Subjective time experience in an intergenerational sample

The roles chronological age and gender play in subjective time experience were explored in a sample of 294 adult men and women. Subjective time experience (STE: the difference between subjective age and chronological age) was found to vary widely among individuals, with some being "accurate" (SA = CA), and others either "retarded" (SA less than CA) or "advanced" (SA greater than CA). Males were more retarded in STE than females at every point in the lifespan, and patterns of age differences in adulthood differed for the two sexes as well. The results suggest that chronological age may play a key role in transitions in STE, and that chronological age is more significant in the STE of women than in the STE of men.     

Pulmonary delivery of nanoparticles of insoluble, iodinated CT X-ray contrast agents to lung draining lymph nodes in dogs

Lung cancer continues to be a leading cause of death around the world. Staging of this disease is critically dependent upon the involvement or noninvolvement of the lymph nodes which drain the region of lung containing the lesion/tumor. Palpation, unenhanced CT, and lymph node excision (i.e., mediastinectomy) are currently used to ascertain the status of these regional draining lymph nodes. The work reported herein details the first efforts toward the pulmonary instillation of iodinated nanoparticles for contrast-enhanced CT of lung draining lymph nodes. The data reflect the impact of dose, time post instillation, and formulation (surfactant) upon the observed CT enhancement of the tracheobronchial lymph nodes of beagle dogs. In addition, initial safety is discussed with both macroscopic and microscopic observations. The results indicate that pulmonary instillation of small volumes of iodinated nanoparticles could be successfully used to aid staging of lung cancer by CT imaging.     

Cardiac risk in surgery. A review and guidelines for risk evaluation and reduction of cardiac risk in general surgery

We report herein the phenotypic and functional analysis of human bone marrow and thymus derived early T cells. Commitment to T cell lineage is acquired during CD7 antigen expression by CD34+ precursors in human bone marrow and before thymus colonization. Early thymocytes show similar phenotypic characteristics as bone marrow T cells. They rapidly acquire CD4 before the dual expression of CD4 and CD8. Their expansion and differentiation is regulated by two major factors: thymic stroma and cytokines produced by these stroma cells or by thymocytes themselves. Among cytokines, IL1 and sCD23 produced by thymic epithelial cells support in vitro early T cell development.     

Preservation with 8-bromo-cyclic GMP improves pulmonary function after prolonged ischemia

BACKGROUND: Cyclic guanosine monophosphate (cGMP) is a potent second messenger for the nitric oxide pathway in the pulmonary vasculature. Increased cytosolic cGMP levels elicit pulmonary vasodilatation resulting in decreased pulmonary vascular resistance and maximized pulmonary function after ischemia-reperfusion injury. We hypothesized that the addition of a membrane-permeable cGMP analogue (8-bromo-cGMP) to a Euro-Collins (EC) preservation solution would ameliorate pulmonary reperfusion injury better than prostaglandin E1 injection alone after prolonged hypothermic ischemia. METHODS: All lungs from New Zealand White rabbits (weight, 3 to 3.5 kg) were harvested en bloc, flushed with EC solution, and reperfused with whole blood for 30 minutes. Group 1 lungs (immediate control) were immediately reperfused. Group 2 lungs (control) were stored inflated at 4 degrees C for 18 hours before reperfusion. Groups 3 and 4 lungs were flushed with EC solution containing 200 micromol/L 8-bromo-cGMP and stored at 4 degrees C for 18 and 30 hours, respectively. Fresh, nonrecirculated venous blood was used to determine single-pass pulmonary venous-arterial oxygen gradients at 10-minute intervals. Assays for cGMP, cyclic adenosine monophosphate, nitric oxide synthase activity, and myeloperoxidase were performed on all lung tissue samples. Wet to dry weight ratios were determined after 2 weeks of passive desiccation. RESULTS: Oxygenation (venous-arterial oxygen gradient), pulmonary artery pressure, pulmonary vascular resistance, and edema formation were significantly improved in groups 3 and 4 (addition of 8-bromo-cGMP to EC plus 18 or 30 hours of hypothermic ischemia). Hypothermic storage (groups 2, 3, and 4) decreased both nitric oxide synthase activity and myeloperoxidase levels compared with immediate reperfusion (group 1). CONCLUSIONS: These results suggest that the addition of a membrane-permeable cGMP analogue to an EC pulmonary flush solution improves pulmonary function after prolonged storage compared with EC and prostaglandin (E1) preservation alone. The finding of myeloperoxidase reduced levels after hypothermic storage and subsequent reperfusion may suggest a more important role for pulmonary hemodynamic control in mitigating pulmonary reperfusion injury.     

