Showing papers by "University of Iowa published in 1992"

Primary structure of dystrophin-associated glycoproteins linking dystrophin to the extracellular matrix

Abstract: The primary sequence of two components of the dystrophin–glycoprotein complex has been established by complementary DNA cloning. The transmembrane 43K and extracellular 156K dystrophin-associated glycoproteins (DAGs) are encoded by a single messenger RNA and the extracellular 156K DAG binds laminin. Thus, the 156K DAG is a new laminin-binding glycoprotein which may provide a linkage between the sarcolemma and extracellular matrix. These results support the hypothesis that the dramatic reduction in the 156K DAG in Duchenne muscular dystrophy leads to a loss of a linkage between the sarcolemma and extra-cellular matrix and that this may render muscle fibres more susceptible to necrosis.

Recombinant tissue plasminogen activator in acute thrombotic and embolic stroke

Abstract: An open angiography-based, dose rate escalation study on the effect of intravenous infusion of recombinant tissue plasminogen activator (rt-PA) on cerebral arterial recanalization in patients with acute focal cerebral ischemia was performed at 16 centers. Arterial occlusions consistent with acute ischemia in the carotid or vertebrobasilar territory in the absence of detectable intracerebral hemorrhage were prerequisites for treatment. After the 60-minute rt-PA infusion, arterial perfusion was assessed by repeat angiography and computed tomography scans were performed at 24 hours to assess hemorrhagic transformation. Of 139 patients with symptoms of focal ischemia, 80.6% (112) had complete occlusion of the primary vessel at a mean of 5.4 +/- 1.7 hours after symptom onset. No dose rate response of cerebral arterial recanalization was observed in 93 patients who completed the rt-PA infusion. Middle cerebral artery division (M2) and branch (M3) occlusions were more likely to undergo recanalization by 60 minutes than were internal carotid artery occlusions. Hemorrhagic infarction occurred in 20.2% and parenchymatous hematoma in 10.6% of patients over all dose rates, while neurological worsening accompanied hemorrhagic transformation (hemorrhagic infarction and parenchymatous hematoma) in 9.6% of patients. All findings were within prospective safety guidelines. No dose rate correlation with hemorrhagic infarction, parenchymatous hematoma, or both was seen. Hemorrhagic transformation occurred significantly more frequently in patients receiving treatment at least 6 hours after symptom onset. No relationship between hemorrhagic transformation and recanalization was observed. This study indicates that site of occlusion, time to recanalization, and time to treatment are important variables in acute stroke intervention with this agent.

Time to recovery, chronicity, and levels of psychopathology in major depression. A 5-year prospective follow-up of 431 subjects

Abstract: • The course of illness of 431 subjects with major depression participating in the National Institute of Mental Health Collaborative Depression Study was prospectively observed for 5 years. Twelve percent of the subjects still had not recovered by 5 years. There were decreasing rates of recovery over time. For example, 50% of the subjects recovered within the first 6 months, and then the rate of recovery declined markedly. Instantaneous probabilities of recovery reflect that the longer a patient was ill, the lower his or her chances were of recovering. For patients still depressed, the likelihood of recovery within the next month declined from 15% during the first 3 months of follow-up to 1 % to 2% per month during years 3, 4, and 5 of this follow-up. The severity of current psychopathology predicted the probability of subsequent recovery. Subjects with moderately severe depressive symptoms, minor depression, or dysthymia had an 18-fold greater likelihood of beginning recovery within the next week than did subjects who were at full criteria for major depressive disorder. Many subjects who did not recover continued in an episode that looked more like dysthymia than major depressive disorder.

An ISEE/Whistler model of equatorial electron density in the magnetosphere

Abstract: Attention is given to an empirical model of equatorial electron density in the magnetosphere covering the L range 2.25-8. Although the model is primarily intended for application to the local time interval 00-15 MLT, a way to extend the model to the 15-24-MLT period is presented. The model describes, in piecewise fashion, the 'saturated' plasmasphere, the region of steep plasmapause gradients, and the plasma trough. Within the plasmasphere the model profile can be expressed as logne - Sigma-xi, where x1 = -0.3145L + 3.9043 is the principal or 'reference' term, and additional terms account for: a solar cycle variation with a peak at solar maximum; an annual variation with a December maximum; and a semiannual variation with equinoctial maxima.

