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The study was designed to investigate the effect of four cycles of 5 weeks starvation followed by 10-week refeeding compared with daily feeding under either natural photoperiod or continuous light ( LL) regime on body composition and flesh quality in Atlantic cod in sea cages, northern Norway. The fish were sampled for body composition and flesh quality parameters at the start of the trial, twice at the end of a 10-week feeding period and twice at the end of a 5-week starvation period. There was effect of both feeding and light regime on growth, the two starving groups losing weight during starvation and regaining weight during refeeding, and the group under LL being heavier. But, the mean overall growth did not vary between groups. Starvation/refeeding regime resulted in higher slaughter yield, but no overall effect was seen on hepatosomatic index, water content, water holding capacity ( WHC), muscle pH, hardness or flesh colour compared with control groups. Continuous light increased gutted weight and slaughter yield, lowered WHC and depressed maturation compared with fish under natural light regime. Increased growth rate resulted in softer fillets and lower muscle pH. [ABSTRACT FROM AUTHOR]

The present study demonstrates that acceleratedphotoperiod advances ovulation in Atlantic salmon, and that exposure to cold water prior to spawning further advances and synchronizes this process while improving egg-survival. High water temperature inhibited both sperm release and ovulation, whereas a GnRHa treatment overrode this temperature effect in most individuals. A decrease in water temperature seemed to accelerate both ovulation and sperm release, and water temperature modulated the plasma 17,20ßP profiles around ovulation and sperm release. The GnRHa treatment markedly increased the volume of strippable milt and the plasma 17,20ßP levels in males. [ABSTRACT FROM AUTHOR]

Maturing male and female Atlantic salmon (Salmo salar L.) were held under three temperature regimes for 10 weeks between September and December: warm (constant 14-16 °C), ambient (decreasing from 11 to 5 °C), and cold (decreasing from 7 to 3 °C). Blood samples were analyzed for plasma steroid levels, and the fish were inspected for the presence of expressible milt (total volume and spermatocrit) and ovulation weekly. Samples of eggs were dry-fertilized with milt stripped from three males held at the same temperatures and incubated until the eyed stage. In females, levels of plasma testosterone (T) and 17β-oestradiol (E2) dropped as ovulation approached, concurrent with a rapid increase in levels of plasma 17α,20β-dihydroxy-4-pregnen-3-one (17,20β-P). In males, levels of T and 11-ketotestosterone (11-KT) peaked 2-3 weeks after the first appearance of expressible milt, while levels of 17,20β-P increased steadily and did not exhibit a definite peak. Exposure of females to cold water amplified and advanced the profiles of all three steroids compared with the ambient group, and increased the survival rates to the eyed egg stage. Cold water had no immediate effect on the male steroid profiles, but later, higher levels of 17,20β-P were evident compared with both the ambient controls and the warm water group, while the effects on 11-KT and T were more variable. Exposure to warm water completely inhibited both milt production and ovulation. Moreover, warm water modulated the steroid profiles of the males with lower 11-KT levels compared with ambient controls and lower 17,20β-P level compared with cold-water-treated males. In females, warm water resulted in total inhibition of the peri-ovulatory peak in 17,20β-P and prevented the normal decline of T and E2 levels associated with ovulation. The findings of the present study are highly relevant for broodstock management in aquaculture, as well in understanding the impact of climate change/temperature variability on wild salmon spawning.

Dialysis-associated steal syndrome is a clinically significant complication associated with the creation of dialysis grafts or fistulae. The distal revascularization and interval ligation (DRIL) procedure is a surgical procedure, which has been used to treat patients with hand ischemia secondary to arterial "steal" from dialysis accesses. This article will review the dialysis-associated steal syndrome and the history, anatomy, and clinical results of the DRIL procedure.

