Supporting perception in the service of dynamic decision making

Skilled performers in complex environments rely heavily on heuristic strategies to cope with the time pressure and complexity of dynamic tasks. We suggest that the use of task simplification strategies based largely on perception and pattern recognition is fundamental to the novice-expert shift in dynamic decision making. We therefore suggest that interface training interventions should support the development of highly effective and robust heuristic strategies, rather than the development of more abstract, cognitively intensive strategies. A pair of empirical studies are presented that investigated the benefits of training interventions aimed at supporting perceptual and pattern-recognitional activities in dynamic environments. Results suggest that the acquisition of skilled performance in dynamic environments can be accelerated by supporting perceptual activities in the service of dynamic decision making. Implications of these results for training, aiding, and interface design are discussed.

Discovery and optimization of a novel class of orally active nonpeptidic endothelin-A receptor antagonists

A novel class of endothelin-A receptor ligands was discovered by high-throughput screening. Lead structure optimization led to highly potent antagonists which can be synthesized in a short sequence. The compounds are endothelin-A-selective, are orally available, and show a long duration of action.

Age-adjusted recurrence risks for relatives of patients with multiple sclerosis

Familial aggregation is a cardinal epidemiological feature of multiple sclerosis, but few investigators have systematically examined recurrence risks for relatives of affected individuals in the United Kingdom. As part of a cross-sectional study of multiple sclerosis in Cambridgeshire, pedigree details were taken on 674 probands. Sex-specific, crude and age-adjusted recurrence risks were assessed amongst relatives of probands, applying a statistical model based on the observed age at onset of affected individuals and providing risks for clinical counselling. Details on year of birth, present age or age at death, and disease status were available on 11 391 relatives of successive probands. Nineteen percent of patients reported an additionally affected relative; 128 non-proband affected relatives were identified and the highest risk was observed for sisters. There was a systematic reduction in relative risk with genetic distance from the proband and no preferential recurrence for maternal or paternal relatives.

A survey of automatic teller machine usage across the adult life span

The purpose of this study was to analyze automatic teller machine (ATM) usage across the adult life span. We conducted an extensive survey of 9000 people in the Memphis and Atlanta metropolitan areas. Approximately 17% of those people responded. The survey assessed detailed demographic information, experience with technology in general, experience specifically related to ATMs, problems and dislikes with ATMs, and reasons that people do not use ATMs. The survey provided a valuable set of data. First, we have detailed information about the demographics and individual characteristics of ATM users and nonusers; importantly, these data are stratified across the adult life span. In addition, we know the likes and dislikes of ATM users and the types of problems they typically have using ATMs. Moreover, we have detailed analysis of why adults of all ages may choose not to use ATMs. Training and design implications of these data are discussed.

The nuclear channel system in endometrial adenocarcinoma exposed to medroxyprogesterone acetate

The nuclear channel system (NCS), giant mitochondria and subnuclear glycogen form a triad of ultrastructural features observed in normal human endometrial epithelium in response to progestational steroids. Both the giant mitochondria and subnuclear glycogen have been described in endometrial adenocarcinoma, but the NCS has not. This article reports the development of the NCS in adenocarcinoma treated with medroxyprogesterone acetate. Previous studies suggest that the NCS in normal tissue is a response to the acyl group in the 17-beta position of the D-ring of some progestational steroids, such as medroxyprogesterone acetate. Medroxyprogesterone acetate was administered to 12 postmenopausal women with endometrial adenocarcinoma. Hysterectomies were performed 8 to 20 days after treatment. Pretreatment specimens were also obtained on 8 of the 12 patients. Using standard electron microscopy procedures, light microscopy on plastic semithin sections was first used to confirm the presence of tumor. Thin sections of malignant endometrium were prepared and evaluated ultrastructurally for progestational alterations. Abnormal giant mitochondria and subnuclear glycogen were found both before and after treatment. The third element of the triad, the NCS, was not observed in any of the available pretreatment biopsies, but was seen in three of the treated specimens. Thus it appears that the NCS is a response to the given progesterone therapy.

Synthesis, structure and antitumor activity of new benz[d,e]isoquinoline-1,3-diones

New benz[d,e]isoquinoline-1,3-diones related to mitonafide (CAS 54824-17-8) and amonafide (CAS 69408-81-7) with double substitution on the chromophore and branched side chains have been synthesized and their biological activity determined. Molecular modeling studies of 3a based on X-ray crystallographic data of mitonafide have shown that the aromatic system intercalates between GC steps of DNA. The in vitro cytotoxic test data using CX-1 and LX-1 cells showed higher cytotoxic activities in disubstituted derivatives compared to both lead compounds. Some of the compounds have been selected for in vivo test using L1210 tumor cells and CX-1 cells. Two of them (3b and 3j) have shown promising activity as good candidates for clinical development.

