Showing papers by "University of Iowa published in 1993"

Classification of subtype of acute ischemic stroke. Definitions for use in a multicenter clinical trial. TOAST. Trial of Org 10172 in Acute Stroke Treatment

Abstract: The etiology of ischemic stroke affects prognosis, outcome, and management. Trials of therapies for patients with acute stroke should include measurements of responses as influenced by subtype of ischemic stroke. A system for categorization of subtypes of ischemic stroke mainly based on etiology has been developed for the Trial of Org 10172 in Acute Stroke Treatment (TOAST). A classification of subtypes was prepared using clinical features and the results of ancillary diagnostic studies. "Possible" and "probable" diagnoses can be made based on the physician9s certainty of diagnosis. The usefulness and interrater agreement of the classification were tested by two neurologists who had not participated in the writing of the criteria. The neurologists independently used the TOAST classification system in their bedside evaluation of 20 patients, first based only on clinical features and then after reviewing the results of diagnostic tests. The TOAST classification denotes five subtypes of ischemic stroke: 1) large-artery atherosclerosis, 2) cardioembolism, 3) small-vessel occlusion, 4) stroke of other determined etiology, and 5) stroke of undetermined etiology. Using this rating system, interphysician agreement was very high. The two physicians disagreed in only one patient. They were both able to reach a specific etiologic diagnosis in 11 patients, whereas the cause of stroke was not determined in nine. The TOAST stroke subtype classification system is easy to use and has good interobserver agreement. This system should allow investigators to report responses to treatment among important subgroups of patients with ischemic stroke. Clinical trials testing treatments for acute ischemic stroke should include similar methods to diagnose subtypes of stroke.

Problem-based learning: a review of literature on its outcomes and implementation issues

Abstract: The effects of problem-based learning (PBL) were examined by conducting a meta-analysis-type review of the English-language international literature from 1972 to 1992. Compared with conventional instruction, PBL, as suggested by the findings, is more nurturing and enjoyable; PBL graduates perform as well, and sometimes better, on clinical examinations and faculty evaluations; and they are more likely to enter family medicine. Further, faculty tend to enjoy teaching using PBL. However, PBL students in a few instances scored lower on basic sciences examinations and viewed themselves as less well prepared in the basic sciences than were their conventionally trained counterparts. PBL graduates tended to engage in backward reasoning rather than the forward reasoning experts engage in, and there appeared to be gaps in their cognitive knowledge base that could affect practice outcomes. The costs of PBL may slow its implementation in schools with class sizes larger than 100. While weaknesses in the criteria used to assess the outcomes of PBL and general weaknesses in study design limit the confidence one can give conclusions drawn from the literature, the authors recommend that caution be exercised in making comprehensive, curriculum-wide conversions to PBL until more is learned about (1) the extent to which faculty should direct students throughout medical training, (2) PBL methods that are less costly, (3) cognitive-processing weaknesses shown by PBL students, and (4) the apparent high resource utilization by PBL graduates.

Two Shorter Forms of the CES-D Depression Symptoms Index:

Abstract: Brief measurement devices can alleviate respondent burden and lower refusal rates in surveys. This article reports on a field test of two shorter forms of the Center for Epidemiological Studies Depression (CES-D) symptoms index in a multisite survey of persons 65 and older. Factor analyses demonstrate that the briefer forms tap the same symptoms dimensions as does the original CES-D, and reliability statistics indicate that they sacrifice little precision. Simple transformations are presented to how scores from the briefer forms can be compared to those of the original.

Sympathetic-Nerve Activity during Sleep in Normal Subjects

Abstract: Background The early hours of the morning after awakening are associated with an increased frequency of events such as myocardial infarction and ischemic stroke. The triggering mechanisms for these events are not clear. We investigated whether autonomic changes occurring during sleep, particularly rapid-eye-movement (REM) sleep, contribute to the initiation of such events. Methods We measured blood pressure, heart rate, and sympathetic-nerve activity (using microneurography, which provides direct measurements of efferent sympathetic-nerve activity related to muscle blood vessels) in eight normal subjects while they were awake and while in the five stages of sleep. Results The mean (±SE) amplitude of bursts of sympathetic-nerve activity and levels of blood pressure and heart rate declined significantly (P<0.001), from 100 ±9 percent, 90 ±4 mm Hg, and 64 ±2 beats per minute, respectively, during wakefulness to 41 ±9 percent, 80 ±4 mm Hg, and 59 ±2 beats per minute, respectively, during stage 4 of non-REM sl...