Cytoplasmic Ca2+ oscillations in pancreatic beta-cells

In the last 15 years it has been a growing interest in the cyclic variations of circulating insulin [46]. After the suggestion that this phenomenon may be due to oscillations of the beta-cell membrane potential [8,39], it was demonstrated that [Ca2+]i oscillates in the glucose-stimulated beta-cell with a similar frequency to that of pulsatile insulin release. The present review describes four types of [Ca2+]i oscillations in the pancreatic beta-cell. The slow sinusoidal oscillations, referred to as type-a, are those which most closely correspond to pulsatile insulin release. Although not affecting the properties of the type-a oscillations in individual beta-cells, the concentration of glucose is a determinant for their generation and further transformation into a sustained increase. Accordingly, cytoplasmic Ca2+ is regulated by sudden transitions between oscillatory and steady-state levels at threshold concentrations of glucose, which are characteristic for the individual beta-cell. This behaviour explains the observation of a gradual recruitment of previously non-secreting cells with increase of the extracellular glucose concentration [44]. However, it still remains to be elucidated how the sudden transitions between these three states translate into the co-ordinated slow oscillations of [Ca2+]i in the intact islet. Cyclic variations of circulating insulin require a synchronization of the [Ca2+]i cycles also among the islets in the pancreas. It is still an open question by which means the millions of islets communicate mutually to establish a pattern of pulsatile insulin release from the whole pancreas. The discovery that the beta-cell is not only the functional unit for insulin synthesis but also generates the [Ca2+]i oscillations required for pulsatile insulin release has both physiological and clinical implications. The fact that minor damage to the beta-cells prevents the type-a oscillations with maintenance of a glucose response in terms of raised [Ca2+]i reinforces previous arguments [54] that loss of insulin oscillations is an early indicator of type-2 diabetes. Further analyses of the [Ca2+]i oscillations in the beta-cells should include not only the mechanisms for their generation and subsequent propagation within or among the islets but also how modulation of their frequency affects the insulin sensitivity of various target cells. The latter approach may be important in the attempts to maintain normoglycemia under conditions minimizing the vascular effects of insulin supposed to precipitate hypertonia and atherosclerosis [70,71,77].     

Rapid inhalation induction in children: 8% sevoflurane compared with 5% halothane

BACKGROUND: Ultrasonography (US) by acknowledged experts enhances the diagnostic performance and reduces the rate of negative laparotomies in patients with suspected acute appendicitis (AA). METHODS: The diagnostic accuracy and clinical impact of routine US performed by surgical residents was prospectively studied in 504 unselected patients admitted for AA. Clinical and US findings were correlated with laparotomy findings and pathological outcome in 135 patients (113 cases with proven AA, prevalence 22.4%) and clinical as well as follow-up data were compared in the remainder. RESULTS: The overall accuracy, sensitivity, and specificity of the clinical diagnosis of AA were 84.9%, 51.3%, and 94.6% and those of US were 93. 6%, 83.1%, and 96.6%. Joint evaluation of the results from clinical evaluation and US further improved diagnostic performance (accuracy 93.4%, sensitivity 84.1%, specificity 96.2) and significantly reduced the rate of diagnostic errors to 3.4% (p < 0.001) and unnecessary laparotomies to 9.6% (p < 0.01) in patients with suspected AA. CONCLUSIONS: Ultrasonographic evaluation of the patient with suspected AA is considered to be of value in surgical practice.     

Protein structure alignment by incremental combinatorial extension (CE) of the optimal path

A new algorithm is reported which builds an alignment between two proteinstructures. The algorithm involves a combinatorial extension (CE) of analignment path defined by aligned fragment pairs (AFPs) rather than themore conventional techniques using dynamic programming and Monte Carlooptimization. AFPs, as the name suggests, are pairs of fragments, one fromeach protein, which confer structure similarity. AFPs are based on localgeometry, rather than global features such as orientation of secondarystructures and overall topology. Combinations of AFPs that representpossible continuous alignment paths are selectively extended or discardedthereby leading to a single optimal alignment. The algorithm is fast andaccurate in finding an optimal structure alignment and hence suitable fordatabase scanning and detailed analysis of large protein families. Themethod has been tested and compared with results from Dali and VAST using arepresentative sample of similar structures. Several new structuralsimilarities not detected by these other methods are reported. Specificone-on-one alignments and searches against all structures as found in theProtein Data Bank (PDB) can be performed via the Web athttp://cl.sdsc.edu/ce.html.     

A frictional Cosserat model for the flow of granular materials through a vertical channel

Summary A rigid-plastic Cosserat model has been used to study dense, fully developed flow of granular materials through a vertical channel. Frictional models based on the classical continuum do not predict the occurrence of shear layers, in contrast to experimental observations. This feature has been attributed to the absence of a material length scale in their constitutive equations. The present model incorporates such a material length scale by treating the granular material as a Cosserat continuum. Thus, localized couple stresses exist, and the stress tensor is asymmetric. The velocity profiles predicted by the model are in close agreement with available experimental data. The predicted dependence of the shear layer thickness on the width of the channel is in reasonable agreement with data. In the limit of small (ratio of the particle diameter to the half-width of the channel), the model predicts that the shear layer thickness scaled by the particle diameter grows as ^-1/3.