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D F Cowan

Publications and source records attributed to D F Cowan.

58 records · Page 4Linked to original sources
PubMedDate not supplied

Experience with a modified fine-needle aspiration biopsy technique in 533 breast cases.

Aspiration cytology depends on skillful preparation of smears, which normally requires a trained cytotechnologist. Collection of aspirates into Saccomanno fixative permits preparation of high-quality smears by trained technologists no matter who does the aspiration. Aspiration by a surgeon was used with palpation and mammography to examine 533 patients in an office-based regional breast health program. Lesions sampled ranged from diffuse thickening to frank tumors. Lesions suspicious to any one of the three examinations were biopsed. Cytologically diagnosable material was obtained in 349 instances: 120 were malignant, 22 suspicious, 12 atypical, and 195 benign. Of the 184 yielding insufficient cells, 116 were benign on palpation and mammography, and 68 were suspicious. Biopsy proved 57 of these benign and 11 malignant. There were no cytologic false positives in the study. There was a 2% false-negative rate on productive aspirates. Nonproductive aspiration occurred in 4.8% of malignant cases.

Adult↗
PubMedDate not supplied

Increased collateral arterial and venous endothelial cell turnover after renal artery stenosis in the dog.

Renal artery stenosis was induced in dogs and collateral arterial formation assessed by serial angiography and histology. Endothelial cell turnover was estimated by radioautography in five normal and five collateral-forming kidneys 18-39 days following stenosis with tritiated thymidine. Normal arterial endothelial labeling was 0.1% with a highly significant (p less than 0.0005), 55-fold increase in endothelial labeling in arterial collateral vessels. A smaller but statistically significant increase in the labeling index was also found in endothelial cells of the renal vein, from a normal of 0.065% to 0.4% (p less than 0.005). An excellent correlation was found between endothelial cell labeling in small arteries and the renal veins (r = 0.97; p less than 0.01). A marked increase in epithelial cell labeling of the ureters draining the stenotic kidneys was also evident (p less than 0.005). Thus, collateral vessel development is characterized by active DNA synthesis in cellular elements, and a humoral factor is implicated in the vascular response.

Angiography↗