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Lien MC, Ruthruff E, Johnston JC. Attentional capture with rapidly changing attentional control settings. ACTA ACUST UNITED AC 2010; 36:1-16. [DOI: 10.1037/a0015875] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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102
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Gebere-Michael SG, Johnston JC, Metaferia GZ, Wuhib MZ, Fernandez HH. Bilaterally symmetric cervical spondylotic amyotrophy: a novel presentation and review of the literature. J Neurol Sci 2009; 290:142-5. [PMID: 20045121 DOI: 10.1016/j.jns.2009.12.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Revised: 11/25/2009] [Accepted: 12/08/2009] [Indexed: 12/12/2022]
Abstract
BACKGROUND Cervical spondylotic amyotrophy (CSA) is considered a syndrome of (1) unilateral upper extremity weakness and atrophy, (2) affecting either the proximal or distal musculature, (3) without sensory impairment or lower extremity dysfunction. AIMS OF STUDY The authors report a novel case of bilaterally symmetric CSA with blurring of the proximal-distal distinction, discuss the pathophysiology, and review the literature. METHODS A 45 year old man presented with a several year history of insidiously progressive bilaterally symmetric upper extremity weakness and wasting, profound in the proximal musculature and moderate to severe in the distal muscle groups. RESULTS Based on the clinical, neuroimaging and electrodiagnostic features, this patient harbors a more severe phenotype of the classical syndrome. CONCLUSION The authors propose expanding the generally accepted definition of CSA to include this bilaterally symmetric form of disease, thereby minimizing diagnostic error or delay. Additionally, based on this case and a review of the literature, adherence to the proximal-distal distinction should be avoided since it is commonly blurred. Accurate diagnosis is crucial since this presentation mimics the motor neuron disease variant Vulpian-Bernhardt syndrome. The importance of early diagnosis is underscored by reports of significant improvement with timely surgical decompression.
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Johnston JC. Life threatening intracerebral hemorrhage with isometheptene mucate, dichlorophenazine and acetaminophen combination therapy. J Forensic Leg Med 2009; 16:489-91. [PMID: 19782324 DOI: 10.1016/j.jflm.2009.07.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2008] [Revised: 04/08/2009] [Accepted: 07/01/2009] [Indexed: 10/20/2022]
Abstract
A 45 year old female with no stroke risk factors suffered a massive intracerebral hemorrhage (ICH) after ingesting Midrin--a combination of isometheptene mucate, dichlorophenazine and acetaminophen. Neuroimaging revealed no evidence of structural disease or underlying vasculopathy. This is the first reported case of isometheptene induced ICH in the absence of underlying cerebrovascular disease. Physicians must be aware of the potential for this complication, and inquire about the use of isometheptene in unexplained cerebral hemorrhages. Neurological communities in countries with nonprescription isometheptene should discourage unsupervised or excessive use of the drug.
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Johnston JC, Shahidi NC, Sadatsafavi M, Fitzgerald JM. Treatment outcomes of multidrug-resistant tuberculosis: a systematic review and meta-analysis. PLoS One 2009; 4:e6914. [PMID: 19742330 PMCID: PMC2735675 DOI: 10.1371/journal.pone.0006914] [Citation(s) in RCA: 291] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2009] [Accepted: 08/05/2009] [Indexed: 11/18/2022] Open
Abstract
Background Treatment outcomes for multidrug-resistant Mycobacterium Tuberculosis (MDRTB) are generally poor compared to drug sensitive disease. We sought to estimate treatment outcomes and identify risk factors associated with poor outcomes in patients with MDRTB. Methodology/Principal Findings We performed a systematic search (to December 2008) to identify trials describing outcomes of patients treated for MDRTB. We pooled appropriate data to estimate WHO-defined outcomes at the end of treatment and follow-up. Where appropriate, pooled covariates were analyzed to identify factors associated with worse outcomes. Among articles identified, 36 met our inclusion criteria, representing 31 treatment programmes from 21 countries. In a pooled analysis, 62% [95% CI 57–67] of patients had successful outcomes, while 13% [9]–[17] defaulted, 11% [9]–[13] died, and 2% [1]–[4] were transferred out. Factors associated with worse outcome included male gender 0.61 (OR for successful outcome) [0.46–0.82], alcohol abuse 0.49 [0.39–0.63], low BMI 0.41[0.23–0.72], smear positivity at diagnosis 0.53 [0.31–0.91], fluoroquinolone resistance 0.45 [0.22–0.91] and the presence of an XDR resistance pattern 0.57 [0.41–0.80]. Factors associated with successful outcome were surgical intervention 1.91 [1.44–2.53], no previous treatment 1.42 [1.05–1.94], and fluoroquinolone use 2.20 [1.19–4.09]. Conclusions/Significance We have identified several factors associated with poor outcomes where interventions may be targeted. In addition, we have identified high rates of default, which likely contributes to the development and spread of MDRTB.
