Statistical models for renal micropuncture studies

Statistical issues relating to data analysis of re-collection micropuncture experiments are presented. In the presence of significant animal-treatment interaction, namely, differential response of each animal at different levels of the treatment, the conventional paired or unpaired t testing would not be entirely appropriate. Accordingly, two analysis of variance (ANOVA) models have been derived for the appropriate paired and unpaired designs of micropuncture experiments. Interactive computer programs have been written for both these analyses, and the results are illustrated with experimental data. An example is presented in which the results are statistically significant with paired t testing and by analysis of variance for unequal number of tubules but not when the animal-treatment interaction is included in the analysis of variance model. To investigate linkage in renal transport mechanisms, we propose the use of partial correlation analysis. Experimental results from our laboratory are used to illustrate these techniques.     

TV requirements for manipulation in space

An analytical and experimental study was conducted to specify a video system for remote manipulation in space. An operator function analysis identified two basic characteristics, work volume and element relationship, which define 4 manipulation tasks chosen for examination. A visual function analysis developed a set of elemental scene parameters which grouped the visual dimensions into major areas of influence. Simulation testing was conducted with a 4 degree-of-freedom motion frame which allowed an operator to perform the manipulation tasks. Four video systems were included in the simulation testing: a black and white and a color monoscopic system, a stereoscopic system, and a black and white 2-view system. A sequential experimental plan first provided an overall analysis of the effects of tasks, scene parameters and video systems. This was followed by a detailed experimental examination of the critical dimensions identified in the first experiment. Results are discussed in terms of a recommended TV system.     

Electron Response of Nal(Tl) and a Comparison with Anthracene and Pilot B

An investigation was made of the relative response of NaI(Tl) to electrons over an energy range of 6 keV to 1 MeV. The light output at 6 keV is quite sensitive to the nature of the exposed surface. The results are given for the two best cleaved NaI(Tl) crystals and compared to the electron response deduced from photon data. There is good agreement above 20 keV, where little sensitivity to changes in surface condition was observed. Similar measurements were made for anthracene and Pilot B. The relative light output per unit energy is shown for all three scintillators. Their merit as low energy electron detectors was found to be significantly affected by the amount of backscattering and the intensity and duration of long lived excitation states arising from ionizing events.     

Static response of a rigid strip bonded to an elastic layer

Summary The problem of a rigid, bonded, rectangular indenter acting on a plane, transversely isotropic elastic layer is solved. The layer is fixed to a rigid foundation and the cases of applied moment and horizontal displacement are considered. In the first case the moment per unit rotation and horizontal displacement are calculated, while in the latter case the horizontal load per unit displacement and the associated torque are found. From the two problems influence coefficients are calculated and their values are given for different materials and layer thicknesses.

---

Das statische Verhalten eines mit einer elastischen Schicht verschweißten starren Streifens

Zusammenfassung Gelöst wird das Problem eines mit einer auf einer starren Unterlage befestigten orthotropen elastischen Schicht verschweißten starren Streifens. Betrachtet werden die Fälle eines auf den Streifen wirkenden äußeren Momentes und einer reinen Horizontalverschiebung des Streifens. Im ersten Fall werden das für eine bestimmte Verdrehung nötige Moment und die zugehörige Horizontalverschiebung ermittelt, im zweiten Fall die Horizontalkraft und das Moment pro Einheitsverschiebung. Einflußzahlen werden berechnet und ihre Werte für verschiedene Werkstoffe und Schichtdicken angegeben.

---

---

With 1 Figure     

HMPAO brain SPECT in acute carbon monoxide poisoning

Technetium-99m-hexamethylpropylene amine oxime (HMPAO) brain images with fanbeam SPECT, in combination with surface three-dimensional display, were used to detect basal ganglion and cerebral cortex anomalies in the acute phase of carbon monoxide (CO) poisoning. METHODS: Ten patients, aged 16-29 yr, with acute CO poisoning and no past history of neurologic disorders were enrolled in this study. After oxygen treatment, all 10 patients were investigated using 99mTc-HMPAO brain images with fanbeam SPECT and surface three-dimensional display. Meanwhile, 6 of 10 patients also received a brain CT scan. RESULTS: CT scan findings were negative in all 6 patients. Fanbeam SPECT demonstrated unilateral or bilateral hypoactivity of basal ganglia in 6 patients. Local hypoactivity anomalies were found in the brain cortex of 7 patients, using surface three-dimensional display of the brain. Only 2 of 10 patients had normal 99mTc-HMPAO brain images. CONCLUSION: This study suggests that, in comparison with traditional brain imaging techniques, 99mTc-HMPAO brain imaging with fanbeam SPECT in combination with surface three-dimensional display is a better tool for early detection of regional cerebral anomalies in acute CO poisoning.     

