Showing papers by "Drexel University published in 1997"

Isolation of a Common Receptor for Coxsackie B Viruses and Adenoviruses 2 and 5

Abstract: A complementary DNA clone has been isolated that encodes a coxsackievirus and adenovirus receptor (CAR). When transfected with CAR complementary DNA, nonpermissive hamster cells became susceptible to coxsackie B virus attachment and infection. Furthermore, consistent with previous studies demonstrating that adenovirus infection depends on attachment of a viral fiber to the target cell, CAR-transfected hamster cells bound adenovirus in a fiber-dependent fashion and showed a 100-fold increase in susceptibility to virus-mediated gene transfer. Identification of CAR as a receptor for these two unrelated and structurally distinct viral pathogens is important for understanding viral pathogenesis and has implications for therapeutic gene delivery with adenovirus vectors.

The validation of a self-report measure of posttraumatic stress disorder : The Posttraumatic Diagnostic Scale

Abstract: The present article reports on the development and validation of a self-report measure of posttraumatic stress disorder (PTSD), the Posttraumatic Diagnostic Scale (PTDS), that yields both a PTSD diagnosis according to Diagnostic and Statistical Manual of Mental Disorders (4th ed.; American Psychiatric Association, 1994; DSM-IV) criteria and a measure of PTSD symptom severity. Two-hundred forty-eight participants who had experienced a wide variety of traumas (e.g., accident, fire, natural disaster, assault, combat) were administered the PTSD module of the Structured Clinical Interview (SCID; Spitzer, Williams, Gibbons, & First, 1990), the PTDS, and scales measuring trauma-related psychopathology. The PTDS demonstrated high internal consistency and test-retest reliability, high diagnostic agreement with SCID, and good sensitivity and specificity. The satisfactory validity of the PTDS was further supported by its high correlations with other measures of trauma-related psychopathology. Therefore, the PTDS appears to be a useful tool for screening and assessing current PTSD in clinical and research settings.

Current issues in recrystallization: a review

Abstract: The current understanding of the fundamentals of recrystallization is summarized. This includes understanding the as-deformed state. Several aspects of recrystallization are described: nucleation and growth, the development of misorientation during deformation, continuous, dynamic, and geometric dynamic recrystallization, particle effects, and texture. This article is authored by the leading experts in these areas. The subjects are discussed individually and recommendations for further study are listed in the final section.

The diagnostic evaluation and multidisciplinary management of neurofibromatosis 1 and neurofibromatosis 2.

Abstract: Objective. —Neurofibromatosis 1 and neurofibromatosis 2 are autosomal dominant genetic disorders in which affected individuals develop both benign and malignant tumors at an increased frequency. Since the original National Institutes of Health Consensus Development Conference in 1987, there has been significant progress toward a more complete understanding of the molecular bases for neurofibromatosis 1 and neurofibromatosis 2. Our objective was to determine the diagnostic criteria for neurofibromatosis 1 and neurofibromatosis 2, recommendations for the care of patients and their families at diagnosis and during routine follow-up, and the role of DNA diagnostic testing in the evaluation of these disorders. Data Sources. —Published reports from 1966 through 1996 obtained by MEDLINE search and studies presented at national and international meetings. Study Selection. —All studies were reviewed and analyzed by consensus from multiple authors. Data Extraction. —Peer-reviewed published data were critically evaluated by independent extraction by multiple authors. Data Synthesis. —The main results of the review were qualitative and were reviewed by neurofibromatosis clinical directors worldwide through an Internet Web site. Conclusions. —On the basis of the information presented in this review, we propose a comprehensive approach to the diagnosis and treatment of individuals with neurofibromatosis 1 and neurofibromatosis 2.

Clinical Characteristics of Women With a History of Childhood Abuse: Unhealed Wounds

Abstract: Objectives. —To determine the prevalence of childhood physical or sexual abuse in women seen in primary care practices; to identify physical and psychologic problems associated with that abuse; and to compare the effects of childhood physical vs sexual abuse and childhood vs adult abuse. Design. —Cross-sectional, self-administered, anonymous survey. Setting. —Four community-based, primary care internal medicine practices. Patients. —A total of 1931 women of varied age and marital, educational, and economic status examined from February through July 1993. Main Outcome Measures. —Prevalence of physical and sexual abuse, physical symptoms, psychological symptoms (Symptom Checklist-22), alcohol abuse (CAGE questions), and street drug use. Results. —Of the 1931 respondents, 424 (22.0%) reported childhood or adolescent physical or sexual abuse. Compared with women who reported never having experienced abuse (n=1257), women who reported abuse as children but not adults (n=204) had more physical symptoms (mean±SE, 6.2±0.2 vs 4.0±0.9;P Conclusions. —Childhood physical or sexual abuse is associated with adult health problems including physical symptoms, psychological problems, and substance abuse; for many variables, this association is as strong as for patients experiencing current abuse.