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Goddard MS, Reid KR, Johnston JC, Khanuja HS. Atraumatic bilateral femur fracture in long-term bisphosphonate use. Orthopedics 2009; 32:orthopedics.41933. [PMID: 19708622 DOI: 10.3928/01477447-20090624-27] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Postmenopausal women with osteoporosis are commonly treated with the bisphosphonate class of medications, one of the most frequently prescribed medications in the United States. In the past 4 years, reports have been published implying that long-term bisphosphonate therapy could be linked to atraumatic femoral diaphyseal fractures. This article presents a case of a 67-year-old woman who presented with an atraumatic right femur fracture. She had a medical history notable for use of the bisphosphonate alendronate for 16 years before being switched to ibandronate for 1 year before presentation. She had sustained a similar fracture on the contralateral side 3 years previously. This case report, in addition to a review of the literature, shows that use of the bisphosphonate class of medications for an extended period of time may result in an increased susceptibility to atraumatic femoral diaphyseal fractures. Some studies have suggested that the reason may be the mechanism of action of bisphosphonates, resulting in decreased bone turnover and remodeling. Studies have not shown if the entire class of medications produce a similar result, but patients who have been treated with any bisphosphonate for an extended period of time should be considered at risk. In patients who have already sustained a femoral diaphyseal fracture, imaging of the contralateral side should be performed to identify cortical thickening as an early sign of fracture risk. Patients should also be questioned about thigh pain.
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Ruthruff E, Johnston JC, Remington RW. How strategic is the central bottleneck: Can it be overcome by trying harder? ACTA ACUST UNITED AC 2009; 35:1368-84. [DOI: 10.1037/a0015784] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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107
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Johnston JC, McCann RS. On the locus of dual-task interference: Is there a bottleneck at the stimulus classification stage? Q J Exp Psychol (Hove) 2006; 59:694-719. [PMID: 16707358 DOI: 10.1080/02724980543000015] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Recent studies have provided evidence that dual-task interference is typically caused by a single-channel bottleneck, but the processing locus of the bottleneck has yet to be pinned down. A bottleneck locus at the response-selection stage is widely advocated, but an earlier locus would be consistent with most previous evidence. Four new experiments used the "locus of slack" method to investigate whether the stages postponed by the central bottleneck include stimulus classification, a very late stage of perceptual processing. The experiments varied stimulus classification difficulty for two different analogueue perceptual judgements. Experiment 1 found only modest absorption into slack for the difficulty of a spatial position judgement. Experiments 2-4 found virtually no absorption into slack for the difficulty of a box-width judgement. These results support a bottleneck locus beginning at or before the stage of stimulus classification and hence prior to the stage of response selection. Other evidence, however, leaves no doubt that response selection is also subject to bottleneck postponement. Two architectures are discussed that can account parsimoniously for both old and new results. One posits a single bottleneck resulting from a unified CPU-like central processor; the other posits multiple bottlenecks resulting from multiple processors accomplishing different substages of central processing.