Biochemistry and regulation of pre-mRNA splicing

During the past year, significant advances have been made in the field of pre-mRNA splicing. It is now clear that members of the serine-arginine-rich protein family are key players in exon definition and function at multiple steps in the spliceosome cycle. Novel findings have been made concerning the role of exon sequences, which function as both constitutive and regulated enhancers of splicing, in trans-splicing and as targets for tissue-specific control of splicing patterns. By combining biochemical approaches in human and yeast extracts with genetic analysis, much has been learned about the RNA-RNA and RNA-protein interactions that are necessary to assemble the various complexes that are found along the pathway to the catalytically active spliceosome.     

A review of methods and instruments for assessing externalizing disorders: theoretical and practical considerations in rendering a diagnosis

This review addresses the most current and widely used methods of assessing childhood and adolescent externalizing disorders. Interviews, rating scales, and self-report instruments are described, and their strengths and weaknesses are discussed. Direct observational techniques in naturalistic and analogue settings are also reviewed. Throughout the article, commentary is offered regarding the psychometric adequacy and clinical validity of these instruments. It is suggested that, although the instruments presently used to assist in diagnosing externalizing disorders generally possess adequate reliability and representational validity, evidence of elaborative validity is lacking. Clinicians and researchers are encouraged to adopt a broader conceptualization of the diagnostic process, to question existing standards for establishing validity, and to consider alternative means of demonstrating diagnostic utility.     

Impaired platelet production of nitric oxide predicts presence of acute coronary syndromes

BACKGROUND: Thrombus formation within a coronary vessel is the acute precipitating event in most acute coronary syndromes. Recently, constitutive nitric oxide synthase (cNOS) has been identified in human platelets, and platelet-derived nitric oxide has been shown to inhibit platelet recruitment after aggregation. However, its role in regulating platelet responses under normal or pathologic conditions has not yet been elucidated. METHODS and RESULTS: We examined nitric oxide (NO) production by platelets isolated from 87 patients undergoing coronary angiography, 37 with stable angina and 50 with unstable angina or a myocardial infarction within 2 weeks. After stimulation with 5 micromol/L ADP, platelet aggregation and NO production were simultaneously measured with an NO-selective microelectrode adapted for use in a standard platelet aggregometer. Mean (+/-SEM) platelet-derived NO production was 1.78+/-0.36 pmol/10(8) and 0.26+/-0.05 pmol/10(8) platelets in coronary patients with stable angina and acute coronary syndromes, respectively (P=0. 0001). By logistic regression analysis, heparin treatment (odds ratio 6.6, CI 1.9 to 22.8, P=0.003), lower platelet-NO production (odds ratio 4.0, CI 1.3 to 11.5, P=0.01), and extent of atherosclerosis (odds ratio 1.5, CI 1.1 to 2.0, P=0.02) were independent predictors of an acute coronary syndrome. In the subset of patients with angiographic evidence of atherosclerosis (n=83), logistic regression demonstrated that platelet NO production (odds ratio 3.9, CI 1.3 to 11.1, P=0.01) and heparin treatment (odds ratio 6.4, CI 1.9 to 22.0, P=0.004) were independent predictors of an acute coronary syndrome, whereas extent of atherosclerosis was not. CONCLUSIONS: In summary, aggregating platelets from patients with acute coronary syndromes produce less NO. Since platelet aggregation and thrombus formation are implicated in unstable angina and myocardial infarction, impaired platelet-derived NO production may contribute to the development of acute coronary syndromes.     

Serum Amyloid A Receptor Blockade and Incorporation into High-Density Lipoprotein Modulates Its Pro-Inflammatory and Pro-Thrombotic Activities on Vascular Endothelial Cells

The acute phase protein serum amyloid A (SAA), a marker of inflammation, induces expression of pro-inflammatory and pro-thrombotic mediators including ICAM-1, VCAM-1, IL-6, IL-8, MCP-1 and tissue factor (TF) in both monocytes/macrophages and endothelial cells, and induces endothelial dysfunction—a precursor to atherosclerosis. In this study, we determined the effect of pharmacological inhibition of known SAA receptors on pro-inflammatory and pro-thrombotic activities of SAA in human carotid artery endothelial cells (HCtAEC). HCtAEC were pre-treated with inhibitors of formyl peptide receptor-like-1 (FPRL-1), WRW4; receptor for advanced glycation-endproducts (RAGE), (endogenous secretory RAGE; esRAGE) and toll-like receptors-2/4 (TLR2/4) (OxPapC), before stimulation by added SAA. Inhibitor activity was also compared to high-density lipoprotein (HDL), a known inhibitor of SAA-induced effects on endothelial cells. SAA significantly increased gene expression of TF, NFκB and TNF and protein levels of TF and VEGF in HCtAEC. These effects were inhibited to variable extents by WRW4, esRAGE and OxPapC either alone or in combination, suggesting involvement of endothelial cell SAA receptors in pro-atherogenic gene expression. In contrast, HDL consistently showed the greatest inhibitory action, and often abrogated SAA-mediated responses. Increasing HDL levels relative to circulating free SAA may prevent SAA-mediated endothelial dysfunction and ameliorate atherogenesis.