Showing papers by "Boston University published in 1986"

Development of criteria for the classification and reporting of osteoarthritis: Classification of osteoarthritis of the knee

Abstract: For the purposes of classification, it should be specified whether osteoarthritis (OA) of the knee is of unknown origin (idiopathic, primary) or is related to a known medical condition or event (secondary). Clinical criteria for the classification of idiopathic OA of the knee were developed through a multicenter study group. Comparison diagnoses included rheumatoid arthritis and other painful conditions of the knee, exclusive of referred or para-articular pain. Variables from the medical history, physical examination, laboratory tests, and radiographs were used to develop sets of criteria that serve different investigative purposes. In contrast to prior criteria, these proposed criteria utilize classification trees, or algorithms.

A Report of Three Cases

Abstract: The authors report the pathologic features of three cases of amyloidosis associated with cystic fibrosis. Renal biopsy led to the diagnosis (case 1) or suspicion (case 2) of amyloidosis in patients who were 23 and 21 years old, respectively. The third patient died at age 22 years, and amyloidosis was not discovered until autopsy. Immunohistochemical staining and potassium-permanganate pretreatment of histologic sections in all three cases provided evidence that the amyloid seen in these patients is of the secondary (AA) type. Congo red staining in each case and electron microscopy in case 1 confirmed the initial diagnosis of amyloidosis. A markedly elevated serum amyloid A protein (160 micrograms/mL; normal less than 1 microgram/mL) in case 1 indicated the presence of large quantities of the precursor protein from which the AA fibrils of secondary amyloid are derived. The kidneys, spleen, and liver contained amyloid deposits in autopsy material from all three cases. Involvement of other organs by amyloid was variable. Review of autopsy material in Boston from 23 additional cystic fibrosis patients with long-term survival did not reveal any evidence of amyloidosis. It appears that secondary amyloidosis is emerging as a significant, although rare, complication of cystic fibrosis as greater numbers of these patients survive into adulthood.

Average case complete problems

Abstract: Many interesting combinatorial problems were found to be NP-complete. Since there is little hope to solve them fast in the worst case, researchers look for algorithms which are fast just “on average,” This matter is sensitive to the choice of a particular NP-complete problem and a probability distribution of its instances. Some of these tasks are easy and some not. But one needs a way to distinguish the “difficult on average” problems. Such negative results could not only save “positive” efforts but may also be used in areas (like cryptography) where hardness of some problems is a frequent assumption. It is shown in [1] that the Tiling problem with uniform distribution of instances has no polynominal “on average” algorithm, unless every NP-problem with every simple probability distribution has it.

Treatment with desmopressin acetate to reduce blood loss after cardiac surgery. A double-blind randomized trial.

Abstract: Bleeding after cardiopulmonary bypass remains a cause for concern, requiring reexploration of the chest in approximately 3 percent of patients who have had operations on the heart. We examined the possibility that this problem might be alleviated by desmopressin acetate (DDAVP), which increases the plasma level of von Willebrand factor and improves hemostasis in mild hemophilia and other conditions associated with defective platelet function. In a double-blind, prospective, randomized trial, we studied the effect of intraoperative desmopressin acetate in 70 patients undergoing various cardiac operations requiring cardiopulmonary bypass. Patients undergoing uncomplicated primary coronary-artery bypass grafting were not included. The drug significantly reduced mean operative and early postoperative blood loss (1317±486 ml in the treated group vs. 2210±1415 ml in the placebo group); of the 14 patients whose 24-hour blood loss exceeded 2000 ml, 11 had received the placebo. Plasma levels of von Willeb...

A randomized, controlled trial of amitriptyline and naproxen in the treatment of patients with fibromyalgia.

Abstract: Sixty-two patients with fibromyalgia were randomly assigned to receive 25 mg of amitriptyline at night, 500 mg of naproxen twice daily, both amitriptyline and naproxen, or placebo in a 6-week, double-blind trial. Amitriptyline was associated with significant improvement in all outcome parameters, including patient and physician global assessments, patient pain, sleep difficulties, fatigue on awakening, and tender point score. Patients taking the combined naproxen-amitriptyline regimen experienced minor, but not significant, improvement in pain when compared with patients who took amitriptyline alone. Amitriptyline, or amitriptyline and naproxen, is an effective therapeutic regimen for patients with fibromyalgia.

