Showing papers by "Case Western Reserve University published in 1990"

Psychometric characteristics of the Multidimensional Scale of Perceived Social Support.

Abstract: The initial study describing the development of the Multidimensional Scale of Perceived Social Support (MSPSS) indicated that it was a psychometrically sound instrument (Zimet, Dahlem, Zimet, & Farley, 1988). The current study attempted to extend the initial findings by demonstrating the internal reliability, factorial validity, and subscale validity of the MSPSS using three different subject groups: (a) 265 pregnant women, (b) 74 adolescents living in Europe with their families, and (c) 55 pediatric residents. The MSPSS was found to have good internal reliability across subject groups. In addition, strong factorial validity was demonstrated, confirming the three-subscale structure of the MSPSS: Family, Friends, and Significant Other. Finally, strong support was also found for the validity of the Family and Significant Other subscales.

Alliances in Industrial Purchasing: The Determinants of Joint Action in Buyer-Supplier Relationships:

Abstract: Recent trends in industrial markets indicate that buyers and sellers are increasingly supplanting conventional “arm's length” arrangements with “alliances” involving closer ties. The authors develo...

Suppression of human colorectal carcinoma cell growth by wild-type p53.

Abstract: Mutations of the p53 gene occur commonly in colorectal carcinomas and the wild-type p53 allele is often concomitantly deleted. These findings suggest that the wild-type gene may act as a suppressor of colorectal carcinoma cell growth. To test this hypothesis, wild-type or mutant human p53 genes were transfected into human colorectal carcinoma cell lines. Cells transfected with the wild-type gene formed colonies five- to tenfold less efficiently than those transfected with a mutant p53 gene. In those colonies that did form after wild-type gene transfection, the p53 sequences were found to be deleted or rearranged, or both, and no exogenous p53 messenger RNA expression was observed. In contrast, transfection with the wild-type gene had no apparent effect on the growth of epithelial cells derived from a benign colorectal tumor that had only wild-type p53 alleles. Immunocytochemical techniques demonstrated that carcinoma cells expressing the wild-type gene did not progress through the cell cycle, as evidenced by their failure to incorporate thymidine into DNA. These studies show that the wild-type gene can specifically suppress the growth of human colorectal carcinoma cells in vitro and that an in vivo-derived mutation resulting in a single conservative amino acid substitution in the p53 gene product abrogates this suppressive ability.

Suicide as escape from self.

Abstract: Suicide is analyzed in terms of motivations to escape from aversive self-awareness. The causal chain begins with events that fall severely short of standards and expectations. These failures are attributed internally, which makes self-awareness painful. Awareness of the self's inadequacies generates negative affect, and the individual therefore desires to escape from self-awareness and the associated affect. The person tries to achieve a state of cognitive deconstruction (constricted temporal focus, concrete thinking, immediate or proximal goals, cognitive rigidity, and rejection of meaning), which helps prevent meaningful self-awareness and emotion. The deconstructed state brings irrationality and disinhibition, making drastic measures seem acceptable. Suicide can be seen as an ultimate step in the effort to escape from self and world.

Minimally modified low density lipoprotein induces monocyte chemotactic protein 1 in human endothelial cells and smooth muscle cells

Abstract: After exposure to low density lipoprotein (LDL) that had been minimally modified by oxidation (MM-LDL), human endothelial cells (EC) and smooth muscle cells (SMC) cultured separately or together produced 2- to 3-fold more monocyte chemotactic activity than did control cells or cells exposed to freshly isolated LDL. This increase in monocyte chemotactic activity was paralleled by increases in mRNA levels for a monocyte chemotactic protein 1 (MCP-1) that is constitutively produced by the human glioma U-105MG cell line. Antibody that had been prepared against cultured baboon smooth muscle cell chemotactic factor (anti-SMCF) did not inhibit monocyte migration induced by the potent bacterial chemotactic factor f-Met-Leu-Phe. However, anti-SMCF completely inhibited the monocyte chemotactic activity found in the media of U-105MG cells, EC, and SMC before and after exposure to MM-LDL. Moreover, monocyte migration into the subendothelial space of a coculture of EC and SMC that had been exposed to MM-LDL was completely inhibited by anti-SMCF. Anti-SMCF specifically immunoprecipitated 10-kDa and 12.5-kDa proteins from EC. Incorporation of [35S]methionine into the immunoprecipitated proteins paralleled the monocyte chemotactic activity found in the medium of MM-LDL stimulated EC and the levels of MCP-1 mRNA found in the EC. We conclude that (i) SMCF is in fact MCP-1 and (ii) MCP-1 is induced by MM-LDL.

p53 gene mutations occur in combination with 17p allelic deletions as late events in colorectal tumorigenesis.