Controllability of Stressful Events and Satisfaction With Spouse Support Behaviors

Abstract: Among married couples, the effect of the controllability of stressful events was tested as a predictor of the type of social support communications provided and preferred. Sixty married individuals disclosed stressful events to their spouse. Controllability of the stress was rated by observers. The Social Support Behavior Code was used to assess the frequency with which each of five types of social support was provided by the spouse. Action-promoting support (information) was provided most frequently when the stressed person had high control over the event. Of the five types of support communications assessed, only information was evaluated differently in high- and low-controllable situations. Both controllability by the support recipient and controllability by his or her spouse were relevant to support evaluations. Results provide limited support for the optimal matching model proposed by Cutrona and Russell (Cutrona, 1990; Cutrona & Russell, 1990).

Strength increases from the motor program: comparison of training with maximal voluntary and imagined muscle contractions.

Abstract: 1. This study addressed potential neural mechanisms of the strength increase that occur before muscle hypertrophy. In particular we examined whether such strength increases may result from training-induced changes in voluntary motor programs. We compared the maximal voluntary force production after a training program of repetitive maximal isometric muscle contractions with force output after a training program that did not involve repetitive activation of muscle; that is, after mental training. 2. Subjects trained their left hypothenar muscles for 4 wk, five sessions per week. One group produced repeated maximal isometric contractions of the abductor muscles of the fifth digit's metacarpophalangeal joint. A second group imagined producing these same, effortful isometric contractions. A third group did not train their fifth digit. Maximal abduction force, flexion/extension force and electrically evoked twitch force (abduction) of the fifth digit were measured along with maximal integrated electromyograms (EMG) of the hypothenar muscles from both hands before and after training. 3. Average abduction force of the left fifth digit increased 22% for the Imagining group and 30% for the Contraction group. The mean increase for the Control group was 3.7%. 4. The maximal abduction force of the right (untrained) fifth digit increased significantly in both the Imagining and Contraction groups after training (10 and 14%, respectively), but not in the Control group (2.3%). These results are consistent with previous studies of training effects on contralateral limbs. 5. The abduction twitch force evoked by supramaximal electrical stimulations of the ulnar nerve was unchanged in all three groups after training, consistent with an absence of muscle hypertrophy. The maximal force of the left great toe extensors for individual subjects remained unchanged after training, which argues against strength increases due to general increases in effort level. 6. Increases in abduction and flexion forces of the fifth digit were poorly correlated in subjects of both training groups. The fifth finger abduction force and the hypothenar integrated EMG increases were not well correlated in these subjects either. Together these results indicate that training-induced changes of synergist and antagonist muscle activation patterns may have contributed to force increases in some of the subjects. 7. Strength increases can be achieved without repeated muscle activation. These force gains appear to result from practice effects on central motor programming/planning. The results of these experiments add to existing evidence for the neural origin of strength increases that occur before muscle hypertrophy.

Depression following myocardial infarction.

Abstract: Objective:Although many investigators have studied mood disorders following myocardial infarction, the prevalence, severity, and persistence of depression have been disputed, and standard rating scales and criteria for depressive disorders have infrequently been utilized The authors' goal was to determine how frequently depressive disorders occur after myocardial infarction, and to investigate predisposing factors for such disordersMethod:Structured clinical interviews were administered to 129 inpatients within ten days of myocardial infarction Patients were also evaluated using standardized rating scales for depression, social function, cognition, and physical impairment DSM-III diagnoses were derived from the structured interviewResults:Major depressive syndromes were present in 19 percent (n = 25) of the patients and were associated with prior history of mood disorder, female sex, large infarcts, and functional physical impairmentConclusion:Major depression is common in the acute post-myocardial

The serum-ascites albumin gradient is superior to the exudate-transudate concept in the differential diagnosis of ascites.