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Ilhan F, Fabrizio EF, McCorkle L, Scheiman DA, Dass A, Palczer A, Meador MB, Johnston JC, Leventis N. Hydrophobic monolithic aerogels by nanocasting polystyrene on amine-modified silica. ACTA ACUST UNITED AC 2006. [DOI: 10.1039/b604323b] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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109
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Lien MC, Ruthruff E, Remington RW, Johnston JC. On the limits of advance preparation for a task switch: do people prepare all the task some of the time or some of the task all the time? J Exp Psychol Hum Percept Perform 2005; 31:299-315. [PMID: 15826232 DOI: 10.1037/0096-1523.31.2.299] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This study investigated the nature of advance preparation for a task switch, testing 2 key assumptions of R. De Jong's (2000) failure-to-engage theory: (a) Task-switch preparation is all-or-none, and (b) preparation failures stem from nonutilization of available control capabilities. In 3 experiments, switch costs varied dramatically across individual stimulus-response (S-R) pairs of the tasks-virtually absent for 1 pair but large for others. These findings indicate that, across trials, task preparation was not all-or-none but, rather, consistently partial (full preparation for some S-R pairs but not others). In other words, people do not prepare all of the task some of the time, they prepare some of the task all of the time. Experiments 2 and 3 produced substantial switch costs even though time deadlines provided strong incentives for optimal advance preparation. Thus, there was no evidence that people have a latent capability to fully prepare for a task switch.
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Ruthruff E, Van Selst M, Johnston JC, Remington R. How does practice reduce dual-task interference: Integration, automatization, or just stage-shortening? PSYCHOLOGICAL RESEARCH 2004; 70:125-42. [PMID: 16703392 DOI: 10.1007/s00426-004-0192-7] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2003] [Accepted: 08/31/2004] [Indexed: 11/26/2022]
Abstract
The present study assessed three hypotheses of how practice reduces dual-task interference: Practice teaches participants to efficiently integrate performance of a task pair; practice promotes automatization of individual tasks, allowing the central bottleneck to be bypassed; practice leaves the bottleneck intact but shorter in duration. These hypotheses were tested in two transfer-of-training experiments. Participants received one of three training types (Task 1 only, or Task 2 only, or dual-task), followed by dual-task test sessions. Practice effects in Experiment 1 (Task 1: auditory-vocal; Task 2: visual-manual) were fully explained by the intact bottleneck hypothesis, without task integration or automatization. This hypothesis also accounted well for the majority of participants when the task order was reversed (Experiment 2). In this case, however, there were multiple indicators that several participants had succeeded in eliminating the bottleneck by automatizing one or both tasks. Neither experiment provided any evidence that practice promotes efficient task integration.
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111
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Ruthruff E, Johnston JC, Van Selst M, Whitsell S, Remington R. Vanishing dual-task interference after practice: has the bottleneck been eliminated or is it merely latent? J Exp Psychol Hum Percept Perform 2003; 29:280-9. [PMID: 12760615 DOI: 10.1037/0096-1523.29.2.280] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Practice can, in some cases, largely eliminate measured dual-task interference. Does this absence of interference indicate the absence of a processing bottleneck (defined as an inability to carry out certain stages in parallel)? The authors show that a bottleneck need not produce any observable interference, provided that there is no temporal overlap in the demand for bottleneck stages on the 2 tasks. Such a "latent" bottleneck is especially likely after practice, when central stages are short. The authors provide new evidence that a latent bottleneck occurred for a participant who produced no interference in M. Van Selst, E. Ruthruff, and J. C. Johnston (1999). These findings demonstrate that the absence of dual-task interference does not necessarily indicate the absence of a processing bottleneck.
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112
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Ruthruff E, Remington RW, Johnston JC. Switching between simple cognitive tasks: the interaction of top-down and bottom-up factors. J Exp Psychol Hum Percept Perform 2002. [PMID: 11766933 DOI: 10.1037//0096-1523.27.6.1404] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
How do top-down factors (e.g., task expectancy) and bottom-up factors (e.g., task recency) interact to produce an overall level of task readiness? This question was addressed by factorially manipulating task expectancy and task repetition in a task-switching paradigm. The effects of expectancy and repetition on response time tended to interact underadditively, but only because the traditional binary task-repetition variable lumps together all switch trials, ignoring variation in task lag. When the task-recency variable was scaled continuously, all 4 experiments instead showed additivity between expectancy and recency. The results indicated that expectancy and recency influence different stages of mental processing. One specific possibility (the configuration-execution model) is that task expectancy affects the time required to configure upcoming central operations, whereas task recency affects the time required to actually execute those central operations.