Abstract: Coordinate loss of one copy of the p53 gene and mutation of the remaining copy occur in colorectal carcinomas and in many other human malignancies. However, the prevalence of p53 gene mutations in carcinomas which maintain both parental copies of p53 has not previously been evaluated. Moreover, it is not known whether p53 gene mutations are limited to malignant tumors or whether they can also occur in benign neoplasms. To answer these questions, a total of 58 colorectal tumors have been examined; in each tumor, allelic losses were assessed using restriction fragment length polymorphisms and p53 gene mutations were assessed by sequencing cloned polymerase chain reaction products. The following conclusions emerged: (a) p53 gene mutations occurred but were relatively rare in adenomas, regardless of size and whether the adenomas were derived from patients with familial adenomatous polyposis; (b) In carcinomas as well as in adenomas, p53 gene mutations were infrequently observed in tumors which contain both copies of chromosome 17p (17% of 30 tumors), while tumors which lost one copy of chromosome 17p usually had a mutation in the remaining p53 allele (86% of 28 tumors); (c) p53 gene mutations were found at similar frequencies in primary tumor samples and in cell lines derived from tumors. These and other data suggest that the rate limiting step in p53 inactivation is point mutation and that once a mutation occurs, loss of the remaining wild-type allele rapidly follows. Both mutations and allelic losses generally occur near the transition from benign to malignant growth, and the p53 gene may play a causal role in this progression.

Controllability, stabilizability, and continuous-time Markovian jump linear quadratic control

Abstract: Consideration is given to the control of continuous-time linear systems that possess randomly jumping parameters which can be described by finite-state Markov processes. The relationship between appropriately defined controllability, stabilizability properties, and the solution of the infinite time jump linear quadratic (JLQ) optimal control problems is also examined. Although the solution of the continuous-time Markov JLQ problem with finite or infinite time horizons is known, only sufficient conditions for the existence of finite cost, constant, stabilizing controls for the infinite time problem appear in the literature. In this paper necessary and sufficient conditions are established. These conditions are based on new definitions of controllability, observability, stabilizability, and detectability that are appropriate for continuous-time Markovian jump linear systems. These definitions play the same role for the JLQ problem as the deterministic properties do for the linear quadratic regulator (LQR) problem. >

Anxiety and Social Exclusion

Abstract: This article elaborates a view of anxiety as deriving from a basic human need to belong to social groups. Anxiety is seen as a pervasive and possibly an innately prepared form of distress that arises in response to actual or threatened exclusion from important social groups. The reasons groups exclude individuals (incompetence, deviance or immorality, and unattractiveness) therefore should all be linked to anxiety, and events that implicate the self as incompetent, guilty, or unattractive should create anxiety. This “exclusion theory” of anxiety can be considered a broader revision of separation anxiety theory and is distinguished from theories that base anxiety on fear of death, fear of castration, and perception of uncertainty. Current evidence from multiple sources is reviewed to show the explanatory power and utility of exclusion theory, and implications of this theory are developed in relation to culturally changing standards of sexual behavior, the motivations underlying the Oedipus complex, and the...

Molecular biology and biochemistry of pyruvate dehydrogenase complexes.

Abstract: In most organisms, the pyruvate dehydrogenase complex catalyzes the pivotal irreversible reaction that leads to the consumption of glucose in the aerobic, energy-generating pathways. A combination of biochemical and molecular biology studies have greatly expanded our understanding of the overall structural organization of this multicomponent system, delineated the locations and elucidated the functions of structural domains of the catalytic components, and revealed significant evolutionary changes. Important to this progress was the deduction of the primary amino acid sequences from cDNA clones for each of the catalytic components from several species. The greatest detail is available for the FAD-containing dihydrolipoamide dehydrogenase component, which is the only component for which tertiary structure information has recently emerged. For the dihydrolipoamide acetyltransferase core component, a similar but species-variable multidomain structure is established that is responsible for the distinct architectures of the inner cores, the peripheral binding of the other components, and the conveyance of reaction intermediates between distantly separated active sites. A second lipoyl-bearing component, protein X, has been shown to play a critical role in the organization and function of the complex from many higher organisms. Although much is known about the means of effector modulation of mammalian complex activity, identification of the signal eliciting its regulation by insulin still poses an exciting challenge.

