Detection of chromoluminance patterns on chromoluminance pedestals I: threshold measurements

Measurement of the detection thresholds of patterns on pedestals of various kinds has the potential of providing insight into the mechanisms that mediate pattern vision. This study is concerned with chromoluminance patterns, that is, patterns that vary over space in luminance, chromaticity, or both. Contrast thresholds for 1 c/deg Gabor patterns (targets) were measured as a function of the contrast of Gabor pedestal patterns (TvC functions), where the pedestals paired with each target were modulated in a wide range of directions in color space. For most target-pedestal pairs, the TvC function decreased (facilitation) and then increased as pedestal contrast increased. The increase went above the absolute contrast threshold (masking) for all target-pedestal pairs except in cases where facilitation occurred at the upper end of the pedestal contrast range. The specific form of the TvC function varied greatly with the target and pedestal, consistent with a general model of pedestal effects proposed by Foley [Journal of the Optical Society of America A, 1994, 11(6)]. There were two sets of target-pedestal pairs for which facilitation did not occur, but masking did occur: pairs in which the target was a luminance modulation and the pedestals were individually isoluminant and pairs in which the pedestal was blue/yellow and the target was in any of our directions except blue/yellow.     

Transmission pathways for sporadic Shiga-toxin producing E. coli infections: A systematic review and meta-analysis

Background

Shiga-toxin E. coli infections remain a public health concern because of the severity of the gastrointestinal illness and associated complications. Transmission pathways are typically elucidated from outbreaks, with foodborne transmission the primary source. However, most STEC cases are sporadic. This systematic review aimed to identify the most common pathways for sporadic STEC transmission and quantify their importance.

Acetylcholinesterase and choline acetyltransferase staining of neurons in the opossum esophagus

The purpose of the present investigation was to identify and compare cholinergic intramural neurons in the lower esophageal sphincter and esophageal body by histochemical staining for acetylcholinesterase and the enzyme that synthesizes acetylcholine, choline acetyltransferase. Opossums were anesthetized and their abdominal cavity was opened by a midline incision to expose the esophagogastric junction. The lower esophageal sphincter was identified manometerically and localized in situ with markers. Tissues were removed, rapidly frozen in freon cooled with liquid nitrogen and serial cryostat sections were obtained from the lower esophageal sphincter and esophageal body. Sections were stained with one of the above histochemical procedures and adjacent sections were stained with Solachrome cyanin , which differentially stains nerve elements from muscle fibers. The muscle of the lower esophageal sphincter and esophageal body was stained with nonspecific cholinesterase with some selectivity of intensity of reaction in the various smooth muscle layers. All identifiable plexus neurons in the esophagus stained for nonspecific cholinesterase and acetylcholinesterase. Nerve fiber tracts were also stained for acetylcholinesterase within the longitudinal and circular layers of the tunica muscularis. Reaction for choline acetyltransferase showed no staining in the muscle layers or nerve fiber tracts of either part of the esophagus studied; however, selected neurons within the myenteric plexus of both regions (approximately 38%) were reactive. There was no significant difference in the number of positive choline acetyltransferase neurons in the lower esophageal sphincter or esophageal body.     

Mammary Ductoscopy and Ductal Washings for the Evaluation of Patients with Pathologic Nipple Discharge

Abstract:  The majority of breast diseases result from lesions of the ductal epithelium. Mammary ductoscopy allows for visualization of intraductal abnormalities, and ductoscopic lavage provides thousands of cells for analysis. We reviewed our experience of 89 cases of patients with pathologic nipple discharge (PND) undergoing ductoscopy-directed duct excision and collection of ductal washings. Patients undergoing ductoscopy-directed duct excision with ductal washings had an 88% abnormal pathology rate. Most abnormalities were benign (71% papillomas), but the atypia rate for this group was 62%. The combination of visualization and pathologic analysis of washings provided the highest predictive value for the diagnosis of papilloma. Cellular yields for this technique were excellent with most specimens yielding >5,000 epithelial cells per high powered field and with evaluable ductal cells in 82% of specimens. Mammary ductoscopy offers the advantage of a high lesion localization rates with intraoperative guidance. The most accurate tool was the combination of ductal washings and ductoscopic visualization, but preoperative use of these techniques is not helpful in most cases. Greater than 90% of patients with PND are found to have a lesion on pathologic examination when using this technique for directed duct excision. Of interest, ductal washings obtained from symptomatic patients with benign diseases are often atypical.