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113
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Binkley RW, Goewey GS, Johnston JC. Regioselective ring opening of selected benzylidene acetals. A photochemically initiated reaction for partial deprotection of carbohydrates. J Org Chem 2002. [DOI: 10.1021/jo00180a008] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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114
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Johnston JC, Hochhaus L, Ruthruff E. Repetition blindness has a perceptual locus: evidence from online processing of targets in RSVP streams. J Exp Psychol Hum Percept Perform 2002; 28:477-89. [PMID: 11999868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Four experiments tested whether repetition blindness (RB; reduced accuracy reporting repetitions of briefly displayed items) is a perceptual or a memory-recall phenomenon. RB was measured in rapid serial visual presentation (RSVP) streams, with the task altered to reduce memory demands. In Experiment 1 only the number of targets (1 vs. 2) was reported, eliminating the need to remember target identities. Experiment 2 segregated repeated and nonrepeated targets into separate blocks to reduce bias against repeated targets. Experiments 3 and 4 required immediate "online" buttonpress responses to targets as they occurred. All 4 experiments showed very strong RB. Furthermore, the online response data showed clearly that the 2nd of the repeated targets is the one missed. The present results show that in the RSVP paradigm, RB occurs online during initial stimulus encoding and decision making. The authors argue that RB is indeed a perceptual phenomenon.
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115
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Johnston JC, Hochhaus L, Ruthruff E. Repetition blindness has a perceptual locus: Evidence from online processing of targets in RSVP streams. ACTA ACUST UNITED AC 2002. [DOI: 10.1037/0096-1523.28.2.477] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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116
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Ruthruff E, Remington RW, Johnston JC. Switching between simple cognitive tasks: the interaction of top-down and bottom-up factors. J Exp Psychol Hum Percept Perform 2001; 27:1404-19. [PMID: 11766933 DOI: 10.1037/0096-1523.27.6.1404] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
How do top-down factors (e.g., task expectancy) and bottom-up factors (e.g., task recency) interact to produce an overall level of task readiness? This question was addressed by factorially manipulating task expectancy and task repetition in a task-switching paradigm. The effects of expectancy and repetition on response time tended to interact underadditively, but only because the traditional binary task-repetition variable lumps together all switch trials, ignoring variation in task lag. When the task-recency variable was scaled continuously, all 4 experiments instead showed additivity between expectancy and recency. The results indicated that expectancy and recency influence different stages of mental processing. One specific possibility (the configuration-execution model) is that task expectancy affects the time required to configure upcoming central operations, whereas task recency affects the time required to actually execute those central operations.
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117
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Abstract
Recent progress in the study of attention and performance is discussed, focusing on the nature of attentional control and the effects of practice. Generally speaking, the effects of mental set are proving more pervasive than was previously suspected, whereas automaticity is proving less robust. Stimulus attributes (e.g. onsets, transients) thought to have a "wired-in" ability to capture attention automatically have been shown to capture attention only as a consequence of voluntarily adopted task sets. Recent research suggests that practice does not have as dramatic effects as is commonly believed. While it may turn out that some mental operations are automatized in the strongest sense, this may be uncommon. Recent work on task switching is also described; optimal engagement in a task set is proving to be intimately tied to learning operations triggered by the actual performance of a new task, not merely the anticipation of such performance.