Victim and perpetrator accounts of interpersonal conflict: autobiographical narratives about anger.

Abstract: Subjects furnished autobiographical accounts of being angered (victim narratives) and of angering someone else (perpetrator narratives). The provoking behavior was generally portrayed by the perpetrator as meaningful and comprehensible, whereas the victim tended to depict it as arbitrary, gratuitous, or incomprehensible. Victim accounts portrayed the incident in a long-term context that carried lasting implications, especially of continuing harm, loss, and grievance. Perpetrator accounts tended to cast the incident as a closed, isolated incident that did not have lasting implications. Several findings fit a hypothesis that interpersonal conflicts may arise when a victim initially stifles anger and then finally responds to an accumulated series of provocations, whereas the perpetrator perceives only the single incident and regards the angry response as an unjustified overreaction. Victim and perpetrator roles are associated with different subjective interpretations.

Cortical-basal ganglionic degeneration

Abstract: We report our experience with 15 patients believed to have cortical-basal ganglionic degeneration. The clinical picture is distinctive, comprising features referable to both cortical and basal ganglionic dysfunction. Characteristic manifestations include cortical sensory loss, focal reflex myoclonus, "alien limb" phenomena, apraxia, rigidity and akinesia, a postural-action tremor, limb dystonia, hyperreflexia, and postural instability. The asymmetry of symptoms and signs is often striking. Brain imaging may demonstrate greater abnormalities contralateral to the more affected side. Postmortem studies in 2 patients revealed the characteristic pathologic features of swollen, poorly staining (achromatic) neurons and degeneration of cerebral cortex and substantia nigra. Biochemical analysis of 1 brain showed a severe, diffuse loss of dopamine in the striatum. This condition is more frequent than previously believed, and the diagnosis can be predicted during life on the basis of clinical findings. However, as with other "degenerative" diseases of the nervous system, a definitive diagnosis of cortical-basal ganglionic degeneration requires confirmation by autopsy.

Voice, exit, and negative word-of-mouth behaviors: An investigation across three service categories

Abstract: Drawing upon Hirschman’s (1970) framework for Exit, Voice and Loyalty, a model is proposed which predicts and explains variation in voice, exit, and negative work-of-mouth behaviors. The findings from extant consumer complaining behavior (CCB) literature are also incorporated into the hypothesized model. Using data from customer dissatisfaction with three different service categories, the proposed model is subjected to empirical investigation. Despite the parsimony of Hirschman’s framework, results show that the hypothesized model provides good model-fit indices in each of the three data sets. In addition, the explanatory power of the model is encouraging, ranging from 36 percent to 50 percent variance explained. However, the support for the hypothesized pattern of CCB rates across the service categories is mixed. Specifically, while voice responses conform to the hypothesized pattern, exit responses do not. Implications stemming from a comparative analysis of the results are discussed, and directions for future research outlined.

Spinal epidural abscess: a ten-year perspective.

Abstract: A retrospective study of spinal epidural abscess spanning 10 years and encompassing 40 patients was done. Epidemiology, clinical features, laboratory findings, radiographic imaging, therapy, and outcome were examined and compared with previous series. An increasing incidence of the disease (up to 1.

