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.

Solid variant of papillary thyroid carcinoma: incidence, clinical-pathologic characteristics, molecular analysis, and biologic behavior.

Solid variant is a rare and poorly characterized variant of papillary thyroid carcinoma. In this study we analyzed 20 primary cases of the solid variant of papillary carcinoma found in a series of 756 papillary carcinomas operated at the Mayo Clinic between 1962 and 1989. The criteria for classification included predominantly (>70%) solid growth pattern of primary tumor, retention of cytologic features typical of papillary carcinoma, and absence of tumor necrosis. For each case of the solid variant, a control case of classical papillary carcinoma matched by age, sex, tumor size, and length of follow-up was selected. The follow-up ranged from 6 to 32 years. Two patients with the solid variant of papillary carcinoma (10%) died from disease 7 and 10 years after initial surgery, while another two patients (10%) are alive with lung metastases. In contrast, the control group had no cases with distant metastases or death from disease. Molecular analyses showed a similar prevalence of RET /PTC rearrangements in both groups. In conclusion, the solid variant of papillary carcinoma is associated with a slightly higher frequency of distant metastases and less favorable prognosis than classical papillary carcinoma. However, it should be distinguished from poorly differentiated thyroid carcinoma, which has a reported lower survival rate compared with the solid variant of papillary carcinoma.

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.

Acquired aortic stenosis in systemic lupus erythematosus.

Two patients with systemic lupus erythematosus had aortic valvular stenosis resulting from massive thrombotic deposits on the valve. This condition has not been described previously, but a similar process has been reported to have caused mitral stenosis in a patient.

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.