PSYCHOSOCIAL TREATMENTS FOR POSTTRAUMATIC STRESS DISORDER: A Critical Review

Abstract: Posttraumatic stress disorder (PTSD) has been the subject of growing recognition since its inception in 1980. Owing in part to the relatively recent inclusion of PTSD in the psychiatric nomenclature, research is only beginning to address its treatment in methodologically rigorous studies. In this review, we discuss issues such as prevalence of trauma and of PTSD, and gold standards for treatment outcome research. We then critically review the extant literature on the treatment of PTSD. Finally, we include a discussion of issues specific to various trauma populations and factors that may influence treatment efficacy across types of trauma.

A Randomized Trial of Enhanced Therapy for Early Syphilis in Patients with and without Human Immunodeficiency Virus Infection

Abstract: Background Reports of neurosyphilis and invasion of cerebrospinal fluid by Treponema pallidum in patients with human immunodeficiency virus (HIV) infection have led to doubts about the adequacy of the recommended penicillin G benzathine therapy for early syphilis. Methods In a multicenter, randomized, double-blind trial, we assessed two treatments for early syphilis: 2.4 million units of penicillin G benzathine and that therapy enhanced with a 10-day course of amoxicillin and probenecid. The serologic and clinical responses of patients with and without HIV infection were studied during one year of follow-up. Results From 1991 through 1994, 541 patients were enrolled, including 101 patients (19 percent) who had HIV infection but differed little from the uninfected patients in their clinical presentations. The rates at which chancres and rashes resolved did not differ significantly according to treatment assignment or HIV status. Serologically defined treatment failures were more common among the HIV-infect...

Strain hardening regimes and microstructural evolution during large strain compression of low stacking fault energy fcc alloys that form deformation twins

Abstract: Constant true strain rate simple compression tests were conducted on annealed, polycrystalline samples of α-brass and MP35N, and the evolution of the true stress (σ)-true strain (e) response was documented. From these data, the strain hardening rate was numerically computed, normalized with shear modulus (G), and plotted against both (σ − σ 0)/G (σ0 being the initial yield strength of the alloy) and e. Such normalized plots for α-brass and MP35N were found to be almost identical to each other, and revealed four distinct stages of strain hardening: stage A, with a steadily decreasing strain hardening rate up to a true strain of about −0.08; stage B, with an almost constant strain hardening rate up to a true strain of about −0.2; stage C, with a steadily decreasing strain hardening rate up to a true strain of about −0.55; and a final stage D, again with an almost constant strain hardening rate. Optical microscopy and transmission electron microscopy (TEM) were performed on deformed samples. The results suggested that stage A corresponded to stage III strain hardening (dynamic recovery) of higher stacking fault energy (SFE) fcc metals such as copper. The onset of stage B correlated with the first observation of deformation twins in the microstructure. Further straining in stage B was found to produce clusters of parallel twins in an increasing number of grains. Stage C correlated with the development of severe inhomogeneity of deformation within most grains, and with the development of significant misorientation between the twin/matrix interface and the {111} plane in the matrix of the grain, i.e., the matrix/twin interface lost coherency with continued deformation. Stage D correlated with extensive formation of secondary twins that resulted in twin intersections in many grains. Early in stage D, some strain localization in the form of shear bands was observed. Although formation of these shear bands had no detectable effect on the macroscopic strain hardening rate, it did correlated with a marked change in texture evolution. Based on these experimental observations, we have developed and presented a physical description of the microstructural phenomena responsible for the various strain hardening stages observed in low SFE fcc alloys.

