Electron-beam CT in the noninvasive assessment of coronary stent patency

RATIONALE AND OBJECTIVES: Coronary artery stents reduce the rate of restenosis in patients who have undergone balloon angioplasty; therefore, the implantation of coronary stents represents an important method in the treatment of coronary stenoses. The authors' purpose was to investigate the usefulness of electron-beam computed tomography (CT) as a noninvasive means of assessing the patency of coronary artery stents in patients who had undergone balloon angioplasty and stent placement. MATERIALS AND METHODS: Electron-beam CT was used to assess stent patency in 177 patients with 285 stents. Contrast material-enhanced multisection flow studies were performed, and the images were evaluated by three investigators and compared with the findings of coronary angiography. RESULTS: Cine loop evaluations and time-attenuation curve analysis led to the correct diagnosis in 167 (94.3%) patients, as confirmed with coronary angiography. Stenoses had occurred in 18 of the 194 vessels with stents, and 14 of these were detected with electron-beam CT. CONCLUSION: Electron-beam CT appears to be a valuable imaging modality in the noninvasive assessment of stent patency in coronary arteries.     

Heterogeneity of variances for carcass traits by percentage Brahman inheritance

Heterogeneity of carcass trait variances due to level of Brahman inheritance was investigated using records from straightbred and crossbred steers produced from 1970 to 1988 (n = 1,530). Angus, Brahman, Charolais, and Hereford sires were mated to straightbred and crossbred cows to produce straightbred, F1, back-cross, three-breed cross, and two-, three-, and four-breed rotational crossbred steers in four non-overlapping generations. At weaning (mean age = 220 d), steers were randomly assigned within breed group directly to the feedlot for 200 d, or to a backgrounding and stocker phase before feeding. Stocker steers were fed from 70 to 100 d in generations 1 and 2 and from 60 to 120 d in generations 3 and 4. Carcass traits included hot carcass weight, subcutaneous fat thickness and longissimus muscle area at the 12-13th rib interface, carcass weight-adjusted longissimus muscle area, USDA yield grade, estimated total lean yield, marbling score, and Warner-Bratzler shear force. Steers were classified as either high Brahman (50 to 100% Brahman), moderate Brahman (25 to 49% Brahman), or low Brahman (0 to 24% Brahman) inheritance. Two types of animal models were fit with regard to level of Brahman inheritance. One model assumed similar variances between pairs of Brahman inheritance groups, and the second model assumed different variances between pairs of Brahman inheritance groups. Fixed sources of variation in both models included direct and maternal additive and nonadditive breed effects, year of birth, and slaughter age. Variances were estimated using derivative free REML procedures. Likelihood ratio tests were used to compare models. The model accounting for heterogeneous variances had a greater likelihood (P < .001) than the model assuming homogeneous variances for hot carcass weight, longissimus muscle area, weight-adjusted longissimus muscle area, total lean yield, and Warner-Bratzler shear force, indicating improved fit with percentage Brahman inheritance considered as a source of heterogeneity of variance. Genetic covariances estimated from the model accounting for heterogeneous variances resulted in genetic correlations of or near unity. These results suggest that different genetic values be considered for genetic evaluation of carcass yield and shear force traits from steers with different degrees of Brahman inheritance.     

Heterogeneity of Atlantic salmon troponin-I

Three non-identical, full length troponin-I (Tn-I) clones were isolated from an Atlantic salmon myotomal (trunk) muscle cDNA library. The primary structures, which are predicted to range from 172 to 180 amino acids in length, exhibit similar percent identity scores when compared with fast, slow and cardiac specific Tn-Is from higher vertebrates. When the sequence data are considered along with the results of Western blotting it is evident that Tn-I is more heterogeneous in Atlantic salmon than has been previously shown in higher vertebrates.     

When Words Are Represented in Memory Like Pictures: Evidence for Spatial Encoding of Study Materials

We examined whether different word displays also differ in terms of the format in which they are represented in memory. Undergraduates studied a text, an outline, a graphic organizer, or a concept map and then were shown either a verbal (digits) or spatial (dots) display. They were then tested on comprehension of the first display and recognition of the second display. Comprehending graphic organizers and concept maps interfered with the spatial concurrent task and vice versa, whereas the verbal concurrent task interfered with comprehension of texts and outlines. These results are consistent with the conjoint retention hypothesis suggesting that spatial encoding may explain the facilitative effects of graphic organizers and concept maps. Copyright 1999 Academic Press.     