A role for the dystrophin-glycoprotein complex as a transmembrane linker between laminin and actin

Abstract: The dystrophin-glycoprotein complex was tested for interaction with several components of the extracellular matrix as well as actin. The 156-kD dystrophin-associated glycoprotein (156-kD dystroglycan) specifically bound laminin in a calcium-dependent manner and was inhibited by NaCl (IC50 = 250 mM) but was not affected by 1,000-fold (wt/wt) excesses of lactose, IKVAV, or YIGSR peptides. Laminin binding was inhibited by heparin (IC50 = 100 micrograms/ml), suggesting that one of the heparin-binding domains of laminin is involved in binding dystroglycan while negatively charged oligosaccharide moieties on dystroglycan were found to be necessary for its laminin-binding activity. No interaction between any component of the dystrophin-glycoprotein complex and fibronectin, collagen I, collagen IV, entactin, or heparan sulfate proteoglycan was detected by 125I-protein overlay and/or extracellular matrix protein-Sepharose precipitation. In addition, laminin-Sepharose quantitatively precipitated purified dystrophin-glycoprotein complex, demonstrating that the laminin-binding site is accessible when dystroglycan is associated with the complex. Dystroglycan of nonmuscle tissues also bound laminin. However, the other proteins of the striated muscle dystrophin-glycoprotein complex appear to be absent, antigenically dissimilar or less tightly associated with dystroglycan in nonmuscle tissues. Finally, we show that the dystrophin-glycoprotein complex cosediments with F-actin but does not bind calcium or calmodulin. Our results support a role for the striated muscle dystrophin-glycoprotein complex in linking the actin-based cytoskeleton with the extracellular matrix. Furthermore, our results suggest that dystrophin and dystroglycan may play substantially different functional roles in nonmuscle tissues.

Materials with structural hierarchy

Abstract: The role of structural hierarchy in determining bulk material properties is examined. Dense hierarchical materials are discussed, including composites and polycrystals, polymers, and biological materials. Hierarchical cellular materials are considered, including cellular solids and the prediction of strength and stiffness in hierarchical cellular materials.

Comprehensive meta-analysis of integrity test validities: Findings and implications for personnel selection and theories of job performance.

Abstract: The authors conducted a comprehensive meta-analysis based on 665 validity coefficients across 576,460 data points to investigate whether integrity test validities are generalizable and to estimate differences in validity due to potential moderating influences. Results indicate that integrity test validities are substantial for predicting job performance and counterproductive behaviors on the job, such as theft, disciplinary problems, and absenteeism. The estimated mean operational predictive validity of integrity tests for predicting supervisory ratings of job performance is.41. Results from predictive validity studies conducted on applicants and using external criterion measures (i.e., excluding self-reports) indicate that integrity tests predict the broad criterion of organizationally disruptive behaviors better than they predict employee theft alone

Nitric oxide (NO) and nociceptive processing in the spinal cord.

Abstract: There is considerable evidence to implicate N-methyl-D-aspartate (NMDA) receptor activation in the mechanisms that underly thermal hyperalgesia in the spinal cord As many of the effects of NMDA receptor activation appear to be ultimately mediated through production of nitric oxide (NO), recent reports have begun to define the role of NO in spinal nociceptive processing From this evidence, it is likely that NO, produced in neurons in the spinal cord that contain NO synthase, like NMDA, plays a pivotal role in multisynaptic local circuit nociceptive processing in the spinal cord Collectively, these reports suggest that the reflex withdrawal response to noxious heat is not mediated through activation of NMDA receptors and subsequent production of NO and cGMP, but that the acute NMDA-produced facilitation of thermal reflexes is NMDA-, NO- and cGMP-mediated and that a sustained production of NO and subsequent activation of soluble guanylate cyclase (GC-S) in the lumbar spinal cord appears to be required for maintenance of the thermal hyperalgesia produced in persistent pain models As our knowledge and understanding of the new and intriguing class of neurotransmitters typified by NO emerges, it is likely that the next few years of pain and analgesia research will focus on the cellular events underlying mechanisms of chronic pain

Conscientiousness and performance of sales representatives: Test of the mediating effects of goal setting.

