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Biomedical subjects

J R Anderson

Publications and source records attributed to J R Anderson.

At least 37 records · Page 2Linked to original sources
PubMed2001

Systemic anaplastic large-cell lymphoma: results from the non-Hodgkin's lymphoma classification project.

Anaplastic large-cell lymphoma (ALCL) is a heterogeneous process that may have a T-cell, B-cell, or indeterminant (null) phenotype and which may or may not express the anaplastic lymphoma kinase (ALK) oncoprotein. Because the clinical significance of these variants of ALCL is unclear, we evaluated the cases of ALCL-T/null and ALCL-B identified in the Non-Hodgkin's Lymphoma Classification Project. We evaluated 1,378 cases of non-Hodgkin's lymphoma (NHL), and a consensus diagnosis of ALCL-T/null was made in 33 patients (2.4%) with a diagnostic accuracy of 85%. Compared to 96 patients with other forms of peripheral T-cell lymphoma (PTCL), those with ALCL-T/null were significantly younger, less likely to have advanced-stage disease or bone marrow involvement, more likely to have a low International Prognostic Index score, and had a significantly better survival. Among those with ALCL-T/null, there were no significant differences in the clinical features or survival on the basis of ALK expression. A consensus diagnosis of ALCL-B was made in 15 patients (1.1%), and the diagnostic accuracy was 67%. However, compared to 366 patients with other forms of diffuse large B-cell lymphoma (DLBCL), those with ALCL-B were no different with regard to clinical features or survival. We conclude that patients with ALCL-T/null have favorable prognostic features and excellent survival and should be separated from those with other forms of PTCL for prognostic and therapeutic purposes. In contrast, patients with ALCL-B appear to be similar to those with other forms of DLBCL.

Adult↗
PubMed2001

Does learning a complex task have to be complex? A study in learning decomposition.

Many theories of skill acquisition have had considerable success in addressing the fine details of learning in relatively simple tasks, but can they scale up to complex tasks that are more typical of human learning in the real world? Some theories argue for scalability by making the implicit assumption that complex tasks consist of many smaller parts, which are learned according to basic learning principles. Surprisingly, there has been rather sparse empirical testing of this crucial assumption. In this article, we examine this assumption directly by decomposing the learning in the Kanfer-Ackerman Air-Traffic Controller Task (Ackerman, 1988) from the learning at the global level all the way down to the learning at the keystroke level. First, we reanalyze the data from Ackerman (1988) and show that the learning in this complex task does indeed reflect the learning of smaller parts at the keystroke level. Second, in a follow-up eye-tracking experiment, we show that a large portion of the learning at the keystroke level reflects the learning even at a lower, i.e., attentional level.

Attention↗
PubMed2001

Effects of changes in experimental design on PET studies of isometric force.

Based on single-cell recordings in primates, the relationship between neuronal activity and force magnitude is thought to be monotonic, at least for a subset of pyramidal cells in the motor cortex. Functional neuroimaging studies have also suggested a monotonic relationship between cerebral activation and force magnitude. In order to more precisely define this relationship and to characterize the activation pattern(s) associated with the modulation of static force, we studied 40 normal subjects using [(15)O]water PET and a simple visuomotor task-application of static force on a micro force sensor with the thumb and index finger of the right hand. When our experimental design did not produce the expected result (evidence of a relationship between cerebral activation and force magnitude in ten subjects), we made serial changes in the experimental protocol, including the addition of control (baseline) trials, and increased the number of subjects in an effort to increase our sensitivity to variations in force magnitude. We compared univariate and multivariate data-analytic strategies, but we relied on our multivariate results to elucidate the interaction of attentional and motor networks. We found that increasing the number of subjects from 10 to 20 resulted in an increase in statistical power and a more stable (i.e., more replicable) but qualitatively similar result, and that the inclusion of control trials in a 10-subject group did not enhance our ability to discern significant brain-behavior relationships. Our results suggest that sample sizes greater than 20 may be required to detect parametric variation in some instances and that failure to detect such variation may result from unanticipated neurobehavioral effects.

Adult↗
PubMed2001

Cardiovascular drug-drug interactions.

The drug-drug interactions discussed in this article have either documented or suspected clinical relevance for patients with cardiovascular disease and the clinician involved in the care of these patients. Oftentimes, drug-drug interactions are difficult, if not impossible, to predict because of the high degree of interpatient variability in drug disposition. Certain drug-drug interactions, however, may be avoided through knowledge and sound clinical judgment. Every clinician should maintain a working knowledge of reported drug-drug interactions and an understanding of basic pharmacokinetic and pharmacodynamic principles to help predict and minimize the incidence and severity of drug-drug interactions.

