Partial-thickness tears of the rotator cuff: evaluation and management

The approach to management of a partial-thickness rotator cuff tear is best made with the understanding that this is not a singular condition. Rather, partial tears represent the common outcome of a variety of insults to the rotator cuff. Degenerative changes due to aging, anatomic impingement, and trauma may all be etiologic agents. Overhead athletes may develop tears due to repetitive microtrauma or internal impingement. Outlet radiographs and magnetic resonance imaging are recommended for routine preoperative evaluation. A nonoperative treatment program for rotator cuff strengthening and stretching is appropriate as initial treatment; modification of activities and anti-inflammatory medication are often used as well. Operative management may be considered when nonoperative treatment fails. Arthroscopic evaluation is required to determine the true extent of the cuff lesion. Arthroscopic subacromial decompression is recommended when outlet impingement is present. Rotator cuff debridement or formal cuff repair is dependent on the size of the cuff defect and the age and activity level of the patient. The importance of recognizing the different causes of partial-thickness rotator cuff tears is emphasized in this review of pathogenesis, clinical diagnosis, imaging, and treatment.     

HPLC analysis of quinolinic acid, a NAD biosynthesis intermediate, after fluorescence derivatization in an aqueous matrix

Quinolinic acid (2,3-pyridine dicarboxylic acid), a biological intermediate in nicotinamide adenine dinucleotide (NAD) biosynthesis in microbes and mammals and a brain excitotoxin, is not fluorescent nor electrochemically active and its detection sensitivity by UV absorption is comparatively low. Quinolinic acid was successfully derivatized in water-based samples by monodansylcadaverine, a fluorescence tag, and analysed by high-performance liquid chromatography (HPLC). No extraction procedure was needed and quinolinic acid was activated by water-soluble carbodiimide and derivatized under mild conditions. As little as 3 pmol (500 pg) of quinolinic acid in 5 microliter of artificial cerebrospinal fluid sample volume could be derivatized and detected at a signal to noise ratio of 3:1. Thus, detection on a mass basis by HPLC after fluorescence derivatization is about 300 times as sensitive as direct determination of quinolinic acid by UV absorbance (500 pg vs 150 ng). A variety of activators, fluorescent tags and reaction solvents and conditions were tested but found to be less effective.     

Fatal hyperthrombotic condition complicating nephrotic syndrome

A twenty-year old woman was admitted to hospital with impaired consciousness and a left hemiparesis. A cerebral CAT-scanning was reported normal. Convulsions and respiratory insufficiency made intubation and mechanical ventilation necessary. Laboratory examination showed an extremely low concentration of albumin in plasma (109 microM) and gross albuminuria was present. No other signs of renal failure occurred. The patient deteriorated during three days and died with signs of cerebral incarceration, despite efforts to reduce intracranial pressure. Autopsy showed a large thrombus of the sagittal sinus as the presumed cause of death. No thrombus was found in the renal vein. The association between nephrotic syndrome and thrombosis is discussed.     

Release of soluble tumour necrosis factor alpha receptors during and after paediatric cardiopulmonary bypass. Correlation with haemodynamic and clinical variables

The release of cytokines during cardiopulmonary bypass (CPB) may contribute to haemodynamic alternations encountered after open heart surgery. Regulatory mechanisms exist and include soluble cytokine receptors. We have measured blood levels of tumour necrosis factor (TNF) and its soluble receptor (TNFsr) during and after open heart surgery in children. Correlation analysis to haemodynamic and clinical variables was performed. Using immunoassays the authors registered a significant increase in plasma levels of TNFsr with peak levels 2 h post-operatively at a level of 1702 +/- 170 pg/ml. The concentration of TNFsr remained significantly elevated until 48 h postoperatively but TNF was not significantly elevated. An inverse correlation existed between peak TNFsr and mean arterial pressure (rho = -0.827, P < 0.05), between TNFsr and cardiac index (rho = -0.8, P < 0.05), between TNFsr and left ventricular stroke work index (rho = -0.983, P < 0.01), between TNFsr and weight (rho = -0.85, P < 0.05) and between TNFsr and body surface area (rho = -0.867, P < 0.05). The authors demonstrate that the smallest children experienced the highest TNFsr concentration post-operatively. Furthermore cardiac performance, expressed as cardiac index and left ventricular stroke work index, correlated inversely to peak TNFsr level post-operatively.     

Talking teletext receiver for the blind

By converting teletext pages into speech, the blind population could be afforded an opportunity of accessing broadcast teletext information normally displayed on the screen of a domestic television receiver. The possibility is examined in this paper. A suitable teletext receiver and decoder are described, and system hardware and software for a talking teletext receiver are discussed. Some human factors affecting the design are also discussed.     

Differences in interferon alpha and beta signaling. Interferon beta selectively induces the interaction of the alpha and betaL subunits of the type I interferon receptor

All Type I interferons (IFNalpha, IFNbeta, IFNomega) bind to the Type I IFN receptor (IFNR) and elicit a common set of signaling events, including activation of the Jak/Stat and IRS pathways. However, IFNbeta selectively induces the association of the alpha subunit of the Type I IFNR with p100, a tyrosyl phosphoprotein, to transduce IFNbeta-specific signals. Using antibodies raised against the different components of the Type I IFNR, we identified p100 as the long form of the beta subunit (betaL subunit) of the Type I IFNR. This was also confirmed in experiments with mouse L-929 cells transfected with truncated forms of betaL. Thus, IFNbeta stimulation of human cells or mouse L-929 transfectants expressing the human alpha and betaL subunits, selectively induces the formation of a signaling complex containing the alpha and betaL subunits of the receptor. The IFNbeta-regulated interaction of the alpha and betaL chains is rapid and transient and follows a similar time course with the tyrosine phosphorylation of these receptor components. These data demonstrate that the signaling specificity for different Type I IFNs is established early in the signaling cascade, at the receptor level, and results from distinct interactions between components of the Type I IFNR.     

Electrical impedance spectroscopy and electrical response in metal/non-metal systems

A new analysis of the electrical response of a macroscopic solid state system to an arbitrary electrical voltage input is presented. The results indicate that with a small, sinusoidal voltage input within the classical frequency range (ω < 10¹⁰Hz), the electrical response in spatially homogeneous systems mirrors first of all the static, spatial distribution of the mobile charge carrier density through the local electrical conductivity relaxation time. This enables any system, inclusive interface and electrical contact regions to be modelled by a simple, passive R, C electrical network, where each of the network elements has a very direct physical meaning. Ultra pure, single crystal silicon, pure polycrystalline silicon and Al-Al₂O₃-Au metal-insulator-metal (MIM) structure are used as illustrative examples.     

Variability in nanoscale CMOS technology

Moore’s Law technology scaling has improved VLSI performance by five orders of magnitude in the last four decades. As advanced technologies continue the pursuit of Moore’s Law, a variety of challenges will need to be overcome. One of these challenges is management of process variation. This paper discusses the importance of process variation in modern CMOS transistor technology, reviews front-end variation sources, presents device and circuit variation measurement techniques (including circuit and SRAM data...