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118
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Ruthruff E, Johnston JC, Van Selst M. Why practice reduces dual-task interference. J Exp Psychol Hum Percept Perform 2001; 27:3-21. [PMID: 11248938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
M. A. Van Selst, E. Ruthruff, and J. C. Johnston (1999) found that practice dramatically reduced dual-task interference in a Psychological Refractory Period (PRP) paradigm with 1 vocal response and 1 manual response. Results from 3 further experiments using the highly trained participants of M. A. Van Selst et al. (1999) support 4 main conclusions: (a) A processing bottleneck exists even after extensive practice; (b) the principal cause of the reduction in PRP interference with practice is shortening of Task 1 bottleneck stages; (c) a secondary cause is that 1 or more, but not all, of the Task 2 substages that are postponed before practice are not postponed after practice (i.e., become automatized); and (d) the extent of PRP reduction with practice depends on the modalities of the 2 responses. A control experiment with 2 manual response tasks showed less PRP reduction with practice than that found by Van Selst et al.
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120
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Markvardsen AJ, David WI, Johnston JC, Johnson JC, Shankland K. A probabilistic approach to space-group determination from powder diffraction data. Acta Crystallogr A 2001; 57:47-54. [PMID: 11124502 DOI: 10.1107/s0108767300012174] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2000] [Accepted: 09/05/2000] [Indexed: 11/10/2022] Open
Abstract
An algorithm for the determination of the space-group symmetry of a crystal from powder diffraction data, based upon probability theory, is described. Specifically, the relative probabilities of different extinction symbols are assessed within a particular crystal system. In general, only a small number of extinction symbols are relatively highly probable and a single extinction symbol is often significantly more probable than any other. Several examples are presented to illustrate this approach.
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121
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Remington RW, Johnston JC, Ruthruff E, Gold M, Romera M. Visual search in complex displays: factors affecting conflict detection by air traffic controllers. HUMAN FACTORS 2000; 42:349-366. [PMID: 11132797 DOI: 10.1518/001872000779698105] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Recent free flight proposals to relax airspace constraints and give greater autonomy to aircraft have raised concerns about their impact on controller performance. Relaxing route and altitude restrictions would reduce the regularity of traffic through individual sectors, possibly impairing controller situation awareness. We examined the impact of this reduced regularity in four visual search experiments that tested controllers' detection of traffic conflicts in the four conditions created by factorial manipulation of fixed routes (present vs. absent) and altitude restrictions (present vs. absent). These four conditions were tested under varying levels of traffic load and conflict geometry (conflict time and conflict angle). Traffic load and conflict geometry showed strong and consistent effects in all experiments. Color coding altitude also substantially improved detection times. In contrast, removing altitude restrictions had only a small negative impact, and removing route restrictions had virtually no negative impact. In some cases conflict detection was actually better without fixed routes. The implications and limitations of these results for the feasibility of free flight are discussed. Actual or potential applications include providing guidance in the selection of free flight operational concepts.
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Wang G, Slepushkin V, Zabner J, Keshavjee S, Johnston JC, Sauter SL, Jolly DJ, Dubensky TW, Davidson BL, McCray PB. Feline immunodeficiency virus vectors persistently transduce nondividing airway epithelia and correct the cystic fibrosis defect. J Clin Invest 1999; 104:R55-62. [PMID: 10587528 PMCID: PMC483477 DOI: 10.1172/jci8390] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/1999] [Accepted: 10/22/1999] [Indexed: 11/17/2022] Open
Abstract
Several problems limit the application of gene transfer to correct the cystic fibrosis (CF) Cl(-) transport defect in airway epithelia. These include inefficient transduction with vectors applied to the apical surface, a low rate of division by airway epithelial cells, failure of transgene expression to persist, and immune responses to vectors or vector-encoded proteins. To address these issues, we used a feline immunodeficiency virus-based (FIV-based) vector. FIV vector formulated with a calcium chelator transduced fully differentiated, nondividing human airway epithelia when applied to the apical surface. FIV-based vector encoding the cystic fibrosis transmembrane conductance regulator cDNA corrected the Cl(-) transport defect in differentiated CF airway epithelia for the life of the culture (>3 months). When this approach was applied in vivo, FIV vector expressing beta-galactosidase transduced 1-14% of adult rabbit airway epithelia. Transduced cells were present in the conducting airways, bronchioles, and alveoli. Importantly, gene expression persisted, and cells with progenitor capacity were targeted. FIV-based lentiviral vectors may be useful for the treatment of genetic lung diseases such as CF. This article may have been published online in advance of the print edition.