Absorption↗
PubMed2001

Serial modules in parallel: the psychological refractory period and perfect time-sharing.

The authors describe ACT-R/perceptual-motor (ACT-R/PM), an integrated theory of cognition, perception, and action that consists of the ACT-R production system and a set of perceptual-motor modules. Each module (including cognition) is essentially serial, but modules run in parallel with one another. ACT-R/PM can model simple dual tasks such as the psychological refractory period (PRP), including subtle results previously explained with executive process interactive control (EPIC, D. E. Meyer & D. E. Kieras, 1997a). The central difference between the theories is that EPIC's productions can fire in parallel, whereas in ACT-R/PM, they are serial. Results from three PRP-like experiments with more demanding cognitive requirements indicate that cognitive processing for the 2 tasks need not overlap. ACT-R's activation-based retrieval processes are critical in accounting for the timing of these tasks and for explaining the dual-task performance decrement.

Attention↗
PubMed2001

Training squirrel monkeys (Saimiri sciureus) to deceive: acquisition and analysis of behavior toward cooperative and competitive trainers.

Three squirrel monkeys (Saimiri sciureus) learned to reach toward a container that covered food if a cooperative trainer rewarded such reaches by giving the food. A competitive trainer kept any food found, but wrong selections by this trainer were also rewarded. The monkeys initially reached toward the baited container indiscriminately, but gradually and with the aid of color-cued containers, all 3 reliably reached "honestly" and "deceptively" in the presence of the cooperative and competitive trainers, respectively. The monkeys did not appear to take the trainers' knowledge about the location of the food into account, and deception did not occur if food was placed under the normally unbaited container. With additional containers present, monkeys misled the competitive trainer into selecting the unbaited container farthest from the baited one. Although not indicative of mental attribution, the monkeys' behavior suggests awareness of the acquired communicative function of the reaching response.

Animals↗
PubMed2001

Larviposition by nasopharyngeal bot fly parasites of Columbian black-tailed deer: a correction.

Previous reports of Cephenemyia jellisoni Townsend (Diptera: Oestridae) larvipositing onto the lips/lower muzzle of deer, with larvae invading via the mouth, are shown to be erroneous. Additional studies with deer models baited with CO2, 1-octen-3-ol and Deer Trail Scent, and muzzle and nostrils treated with insect adhesive, revealed that only C. apicata Bennett & Sabrosky larviposited onto the lips/lower muzzle; C. jellisoni, by contrast, larviposited into the nostrils. Larval depositions were associated with females of both species observed attacking models. Females of both species also were found stuck on adhesive-treated, baited models not attended by observers. During several seasons of exposure, such models received 89 C. jellisoni larvipositions into the nostrils and 87 C. apicata larvipositions onto the lips/lower muzzle. In laboratory experiments nearly all larvae of both species remained stuck in adhesive within 1 mm or less of where they were deposited.

Animals↗
PubMed2001

Replicative Mcm2 protein as a novel proliferation marker in oligodendrogliomas and its relationship to Ki67 labelling index, histological grade and prognosis.

The grading and prognostic assessment of oligodendrogliomas is severely constrained and there remains a need for improved diagnosis. Recently, we have identified the minichromosome maintenance (MCM) family of proteins as a novel class of proliferation markers. Mcm2 is a protein which forms part of the prereplicative complex. It is necessary for this complex to be assembled at origins of future DNA replication during the G1 phase to allow genome replication in the subsequent S phase. Our aim was to determine whether analysis of Mcm2 protein expression in oligodendrogliomas is of diagnostic value. Immunohistochemical staining for Mcm2 was performed on an archival series of 32 oligodendrogliomas. These tumours have been previously characterized for Ki67, mitotic labelling index and outcome. Cells showing expression of Mcm2 were quantified as a percentage to provide an Mcm2 labelling index. We have demonstrated a good correlation between Mcm2 and Ki67 labelling indices (r = 0.76, P < 0.01) but immunohistochemistry for Mcm2 consistently identified a higher proportion of cells. Mcm2 labelling index was higher in grade III than grade II tumours (P < 0.001). Cases with a high Mcm2 labelling index showed a poorer prognosis than those with a low index (P = 0.497) in univariate analysis, but with wide variation in this small series. Demonstration of Mcm2 expression is of value to demonstrate the proliferative fraction of tumours and is likely to be of prognostic value. Its study in a larger series is therefore warranted.