Abstract: ▪Objective:To compare the serum-ascites albumin gradient to the exudate-transudate concept in the classification of ascites. ▪Design:Prospective collection of ascitic fluid data from patie...

Measuring Causal Attributions: The Revised Causal Dimension Scale (CDSII)

Abstract: Although attribution theory continues to be a fertile area of social psychological research, much of the extant literature has suffered from questionable measurement of the constructs of interest. This is especially true in the case of assigning causal attributions placement in theorized dimensional space. Russell's (1982) Causal Dimension Scale represented an important development toward more precise measurement of causal dimensions; however, it has been criticized on a number of fronts. The present report presents the rationale for and initial psychometric properties of a revised version of the scale, the CDSII. Employing data from four studies, a confirmatory factor analysis is reported examining the goodness of fit of the hypothesized four factor oblique structure to the data. The results are discussed in terms of possible applications of the CDSII and the need for further validity testing.

Induction of nitric oxide synthase in glial cells.

Abstract: Primary astrocyte cultures, C6 glioma cells, and N18 neuroblastoma cells were assayed for nitric oxide synthase (NOS) activity with a bioassay of cyclic GMP production in RFL-6 fibroblasts. Treatment of astrocyte cultures for 16-18 h with lipopolysaccharide (LPS) induced NOS-like activity that was L-arginine and NADPH dependent, Ca2+ independent, and potentiated by superoxide dismutase. Induction was evident after 4 h, was dependent on the dose of LPS, and required protein synthesis. Treatment of astrocyte cultures with leucine methyl ester reduced microglial cell contamination from 7 to 1%, with a loss of 44% of NOS-like activity. C6 cells treated with LPS also showed Ca(2+)-independent and L-arginine-dependent NOS-like activity. N18 cells demonstrated constitutive Ca(2+)-dependent NOS-like activity that was not enhanced by LPS induction. These data indicate that NOS-like activity can be induced in microglia, astrocytes, and a related glioma cell line as it can in numerous other cell types, but not in neuron-like N18 cells.

The Social Amplification of Risk: Theoretical Foundations and Empirical Applications

Abstract: The article presents the framework of social amplification of risk which integrates the technical assessment and the social experience of risk. Risk perception research has revealed that contextual factors shape individual risk estimations and evaluations. Identification of these factors, such as voluntariness, personal ability to influence risks, familiarity with the hazard, and catastrophic potential, provides useful information about the elements that individuals consider in constructing their interpretation of risks. In addition, analyses of people's heuristics in making inferences have shed some light on how risk information is generalized and evaluated intuitively. These psychological studies fail to explain, however, why individuals attend to certain characteristics of risks and ignore others. Furthermore, in focusing only on the individual as an information processor, these studies exclude from the analysis the social and cultural variance of risk interpretations. The social amplification framework postulates that the social and economic impacts of an adverse event are determined not only by the direct physical consequences of the event, but by the interaction of psychological, cultural, social, and institutional processes that amplify or attenuate public experience of risk and result in secondary impacts.

Discriminant validity of measures of job satisfaction, positive affectivity and negative affectivity

Abstract: The discriminant validity of measures used to assess job satisfaction, positive affectivity and negative affectivity was empirically evaluated using data collected from a sample of 550 employees of a 327-bed Veterans Administration Medical Center. Confirmatory factor analysis with LISREL as the estimation technique was used to test the hypothesized three-factor configuration. Results of this test and other data supported the discriminant validity of the three constructs.

Comparative Efficacy of Alternative Hand-Washing Agents in Reducing Nosocomial Infections in Intensive Care Units

Abstract: Background. Effective hand-washing can prevent nosocomial infections, particularly in high-risk areas of the hospital. There are few clinical studies of the efficacy of specific hand-cleansing agents in preventing the transmission of pathogens from health care workers to patients. Methods. For eight months, we conducted a prospective multiple-crossover trial involving 1894 adult patients in three intensive care units (ICUs). In a given month, the ICU used a hand-washing system involving either chlorhexidine, a broad-spectrum antimicrobial agent, or 60 percent isopropyl alcohol with the optional use of a nonmedicated soap; in alternate months the other system was used. Rates of nosocomial infection and hand-washing compliance were monitored prospectively. Results. When chlorhexidine was used, there were 152 nosocomial infections, as compared with 202 when the combination of alcohol and soap was used (adjusted incidence-density ratio [IDR], 0.73; 95 percent confidence interval, 0.59 to 0.90). The l...