Multisomatoform Disorder: An Alternative to Undifferentiated Somatoform Disorder for the Somatizing Patient in Primary Care

Abstract: Background: For clinical or research use in primary care, theDSM-IVdiagnostic criteria for somatization disorder are too restrictive, while the criteria for undifferentiated somatoform disorder are overly inclusive. In this article, we examine the validity of multisomatoform disorder, defined as 3 or more medically unexplained, currently bothersome physical symptoms plus a long (≥2 years) history of somatization. Methods: Data from the Primary Care Evaluation of Mental Disorders Study of 1000 patients from 4 primary care sites were analyzed. The outcomes assessed were 6 domains of health-related quality of life, using the 20-item Short-Form General Health Survey; selfreported disability days and health care use; satisfaction with care; and physician-rated difficulty of the encounter. Results: Multisomatoform disorder was diagnosed in 82 (8.2%) of the 1000 patients who were enrolled in the Primary Care Evaluation of Mental Disorders Study. Compared with mood and anxiety disorders, multisomatoform disorder was associated with comparable impairment in health-related quality of life, more self-reported disability days and clinic visits, and greater clinician-perceived patient difficulty. Conclusions: Multisomatoform disorder may be a valid diagnosis and potentially more useful than the DSM-IV diagnosis of undifferentiated somatoform disorder. Also, because multisomatoform disorder has a large and independent effect on impairment, its diagnosis should not be precluded simply because of a coexisting mood or anxiety disorder.

Sensor fusion for mobile robot navigation

Abstract: We review techniques for sensor fusion in robot navigation, emphasizing algorithms for self-location. These find use when the sensor suite of a mobile robot comprises several different sensors, some complementary and some redundant. Integrating the sensor readings, the robot seeks to accomplish tasks such as constructing a map of its environment, locating itself in that map, and recognizing objects that should be avoided or sought. The review describes integration techniques in two categories: low-level fusion is used for direct integration of sensory data, resulting in parameter and state estimates; high-level fusion is used for indirect integration of sensory data in hierarchical architectures, through command arbitration and integration of control signals suggested by different modules. The review provides an arsenal of tools for addressing this (rather ill-posed) problem in machine intelligence, including Kalman filtering, rule-based techniques, behavior based algorithms, and approaches that borrow from information theory, Dempster-Shafer reasoning, fuzzy logic and neural networks.

Predictors of Posttraumatic Stress Symptoms in Childhood Cancer Survivors

Abstract: Objective. The diagnosis and treatment of childhood cancer are extremely stressful experiences, with psychological sequelae which can persist many years after the end of treatment. This study investigated the relative contributions of general anxiety, treatment intensity, medical sequelae of treatment, and the subjective appraisal of life threat and treatment intensity to later posttraumatic stress symptoms, such as intrusive memories, avoidance, and hypervigilance. Method. One hundred eighty-six childhood cancer survivors ages 8 through 20 years, off of treatment for more than 1 year, and their parents completed questionnaires. Medical sequelae of treatment and intensity of treatment were rated by a pediatric oncologist. Results. Significant, independent predictors of persistent posttraumatic stress symptoms included: 1) the survivor9s retrospective subjective appraisal of life threat at the time of treatment, and the degree to which the survivor experienced the treatment as “hard” or “scary”; 2) the child9s general level of anxiety; 3) history of other stressful experiences; 4) time since the termination of treatment (negative association); 5) female gender; and 6) family and social support. Mother9s perception of treatment and life threat contributed to anxiety and subjective appraisal for the survivor, but did not independently contribute to posttraumatic stress symptoms. Conclusions. Symptoms of posttraumatic stress seem to decrease with time, but are persistent in a subset of childhood cancer survivors. Other than time and gender, the predictors of posttraumatic stress symptoms are primarily subjective factors (ie, anxiety and subjective appraisal) rather than objective stressors of treatment and medical sequelae.

Incidence of tuberculosis in the United States among HIV-infected persons. The Pulmonary Complications of HIV Infection Study Group.

Abstract: Background: The resurgence of tuberculosis in the United States is largely linked to the human immunodeficiency virus (HIV) epidemic. Despite this link, the epidemiology of tuberculosis and prevent...

β-Arrestin1 Knockout Mice Appear Normal but Demonstrate Altered Cardiac Responses to β-Adrenergic Stimulation

Abstract: β-Arrestin1 knockout mice were studied to define the physiological role of β-arrestin1 in the regulation of G protein–coupled receptors. β-Arrestin1 is thought to be involved in the desensitization of many G protein–associated cell surface receptors, particularly β-adrenergic receptors. Homozygous knockout mice are overtly normal. Resting cardiovascular parameters modulated by β-adrenergic receptors such as heart rate, blood pressure, and left ventricular ejection fraction are not changed. However, homozygous mutants are more sensitive to β-receptor agonist–stimulated increases in ejection fraction, consistent with a role of β-arrestin1 in β-adrenergic receptor desensitization. We conclude that β-arrestin1 is important for in vivo G protein–coupled receptor desensitization and that this aspect of desensitization represents a mechanism for fine-tuning responses. However, β-arrestin1 does not appear to be required for development or for other essential biological functions.