Antibodies, Monoclonal↗
PubMed2001

Controversies in the management of paratesticular rhabdomyosarcoma: is staging retroperitoneal lymph node dissection necessary for adolescents with resected paratesticular rhabdomyosarcoma?

PURPOSE: Use of retroperitoneal lymph node dissection (RPLND) in paratesticular rhabdomyosarcoma (PTRMS) is controversial and has changed over the past 2 decades. The Intergroup Rhabdomyosarcoma Study Group (IRSG) required ipsilateral RPLND (IRPLND) for all patients with PTRMS treated on IRS-III (1984-91), but changed to clinical evaluation of RPLNs using computerized tomography (CT) in IRS-IV (1991 through 1997). In IRS-IV, only those patients with identified lymph node involvement on CT required surgical evaluation of the RPLNs. Nodal radiation therapy was administered only to patients with RPLNs recognized as positive; such patients received more intensive chemotherapy as well. Thus, they compared the incidence of recognized RPLN involvement using these 2 different approaches. They then analyzed patient outcome to determine whether this change in management affected outcome. METHODS: Eligible patients with group I or II PTRMS who were treated on IRS III (n = 100) or IRS IV (n = 134) were analyzed. Failure-free survival (FFS) and survival (S) rates were estimated using the Kaplan-Meier method and compared using the log-rank test. RESULTS: There was a significant change in the distribution of patients with group I versus II tumors from IRS-III to IRS-IV (group I, 68% in IRS-III versus 82% in IRS-IV). This was the result of decreased node recognition when CT was used to stage RPLNs in IRS-IV and was most notable for adolescents (>10 years of age). Overall, 3-year FFS was 92% for patients treated on IRS-III and 86% for those treated on IRS-IV (P =.10), whereas survival estimates were 96% and 92%, respectively (P =.30). Adolescents were at higher risk of RPLN relapse than were children (<10 years of age) and their FFS and survival were worse, regardless of IRS protocol. Furthermore, adolescents with recognized group II tumors experienced better 3-year FFS than those with group I tumors on IRS-IV (100% versus 68%, P =.06), most likely as a result of receiving radiotherapy and intensified chemotherapy. CONCLUSIONS: Use of only CT scan evaluation of RPLN in IRS-IV led to a decrease in identification of RPLN involvement in boys who present with localized PTRMS, and a higher rate of regional relapse as compared with IRS-III. Adolescents had much higher likelihood of RPLN disease, and they fared significantly worse than did younger children on both studies. Furthermore, adolescent boys with group I tumors experienced worse FFS than those with Group II tumors on IRS-IV, probably because some patients with group II tumors were not identified by CT imaging and thus received less effective therapy. These data suggest that adolescents should have ipsilateral RPLN dissection as part of their routine staging, and those with positive lymph nodes require intensified chemotherapy as well as nodal irradiation.

Adolescent↗
PubMed2001

People don't keep their heads still when looking to one side, and other people can tell.

Twenty pairs of photographs were made of adults looking 25 degrees to the left and 25 degrees to the right while attempting to face forwards. The eye regions of each photograph were concealed. Twenty adults attempted to sort each pair into left-looking and right-looking pictures. They were successful 65% of the time, p < 0.001. This suggests models have difficulty looking to one side without a perceptible head turn or comparable facial cue. This previously unrecognised phenomenon has implications for research on detection of gaze.

Adult↗
PubMed2001

Cytomegalovirus disease in the lower female genital tract.

Cytomegalovirus (CMV) can cause life-threatening disease in immunocompromised patients, such as those with human immunodeficiency virus (HIV). It is a rare but important cause of ulceration in the female genital tract. We report on three cases of CMV disease in the female genital tract. One patient presented with vulvar ulceration and fevers, and two patients presented with bleeding cervical lesions. All diagnoses were confirmed by histology. All patients were treated with intravenous ganciclovir with good result. CMV disease of the female genital tract may result in significant morbidity, with fever, pain, bleeding, and superinfection, and it may be associated with the development of pelvic inflammatory disease and cervical intraepithelial neoplasia. There are several options for diagnosis and for safe treatment.

AIDS-Related Opportunistic Infections↗
PubMed2001

Rhabdomyosarcoma and undifferentiated sarcoma in the first two decades of life: a selective review of intergroup rhabdomyosarcoma study group experience and rationale for Intergroup Rhabdomyosarcoma Study V.

