feeding frequency was significantly lower than snapper fed at other rates (i.e. 2FE = 2FL = 4F < 8F). Snapper fed later in a photoperiod regime generally performed better than snapper fed earlier. Results from this study indicate that in order to maximize weight gain, survival and AFCR and to reduce size heterogeneity, newly weaned snapper should be reared under a 18L:6D photoperiod and, for fish fed 10% BW day- 1, fed 8 times day- 1. © 2006 Elsevier B.V. All rights reserved
Ontogenetic milestones of chemotactic behaviour reflect innate species-specific response to habitat cues in larval fish
© 2017 The Association for the Study of Animal Behaviour The distribution and connectivity of marine populations are largely dependent on biophysical factors affecting pelagic larval dispersal between spawning at adult spawning sites and settlement to juvenile nursery habitats. Behaviour and swimming ability of pelagic larvae are increasingly understood to influence patterns of dispersal, but it is unclear which sensory cues are involved and when during ontogeny these abilities first develop. Here we studied the early ontogenetic development of responses to olfactory cues from coastal and estuarine waters in larvae of two temperate estuarine-associated fish species, Australian bass, Macquaria novemaculeata, and mulloway, Argyrosomus japonicus, to determine when olfaction begins to influence dispersal. Olfactory responses to habitat-associated cues were not present when larvae first transitioned from nonswimming to swimming (indicated by flexion of the notochord), but emerged after ca. 7 days in a species-specific manner that was consistent across different cohorts. Based on general additive models (GAMs), age (in days posthatch) best explained the ontogenetic pattern in both species. The emergence of chemotactic responses coincides with an exponential increase in swimming endurance reported for these species. This suggests the existence of ontogenetic milestones during larval development that, once reached, trigger active influence on dispersal. Salinity and pH did not influence choice behaviour after these ontogenetic milestones; however, the presence of cues generated by seagrass harvested from the estuary habitat elicited strong responses in fish larvae consistent with species-specific habitat preferences, indicating an important role for aquatic vegetation in driving these behaviours
The effect of stocking density and repeated handling on\ud the growth of juvenile mulloway, Argyrosomus japonicus\ud (Temminck & Schlegel 1843)
The effect of stocking density on the growth of mulloway, Argyrosomus japonicus, was tested with 17 g fish stocked at 4.08, 8.16, or 16.32 kg m−3 in 50 l aquaria. Weight checks were carried out every 2 weeks to track performance. Each density treatment was also compared to a nonhandled control group to establish if handling during weight checks influenced the growth of mulloway. Mulloway performed poorly at the lowest density and, under the current experiment conditions, growth did not appear to be negatively affected by regular handling