Abstract: The authors used 91 sales representatives to test a process model that assessed the relationship of conscientiousness to job performance through mediating motivational (goal-setting) variables. Linear structural equation modeling showed that sales representatives high in conscientiousness are more likely to set goals and are more likely to be committed to goals, which in turn is associated with greater sales volume and higher supervisory ratings of job performance. Results also showed that conscientiousness is directly related to supervisory ratings. Consistent with previous research, results showed that ability was also related to supervisory ratings of job performance and, to a lesser extent, sales volume

Nurses' job satisfaction: a meta-analysis of related variables.

Abstract: The purpose of this study was to describe the magnitude of the relationships between nurses' job satisfaction and the variables most frequently associated with it. A meta-analysis of data from 48 studies with a total of 15,048 subjects revealed that job satisfaction was most strongly associated with stress (-.609) and organizational commitment (.526). Seven variables had correlations between .20 and .50: communication with supervisor, autonomy, recognition, routinization, communication with peers, fairness, and locus of control. Four other variables frequently included in these studies had low correlations (less than .20): age, education, tenure, and professionalization. The influence of employment site, date of study, and measures used on the size and consistency of estimates was described.

Patient-related barriers to management of cancer pain

Abstract: Patients' reluctance to report pain and to use analgesics are considered major barriers to pain management. To explore this problem, 270 patients with cancer completed a 27-item self-report questionnaire (BQ) that assessed the extent to which they have concerns about reporting pain and using pain medication. The 8 specific concerns included fear of addiction, beliefs that 'good' patients do not complain about pain, and concern about side effects. Patients also completed a measure of pain severity and pain interference (the BPI). The percentages of patients having concerns assessed by the BQ ranged from 37% to 85%. Those who were older, less educated, or had lower incomes were more likely to have concerns. Higher levels of concern were correlated with higher levels of pain. Based on their reports of pain medications used in the past week and on their reports of pain severity, patients were categorized as under-medicated versus adequately medicated. Those who were under-medicated reported significantly higher levels of concern. The data are discussed in terms of implications for research and practice.

Nouns and verbs are retrieved with differently distributed neural systems

Abstract: In a task designed to elicit the production of verbs, the patients known as AN-1033 and Boswell consistently produced the correct target words, performing no differently from normal controls. However, in a similar task designed to elicit the production of nouns, both patients performed quite defectively, and their scores were many SDs below those of controls. Language processing was otherwise normal--i.e., there were no impairments in grammar, morphology, phonetic implementation, or prosody; reading and writing were normal. In a third patient (KJ-1360), we obtained the reverse outcome--i.e., retrieval of common and proper nouns was preserved, but verb retrieval was defective. Together, the findings in the three patients constitute a double dissociation between noun and verb retrieval. In AN-1033 and Boswell, the lesions are located outside the so-called language areas (left frontoparietal operculum, posterior temporal region, inferior parietal lobule), where damage is associated with aphasia. The region of damage shared by the two patients is in left anterior and middle temporal lobe. This sector of left hemisphere contains systems for the retrieval of nouns that denote concrete entities. We propose that those systems are not essential for the retrieval of verbs and not involved in the vocal implementation of word forms. Those systems perform a two-way lexical-mediation role for concrete nouns and promote the reconstruction of a word form after the processing of sensory-motor characteristics of the entity denoted by that word. The findings in patient KJ-1360, whose lesion is in left premotor cortex, suggest that equivalent mediation systems for verbs are located in the left frontal region.

Toward a synthesis of parental socialization and child temperament in early development of conscience.

Abstract: It is argued that, while research on conscience development has emphasized the contribution of parental socialization, the influence of children's temperament has been largely neglected. Two developmental processes that result in the formation of two respective components of conscience are proposed: (1) development of the tendency to experience affective discomfort, guilt, and anxiety associated with wrongdoing; and (2) development of behavioral control—the ability to inhibit a prohibited action, to suppress an antisocial or destructive impulse, and to perform a more prosocial/desirable behavior. Individual differences among children and qualities of parental socialization in relation to both processes are considered as they contribute to conscience development. Relevant evidence from neopsychoanalytic, attributional, social-learning, and temperament models is reviewed. New avenues of research that integrate socialization and temperament perspectives in a developmental framework are proposed. The importance of the study of early developmental periods is emphasized.