Creating electrical contacts between metal particles using directed electrochemical growth

Abstract: Electrical connections in microelectronics are usually established by means of photolithography to define the conducting channels But methods that do not involve lithography have been explored, such as the use of electrodeposition1 or electropolymerization2,3,4,5,6 to grow random structures of conducting material between two electrodes This approach has been used to make diodes, transistors and signal amplifiers based on conducting polymers2,3 Template-based7,8,9,10,11,12 and thermal plating13 strategies have also been used to direct the growth of electrically conducting media One advantage of these approaches over photolithography is the possibility of forming contacts in three dimensions and so achieving enhanced data-processing densities Previous electrochemical approaches have required that the electrodes to be connected are physically linked to the external voltage source Here we show that electrodissolution and electrodeposition processes in an applied electric field can be exploited to create directional growth of copper deposits between copper particles that are not connected to an external circuit Moreover, the particles distort the electric field in such a way as to focus the diffusion of copper ions and consequently the direction of ‘wire’ growth, enabling the particles to be connected to one another in a directional and controllable manner This suggests that appropriately directed electric fields may be used to connect an array of such particles into an arbitrary circuit pattern

Electrospray sample preparation for improved quantitation in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Abstract: The goal of this work is the development of a rapid and objective matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) method for the quantitation of peptides and proteins in human plasma suitable for use in the Good Laboratory Practices (GLP) environment, where the analytical method, validation and pharmacokinetic parameters derived from concentration data will be scrutinized by global regulatory agencies. Electrospray deposition has traditionally been used to prepare thin, uniform samples for a number of techniques, including Cf-252 plasma desorption and secondary ion mass spectrometry. Here the electrospray process of sample application is used to reduce the segregation of analyte from matrix during the sample drying step. The small droplets formed during the electrospray process are found to significantly improve the homogeneity of the sample surface prepared. Experiments comparing the traditional air dried and electrosprayed methods of sample preparation show that the increase in sample homogeneity from electrosprayed samples decreases both the within-sample spot and between-sample spot variability, resulting in a decrease in percent coefficient of variation (%CV) for the recorded MALDI mass spectra. The increase in sample homogeneity permits a more objective use of MALDI-TOFMS as a quantitative analytical method and has led to the development of an assay for the determination of desamino-[8-D-arginine] vasopressin (DDAVP) using arginine vasopressin (AVP) as internal standard in human plasma. The range of quantitation observed (2.0-10 micrograms/mL) is of limited value for bioanalytical application; however, the analysis of neat standards shows lower quantitation limits are easily achieved.

D4 Dopamine-Receptor (DRD4) Alleles and Novelty Seeking in Substance-Dependent, Personality-Disorder, and Control Subjects

Abstract: Two reports have been published suggesting an association between the personality trait of novelty seeking and the DRD4*7R allele at the D4 dopamine-receptor locus (with heterozygotes or homozygotes for DRD4*7R having higher novelty seeking). We studied novelty seeking and four coding-sequence polymorphisms affecting protein structure in the D4 dopamine-receptor gene (DRD4) in a sample of 341 American subjects, of whom 224 are of primarily European ancestry and 117 are of primarily African ancestry. These subjects had diagnoses of substance dependence or personality disorder (PD) or were screened to exclude major psychiatric diagnosis. We found that, although the substance-dependent subjects had significantly higher novelty seeking than the control and PD subjects, they did not differ in DRD4*7R allele frequency. There was no association between any DRD4 polymorphism and novelty seeking in any population or diagnostic group, except for a significant association between the DRD4*7R allele and lower novelty seeking among European American females and African American substance abusers. The novelty seeking of subjects heterozygous for a null mutation did not differ from that of subjects with two functional alleles. We conclude that the most likely explanation of these results is that the DRD4 VNTR does not influence directly the trait of novelty seeking, in these samples.