PURPOSE: To review the importance of prognostic factors in developing new protocols for children with rhabdomyosarcoma (RMS). PATIENTS AND METHODS: Four studies conducted by the Intergroup Rhabdomyosarcoma Study (IRS) Group from 1972 through 1991. RESULTS: Favorable prognostic factors are: (1) undetectable distant metastases at diagnosis; (2) primary sites in the orbit and nonparameningeal head/neck and genitourinary nonbladder/prostate regions; (3) grossly complete surgical removal of localized tumor at the time of diagnosis; (4) embryonal/botryoid histology; (5) tumor size < or = 5 cm; and (6) age younger than 10 years at diagnosis. The IRS-V protocols are risk-based and refine therapy by reducing exposure to cyclophosphamide and radiation therapy (XRT) in patients at low risk while adding new, active agents such as topotecan or irinotecan to the standard therapy of vincristine, actinomycin D, and cyclophosphamide (VAC) plus XRT for patients with unfavorable histology or advanced disease. Collection of biologic specimens from patients with newly diagnosed disease continues to identify other factors that may distinguish patients with favorable features from those who need more intensive therapy. A new protocol that takes into account their previous treatment is needed for patients with recurrent disease. This program (being planned) does not include bone marrow/stem cell reconstitution because this strategy has thus far failed to improve survival rates of patients with metastases at diagnosis. CONCLUSION: Better understanding of biologic differences and new, active agents are needed to improve outcome of patients with unfavorable features at presentation.

Adolescent↗
PubMed2001

A hybrid model of categorization.

Category learning is often modeled as either an exemplar-based or a rule-based process. This paper shows that both strategies can be combined in a cognitive architecture that was developed to model other task domains. Variations on the exemplar-based random walk (EBRW) model of Nosofsky and Palmeri (1997b) and the rule-plus-exception (RULEX) rule-based model of Nosofsky, Palmeri, and McKinley (1994) were implemented in the ACT-R cognitive architecture. The architecture allows the two strategies to be mixed to produce classification behavior. The combined system reproduces latency, learning, and generalization data from three category-learning experiments--Nosofsky and Palmeri (1997b), Nosofsky et al., and Erickson and Kruschke (1998). It is concluded that EBRW and ACT-R have different but equivalent means of incorporating similarity and practice. In addition, ACT-R brings a theory of strategy selection that enables the exemplar and the rule-based strategies to be mixed.

Cognition↗
PubMed2001

Decreased expression of cellular prostatic acid phosphatase increases tumorigenicity of human prostate cancer cells.

PURPOSE: Understanding cell proliferation regulation in hormone refractory prostate cancer may provide answers for novel solutions. Protein tyrosine phosphatases have been thought to have key roles in regulating cell proliferation and be involved in oncogenesis, although to our knowledge their functional roles in human prostate cancer remain unknown. Human prostatic acid phosphatase (PAcP), a major phosphatase in prostate epithelium, has been shown to function as a neutral protein tyrosine phosphatase in these cells. We evaluated the biological significance of cellular prostatic acid phosphatase expression in human prostate cancer cells. MATERIALS AND METHODS: Immunohistochemical testing of human prostate cancer archival specimens was done to evaluate the expression of cellular PAcP. Immunoprecipitation and immunoblotting were performed to determine cellular PAcP and SH2 domain-bearing tyrosine phosphatase-1 levels as well as tyrosine phosphorylation of c-ErbB-2/neu in different human prostate cancer cells. The biological behavior of LNCaP derivative sublines was characterized in vitro and in vivo by soft agar analysis and xenograft animal inoculation. RESULTS: Immunohistochemical staining of human prostate clearly showed that cellular levels of PAcP significantly decreases in prostate cancer cells (p <0.001). The results of biochemical characterization revealed that the cellular level of PAcP but not SHP-1, another differentiation associated protein tyrosine phosphatase, consistently correlated negatively with the growth of several human prostate cancer cell lines. Reintroducing cellular PAcP activity in prostate cancer cells by PAcP complementary DNA transfection resulted in decreased tyrosine phosphorylation of c-ErbB-2/neu, decreased proliferation rates in culture as well as decreased anchorage independent growth in soft agar. The xenograft animal model demonstrated that a higher tumor growth rate as well as larger size is associated with a lower level of cellular PAcP. CONCLUSIONS: Cellular PAcP can down-regulate prostate cancer cell growth, at least partially by dephosphorylating c-ErbB-2/neu. Therefore, decreased cellular PAcP expression in cancer cells may be involved in prostate cancer progression.

Acid Phosphatase↗