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Anbazhagan R, Tihan T, Bornman DM, Johnston JC, Saltz JH, Weigering A, Piantadosi S, Gabrielson E. Classification of small cell lung cancer and pulmonary carcinoid by gene expression profiles. Cancer Res 1999; 59:5119-22. [PMID: 10537285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Small cell lung cancer is a common type of lung cancer that is generally classified within the spectrum of neuroendocrine lung neoplasms. Using high-density cDNA arrays, we profiled gene expression of small cell lung cancers and compared these expression profiles to those of normal bronchial epithelial cells and pulmonary carcinoids, which are classified as benign neuroendocrine tumors. We found the overall expression profiles of two small cell lung cancer cell lines, two microdissected tissue samples of primary small cell lung cancer, and cultured bronchial epithelial cells to be relatively similar to one another, with an average Pearson correlation coefficient for these comparisons of 0.63. However, we found the expression profiles of small cell lung cancers (and bronchial epithelial cells) to be surprisingly dissimilar to those of two samples of pulmonary carcinoid tumors, with an average correlation coefficient for these comparisons of 0.20. We then compared the pulmonary carcinoid expression profiles to those of two samples of infiltrating astrocytic brain cancers (oligodendroglioma and high-grade astrocytoma) and found similarity of gene expression among these four samples (average correlation coefficient, 0.57). These gene expression profiles suggest that small cell lung cancers are closely related to (and possibly derived from) epithelial cells, and that pulmonary carcinoids are related to neural crest-derived brain tumors. More generally, our results suggest that broad profiles of gene expression may reveal similarities and differences between tumors that are not apparent by traditional morphological criteria.
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Van Selst M, Ruthruff E, Johnston JC. Can practice eliminate the psychological refractory period effect? J Exp Psychol Hum Percept Perform 1999; 25:1268-83. [PMID: 10531663 DOI: 10.1037/0096-1523.25.5.1268] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Can people learn to perform two tasks at the same time without interference? To answer this question, the authors trained 6 participants for 36 sessions in a Psychological Refractory Period (PRP) experiment, where Task 1 required a speeded vocal response to an auditory stimulus and Task 2 required a speeded manual response to a visual stimulus. The large PRP effect found initially (353 ms in Session 1) shrank to only about 40 ms over the course of practice, disappearing entirely for 1 of the 6 participants. This reduction in the PRP effect with practice is considerably larger than has been previously reported. The obtained pattern of factor interactions between stimulus onset asynchrony and each of three task difficulty manipulations (Task 1 judgment difficulty, Task 2 stimulus contrast, and Task 2 mapping compatibility) supports a postponement (bottleneck) account of dual-task interference, both before and after practice.
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Anbazhagan R, Bornman DM, Johnston JC, Westra WH, Gabrielson E. The S387Y mutations of the transforming growth factor-beta receptor type I gene is uncommon in metastases of breast cancer and other common types of adenocarcinoma. Cancer Res 1999; 59:3363-4. [PMID: 10416594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Recently, mutations of the transforming growth factor-beta receptor type I gene have been reported to occur at high frequency in breast cancer metastases, with all mutations being an identical C to A transversion at nucleotide 1160 of the gene (T. Chen et al, Cancer Res., 58: 4805-4810, 1998). This mutation would result in a serine to tyrosine substitution at codon 387 (S387Y) and would reportedly disrupt receptor function. Because this mutation reportedly occurred at high frequency in breast cancer metastases (42%) and much less frequently in primary breast cancer tumors (6%), this would seem to represent a pivotal genetic alteration in breast cancer progression. To further investigate the possible role of this specific genetic alteration in the progression of breast cancer and other forms of adenocarcinoma, we analyzed 20 breast cancer metastases, 15 lung adenocarcinoma metastases, and 13 colorectal cancer metastases for possible mutations at this site. Using both single-strand conformation polymorphism screening and sequencing, we found no mutations of this gene in any of our samples. Our results suggest the S387Y mutation of the transforming growth factor-beta receptor type I gene is not common in these types of human cancers.
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