Corneal asphericity in eye bank eyes implanted with the intrastromal corneal ring.

OBJECTIVE: To evaluate the effects of the intrastromal corneal ring, a device developed to reduce myopia, on corneal asphericity in a large set of eye bank eyes. METHODS: Forty-one deturgesced eye bank eyes were implanted with intrastromal corneal rings of five different thicknesses, ranging from 0.25 mm to 0.45 mm. Corneal asphericity, before and after implantation, was examined using two different metrologies. Corneal asphericity profiles were produced from dioptric power data collected from videokeratography. To statistically assess the corneal asphericity differences between exam times for each intrastromal corneal ring thickness, dependent sample confidence intervals (95%) were calculated for the mean differences between preoperative and postoperative measures for each topographic diameter zone. Laser holographic interferometry was used to inspect corneal asphericity in one eye bank eye case study for four intrastromal corneal ring sizes. Wave unit map and geometric zonal spot ray tracing analyses derived from laser holographic interferometry topography were surveyed. RESULTS: Videokeratographic analysis suggested that preoperative corneal shape was prolate, i.e., flattened from central to paracentral cornea. Corneal shape became more prolate with intrastromal corneal ring implantation for all intrastromal corneal ring thicknesses. Laser holographic interferometry demonstrated that prolate asphericity was preserved with the intrastromal corneal ring sizes tested and that optical collection efficiency of the cornea was not diminished. CONCLUSION: Using two different measurement techniques, this eye bank eye study demonstrated that intrastromal corneal rings maintain prolate corneal asphericity.

Arterial bullet embolism.

We report a case of an arterial bullet embolus and compare it with other cases found in the literature. A 27-year-old white male sustained a .22 caliber gunshot wound that penetrated the abdominal aorta and traveled within the arterial system to occlude the left superficial femoral artery. The case was typical in that projectiles that embolize within the vascular system originate as a low kinetic energy missile injury of the trunk. Atypically, the patient developed ischemic changes from the embolus immediately. After direct aorta repair and immediate transverse arteriotomy bullet removal, the patient recovered fully.

Residual milk in Friesland sheep and the galactopoietic effect associated with oxytocin treatment.

Mature lactating Friesland ewes had a mean lactation yield of 293 +/- 26 kg during a lactation period of 35 +/- 2 weeks giving an average daily milk yield of 1.2 kg/d. Ewes were injected intravenously after normal milking with either saline (sham) or oxytocin and then remilked to determine the volume of residual (alveolar) milk. After a long milking interval of 16 h oxytocin treatment gave a significantly greater total daily milk yield than the sham treatment (oxytocin minus saline, morning milking, 0.199 +/- 0.038 kg, mean +/- s.e.m., P less than 0.01) Oxytocin had a small significant reverse effect after a short milking interval of 8 h (afternoon milking, -0.065 +/- 0.022 kg, P less than 0.05). The average increase in total daily yield over four stages of lactation was 0.133 +/- 0.029 kg (P less than 0.01), or 11% of the average daily milk yield. The galactopoietic effect of oxytocin was associated with the efficient removal of residual (alveolar) milk. Residual milk accounted for 7.4 and 27.2% of the total daily milk yield in ewes treated with saline or oxytocin respectively. Residual milk expressed as a proportion of daily total milk yield remained steady in ewes studied between April and July, but declined in September when yields were less than 1 kg/d.

Nonpalpable breast lesions: wire localization and excisional biopsy.

From January, 1984, through July, 1984, 53 women with 56 nonpalpable suspicious mammographic breast lesions underwent breast biopsy directed by pre-operative needlewire localization. All of the suspicious lesions were removed at the first operation, and, although in 10 patients, the localization wire was greater than 2 cm from the lesion, this did not increase the number of attempts required to excise the lesion. Once the specimen and wire were removed, a radiograph was taken to assure removal of the suspicious area. Also, once the blocks were cut, they were x-rayed to pinpoint further which histopathologic sections would include the area in question. Six of the 56 suspicious mammographic lesions removed were intraductal breast carcinomas. All were Stage I tumors. The remainder of the lesions were benign including 24 with nonproliferative fibrocystic changes, 31 with proliferative fibrocystic changes and only one demonstrating proliferative changes with atypical hyperplasia. This procedure can be performed effectively on outpatients utilizing local anesthesia. Excellent communication among surgeon, radiologist, and surgical pathologist is imperative.

Cholecystokinin cholecystography: is it a useful test?

We reviewed 57 patients, who during the last four years had cholecystokinin cholecystography during evaluation of abdominal pain, and found this test to be reliable for diagnosing chronic acalculous cholecystitis. Eighty-eight percent of the patients in whom abdominal pain was reproduced during cholecystokinin cholecystography and who had less than 50% contraction of the gallbladder were cured or improved after cholecystectomy.

Hemispheric asymmetry for face recognition: cognitive style and the "crossover" effect.

Photographs of faces were serially presented for central viewing, while Ss made either "social" or "physical" judgments about each face. Subsequent tachistoscopic recognition of laterally displaced targets displayed a pattern of contrasting visual field superiorities for faces seen under the two conditions. This "crossover" pattern occurred in opposite directions for reaction time and for accuracy. Field dependent and field independent Ss displayed the crossover equally, but crossovers by field independent Ss showed a consistent direction within each dependent measure, whereas those by field dependent Ss were equally divided between the two directions. Choices of encoding strategy by field independent Ss appear to be more strongly task-determined than those by field dependent Ss, but the relation between the encoding manipulation, presumed encoding strategy differences, and specific visual field advantage remains unknown.

Hemiretinal differences in face recognition: accuracy versus reaction time.

A face-recognition task involving monocular presentation of laterally displaced stimuli yielded a nasal hemiretinal advantage for reaction time for correct identifications, but a temporal hemiretinal advantage for accuracy (d'). These hemiretinal effects, in conjunction with eye dominance, could in principle distort or obscure interpretations of hemispheric processing differences obtained with binocular stimulation.

Hemispheric asymmetry for face recognition: some effects of visual masking, hemiretinal stimulation and learning task.

Five overlearned target faces were presented hemiretinally and identified by name on the recognition trials (Experiment 1). A post-exposure pattern mask was projected by the opposite eye to either the same (MASK) or the opposite (DISTRACTOR) hemisphere as the targets. Target exposure durations yielding 50% accuracy showed significant left-hemisphere and temporal hemiretinal superiorities in DISTRACTOR, but not in MASK. In Experiment 2, recognition accuracy for six faces at a constant exposure duration, under DISTRACTOR and no-mask control conditions, replicated the left-hemisphere advantage. Manipulation of the information accompanying targets during the initial learning task, to encourage either "social" or "physical" encoding of the faces, produced a "crossover" pattern of contrasting hemispheric asymmetries under the two encoding conditions. The overall results suggest that within this design, face recognition can be accomplished in three different ways, producing either no hemispheric asymmetry, undirectional asymmetry, or complex, contrasting asymmetries. These effects appear to have different functional loci. Hemiretinal differences and individual differences in encoding strategies also contributed to complex patterns of hemispheric asymmetry.