Quantitative analysis of O-isopropyl methylphosphonic acid in serum samples of Japanese citizens allegedly exposed to sarin: estimation of internal dosage

A convenient and rapid micro-anion exchange liquid chromatography (LC) tandem electrospray mass spectrometry (MS) procedure was developed for quantitative analysis in serum of O-isopropyl methylphosphonic acid (IMPA), the hydrolysis product of the nerve agent sarin. The mass spectrometric procedure involves negative or positive ion electrospray ionization and multiple reaction monitoring (MRM) detection. The method could be successfully applied to the analysis of serum samples from victims of the Tokyo subway attack and of an earlier incident at Matsumoto, Japan. IMPA levels ranging from 2 to 135 ng/ml were found. High levels of IMPA appear to correlate with low levels of residual butyrylcholinesterase activity in the samples and vice versa. Based on our analyses, the internal and exposure doses of the victims were estimated. In several cases, the doses appeared to be substantially higher than the assumed lethal doses in man.     

Chronic pain in a community-based sample of men with spinal cord injury: prevalence, severity, and relationship with impairment, disability, handicap, and subjective well-being

OBJECTIVE: To assess the prevalence, severity, and correlates of chronic pain in a community-based sample of men with spinal cord injury (SCI). DESIGN: Survey. SETTING: Community. PARTICIPANTS: Seventy-seven men with SCI randomly selected from a sampling frame solicited from the community. METHOD: Participants completed standardized questionnaires assessing many areas of life, were interviewed in their homes, and underwent a physical examination at a hospital. There they were interviewed by an anesthesiologist regarding chronic pain, and a nurse administered objective pain measures. RESULTS: Seventy-five percent of the men reported chronic pain. Chronic pain was associated with more depressive symptoms, more perceived stress, and poorer self-assessed health. Greater intensity of pain was related to less paralytic impairment, violent etiology, and more perceived stress. Area of the body affected by pain was related to independence and mobility. CONCLUSIONS: Because of the high prevalence of chronic pain in the population with SCI and its relation to disability, handicap, and quality of life, health care providers need to give this issue the same priority given to other SCI health issues. Analysis of individual pain components provides better information than assessing overall pain. It is futile to treat SCI pain without giving full attention to subjective factors.     

Relation of factor V Leiden genotype to risk for acute deep venous thrombosis after joint replacement surgery

C-peptide, which is released from the pancreatic beta cells into the circulation in amounts equimolar with insulin, fulfills an important function in the assembly of the two-chain insulin structure, but has otherwise been considered to be biologically inactive. However, during the last few years several experimental and clinical studies have demonstrated that replacement of C-peptide in patients with insulin-dependent diabetes mellitus elicits several physiological effects. Thus, during short-term substitution of C-peptide (1-3 h) decreased glomerular hyperfiltration, augmented whole body and skeletal muscle glucose utilisation, improved autonomic nerve function and a redistribution of microvascular skin blood flow could be observed. In addition, replacement of C-peptide during a period of 1-3 months has been shown to improve renal function as well as autonomic and sensory nerve function in IDDM patients. The mechanisms behind these effects remain unclear, but recent investigations have indicated that an increase in Na+K+ATPase activity and a stimulation of the endothelial nitric oxide synthase may contribute to the observed physiological effects of C-peptide. Not only the intact C-peptide molecule, but also fragments from the C-terminal and mid-portion of the molecule have been shown to exert biological effects. Further research will be necessary to evaluate the underlying mechanism and the clinical impact of C-peptide replacement in IDDM patients.     

Crystal structure of the complex of the cyclin D-dependent kinase Cdk6 bound to the cell-cycle inhibitor p19INK4d

The crystal structure of the cyclin D-dependent kinase Cdk6 bound to the p19 INK4d protein has been determined at 1.9 A resolution. The results provide the first structural information for a cyclin D-dependent protein kinase and show how the INK4 family of CDK inhibitors bind. The structure indicates that the conformational changes induced by p19INK4d inhibit both productive binding of ATP and the cyclin-induced rearrangement of the kinase from an inactive to an active conformation. The structure also shows how binding of an INK4 inhibitor would prevent binding of p27Kip1, resulting in its redistribution to other CDKs. Identification of the critical residues involved in the interaction explains how mutations in Cdk4 and p16INK4a result in loss of kinase inhibition and cancer.