The effects of photoperiod and feeding regimes on plasma IGF-I levels and their relationship with growth rate of juvenile halibut (initial mean weight 364 g) were investigated by rearing fish under five different photoperiod regimes and two feeding regimes for 14 months. The entire photoperiod experiment was divided into 3 phases where the fish in each phase were exposed to either natural photoperiod (N), stimulated photoperiod with long day and short night (S) or continuous light (L). Thus, the following five photoperiod combinations were tested: a) Control group (NNN) b) Group 2A (NLN) c) Group 2B (NNL) d) Long day-natural group (SNN) e) Production group (LNN). In addition, the Control group was split into two parts and fed according to two different feeding regimes: a) Continuous fed group: Fish fed every day. b) Starvation/re-fed group: Fish were starved for 5 weeks and then re-fed for 10 weeks, and the treatment repeated during the whole experimental period. The analyses of IGF-I were performed from individually tagged fish in all groups in September 2005 and March 2006. In order to test how rapidly starvation affects circulating IGF-I levels samples were taken from the Starvation/re-fed group after a 10 days starvation (September) and immediately after 10 weeks of feeding (March). A significant relationship between IGF-I levels and individual growth in the preceding period and photoperiod and starvation treatment was found on both occasions. In conclusion, the present study indicates that plasma IGF-I levels are correlated to growth in Atlantic halibut, and affected by photoperiod treatment or compensatory growth during re-feeding. Correlation between individual growth rate and IGF-I levels was low, but significant, highlighting the complexity of how environmental factors affect the endocrine and physiological regulation of growth in fish.

Atlantic salmon (Salmo salar L.) females (2 SW), maturing for the first time, were reared under one of three temperature regimes (high: 14.3 +/- 0.5 degrees C; natural: 10.6 +/- 1.0 degrees C; and cold: 6.9 +/- 1.0 degrees C) in combination with one of two experimental treatments; an injection of GnRH analogue (GnRHa) contained in biodegradable microspheres, or a sham injection (microspheres only). The six experimental groups were then reared under simulated natural photoperiod for 4 weeks. Blood samples were drawn for analysis of plasma steroid levels and the fish were inspected for ovulation weekly. Batches of stripped eggs were incubated in triplicate incubators in raceways until the eyed stage. Treatment with GnRHa resulted in a substantial advancement and synchronization of ovulation at all temperatures, while exposure to cold water also appeared to advance ovulation slightly. While 75% (warm and cold) to 90% (natural) of GnRHa fish ovulated during the 4-week trial, only 30% of sham-treated females exposed to cold water, and none of the sham-treated fish held at higher temperatures, ovulated during this period. Survival rates of embryos to the eyed-stage were significantly higher for broodstock exposed to cold water. Plasma levels of testosterone (T), 17beta-oestradiol (E2), and 17alpha,20beta-dihydroxy-4-pregnen-3-one (17,20betaP) were all significantly affected by treatment with GnRHa and, to a lesser extent, temperature. The efficiency of GnRHa in counteracting the negative effects of high temperature on ovulation and the associated changes in circulating sex steroids suggest that temperature inhibition operates at least in part at the brain or pituitary.

Three forms of GnRH, chicken (c) GnRH-II, salmon (s) and seabream (sb) GnRH, were immunologically characterized in the brain and pituitary of turbot by ELISA. cGnRH-II and sGnRH were detected in the brain, while sbGnRH and sGnRH (but not cGnRH-II) were detected in the pituitary. In females, the levels of cGnRH-II in the turbot brain extracts increased from May to July, concomitant with an increase in oocyte diameter. In the pituitary, sbGnRH was found to be the dominant form, with levels 100-600-fold those of sGnRH. Both sGnRH and sbGnRH in the pituitary showed variation during the spawning season; sbGnRH increased from May to July and correlated with the increase in oocyte diameter, while sGnRH decreased. The overall patterns were the same for male turbot, although levels were generally lower. These findings suggest that sbGnRH could be controlling reproduction in the turbot. However, the seasonal variation in sGnRH indicates a potential physiological role in turbot reproduction. This study gives the first immunological indications that sbGnRH is present in the pituitary of a pleuronectiform fish, and will provide the basis for further studies on the endocrine regulation of reproduction in flatfish.