Oncocytic metaplasia of bile duct epithelium in hepatic GVHD

A 15-year-old female underwent matched unrelated BMT for chemotherapy resistant ALL. She died 3 months later from septicaemia complicating grade IV GVHD. Light and electron microscopic examination of the post-mortem liver confirmed GVHD and showed oncocytic metaplasia of interlobular bile duct epithelium. We report that oncocytic metaplasia of bile duct epithelium is part of the pathological spectrum of hepatic GVHD.

Providing for the needs of a dependent patient at home

This article describes the complex nursing and social needs of a patient and her carer which were addressed before discharge home from units for the care of older people. It demonstrates how community care can work given effective planning coordination, collaboration and carer support.

Benzimidazo[1,2-c]quinazolines: a new class of antitumor compounds

A series of substituted benzimidazo[1,2-c]quinazolines have been synthesized. This class of compound has been designed by structural comparison with other intercalator patterns. The determination of in vitro activities has shown high inhibitory values.

Small bowel transplantation for pediatric short bowel syndrome: evaluation of the graft length required for development and the immunologic aspects relating to graft length

Small bowel transplantation (SBT) is thought to be the only radical treatment for short bowel syndrome in childhood. It is very important that the length of the graft and the type of intestine be chosen carefully because this will determine the outcome of transplantation. This model of short bowel syndrome in the rat confirms that total intestinal resection results in malnutrition and failure to gain weight. After 10 cm of ileum was transplanted orthotopically in a syngeneic combination in rats with total intestinal resection, the animals gained weight. The authors determined that 10 cm of terminal ileum is the minimum length required for survival. Second, the immunologic basis of lethal graft-versus-host reaction (GVHR) as it relates to the intestinal graft length was also evaluated. Ileal grafts of 10 cm from LEW (RT1l) rats were implanted heterotopically into (LEW x BN)F1 rats. Ileal grafts of 10 or 40 cm were implanted from BN(RT1n) rats into (LEW x BN)F1 animals. A lethal GVHR always occurred after grafting a 10 cm ileum in the LEW/F1 combination, whereas only 17% of the BN/F1 recipients died of typical GVHR. However, in the latter combination, 67% lethal GVHR was induced when 40 cm of the intestinal graft was implanted. These results indicate that mesenteric lymph nodes are a major source of lethal GVHR, but gut-associated lymphoid tissue can also induce this.

Pentoxifylline therapy for chronic claudication: are patients dependent on therapy?

BACKGROUND

The purpose of this study was to evaluate the efficacy of long-term pentoxifylline therapy.

METHODS

Fifty consecutive patients on long-term pentoxifylline therapy entered a weaning program. The standard dose of 400 mg three times a day was reduced to 400 mg twice a day for 1 month, 400 mg daily for an additional month, and then withdrawn completely for 3 months. Subjective evaluation of each patient's symptoms and objective measurements (treadmill testing for initial claudication distance, maximum walking distance, and ankle/brachial indexes) were evaluated during treatment withdrawal.

RESULTS

Twenty-seven patients tolerated withdrawal of therapy without symptomatic deterioration. Seven of nine patients who did not tolerate weaning had deterioration of treadmill ICD/MWD parameters; there was a significant absolute decrease (p = 0.016) in MWD from 430 +/- 78 to 221 +/- 23 feet. Patients with an initial low MWD were less likely to tolerate weaning. Sixty percent of the patients with successful weaning had clinically asymptomatic deterioration of treadmill ICD/MWD parameters.

CONCLUSIONS

A substantial number of patients who have been on long-term successful pentoxifylline therapy for claudication can be weaned from the drug. Asymptomatic deterioration of treadmill test parameters is not an indication for resuming therapy.

Progress on smoking control in Western Australia

In 1990, 20 years of campaigning by the Western Australian branch of the Australian Council on Smoking and Health succeeded in getting tobacco advertising banned in Western Australia and a fund set up to replace the sponsorship of sport by tobacco companies. The council coordinated the activities of the mainly professional medical organisations that formed its members, ensuring that messages about the dangers of tobacco were consistently presented from different angles. The campaigners also ensured that medical data were reworked for presentation to decision makers and public, invaded the corporate world, and minimised opposition by enlisting the support of sportspeople opposed to tobacco sponsorship. The council hopes now that elimination of advertising will reduce the prevalence of smoking.

Olfactory receptor gene cluster on human chromosome 17: possible duplication of an ancestral receptor repertoire

A gene superfamily of olfactory receptors (ORs) has recently been identified in a number of species. These receptors share a seven transmembrane domain structure with many neurotransmitter and hormone receptors, and are likely to underlie the recognition and G-protein-mediated transduction of odorant signals. Previously, OR genes cloned in different species were from random locations in the respective genomes. We report here the cloning of 16 human OR genes, all from chromosome 17 (17p13.3). The intronless coding regions are physically mapped (on 35 cosmids) in one 0.35Mb long contiguous cluster, with an average intergenic separation of 15kb. The human OR genes in the cluster belong to four different gene subfamilies, displaying as much sequence variability as any randomly selected group of ORs. This suggests that the cluster identified may be one of several copies of an ancestral OR gene repertoire whose existence may predate the divergence of mammals. The latter may have duplicated in some species to form the present mammalian OR gene repertoire, with several hundred genes. The human chromosome 17 OR gene cluster may thus be a good model for understanding human olfaction, as well as the ontogeny and phylogeny of the OR gene superfamily.

