Reproductive energy expenditure and changes in body morphology for a population of Chinook salmon Oncorhynchus tshawytscha with a long distance migration.

Energetic demands of a long freshwater migration, extended holding period, gamete development and spawning were evaluated for a population of stream-type Chinook salmon Oncorhynchus tshawytscha. Female and male somatic mass decreased by 24 and 21%, respectively, during migration and by an additional 18 and 12% during holding. Between freshwater entry and death after spawning, females allocated 14% of initial somatic energy towards gonad development and 78% for metabolism (46, 25 and 7% during migration, holding and spawning, respectively). Males used only 2% of initial somatic energy for gonad development and 80% on metabolic costs, as well as an increase in snout length (41, 28 and 11% during migration, holding and spawning, respectively). Individually marked O. tshawytscha took between 27 and 53 days to migrate 920 km. Those with slower travel times through the dammed section of the migration corridor arrived at spawning grounds with less muscle energy than faster migrants. Although energy depletion did not appear to be the proximate cause of death in most pre-spawn mortalities, average final post-spawning somatic energy densities were low at 3·6 kJ g-1 in females and 4·1 kJ g-1 in males, consistent with the concept of a minimum energy threshold required to sustain life in semelparous salmonids.

Using otolith chemical and structural analysis to investigate reservoir habitat use by juvenile Chinook salmon Oncorhynchus tshawytscha.

Isotopic composition of (87) Sr:(86) Sr and natural elemental tracers (Sr, Ba, Mg, Mn and Ca) were quantified from otoliths in juvenile and adult Chinook salmon Oncorhynchus tshawytscha to assess the ability of otolith microchemistry and microstructure to reconstruct juvenile O. tshawytscha rearing habitat and growth. Daily increments were measured to assess relative growth between natal rearing habitats. Otolith microchemistry was able to resolve juvenile habitat use between reservoir and natal tributary rearing habitats (within headwater basins), but not among catchments. Results suggest that 90% (n = 18) of sampled non-hatchery adults returning to the Middle Fork Willamette River were reared in a reservoir and 10% (n = 2) in natal tributary habitat upstream from the reservoir. Juveniles collected in reservoirs had higher growth rates than juveniles reared in natal streams. The results demonstrate the utility of otolith microchemistry and microstructure to distinguish among rearing habitats, including habitats in highly altered systems.

Migration depths of adult steelhead Oncorhynchus mykiss in relation to dissolved gas supersaturation in a regulated river system.

Adult steelhead Oncorhynchus mykiss tagged with archival transmitters primarily migrated through a large river corridor at depths >2 m interspersed with frequent but short (<5 min) periods closer to the surface. The recorded swimming depths and behaviours probably provided adequate hydrostatic compensation for the supersaturated dissolved gas conditions encountered and probably limited development of gas bubble disease (GBD). Results parallel those from a concurrent adult Chinook salmon Oncorhynchus tshawytscha study, except O. mykiss experienced greater seasonal variability and were more likely to have depth uncompensated supersaturation exposure in some dam tailraces, perhaps explaining the higher incidence of GBD in this species.

Medic aid managed care. The NMA white paper.

The Nebraska Medical Association understands that our state has finite financial resources and must balance that reality against its obligations to its citizens. Our State Legislature has directed that a "Managed Care" format be used with the Medicaid Program, assuming that the dollars allocated to it will be frugally and wisely spent. This is only an appropriate exercise of its fiscal responsibility, and we respect that. The NMA believes, however, that while all parties must work collectively toward that end, at the same time, we must acknowledge that denial of appropriate care is false economy, and poor management is costly in the long-term. Further, no plan of this complexity is likely to begin and finish in the same form, but rather must evolve. The NMA believes that all involved should strive to achieve an effective and cost-efficient system which cares about and for its clients. Finally, we must acknowledge the heterogeneity of our state, and we must therefore recognize that a plan which "fits" for one region will not predictably meet the needs and conditions of another.

Percutaneous extraction of a fractured, exposed atrial "J" lead retention wire.

The recent identification of fracturing of the retention wire in the Telectronics atrial lead, models 329-701 and 330-801, and the report of death due to cardiac tamponade caused by aortic puncture resulting from protrusion of the retention wire, necessitates fluoroscopic screening of these patients and the explantation of all leads identified to have the component failure. We present in this paper a percutaneous alternative to lead explantation in patients with protrusion of the retention wire through the polyurethane insulation and with an otherwise properly functioning atrial lead.

Mid-diastolic aortic valve opening in severe acute aortic regurgitation.

A case of severe acute aortic regurgitation is reported. Echocardiographic findings included mid-diastolic opening of the aortic valve, premature closure of the mitral valve, diastolic shuddering of the anterior mitral leaflet, probable demonstration of the flail aortic cusp in the left ventricular outflow tract, and increased left atrial and left ventricular dimensions. Correlation with hemodynamic, angiographic and surgical evidence is made.

Reflex vasodilation induced by coronary angiography in human subjects.

In order to evaluate the reflex peripheral vascular effects of coronary arteriography, forearm blood flow was measured plethysmographically and forearm vascular resistance calculated before and during coronary angiography with Hypaque-M, 75%, and Renografin-76. The injection of Hypaque into the left coronary artery resulted in a forearm vasodilation which could not be duplicated by an injection of a comparable amount of contrast into the ascending aorta, three centimeters above the coronary ostia. Forearm blood flow rose from 2.95 to 5.41 ml/min/100 ml (83.4%) and forearm vascular resistance fell from 35.8 to 19.9 mm Hg/ml/min/100 ml (44.4%). Renografin injected into the left coronary artery resulted in less forearm vasodilation (21% increase in forearm blood flow and 32% decrease in forearm vascular resistance). When coronary arteriography was repeated following injection of atropine into the brachial artery, no forearm vasodilation occurred. It is suggested that in human subjects myocardial or coronary artery receptors can be activated by the intracoronary injection of iodinated contrast media which results in a forearm vasodilation.

Membranous subaortic stenosis complicated by aneurysm of the membranous septum and mitral valve prolapse.

The clinical, echocardiographic, and catheterization findings in a patient with discrete subaortic stenosis, aneurysm of the membranous interventricular septum, and mitral valve prolapse are presented. Echocardiography showed a subaortic membrane, abnormal aortic valve motion, accentuated systolic anterior motion of the membranous interventricular septum, and prolapsing mitral leaflets. Cardiac catheterization confirmed the diagnoses. The possible functional interrelationship of these lesions is discussed.

Aortic root dissection: echocardiographic demon-stration of torn intimal flap.

An unusual case of aortic root aneurysm with dissection is described. A large intimal tear allowed a flap of aortic tissue to sag into the lumen. The echocardiographic and angiographic findings simulated an aortic supravalvular membrane. Surgical replacement of the aortic valve and aortic root was successfully accomplished.