The enduring psychosocial consequences of mania and depression.

Abstract: Objective The authors sought to determine the scope, severity, and persistence of psychosocial impairment arising from bipolar and unipolar affective disorder. Method Patients with bipolar (N = 148) or unipolar (N = 240) major affective disorder were assessed as they sought treatment and again after a 5-year follow-up. Concurrently, parents, siblings, and adult children underwent similar assessments and were followed for 6 years. To quantify the impact of affective disorder, probands were individually matched to relatives who had no lifetime history of affective disorder. Sixty-nine relatives who were depressed at intake constituted a separate, nonclinical study group and were also matched to relatives who were well. Results Both unipolar and bipolar patients began follow-up with deficits in annual income. Relative to comparison subjects, affective disorder groups were significantly more likely to report declines in job status and income at the end of follow-up and significantly less likely to report improvements. Similarly, both bipolar and unipolar patients showed significant deficits in nearly all other areas of psychosocial functioning measured at follow-up. Except for relationships with spouses, deficits did not differ significantly by polarity. Surprisingly, probands with recovery sustained throughout the final 2 years of follow-up also showed severe and widespread impairment. Relatives with major depression exhibited substantial deficits on follow-up, but job status and income were not significantly affected. Conclusions The psychosocial impairment associated with mania and major depression extends to essentially all areas of functioning and persists for years, even among individuals who experience sustained resolution of clinical symptoms.

Macrophage phagocytosis of virulent but not attenuated strains of Mycobacterium tuberculosis is mediated by mannose receptors in addition to complement receptors.

Abstract: We have examined macrophage receptors that mediate phagocytosis of virulent strains (Erdman and H37Rv) and an attenuated strain (H37Ra) of the intracellular pathogen, Mycobacterium tuberculosis. Adherence of the three strains to monocyte-derived macrophages (MDM) is markedly enhanced (>threefold) in the presence of low levels of fresh serum and requires heat-labile serum components because heat inactivation of serum reduces adherence by 65 +/- 5 to 71 +/- 2%. In the presence and absence of serum, adherence of the three strains to MDM is comparable. By electron microscopy, all bacteria are ingested and reside in phagosomes. C receptors (CR) play an important role in adherence of the three strains to MDM in the presence and absence of serum. mAb against CR1, CR3, and CR4 inhibit adherence of Erdman M. tuberculosis in fresh serum by 75 +/- 3% and inhibit the low level of adherence of Erdman (71 +/- 13%), H37Rv (72 +/- 1%), and H37Ra (64 +/- 14%) M. tuberculosis in the absence of serum. Mannose receptors (MR) play an important role in mediating macrophage adherence of the virulent strains but not the attenuated strain of M. tuberculosis. Preincubation of MDM with soluble mannan or mannose-BSA consistently and significantly inhibits adherence of Erdman and H37Rv (up to 60 +/- 7%) but not H37Ra (0 +/- 1 to 5 +/- 5% enhancement of adherence) in the absence of serum. Down-modulation of macrophage MR on mannan substrates inhibits adherence of Erdman (52 +/- 8%) and H37Rv (55 +/- 6%) but not H37Ra (2 +/- 2% enhancement of adherence). Preincubation of MDM with soluble N-acetylglucosamine-BSA also significantly inhibits adherence of the virulent strains (42 +/- 3%). Preincubation of MDM with glucose-BSA minimally inhibits adherence of the three strains (2 +/- 4 to 12 +/- 5%). Anti-MR antibody inhibits adherence of Erdman (57 +/- 2%) and H37Rv (44 +/- 4%) but not H37Ra (4 +/- 5% enhancement of adherence). Inhibition of adherence of zymosan was comparable with that seen with virulent strains of M. tuberculosis in these studies. Down-modulation of macrophage MR also inhibits adherence of Erdman (48 +/- 9%) and H37Rv (20 +/- 2%) in the presence of serum. Simultaneous blockade of MR and CR does not further inhibit adherence of the virulent M. tuberculosis strains over that seen with blocking CR alone.(ABSTRACT TRUNCATED AT 400 WORDS)

