Electronic structure and local distortions in epitaxial ScGaN films.

High energy resolution fluorescence-detected x-ray absorption spectroscopy and density functional theory calculations were used to investigate the local bonding and electronic structure of Sc in epitaxial wurtzite-structure ScxGa1-xN films with x ≤ 0.059. Sc atoms are found to substitute for Ga atoms, accompanied by a local distortion involving an increase in the internal lattice parameter u around the Sc atoms. The local bonding and electronic structure at Sc are not affected strongly by the strain state or the defect microstructure of the films. These data are consistent with theoretical predictions regarding the electronic structure of dilute Sc(x)Ga(1-x)N alloys.

Uncertainty and expectations: taking care of a cardiac surgery patient at home.

Family members of postsurgical patients are, by necessity, taking on the caregiving role sooner without any specified resources to help them. The input of these caregivers is essential so nurses can understand their concerns, needs, and struggles and develop strategies to support the caregivers in their caregiving role. This study was designed to increase nursing knowledge regarding the experiences of being a caregiver of a cardiac surgery patient during the immediate postdischarge period. The qualitative research method of Interpretative Description, first described by Thorne, Kirkham, and MacDonald-Emes in 1997 guided the study. In-depth interviews were held with eight spousal caregivers. Findings revealed that the experience was molded by caregivers' past participation as a caregiver, as well as caregivers' and care recipients' outlook on life, their interpersonal relationship, and their expectations. Caregivers engaged in the process of caregiving that involved being vigilant and monitoring the care recipient's recovery, implementing strategies to assist the recovery process, and taking on a role to provide care and seek help as required. The encounter with caregiving affected all realms of caregivers' lives, and they experienced feelings of stress, vulnerability, and having to put their lives on hold; these feelings were often compounded by uncertainty.

Fine-needle aspiration of thyroid nodules: correlation between cytology and histology and evaluation of discrepant cases.

BACKGROUND: The purpose of this study was to evaluate the results of thyroid fine-needle aspiration (FNA) and to determine the reasons for the discrepancies between the cytologic and histologic diagnoses. METHODS: The authors evaluated the cytologic and histologic results of 133 FNAs obtained from 92 patients who underwent subsequent thyroidectomies. RESULTS: The initial cytologic results were indeterminate in 39 of 133 cases (29%) because a neoplasm could not be ruled out. These cases corresponded histologically to 9 adenomatoid nodules (ANs), 14 follicular adenomas (FAs), and 16 malignant thyroid neoplasms. The reported FNA diagnoses of the remaining 94 cases (71%) were 48 ANs, 19 follicular neoplasms (FNs), 21 papillary carcinomas (PCs), and 6 cases of Hashimoto's thyroiditis (HT). Correlation of cytology and histology showed that 69 of 94 FNA results (73%) correlated with the histologic diagnoses, whereas 25 (27%) were discrepant. The discrepancies resulted from cytodiagnostic errors in 13 cases (52%), suboptimal smears in 11 (44%), and an FNA sampling error in 1 (4%). The false-negative rate of FNA was 19% and the false-positive rate was 6%. CONCLUSIONS: Diagnostic pitfalls and indeterminate FNA diagnoses were predominantly due to overlapping cytologic criteria between ANs, FNs, and follicular variants of PCs. Rendering a definite diagnosis on suboptimal FNA samples is also a significant source of pitfalls.

Avoiding complications of long-term venous access.

Indwelling venous catheters are invaluable for long-term chemotherapy, antibiotics, and hyperalimentation. However, their placement and chronic use can cause serious complications. This study was done to develop guidelines for minimizing complications of long-term vascular access. Complications associated with 355 lines placed in 297 patients were recorded prospectively at the George Washington University Hospital. Single or double lumen catheters were placed via the infraclavicular subclavian approach (126), external jugular cutdown (133), internal jugular cutdown (22), and cephalic vein cutdown (42). While catheters were malpositioned in 15 cases (5.2%), route of placement did not influence this adverse outcome. Pneumothorax occurred only in the subclavian approach (5.6%). Axillary vein thrombosis was significantly more prevalent in catheters placed via the subclavian vein (10.3%) compared with the external jugular (2.3%) P < 0.05 or cephalic (2.3%) vein. Line sepsis occurred in 28 instances; this was statistically associated with an abnormal white blood count and with the use of double-lumen catheters (double-lumen catheter sepsis = 18.4%, single lumen = 4.4%, P < 0.01). The morbidity of long-term venous catheters is affected significantly by the route of placement, the number of catheter lumens, and the pre-placement white blood count. As a result of our analysis, we recommend single-lumen catheter placement using the external jugular cutdown route whenever possible.

The diagnostic challenge of metastatic linitis plastica. Two cases and a consideration of the problem.

Linitis plastica of the stomach is usually difficult to diagnose preoperatively and can extend locally and metastasize widely before recognition. This insidious manner of spread may cause unusual presentations in organs distant from the stomach. The authors recently treated two patients who were initially found to have radiologic abnormalities of the colon and bladder, respectively. One patient was surgically explored with a view towards the resection of a primary colonic tumor, the other to determine the nature of a bladder tumor. Intraoperative histologic interpretation of frozen tissue samples from the gastric wall in each case radically altered the surgical approach and the prognosis. The clinical presentations illustrate that it may be difficult to obtain preoperative diagnostic tissue samples in such cases and that it is important for the surgeon to inspect and palpate the stomach wall during all abdominal explorations for cancer.

Fine needle aspiration in the treatment of ganglion cysts.

Twenty-eight ganglion cysts in 21 patients were diagnosed by fine needle aspiration (FNA) in the Cytopathology Service of The George Washington University Medical Center from January 1979 to December 1984. Twenty-four of these were aspirated by a pathologist. One patient had two ganglions. Seven of the 21 patients had recurrences and six were reaspirated. In five of those patients the cysts never attained their original size or interfered with function. Follow-up ranged from three to 71 months. Based upon our experience, we believe that FNA is a simple, fast, effective, nontraumatic, inexpensive method of treating ganglion cysts.

Rectosigmoid perforations in homosexual patients.

Five cases of rectosigmoid injury in homosexual males are presented. Early diagnosis based upon an index of suspicion and supported by careful history and physical examination and roentgenography led to prompt surgical intervention and resulted in low morbidity.