Further development of a three-node triangular shell element

A three-node triangular shell element having six d.o.f. per node can be economically generated as a flat element that combines well-known formulations for membrane stiffness and plate bending stiffness. Early elements of this type were inaccurate because the membrane response was poor. Researchers improved the membrane response by adding drilling d.o.f. and by underintegrating the membrane stiffness matrix. More recent research has dealt with the addition of membrane-bending coupling within individual elements and the suppression of mechanisms. The present work intends to continue the improvement by modifying the membrane stiffness, simplifying the membrane-bending coupling device and suppressing mechanisms without degrading performance or causing the mesh to lock.     

Closed intramedullary femoral osteotomy. Shortening and derotation procedures

Closed osteotomy and nailing were performed on 37 patients for leg-length inequality or rotational deformities. Shortening operations were performed in 31 patients, derotation in six. Preoperatively, the leg-length discrepancy ranged from 2 to 6.6 cm. All femoral shortenings resulted in correction to less than 1 cm. Preoperatively, rotational deformities averaged 58 degrees; all were corrected to within 5 degrees of normal. Follow-up observation averaged 3.3 years. There were no nonunions or infections. All patients regained preoperative joint range of motion (ROM). Thirteen patients were Cybex tested one year or more postoperatively; all had quadriceps and hamstring strength equal to or greater than the contralateral leg, except for two patients who had suffered additional trauma to the shortened femur. Closed femoral osteotomy is an effective, safe, and reproducible means to obtain lower limb length correction in patients with leg-length inequality or rotational abnormality.     

The modification of hemoglobin by citrate

Citrate, when activated by a water-soluble carbodiimide, covalently modifies hemoglobin. At pH values near neutrality, complete modification of the N-terminal valine residues of alpha- and beta-globin chains can be accomplished with a high degree of specificity. These groups react at a much more rapid rate than a slower reacting set of functional groups. Modification of hemoglobin with citrate alters the oxygen affinity of the protein. Although the p50 is not changed, the cooperative nature of oxygen binding is greatly decreased. Hemoglobin S modified with citrate is more soluble than unmodified hemoglobin S. The time taken for deoxygenated hemoglobin S to come out of solution in concentrated phosphate solutions is increased by citrate modification.     

A comparison of self-reported drug use with a urine drug screen in a working population: Correction.

Reports an error in the original article by R. Bharucha-Reid et al (Experimental and Clinical Psychopharmacology, 1995, Vol 3 [3], 280–286). Rachel Kaufmann was inadvertently misspelled. (The following abstract of this article originally appeared in record 1996-92908-001.) This study summarized information on 162 workers who completed urine screen and self-report concerning drug use. It is the first to compare self-report of drug use in the workplace with a urine screen in which individual participant (nonaggregate) data were used. The findings indicate that agreement between the 2 methods of drug detection, although statistically significant, is at best only moderate. The level of agreement was consistent for segments of the sample when divided by sociodemographic characteristics. Although urine screen may be the more reliable and accurate method of detecting prevalence of drug use, self-report must be considered to assess drug use histories and the role of other variables. These 2 methods should be considered as complementary assessment techniques; the appropriate method depends on the conditions and purposes of the drug use study. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exploratory and confirmatory tests of the big five and Tellegen's three- and four-dimensional models

Using about 600 college students and exploratory and confirmatory factor analysis, three models of personality structure were tested: the Big Five, as measured by the NEO Personality Inventory (P.T. Costa & R. R. McCrae, 1985), and A. Tellegen's (1985) three- and four-dimensional models, as measured by the Multidimensional Personality Questionnaire (A. Tellegen, 1982). Both factor methods indicated considerable support for, but also some divergences from, the models. We concluded that parsimonious personality models are unlikely to meet conventional goodness-of-fit criteria in confirmatory factor analysis, because of the limited simple structure of personality measures and the personality domain itself. Poor fits of a priori models highlighted not only the limited specificity of personality structure theory, but also the limitations of confirmatory factor analysis for testing personality structure models.     

Cortical potentials evoked by tooth pulp stimulation differentiate between the analgesic and sedative effects of morphine in awake rats

This study was undertaken to determine whether the cortical potential (CEP) evoked by noxious electrical stimulation of the incisor tooth pulp can be used to measure analgesia in the presence of sedation in the awake rat. Changes in the CEP produced by morphine (5, 10 and 20 mg/kg s.c.), an opioid analgesic with sedative effects, were compared with those produced by droperidol (1.25 mg/kg s.c.), a neuroleptic agent with no analgesic activity. Both drugs had similar small effects on CEP latency. However, whereas morphine produced a dose-related decrease in amplitude and area under the curve, particularly in the earliest component of the CEP, droperidol produced an increase in amplitude and area under the curve. Naloxone (0.5-2 mg/kg s.c.) reversed all effects of morphine. Similar CEPs could be evoked by electrical stimulation of the tooth pulp or surrounding gingiva in lightly anesthetized rats. However, the tooth pulp stimulation-evoked CEP was unchanged after anesthesia of the gingiva with lidocaine, and the gingiva-evoked CEP was unchanged after anesthesia of the tooth pulp. Therefore, stimulation of the rat's incisor can selectively activate intrapulpal fibers, which are sufficient to generate a CEP. This CEP is an indicator of nociception which can be used to distinguish the analgesic effects of drugs such as morphine from their sedative effects.     

Growth advantage of human leiomyoma cells compared to normal smooth-muscle cells due to enhanced sensitivity toward insulin-like growth factor I

Human uterine leiomyomas exhibit increased IGF-I binding compared to myometrium, while both tissues show IGF-I gene expression. In this study we have examined the functional importance of these findings by testing the presence of IGF-I in 15 leiomyoma biopsies and in 18 myometrium biopsies and the capacity of smooth-muscle cells cultured from these tissues to react to IGF-I. The mean IGF-I peptide concentration in leiomyomas was 3 times higher than in myometrium. This resulted from increased IGF-I uptake in leiomyomas rather than from increased synthesis, as these tissues contain higher concentrations of type-I IGF receptors, as detected by immunohistochemistry, and equal levels of IGF-I mRNA. Blocking IGF-I transport with cytochalasin-B and with the type-I IGF receptor blocking antibody alpha IR3 in cultured cells induced decreased immunostaining intensity for IGF-I in most myometrium and leiomyoma cultures, indicating that the detected IGF-I is internalized. Depending on the culture conditions, IGF-I administration yielded increased survival or a higher proliferation rate in leiomyoma cultures than in myometrium cultures, indicating the increased importance of exogenous IGF-I for the growth of transformed smooth-muscle cells. We conclude that the increased concentrations of type-I IGF receptors in leiomyoma compared to myometrial smooth-muscle cells are functional with respect to the enhanced internalization of IGF-I and that they provide these tumor cells with a growth advantage compared to their normal counterparts.     

Regulation of the expression of the tissue transglutaminase gene by DNA methylation

We have investigated the role of DNA methylation in the regulation of the expression of the human tissue transglutaminase gene. Studies on the methylation of the transglutaminase promoter in normal and neoplastic human cells demonstrated that the promoter is methylated in vivo and hypomethylation of the promoter is correlated with constitutive gene expression. Demethylation of the promoter in vivo by treatment of the cells with 5-azacytidine increased transglutaminase expression and hypermethylation of the promoter in vitro suppressed its activity. These studies suggest that alternations in DNA methylation may be one of the mechanisms regulating the tissue-specific expression of the tissue transglutaminase gene.