The probability of transmitter release at a mammalian central synapse

Abstract: When an action potential reaches a synaptic terminal, fusion of a transmitter-containing vesicle with the presynaptic membrane occurs with a probability (pr) of less than one. Despite the fundamental importance of this parameter, pr has not been directly measured in the central nervous system. Here we describe a novel approach to determine pr, monitoring the decrement of NMDA (N-methyl-D-aspartate)-receptor mediated synaptic currents in the presence of the use-dependent channel blocker MK-801 (ref. 2). On a single postsynaptic CA1 hippocampal slice neuron, two classes of synapses with a sixfold difference in pr are resolved. Synapses with low pr contribute to over half of transmission and are more sensitive to drugs enhancing transmitter release. Switching between these two classes of synapses provides the potential for large changes in synaptic efficacy and could underlie forms of activity-dependent plasticity.

Nucleic acid hybridization and amplification method for detection of specific sequences in which a complementary labeled nucleic acid probe is cleaved

Abstract: A method of detection of nucleic acid (DNA or RNA) target sequence in which such a sequence serves as a cofactor for a catalytic reaction in which a complementary, labeled nucleic acid probe is cleaved such that the target sequence is released intact and can repeatedly recycle through the reaction pathway, thereby providing signal amplification.

Determinants of Employee Job Satisfaction: An Empirical Test of a Causal Model

Abstract: The job satisfaction model embedded in the Price-Mueller turnover model was revised and estimated. The revised model examined the effects of a series of environmental, job characteristics, and personality variables that were excluded from the Price-Mueller model. Two-wave longitudinal data were collected from 405 employees of a 327-bed Veterans Administration Medical Center. Four different models representing refinements of the proposed model were estimated using LISREL maximum likelihood methods. The exclusion of important job characteristics (role conflict, supervisory support, and task significance) by the Price-Mueller model was not found to have a significant impact on the explanatory power of the revised model. However, the exclusion of an environmental factor (opportunity) and a personality variable (positive affectivity) was found to be a serious omission. Overall, it was found that the degree to which employees like their job is influenced by a combination of characteristics of the environment (o...

The outcome of Charnley total hip arthroplasty with cement after a minimum twenty-year follow-up. The results of one surgeon.

Abstract: We evaluated the results of 330 total hip arthroplasties that were performed with use of the Charnley prosthesis and cement in 262 patients by the senior one of us between July 1970 and April 1972. All hips had been thoroughly assessed preoperatively to document the patient's functional level. All patients had been disabled because of pain in the hip or a fracture of the hip, and 212 patients (81 per cent) had used walking aids. At a minimum of twenty years after the index operation, eighty-three patients (ninety-eight hips) were still living, 174 patients (224 hips) had died, and five patients (eight hips) had been lost to follow-up. The outcome of the arthroplasty was determined for all except the five latter patients. Thus, the outcome of 322 (98 per cent) of the 330 arthroplasties was known at the latest follow-up evaluation. Radiographs were available for sixty-three of the eighty-three patients (seventy-six [78 per cent] of the ninety-eight hips) who were alive for the entire follow-up period. Of the ninety-eight hips in the living patients, eighty-three (85 per cent) caused no pain, fourteen (14 per cent) caused mild pain, and one (1 per cent) caused moderate pain. Fifty-two hips (53 per cent) were in patients who did not use walking aids, and only seven (7 per cent) were in patients who used support for walking because of the hip. At the minimum twenty-year follow-up, thirty-two (10 per cent) of the 322 hips that had been followed had been revised: eight (2 per cent), because of loosening with infection; twenty-one (7 per cent), because of aseptic loosening; and three (1 per cent), because of dislocation. Of the ninety-eight hips of the patients who were still alive, fifteen (15 per cent) had been revised: three (3 per cent), because of loosening with infection; eleven (11 per cent), because of aseptic loosening; and one (1 per cent), because of dislocation. The rate of revision due to aseptic loosening of the acetabular component in all 322 hips was 6 per cent (eighteen hips), while in the ninety-eight hips of the patients who were alive at least twenty years after the arthroplasty, it was 10 per cent (ten hips). The rate of revision because of aseptic loosening of the femoral component in all 322 hips was 2 per cent (eight hips), while in the ninety-eight hips of the living patients, it was 3 per cent (three hips).(ABSTRACT TRUNCATED AT 400 WORDS)