Temperature-dependent exciton linewidths in semiconductors

Abstract: The temperature-dependent linewidths of excitons in semiconductors due to the interaction of the exciton with both LO phonons and with acoustic phonons are studied with use of a Green's-function approach in which the exciton-phonon interaction is treated perturbatively. The interaction between the excitons and the LO phonons is taken to be of the Fr\"ohlich form, and the contribution to the linewidth is obtained in closed form. In this case it is found that scattering of the exciton to both bound and continuum states is important and that it is important to treat the continuum states fully as Coulomb scattering states. In describing optical-absorption processes, the fact that absorption occurs from polariton states, which are states composed of excitons coupled to light, is taken into account. The linewidths due to the exciton--LO-phonon interaction are evaluated for a series of II-VI and III-V compound semiconductors, and are shown to account for the existing experimental results for temperatures \ensuremath{\gtrsim}80 K. The contributions to the linewidth due to the interaction of excitons with acoustic phonons via both the deformation potential and the piezoelectric couplings are treated, and it is found that the deformation-potential coupling dominates for all of the materials considered. Because of the small velocity of sound, scattering to only intraband intermediate states, i.e., those in which the internal exciton quantum numbers do not change, is found to contribute to the linewidth. In the case of acoustic phonons, it is found to be important to treat optical absorption as originating from polariton states in order to evaluate properly the magnitude of this contribution to the linewidth. The acoustic-phonon contribution to the linewidths is compared with experiment for temperatures \ensuremath{\lesssim}80 K, for which it dominates the temperature dependence.

A formal model of program dependences and its implications for software testing, debugging, and maintenance

Abstract: A formal, general model of program dependences is presented and used to evaluate several dependence-based software testing, debugging, and maintenance techniques Two generalizations of control and data flow dependence, called weak and strong syntactic dependence, are introduced and related to a concept called semantic dependence Semantic dependence models the ability of a program statement to affect the execution behavior of other statements It is shown that weak syntactic dependence is a necessary but not sufficient condition for semantic dependence and that strong syntactic dependence is necessary but not sufficient condition for a restricted form of semantic dependence that is finitely demonstrated These results are used to support some proposed uses of program dependences, to controvert others, and to suggest new uses >

A Multicenter Study of Physicians' Knowledge of the Pulmonary Artery Catheter

Abstract: We administered a 31-question multiple-choice examination to 496 physicians practicing in 13 medical facilities in the United States and Canada to assess their knowledge and understanding of the use of the pulmonary artery catheter and interpretation of data derived from it. The mean test score was 20.7 (67% correct), with an SD of 5.4 and a range of 6 to 31 (19% to 100%). Mean scores varied independently by training, frequency of use of pulmonary artery catheter data in patient treatment, frequency of inserting a pulmonary artery catheter, and whether the respondent's hospital was a primary medical school affiliate. Given the variability in physician understanding of the pulmonary artery catheter, we believe that credentialing policies should be reevaluated and that consideration should be given to restricting its use to individuals with documented competency. (JAMA. 1990;264:2928-2932)

Inhibition of neurite outgrowth on astroglial scars in vitro

Abstract: Traumatic injury to the adult mammalian CNS results in the formation of an astroglial-mesenchymal scar that seals the wound site but blocks axonal regeneration in the process The mechanism that leads to this inhibition of axon outgrowth has been proposed to be either a physical barrier blocking the advancement of the growth cone or chemical factors actively inhibiting axon outgrowth At present, it is unknown whether one or both of these mechanisms are responsible for the inhibitory nature of the glial scar in vivo Using a model of CNS trauma that allows for removal of an adult rat glial scar intact on a nitrocellulose support and placement in vitro with the upper surface exposed, we addressed the question of whether the inhibitory effects could be accounted for by chemical components at the scar surface A purified population of rat hippocampal neurons was seeded onto the scar explants as well as onto explants taken from neonatal rat cerebral cortex, and the extent of neurite outgrowth was compared We found that the glial scar, at best, stimulates only minimal neurite outgrowth over its surface when compared to the immature environment explanted in the same manner This growth-inhibitory state cannot merely be explained by neuronotoxic factors or fibroblasts preventing astrocyte-mediated neurite outgrowth The inhibition is more probably due to the expression of molecules on the surface of the adult scar that either directly inhibit growth cones or inhibit them indirectly by occluding neurite-promoting factors in the extracellular matrix or on the astrocyte surface

Cellular signaling by peptides of the endothelin gene family.