Cognitive Therapy and Pharmacotherapy for Depression: Singly and in Combination

Abstract: • Cognitive therapy and imipramine hydrochloride tricyclic pharmacotherapy, each singly and in combination, were compared in the treatment of nonpsychotic, nonbipolar depressed outpatients. One hundred seven patients were randomly assigned to 12 weeks of active treatment; 64 patients completed the full course of treatment. Rates of attrition were high but not differential. Cognitive therapy and pharmacotherapy did not differ in terms of symptomatic response, either in the primary analyses or in secondary analyses restricted to more severely depressed outpatients. Initial severity did predict response within pharmacotherapy alone, but not within cognitive therapy. Combining cognitive therapy with pharmacotherapy did not markedly improve response over that observed for either modality alone, although such nonsignificant differences as were evident did favor the combined treatment. Two patients died as a consequence of suicide attempts, both of which involved study medication.

Mammalian Facilitative Glucose Transporter Family: Structure and Molecular Regulation

Abstract: Except for the active uptake of glucose from the lumen of the small intestine and proximal tubule of the kidney, the" transport of glucose across cell membranes' occurs by facilitated diffusion. Currently, cDNAs encoding five structurally-related proteins with the properties of faCilitative glucose transporters have been isolated and characterized (Table I). The five isoforms have been designated GLUT lIerythrocyte , GLUT2/liver, GLUT3/brain, GLUT4/muscle-fat, and GLUT5/smali intestine (25,52). In addition to these five functional facilitative glucose transporters, an expressed facilitative glu­ cose transporter pseudogene-like sequence (GLUT6) has been identified in human tissues (39). This sequence is part of a ubiquitously expressed mRNA, but does not encode a functional protein. The purification and characteriZation of the human erythrocyte glucose transporter provided the basiS" for th"e isolation of human and rat GLUT 1

Differential relapse following cognitive therapy and pharmacotherapy for depression.

Abstract: • Patients successfully treated during a 3-month period with either imipramine hydrochloride pharmacotherapy, cognitive therapy, or combined cognitive-pharmacotherapy were monitored during a 2-year posttreatment follow-up period. Half of the patients treated with pharmacotherapy alone continued to receive study medications for the first year of the follow-up. All other patients discontinued treatment at the end of the acute treatment phase. Patients treated with cognitive therapy (either alone or in combination with medication) evidenced less than half the rate of relapse shown by patients in the medication—on continuation condition, and their rate did not differ from that of patients provided with continuation medication. It appears that providing cognitive therapy during acute treatment prevents relapse. Whether this preventive effect extends to recurrence remains to be determined.

DNA position-specific repression of transcription by a Drosophila zinc finger protein.

Abstract: Expression of the yellow (y) gene of Drosophila melanogaster is controlled by a series of tissue-specific transcriptional enhancers located in the 5' region and intron of the gene. Insertion of the gypsy retrotransposon in the y2 allele at -700 bp from the start of transcription results in a spatially restricted phenotype: Mutant tissues are those in which yellow expression is controlled by enhancers located upstream from the insertion site, but all other structures whose enhancers are downstream of the insertion site are normally pigmented. This observation can be reproduced by inserting just a 430-bp fragment containing the suppressor of Hairy-wing [su(Hw)]-binding region of gypsy into the same position where this element is inserted in y2, suggesting that the su(Hw)-binding region is sufficient to confer the mutant phenotype. Insertion of this sequence into various positions in the y gene gives rise to phenotypes that can be rationalized assuming that the presence of the su(Hw) protein inhibits the action of those tissue-specific enhancers that are located more distally from the su(Hw)-binding region with respect to the promoter. These results are discussed in light of current models that explain long-range effects of enhancers on gene expression.