Differential Patterns of Memory Loss Among Patients With Alzheimer's Disease, Huntington's Disease, and Alcoholic Korsakoff's Syndrome

Abstract: • Patients with Huntington's disease (HD), alcoholic Korsakoff's syndrome (KS), and Alzheimer's disease (AD) were compared with normal control subjects on a task designed to assess recognition memory for different classes of stimuli: spatial, verbal, color, pattern, and facial. In addition, recall of verbal stimuli was assessed at two delay intervals. On recognition testing, AD and KS patients were impaired on each of the five stimulus conditions. However, HD patients, though impaired on four of the recognition conditions, were unimpaired when verbal stimuli were used. On recall testing, the AD, HD, and KS groups were equally impaired at the shorter delay (15 s). However, at the longer delay (two minutes), the KS and HD patients, though still impaired relative to the normal control group, performed significantly better than the AD group.

Multinational corporations vs. domestic corporations: financial performance and characteristics

Abstract: The analysis in this paper is composed of two segments. First, the financial performance of a sample of multinational corporations (MNCs) is compared with that derived for a control group of domestic corporations (DMCs) using market-based performance measures. Then, the paper presents a comparison of selected financial characteristics of the firms in the two groups. The results suggest the DMCs appear to have a significantly superior risk-adjusted market-based performance, are significantly less capitalized, and have higher total risk as well as higher systematic risk. The fact that MNCs are substantially larger than DMCs is not found to be a significant factor in explaining the observed difference between the two groups' performance.

Neural dynamics of word recognition and recall: attentional priming, learning, and resonance.

Abstract: Data and models about recognition and recall of words and nonwords are unified using a real-time network processing theory. Lexical decision and word frequency effect data are analysed in terms of the same theoretical concepts that have unified data about development of circular reactions, imitation of novel sounds, matching phonetic to articulatory requirements, serial and paired associate verbal learning, free recall, unitization, categorical perception, selective adaptation, auditory contrast, and word superiority effects. The theory, called adaptive resonance theory, arose from an analysis of how a language system self-organizes in real-time in response to its complex input environment. Such an approach emphasizes the moment-by-moment dynamical interactions that control language development, learning, and stability. Properties of language performance emerge from an analysis of the system constraints that govern stable language learning. Concepts such as logogens, verification, automatic activation, interactive activation, limited-capacity processing, conscious attention, serial search, processing stages, speed-accuracy trade-off, situational frequency, familiarity, and encoding specificity are revised and developed using this analysis. Concepts such as adaptive resonance, resonant equilibration of short term memory, bottom-up adaptive filtering, top-down adaptive template matching, competitive masking field, unitized list representation, temporal order information over item representations, attentional priming, attentional gain control, and list-item error trade-off are applied.

The Practice of Psychiatric Rehabilitation: Historical, Conceptual, and Research Base

Abstract: With the recognition that most psychiatric disorders are associated with severe and persisting disability and the development of effective procedures for improving the long-term outcome of patients, the term "psychiatric rehabilitation" is becoming routinely used in the mental health field. Psychiatric rehabilitation has begun to take its place as a viable, credible intervention approach, even infiltrating professionals' jargon and administrators' program descriptions. The field of psychiatric rehabilitation has progressed to the stage where its history can be traced; its conceptual base and treatment strategies described; its practice observed, monitored, and replicated; and its future growth anchored in a research foundation.

Tip splitting without interfacial tension and dendritic growth patterns arising from molecular anisotropy

Abstract: Two growth mechanisms of considerable recent interest are related to a single statistical mechanical model. Tip splitting without interfacial tension occurs when a fluid pushes into another miscible fluid of higher viscosity. Dendritic growth occurs when anisotropic molecules aggregate—a common example is the snowflake. We find that both structures are fractal objects, and can be obtained from a single statistical mechanical model, implying that there is a relation between the underlying physical processes involved.

High potassium conductance in astrocyte endfeet

Abstract: The distribution of potassium conductance over the surface of freshly dissociated salamander astrocytes was determined by monitoring cell depolarizations evoked by focal increases in the extracellular potassium concentration. The specific potassium conductance of the endfoot processes of these cells was approximately tenfold higher than the conductance of other cell regions. This dramatically nonuniform conductance distribution may play an important role in the regulation of extracellular potassium levels by glia in the brain.

