Critical Care of Nursing in Nebraska

(Ed. note) The University of Nebraska School of Nursing has two campuses: one, the Medical Center in Omaha; the other, the Lincoln Division campus, an hour or so away. The worsening economy of Nebraska agriculture forced the State to examine its expenses, and the Chancellor proposed elimination of the Lincoln nursing program. The Regents voted not to close it. The details of the issues and the concepts of strategy and negotiation used by the College of Nursing to effect this change of policy will be published in Nursing and Health Care in articles by the Dean, Rosalee Yeaworth, and the then Associate Dean, Nancy Langs ton. In an unusual editorial collaboration, IMAGE presents the rest of the story in this piece by the faculty and students—the "grassroots."     

Diameter changes of occluded venous coronary artery bypass grafts in electron beam tomography: preliminary findings.

OBJECTIVE: To differentiate acute from chronic graft occlusions through diameter measurements by means of electron beam tomography (EBT). METHODS: Contrast enhanced EBT volume studies were carried out in 37 patients with one or more occluded venous coronary bypass grafts. Seventeen of 37 patients did not meet the inclusion criteria and were excluded from the assessment. The remaining 20 patients had a total of 39 bypasses (16 patent, 23 occluded) and were assigned to one of three groups: group A consisted of patent grafts only (patent grafts, 13 patients). Group B comprised 11 of 23 occluded grafts diagnosed within 10 days after bypass surgery (acutely occluded grafts, ten patients). Group C contained 12 of 23 bypass occlusions that were at least 6 months old as documented by coronary angiography (chronically occluded grafts, ten patients). The mean graft diameter was determined by repetitive measurements on a workstation through blinded readers. The Mann-Whitney-U-test for unpaired samples was used for statistical evaluation. RESULTS: Mean graft diameter for groups A-C (patent, acutely, and chronically occluded bypasses, respectively) was 3.9 mm (+/-0.6; n=16), 5.4 mm (+/-1.9; n=11), and 0.3 mm (+/-.9; n=12), respectively (P<0.01 each). Sensitivity and specificity for the detection of acute and chronic occlusions were 87 and 92% (cut-off 4.5 mm), respectively, and 92 and 96% (cut-off 1 mm), respectively. CONCLUSIONS: EBT may allow for non-invasive differentiation between acute and chronic venous coronary bypass occlusions. This could help prevent unnecessary invasive recanalization procedures. Body veins may conserve their ability to increase in diameter in acute thrombosis when transplanted as coronary bypasses.     

Effects of passive cardiac containment on left ventricular structure and function: verification by volume and flow measurements.

BACKGROUND: The cardiac support device (CSD, Acorn) is a compliant, textile-mesh graft placed around the ventricles to prevent further dilatation and to improve function in congestive heart failure. The aim of this study was to verify post-operative changes in left ventricular volumes, ejection fraction, blood flow, and myocardial mass. METHODS: Fourteen patients underwent contrast-enhanced, electrocardiography-triggered electron-beam computerized tomography before and 6 to 9 months after CSD implantation. We measured volume and flow using the slice-summation method and the indicator-dilution technique. RESULTS: We found significant changes for the following parameters: end-diastolic volume decreased from 382.9 +/- 140.2 ml to 311.3 +/- 138.7 ml, end-systolic volume from 310.4 +/- 132.4 ml to 237.4 +/- 133.8 ml, end-diastolic diameter from 75.3 +/- 7.8 mm to 70.7 +/- 11.6 mm, end-systolic diameter from 65.8 +/- 7.8 mm to 60.0 +/- 14.0 mm, and myocardial mass from 298.6 +/- 79.6 g to 263.1 +/- 76.8 g. Ejection fraction increased from 20.3% +/- 6.4% to 27.8% +/- 13.1%. We found no significant differences for stroke volume (from 72.5 +/- 24.6 ml to 73.8 +/- 23.6 ml), heart rate (from 80.5 +/- 11.0 beats per minute to 76.5 +/- 6.8 beats per minute), and total cardiac output (from 5.8 +/- 1.9 liter/min to 5.6 +/- 1.8 liter/min). Mitral regurgitation fraction decreased from 30.5% +/- 15.5% to 15.6% +/- 12.8%, increasing antegrade cardiac output from 3.8 +/- 0.9 liter/min to 4.7+/-1.5 liter/min. For most parameters, pre- and post-operative values in these patients differed significantly from those in an age- and gender-matched control group. In each patient, we observed a small hyperdense stripe along the pericardium after surgery, but we observed no local complications. CONCLUSION: Three-dimensional structural and functional data obtained by computerized tomography volume and flow measurements confirm the safety and efficacy of CSD implantation.     

Basic extraction studies of benzylpenicillin and its determination by liquid chromatography with pre-column derivatisation

In order to develop a sensitive and precise chemical bioanalysis of benzylpenicillin in biological fluids, basic studies on benzylpenicillin are presented. These studies include pH dependent stability, extraction in aqueous ethylacetate systems in different pH and buffer compositions. A pre-column derivatisation LC method for the detection of benzylpenicillin also is described. The derivatisation of the sample is performed by the beta-lactam ring specific formation of the mercuric(II)mercaptide of the penicillenic acid in the presence of imidazole. The UV spectral properties of the derivative are utilised for detection. The chromatographic conditions are optimised with reference to the pH, the methanol, the imidazole and the mercury(II)chloride content of the mobile phase as well as the column temperature.     

Incidence and morphology of spontaneous thyroid tumours in different strains of rats

The incidence and morphology of thyroid neoplasms in different strains and stocks of rats are reported. The frequency of thyroid tumours varied to a great extent between different strains of rats. Low incidences were observed in DA/Han (0.85 per cent) and BDII/Han rats (1.25 per cent), while somewhat higher incidences occurred in Han:WIST rats (7.3 per cent). The highest number of thyroid tumour-bearing rats was found in the Han:SPRD stock (55.5 per cent). Thyroid neoplasms were classified histologically as polymorphofollicular adenomas, papillary adenomas, cystadenomas, polymorphofollicular carcinomas, papillary carcinomas, C-cell adenomas and C-cell carcinomas (medullary carcinomas). C-cell neoplasms were predominant in Han:SPRD rats (93.0 per cent), while the majority of tumour-bearing Han:WIST rats (61.4 per cent) had follicular tumours.     

Long-term stable fibrin gels for cartilage engineering

It is essential that hydrogel scaffold systems maintain long-term shape stability and mechanical integrity for applications in cartilage tissue engineering. Within this study, we aimed at the improvement of a commercially available fibrin gel in order to develop a long-term stable fibrin gel and, subsequently, investigated the suitability of the optimized gel for in vitro cartilage engineering. Only fibrin gels with a final fibrinogen concentration of 25mg/ml or higher, a Ca(2+) concentration of 20mm and a pH between 6.8 and 9 were transparent and stable for three weeks, the duration of the experiment. In contrast, when preparing fibrin gels with concentrations out of these ranges, turbid gels were obtained that shrank and completely dissolved within a few weeks. In rheological characterization experiments, the optimized gels showed a broad linear viscoelastic region and withstood mechanical loadings of up to 10,000 Pa. Bovine chondrocytes suspended in the optimized fibrin gels proliferated well and produced the extracellular matrix (ECM) components glycosaminoglycans and collagen type II. When initially seeding 3 million cells or more per construct (5mm diameter, 2mm thick), after 5 weeks of culture, a coherent cartilaginous ECM was obtained that was homogenously distributed throughout the whole construct. The developed fibrin gels are suggested also for other tissue engineering applications in which long-term stable hydrogels appear desirable.