Diet vs. shape content of popular male and female magazines: A dose-response relationship to the incidence of eating disorders?

Abstract: We hypothesized that the substantial difference in incidence of eating disorders between men and women would be correlated with a similar difference in sociocul-tural norms promoting thinness. The 10 popular magazines most commonly read by young men and young women were examined for advertisements and articles promoting weight loss or shape change. The women's magazines contained 10.5 times as many advertisements and articles promoting weight loss as the men's magazines (p <.005), the same ratio reported from several sources for cases of anorexia nervosa. Men, however, were disproportionately subjected to incentives to change body shape compared to weight loss (p <.01). This study supports the hypothesis that the comparative frequency of eating disorders in males vs. females is more closely related to the differing extent of gender-related reinforcement of related dieting behavior than any known biological parameter. It is plausible that a dose-response relationship exists between sociocultural reinforcements promoting thinness and the incidence of eating disorders in any particular population group.

Dynamic models of infectious diseases as regulators of population sizes.

Abstract: Five SIRS epidemiological models for populations of varying size are considered. The incidences of infection are given by mass action terms involving the number of infectives and either the number of susceptibles or the fraction of the population which is susceptible. When the population dynamics are immigration and deaths, thresholds are found which determine whether the disease dies out or approaches an endemic equilibrium. When the population dynamics are unbalanced births and deaths proportional to the population size, thresholds are found which determine whether the disease dies out or remains endemic and whether the population declines to zero, remains finite or grows exponentially. In these models the persistence of the disease and disease-related deaths can reduce the asymptotic population size or change the asymptotic behavior from exponential growth to exponential decay or approach to an equilibrium population size.

Brief functional assessment techniques to evaluate aberrant behavior in an outpatient setting: a summary of 79 cases

Abstract: Previous investigators have analyzed the maintaining conditions for aberrant behaviors using brief functional assessment procedures. These assessment procedures have been used in one of our outpatient clinics, the Self-Injurious and Aggressive Behavior Service. This study presents a descriptive summary of the results from 79 cases during a 3-year period. The outcomes of the brief assessment were evaluated across three variables: (a) referring topography, (b) control over behavior as evaluated through brief multielement designs, and (c) the identified maintaining conditions for aberrant behavior. The limitations and future utility of brief functional assessments for identifying distinct maintaining contingencies are discussed.

Dietary Assessment of Older Iowa Women with a Food Frequency Questionnaire: Nutrient Intake, Reproducibility, and Comparison with 24-Hour Dietary Recall Interviews

Abstract: The authors report the results of a dietary survey of 38,121 Iowa women, 55-69 years of age in 1986, based on a semiquantitative food frequency questionnaire previously tested among Boston-area women aged 34-59 years. The Iowa women, compared with the younger Boston-area women, consumed a similar amount of calories (1,767 vs. 1,844 kcal) and a similar amount of total calories from fat (35 vs. 37%) but had markedly greater intake of the following micronutrients after including supplement use: iron (+18%), calcium (+33%), vitamin A (+43%), riboflavin (+46%), thiamine (+50%), and pyridoxine (+122%). The reproducibility of the questionnaire was examined in two more administrations to 44 of the Iowa women in January and June of 1988. Reproducibility was highest for alcohol (Pearson's r = 0.99), caffeine (r = 0.95), and vitamin E (r = 0.90) and lowest for sucrose (r = 0.53), polyunsaturated fat (r = 0.56), and iron (r = 0.59). Micronutrient intakes were generally more reproducible than macronutrient intakes. The agreement between the June 1988 questionnaire and the average of five 24-hour dietary recalls was also assessed in the 44 subjects. The median correlations of energy-adjusted intake were as follows: for macronutrients, r = 0.45; for micronutrients without supplements, r = 0.33; and for micronutrients with supplements, r = 0.64. This food frequency questionnaire appears to be reasonably reproducible and accurate, so that its use may be extended to epidemiologic studies of older women with a broad range of socioeconomic backgrounds.