Report of the Task Force on Diagnosis and Management of Meningitis.

Abstract: Children still die or suffer permanent neurologic sequelae as a result of bacterial meningitis. Prompt diagnosis and aggressive management are the goals, but early signs of meningitis are often subtle and nonspecific and, therefore, may be recognized only in retrospect. The physician must identify among the many febrile children seen every day in office practice—most of whom have spontaneously resolving illnesses usually caused by viruses—the few children who have serious bacterial infection requiring early intervention. No single test or battery of tests replaces the clinical acumen of the physician in identifying the child with early signs of bacterial meningitis. Because of controversies about diagnosis and treatment of meningitis voiced in various forums, including the courtroom, the Task Force on Diagnosis and Management of Meningitis has been asked by the Executive Board of the American Academy of Pediatrics to prepare a report on the causes, diagnosis, management, and outcome of meningitis in infants and children. This task force selected for discussion issues of current relevance and controversy in the diagnosis and treatment of bacterial and nonbacterial meningitis. Many other aspects of meningitis are discussed elsewhere. Commentaries on the prevention of disease by chemoprophylaxis (antimicrobial agents) or immunoprophylaxis (vaccines) have been prepared by the Committee on Infectious Diseases of the American Academy of Pediatrics. In addition the Morbidity and Mortality Weekly Report (Centers for Disease Control, Atlanta) publishes recommendations on vaccine usage and chemoprophylaxis formulated by the Advisory Committee on Immunization Practices. These resources are of value to the practitioner who cares for children and needs information on optimal measures for the treatment and prevention of meningitis.

Units in the production of narrative discourse

Abstract: (1986). Units in the production of narrative discourse. Discourse Processes: Vol. 9, No. 4, pp. 391-422.

Imipramine and Chlordiazepoxide in Depressive and Anxiety Disorders: II. Efficacy in Anxious Outpatients

Abstract: • A double-blind, placebo-controlled comparison at three collaborating university sites included 242 patients diagnosed as having anxiety disorders. A two-week placebo washout period preceded random assignment to eight weeks of imipramine hydrochloride, chlordiazepoxide hydrochloride, or placebo treatment. Antianxiety effects of imipramine were superior to those of the other two agents by the second treatment week; these effects became more clearly significant thereafter and were independent of degree of both baseline depression and anxiety. Excluding patients with possible panic-phobic syndromes from the analyses removed most significant antiphobic and antidepressant effects of imipramine but left intact imipramine's significantly superior antianxiety effects.

Avoiding obstacles and resolving kinematic redundancy

Abstract: While obstacles in a robot workspace can effectively reduce the number of degrees of freedom, there need not be a corresponding loss of functionality for kinematically redundant mechanisms. In this paper, disk-like obstacles for a planar three-bar mechanism are classified. The extended Jacobian technique is used to implement an obstacle avoidance technique based on optimizing a distance criterion. The feasibility of applying multiple constraints or optimality criteria for resolving redundancy is investigated.

Pattern in the laminar origin of corticocortical connections

Abstract: The laminar origin of cortical projections to the frontal cortex was studied in 17 adult rhesus monkeys with the use of the retrograde transport of horseradish peroxidase (HRP). The frontal regions injected with HRP extended from the posterior periarcuate region to the frontal pole. The architectonic boundaries of areas containing HRP-labeled neurons were determined from matched sections stained for the visualization of cell bodies, myelin, or acetylcholinesterase. The results showed that the laminar origin of both nearby and distant corticocortical projections was correlated with the architectonic differentiation of the regions giving rise to the projecting afferent fibers. Frontally directed projections from limbic cortices, which show a redimentary laminar organization, emanated mainly from deep layers. On the other hand, projections from increasingly more differentiated cortices arose progressively from the upper (or superagranular) layers. This pattern was observed for projections originating along the axis of architectonic differentiation of the visual, somatosensory, auditory, motor, and preforntal cortical systems. Thus, as the cortical architecture within each system changes from limbic areas toward the primary cortices, the origin of frontally directed projections shifts from predominantly infragranular to predominantly superagranular layers.

