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R Lindstrom

Publications and source records attributed to R Lindstrom.

13 recordsLinked to original sources
PubMed1989

Accuracy and reproducibility of KeraScanner analysis in PERK corneal topography. PERK Study Group.

The measurement of the corneal radius of curvature centrally and in the corneal periphery is exceedingly difficult because of variables in photography and data acquisition. We present a technique of Automated image scanning of corneal photographs which provides a more accurate and reproducible analysis of the paracentral corneal contour. We analyzed the sources of error of corneal topography measurement. CorneaScope photographs of calibration balls were generated by each Prospective Evaluation of Radial Keratotomy (PERK) Surgical Center. The 90% confidence intervals for individual ring-radial positions on the 8.00 and 10.00 mm balls were 7.91 to 8.09 mm and 9.89 to 10.11 mm respectively. Our isopter method of analysis for clinical comparison averages all eight radii of curvature for each CorneaScopef ring. This isopter technique reduces the corresponding 90% confidence intervals to 7.96 to 8.03 and 9.95 to 10.06 mm. The measurement variability of a 10 mm calibration ball decreased in the following order: calibration ball positioning, scanner personnel, photograph movement between scans, and nonrepositioned scanning. Photographs of calibration balls demonstrate +/- 4 microns of measurement resolution and patient corneal photographs may be evaluated to +/- 40 microns. This automated scanning system provides consistent data when digitizing keratographs.

Biometry↗
PubMed1975

Ultrastructure of human organ-cultured cornea. II. Stroma and epithelium.

The stroma and epithelium of human corneas that had been stored in organ culture medium for 10 to 22 days at 37 C were examined by light and electron microscopy. Total corneal thickness was found to be doubled at ten days and there was no further increase even at 22 days. The posterior portion of the stroma was more hydrated than the anterior region. Stromal cells were reduced in number and normal-appearing cells were present only in superficial stroma. The epithelial basement membrane was irregular and thickened. Although the epithelium was reduced to three or four cells in thickness and the intercellular spaces were dilated, the epithelial cells contained normal subcellular organelles and appeared to be viable.

Basement Membrane↗
PubMed1975

Thigh emphysema and hip pain secondary to gastrointestinal perforation.

A patient presenting with thigh emphysema and hip pain may suggest intra-abdominal pathology. Three new and 19 previously reported cases of thigh emphysema secondary to bowel disease are reviewed. The thigh and hip manifestations can obscure the primary intra-abdominal process either due to the obvious emphysema or to the obtunded abdominal signs secondary to associated neuropathy. Only one of 22 patients with thigh emphysema secondary to bowel perforation had gas gangrene. Early diagnosis of this clinical association is essential since eight of the 11 deaths occurred within a few days after admission. Right-sided thigh emphysema suggests appendicitis, whereas left-sided emphysema is more likely to be secondary to left colonic diverticulitis or carcinoma.

Appendicitis↗
PubMedDate not supplied

Ultrasonic visualization of the non-opacified gallbladder: response of the normal and obstructed canine gallbladder to C8CCK.

In vitro studies of a simulated gallbladder show that B-scan ultrasonography is as reliable as radiography in measuring changes in volume of the organ. The width or planimetric area of the sonogram correlates with the change in balloon volume and with similar radiographic measurements. In vivo measurements of the normal canine gallbladder stimulated by a carefully prescribed infusion of C8CCK in the dose range of 2.2 to 5.5 ng/kg/min over an 8 to 10 minute interval, showed a clearly defined decrease in gallbladder width. In ligation and division of the common bile duct no change in gallbladder size was demonstrated. We conclude that sonography alone can be used to measure a change in gallbladder size to better differentiate complete obstruction of the common bile duct from medical causes in the jaundiced patient.

Animals↗