Sensory circumventricular organs and brain homeostatic pathways

Abstract: Circumventricular organs (CVOs), small structures bordering the ventricular spaces in the midline of the brain, have common morphological and endocrine-like characteristics that distinguish them from the rest of the nervous system. Among their unique features are cellular contacts with two fluid phases--blood and cerebrospinal fluid--and neural connections with strategic nuclei establishing circuitry for communications throughout the neuraxis. A variety of additional morphological and functional characteristics of the CVOs implicates this group of structures in a wide array of homeostatic processes. For three of the circumventricular organs--the subfornical organ (SFO), the organum vasculosum of the lamina terminalis (OVLT), and the area postrema (AP)--recent findings demonstrate these structures as targets for blood-borne information reaching the brain. We propose that these three sensory CVOs interact with other nuclei in the maintenance of several homeostatic processes by way of neural and humoral links. We emphasize the collective role of brain CVOs in the maintenance of body fluid homeostasis as a model for the functional integration of these fascinating "windows of the brain" within central neurohumoral systems.

Increased manganese superoxide dismutase expression suppresses the malignant phenotype of human melanoma cells.

Abstract: Introduction of a normal human chromosome 6 into human melanoma cell lines results in suppression of tumorigenicity. This suggests that a gene(s) on chromosome 6 controls the malignant phenotype of human melanoma. Because antioxidants can suppress the tumor-promotion phase of carcinogenesis, and because the antioxidant enzyme manganese superoxide dismutase (MnSOD) has been localized to a region of chromosome 6 frequently lost in melanomas, we have examined the effect of transfecting sense and antisense human MnSOD cDNAs into melanoma cell lines. Cell lines expressing abundant (+)-sense MnSOD-5 cDNAs significantly altered their phenotype in culture and lost their ability to form colonies in soft agar and tumors in nude mice. In contrast, the introduction of antisense MnSOD or +psv2neo had no effect on melanoma tumorigenicity. These findings indicate that stable transfection of MnSOD cDNA into melanoma cell lines exerts a biological effect that mimics that observed after introduction of an entire human chromosome 6.

Association of depression with 10-year poststroke mortality.

Abstract: Objective Depression has been linked to higher than expected mortality from natural causes, particularly among elderly patients with physical illness. The authors examined the effect of depression on mortality among a group of stroke patients followed up for 10 years. Method A consecutive series of 103 patients was assessed for major or dysthymic (minor) depression approximately 2 weeks after stroke with the use of a structured mental status examination and DSM-III diagnostic criteria. Vital status was determined for 91 of these patients 10 years later. Results Forty-eight (53%) of the 91 patients had died. Patients with diagnoses of either major or minor depression were 3.4 times more likely to have died during the follow-up period than were nondepressed patients, and this relationship was independent of other measured risk factors such as age, sex, social class, type of stroke, lesion location, and level of social functioning. The mortality rate among depressed patients with few social contacts was especially high: over 90% had died. Conclusions These results indicate that depressed mood following stroke is associated with an increased risk of subsequent mortality. Patients who are depressed and socially isolated seem to be particularly vulnerable.

Optimization of surface micromorphology for enhanced osteoblast responses in vitro.

Abstract: The response of osteoblast-like cells to different implant surface textures was evaluated in this laboratory study. Rough disks of commercially pure titanium were cut from bar stock and prepared as irregular or regular surface morphology at the microscopic level. The irregular samples were polished

Advances in negative Poisson's ratio materials

Abstract: Poisson’s ratio is defined as the lateral contraction strain in a solid divided by the longitudinal extension strain measured in a simple tension experiment. In almost all materials Poisson’s ratio, usually denoted by v, is positive. For isotropic materials (those in which the properties are independent of direction), energy arguments in the theory of elasticity[’] may be used to show that 1 2 v I 112. The relationship between shear modulus G, bulk modulus K, and Poisson’s ratio v for isotropic materials is given by Equation (1).