Analytic torsion and closed geodesics on hyperbolic manifolds

Abstract: Pour une variete hyperbolique orientee fermee X et ρ une representation orthogonale de Π 1 X, on definit une fonction zeta de type Ruelle Rρ(s) pour Re(s) grand comme le produit sur les geodesiques closes premieres γ des facteurs det [I−ρ(γ) exp(−sl(γ))], ou l(γ) est la longueur de γ. On continue analytiquement Rρ(s) et on calcule son terme principal en s=0

The concept of activity in Soviet psychology : Vygotsky, his disciples and critics

Abstract: The concept of activity is deeply ingrained in Soviet psychological theory, and exactly for that reason contemporary Soviet psychologists have found it extremely difficult to define it clearly This concept was first suggested by Lev Vygotsky as a theoretical remedy for psychological systems that tautologically "explained" phenomena of consciousness through the concept of consciousness Vy- gotsky' s disciples, notably Alexei Leontiev, departed from the original concept of their teacher The demarcation line separating Vygotsky's theory from that of Leontiev oc- curred in the evaluation of the relative importance of se- miotic mediation and practical actions for the development of intelligence Currently there is a revival of interest in the problem of activity both in the Soviet Union and in the United States The concept of activity plays as important and ambiguous a role in Soviet psychology as did the concept of behavior in American studies circa 1920 to 1950 and the concept of consciousness in European psychology of the late 19th century Activity has been the chief category of psycho- logical research in contemporary Soviet psychology since the beginning; and exactly for that reason, the concept of activity has been extremely difficult for Soviet psy- chologists to define clearly Since the time of its inception in the 1920s, this category has undergone a metamor- phosis and has been the subject of so many disputes that it cannot be adequately comprehended out of the context of its history The goal of this article is to provide a historical- theoretical analysis of the evolution of the concept of ac- tivity in Soviet psychology The origin of this concept can be found in the early writings of Lev Vygotsky (1896- 1934), who suggested that socially meaningful activity (Tdtigkeit) may serve as an explanatory principle in re- gard to, and be considered as a generator of, human con- sciousness Further, I review the process of incorporating the concept of activity into Vygotsky's cultural-historical theory of higher mental functions and discuss its relevance for Vygotsky's studies in the development of language and concept formation The most dramatic event in the history of the concept of activity occurred in the mid- 1930s when a group of Vygotsky's disciples came up with a "revisionist" version of activity theory that put practical (material) actions at the forefront while simultaneously playing down the role of signs as mediators of human activity This revisionist position was elaborated theoret- ically by Alexei Leontiev, who subsequently gained the status of official interpreter of Vygotsky's ideas Thus the myth of succession between Vygotsky's and Leontiev's schools of psychology was born Only in the late 1970s has this myth been subjected to a critical scrutiny, and Vygotsky's genuine views have attracted a renewed in- terest For a long period of time, the concept of activity has remained a local affair of Soviet psychology In his clas- sical book The New Man in Soviet Psychology, Raymond Bauer (1952) neglected entirely the concept of activity More recent studies, such as those of Ted Payne (1968), Levy Rahmani (1973), and Luciano Mecacci (1979), mentioned this problem but hardly made it a center of their work The major breakthrough occurred when a volume of translations, The Concept of Activity in Soviet Psychology, edited by James Wertsch, appeared in 1981 Since then, there has been a growing interest among American psychologists in the problem of activity To comprehend this problem properly, one should, however, be cognizant of its complex history and the current re- evaluation of it by the younger generation of Soviet psy- chologists Activity as a n Explanatory Principle

Don't Put Your Leg in Your Mouth: Transfer in the Acquisition of Idioms in a Second Language.

Abstract: The study reported in this article investigated whether second language learners use knowledge of their first language to comprehend and produce idioms in the second language. Subjects were 12 Venezuelan advanced learners of English. Comprehension of 45 English idioms—15 identical in form and meaning to their Spanish equivalents, 15 similar to their Spanish equivalents, and 15 different from the corresponding Spanish idioms—was tested with a multiple-choice test and a definition test. Production of the same 45 idioms was tested with a discourse-completion test and a translation test. Results showed identical idioms were the easiest to comprehend and produce. Similar idioms were comprehended almost as well but showed interference from Spanish. Different idioms were the most difficult to comprehend and produce but showed less interference than similar idioms. Subjects used both inter- and intralingual strategies to produce idioms they did not know. Within each type, the idioms that were comprehended and produced most correctly were those which were frequently used and transparent and which had simple vocabulary and structure.