Statistical analysis of data from the Third International IALSC Workshop on Lung Tumor and Differentiation Antigens

The main aim of the statistical analysis of data collected in the Third International IALSC Workshop on Lung Tumor and Differentiation Antigens, was to identify groups of monoclonal antibodies (MAbs) having similar profiles of reactivity against a variety of cell types in flow cytometry, histology, immunofluorescence and immunocytochemistry experiments. This was achieved through cluster analysis. We describe the methods used in the cluster analysis, and in the data processing leading to it.

Aggregation bias and the use of regression in evaluating models of human performance

Regression analyses are increasingly being used to provide confirmatory evidence for models of human performance. The amount of information made available to judge these models is reduced because clearly established standards in the techniques of performing and reporting regression analyses are lacking. This paper addresses two primary problems in regression analysis: aggregation of data and the aggregation of variables into composite models. We provide examples of the misuse of regression techniques and recommend ways in which the amount of information made available to evaluate the model being tested can be maximized in analysis and reporting.

Spatial and temporal characteristics of rapid cursor-positioning movements with electromechanical mice in human-computer interaction

This research examines how people make movements with pointing devices during human-computer interaction. It specifically concerns the perceptual-motor processes that mediate the speed and accuracy of cursor positioning with electromechanical mice. In three experiments we investigated the spatial and temporal characteristics of positioning movements made with a mouse, analyzing subjects' speed and accuracy as a function of the types of targets that the movements had to reach. Experiment 1 required rapid and accurate horizontal movements to targets that were vertical ribbons located at various distances from the mouse's starting location. The targets for Experiments 2 and 3, respectively, were vertical lines having various heights and rectangular boxes having various heights and widths. Constraints on movement distance along the primary (that is, horizontal) line of motion had the greatest effects on total positioning times. However, constraints on movement distance along a secondary (vertical) line of motion also affected total positioning times significantly. These effects may be localized in different phases of movements (e.g., movement execution and verification). The duration of movement execution (i.e., physical motion) depends primarily on the target distance, whereas the duration of movement verification (i.e., check for endpoint accuracy) depends primarily on target height and width. A useful account of movement execution is provided by stochastic optimized-submovement models, which have significant implications for designing mice and menu-driven displays.

Use of 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside for the isolation of beta-galactosidase-positive bacteria from municipal water supplies

A new medium, mX-Gal, has been developed for the membrane filter enumeration of beta-galactosidase-positive bacteria in municipal water supplies. mX-Gal medium contains the chromogenic beta-galactosidase substrate 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-Gal). All Aeromonas, Citrobacter, and Enterobacter strains isolated from raw water on mX-Gal medium were beta-galactosidase positive. In contrast, only 10 to 20% of these strains produced a red colony with a metallic sheen on m-Endo agar LES medium. Of 674 chlorinated water samples analyzed for total coliforms on m-Endo agar LES medium and for beta-galactosidase-positive bacteria on mX-Gal medium, 18 that were negative for coliforms on m-Endo agar LES showed beta-galactosidase-positive bacteria on mX-Gal. Of a total of 50 beta-galactosidase-positive bacteria isolated from these samples, 76% were identified as Aeromonas hydrophila.

Hepatitis B virus infection in liver allografts

Liver transplantation of hepatitis B surface antigen (HBsAg)-positive patients has been associated with high morbidity and mortality secondary to hepatitis B (HB) recurrence in the graft. Eight patients of the Queensland Liver Transplant Service were HBsAg positive pretransplant. Six acquired HB infection of the graft, one developed serological recurrence of HB before early death from sepsis, and one HB e antigen-negative patient permanently cleared the virus. HB-infected grafts showed early expression of viral antigen, acute hepatitis, fibrosing cholestatic hepatitis, chronic active hepatitis, cirrhosis, or minimal changes associated with a carrier state. Only in the latter case was HB mild and nonprogressive. Cases of fibrosing cholestatic hepatitis progressed rapidly to liver failure; they showed fibrosis and plates of ductular epithelium extending from portal tracts into lobules, cholestasis, ballooning of hepatocytes, and prominent hepatocyte expression of viral antigens. Perioperative HB immunoglobulin proved ineffective in preventing HB recurrence. One other patient became HBsAg positive for the first time after retransplantation; he developed severe acute hepatitis, then chronic active hepatitis. Our biopsy findings support the view that, in liver allografts, the HB virus may be directly cytopathic.