Effects of nutrient limitation on biochemical constituents of Ankistrodesmus falcatus

Abstract: 1. Cell size and volume changed as a function of the type of resource limitation, with nitrogen-limited cells being smaller and less dense and phosphorus-limited cells being larger and more dense than non-limited cells. 2. The major biochemical constituents of the green alga Ankistrodesmus falcatus varied as a function of nitrogen or phosphorus limitation (15% of maximum growth rate) compared to cells growing at their maximum rate. Nitrogen-limited cells had much lower protein content and phosphorus-limited cells had higher carbohydrate and lipid contents than cells growing under no limitation. 3. Phosphorus-limited cells had a higher total lipid content than either nitrogen-limited or non-limited cells, but the lipid class composition was similar. 4. The protein : lipid ratio was lowest (0.38) in the nitrogen-limited cells, intermediate in the phosphorus-limited cells (0.44) and highest in the non-limited control cells (1.14).

Size Effects in Barium Titanate Particles and Clusters

Abstract: Clustering has an important effect on the tetragonal-cubic transformation of barium titanate (BaTiO3) particles. Small particles that would be cubic if they were by themselves can be tetragonal if they are in a cluster. The effects of clustering are shown in the behavior of the c/a ratio of the particles and the enthalpy change, ΔH, of transition as a function of particle size. The c/a ratio and the value of ΔH both decrease at a smaller particle size than those which are observed in samples where clustering is minimal. Our results are consistent with the observation that very small grains in polycrystalline samples can remain tetragonal even though the grain size is so small that it would be cubic if it were an individual particle. The transition temperature, TC, on the other hand, is insensitive to the particle size, which is similar to the observation in polycrystalline BaTiO3 that TC is insensitive to the grain size. The observed clustering effect is suggested to result from the reduction of depolarization energy of particles in clusters.

Improving physician - Patient communication in cancer care: Outcome of a workshop for oncologists

Abstract: Background Physicians caring for cancer patients receive little formal training in difficult communications such as breaking bad news, discussing life support, and addressing patients' emotional concerns. Methods The authors conducted a three-day workshop in communication skills for nine oncology attendings and three fellows. Topics for the workshop were selected by participants by a pre-workshop questionnaire. Small groups of four to five participants interviewed simulated patients who role-played scripts based on the selected topics. Sessions on self-awareness and one on planning for continuing the work of the group after the workshop were included. Results Responses to pretest and posttest questionnaires showed that the workshop increased the participants' confidence in a number of communication areas and also in managing physician burnout. Process issues such as patient death and expectations for cure were also discussed. Conclusion Interactive workshops offer a promising way of teaching communication skills and aspects of the physician-patient relationship to oncologists. Conclusions regarding outcome, however, are preliminary and tentative, and long-term results are uncertain.

Accurate characterization of machine compliance for simple compression testing

Abstract: Correction for machine compliance is an important step in analyzing the data obtained in many mechanical testing procedures. The difficulties associated with compliance correction, as they apply to the simple compression mode of testing, are explored in this paper. The commonly employed approach is to extend the procedure suggested in the ASTM standards for testing high modulus, single-filament materials, which implicitly assumes that the machine behaves as a linear spring with a constant compliance factor. It is shown in this paper that this approach results in different values for the machine compliance factor for different materials. The nonuniqueness of the machine compliance factor is attributed to the inherent nonlinearity of the machine compliance, i.e., the nonlinear dependence of the nonsample displacement on the applied load. Through a set of mechanical tests on a range of materials, it has been demonstrated that it is necessary to characterize this nonlinear compliance relationship for the machine to obtain accurate and consistent measurements.

High-resolution CT in the acute exacerbation of cystic fibrosis: evaluation of acute findings, reversibility of those findings, and clinical correlation.

Abstract: The aims of this study were threefold: to compare high-resolution CT (HRCT) of adult patients with cystic fibrosis (CF) during acute exacerbations with asymptomatic patients with CF, to evaluate reversibility of HRCT abnormalities after exacerbations, and to correlate HRCT with clinical parameters.Nineteen symptomatic and eight asymptomatic patients were prospectively evaluated by HRCT and pulmonary function tests (PFTs). Symptomatic patients were reassessed 2 weeks after the exacerbation. Studies were independently reviewed by two radiologists using a modified Bhalla scoring system, noting the presence, extent, and severity of bronchiectasis, peribronchial thickening, mucus plugging, and atelectasis or consolidation. Modifications to the Bhalla system included evaluation of the presence and profusion of centrilobular nodules and air-fluid levels within bronchiectatic cavities. The highest possible score was 24 points. Higher scores indicated greater severity. Mosaic perfusion was noted but not included i...