Objective: In 90% of normal subjects, the left hemisphere is dominant for language function. We investigated whether congenital lesions of the left perisylvian regions altered cortical language representation in right-handed individuals., Methods: Using functional magnetic resonance imaging, we studied language hemispheric dominance in five right-handed adult patients with congenitally acquired arteriovenous malformations (AVMs) originating from left hemispheric cortical language regions. The AVMs had not caused neurological symptoms during early development, but patients presented as adults with migraine, seizure, or minor hemorrhage. Results obtained from the AVM patients were contrasted to those from right-handed brain-injured stroke patients recovering from aphasia and to those from right-handed normal subjects., Results: During silent picture naming and verb generation tasks, cortical language networks lateralized primarily to the right hemisphere in the AVM group, compared with the left hemisphere in the normal group. This right hemisphere-shifted language network in the AVM group exceeded the shifts toward right hemispheric dominance found in the stroke group., Conclusion: Patients with AVMs affecting the left perisylvian regions recruited the right hemisphere into language processing networks during early development, presumably in response to congenitally aberrant circulation. This early right hemisphere recruitment in the AVM patients exceeded the similar process in the brains of stroke patients whose left cortical language networks were damaged in adulthood. Our data provide evidence of effective plasticity in the developing human brain compared with the mature brain response to injury. Knowledge of cortical language representation should assist presurgical planning in patients with developmental anomalies affecting apparently language-dominant brain regions.

Background: Spreading depression of Leao has been hypothesized as the basis for the visual aura of the migraine attack, supported by cerebral blood flow measurements of spreading hypoperfusion. The early depolarizing or activation phase of experimental spreading depression, however, is associated with a transient but pronounced cerebral blood flow increase that precedes spreading hypoperfusion., Objective: To study this early phase of the migraine attack, we investigated visually triggered attacks of headache and visual symptoms using a red-green checkerboard stimulus in patients with migraine., Interventions: We studied occipital cortex activation during visual stimulation by measuring occipital cortex perfusion with functional magnetic resonance imaging-blood oxygenation level-dependent contrast in 10 patients with migraine with aura and 2 patients with migraine without aura and 6 healthy subjects., Results: In 6 patients with migraine with aura and 2 patients with migraine without aura, their typical headache with (n = 2) or without visual change was visually triggered at 7.3 minutes (mean time) after visual stimulation began. In 5 of these patients, the onset of headache or visual change, or both, was preceded by suppression of initial activation (mean onset time, 4.3 minutes; P<.001) The suppression slowly propagated into contiguous occipital cortex at a rate ranging from 3 to 6 mm/ min. This neuronal suppression was accompanied by baseline contrast intensity increases that indicated vasodilatation and tissue hyperoxygenation., Conclusions: We conclude that visually triggered headache and visual change in patients with migraine is accompanied by spreading suppression of initial neuronal activation and increased occipital cortex oxygenation. We postulate that this spreading suppression may be associated with initial activation of a migraine attack, independent of whether there are associated aura symptoms. We further postulate that there may be an association between vasodilation accompanying the initial stage of suppression and the induction of headache.

Over the past 25 years, neuroimaging techniques have advanced rapidly. These techniques, including computed tomography, magnetic resonance imaging, positron emission tomography and single photon emission computed tomography, have improved our understanding of the relationships of language, language disorder, and brain language organization. In this article, we review the contribution of these neuroimaging techniques to the fields of brain language function and speech-language disorders after ischemic stroke. We also discuss the future of these techniques in the research and clinical arenas of ischemic stroke and aphasia rehabilitation.

Brain and cerebrospinal fluid (CSF) movements are influenced by the anatomy and mechanical properties of intracranial tissues, as well as by the waveforms of driving vascular pulsations. The authors analyze these movements so that the purely hemodynamic factors are removed and the underlying mechanical couplings between brain, CSF, and the vasculature are characterized in global fashion. These measurements were used to calculate a set of impulse response functions or modulation transfer functions, characterizing global aspects of the vasculature's mechanical coupling to the intracranial tissues, the cervical CSF, and the cervical spinal cord. These functions showed that a sudden influx of blood into the head was rapidly accommodated by some type of intracranial reserve or capacity. After this initial response, an equal volume of CSF was driven through the foramen magnum over the next 200-300 ms as the intracranial reserve relaxed to its base-line state.