Abstract: Endothelins (ET) are a family of regulatory peptides synthesized by selected endothelial and epithelial cells that act in a paracrine fashion on nearby smooth muscle or connective tissue cells. We review the pathways of transmembrane signaling triggered by binding of endothelin peptides to receptors on the plasma membrane. Although our understanding of many components is unclear, endothelin peptides appear to evoke a phosphoinositide-linked signaling system that bears a striking resemblance to signaling pathways activated by other regulatory peptides. Expression of endothelin receptors and specific pathways stimulated by activated receptors are controlled in a cell- and tissue-specific manner, which perhaps explains the diverse biological actions of endothelin in different tissues. Complex negative feedback pathways regulate endothelin-induced signaling at the receptor and second messenger levels. Moreover, by regulating the activity of sequence-specific DNA binding proteins, short-term signals by ET can ...

Effects of six months of clozapine treatment on the quality of life of chronic schizophrenic patients.

Abstract: The effect of approximately six months of treatment with clozapine on the quality of life of 38 treatment-resistant schizophrenic patients was prospectively studied in an open trial. The Quality of Life Scale was used to provide an objective measure of changes in patients' psychosocial functioning. Significant improvement was noted on all four factors of the scale. The ratings tended to be negatively correlated with ratings on the Brief Psychiatric Rating Scale at baseline and at six months. At 12 months, patients' rehospitalization rate was reduced by 83 percent and was independent of the six-month quality-of-life ratings.

Method for treating connective tissue disorders

Abstract: The present invention is directed to various processes and devices for utilizing isolated and culturally expanded marrow-derived mesenchymal cells (i.e. mesenchymal stem cells) for treating skeletal and other connective tissue disorders.

Geology, geochronology, and rift basin development in the central sector of the Main Ethiopia Rift

Abstract: Based on stratigraphic relationships and K/Ar dating of volcanic rocks from both of the escarpments, flanking plateaus, and from the rift floor of the central sector of the Main Ethiopian Rift, six major volcanic episodes are recognized in the rift9s development over a time span from the late Oligocene to the Quaternary. Using the K/Ar data, correlation of volcanic units from the six periods of activity throughout the study area forms the basis for establishing six time-stratigraphic chronozones for the central sector that are related to volcanism in the Ethiopian Cenozoic volcanic province. The oldest basalt and rhyolite flows exposed along the rift margins of the central sector are time correlative to, or older than, those in river canyons (for example, Blue Nile) on the adjacent northwest plateau. A thinned Mesozoic stratigraphic sequence along the Guraghe western rift margin suggests that doming may have preceded volcanism and rifting of the Cenozoic. By late Miocene time, at least by 8.3 Ma and 9.7 Ma, the eastern and western faulted margins, respectively, of the rift had formed at Guraghe and at Agere Selam as indicated by containment of flows of that age within the rift wall during eruption. A paroxysm of calc-alkaline ignimbrite activity produced voluminous flows nearly fully contained within the rift during the Pliocene epoch. The Munesa Crystal Tuff (3.5 Ma), a prominent marker tuff exposed on both rift margins, is present at depth in a geothermal well beneath the rift floor and indicates a minimum of 2 km of downthrow in the central sector since its eruption. Structural and stratigraphic relationships in the central sector indicate a two- stage rift development. This is characterized by an early phase (late Oligocene or early Miocene) of a series of alternating opposed half-grabens along the rift with alternating polarity, such as that in the present Gregory and Western Rifts of East Africa and symmetrical rifts that evolved from these grabens in late Miocene or early Pliocene time. Thus, evolution from alternating half-graben to a full symmetrical graben with a medially located neovolcanic zone that is bifurcated to marginal grabens in the northern part of the study area may be a fundamental part of the rifting process. The study indicates that there are major petrologic and tectonic differences between the Main Ethiopian Rift and the Gregory (Kenyan) Rift.

Outcome in Manic Disorders: A Naturalistic Follow-up Study

Abstract: • To study outcome in manic patients treated under routine clinical conditions, 73 manic and 66 unipolar depressed patients were followed up 1.7 years after hospitalization. A surprisingly large percentage of manic patients showed difficulty in post-hospital adjustment, and over 40% experienced a manic syndrome during the follow-up period. Manic patients showed poorer outcomes than did unipolar depressives. Manic patients taking lithium carbonate did not show better outcome than those not taking lithium carbonate. The results suggest (1) many hospitalized manic patients have a severe, recurrent, and pernicious disorder; and (2) in routine clinical practice, lithium carbonate treatment is an effective prophylaxis for fewer than the 70% to 80% of manic patients previously reported.