Home About us Contact
|
Home About us Contact | ||
|
|
||
Acute Injury (acute + injury)
Selected AbstractsMeasurement of physical work capacity during arm and shoulder lifting at various shoulder flexion and ad/abduction anglesHUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 2 2003Jung-Yong Kim The purpose of this study was to provide information on physical work capacity during arm and shoulder lifting at various shoulder flexion and ad/abduction angles. We measured the maximum voluntary contractions (MVCs) in 20 male participants during controlled one-arm lifting. The lifting involved upward motion of the scapula at various shoulder angles. Simultaneously, the electromyographic (EMG) activity of 3 shoulder muscles and psychophysical workload were also recorded. The various measurements were compared to provide a multidimensional assessment of the physical work capacity of the shoulder at various working angles. In particular, 90 and 120 degrees of flexion, 30 degrees of adduction, and 90 degrees of abduction were found to be the most vulnerable angles based on the measured MVCs. The average root mean square value of the EMG increased most significantly at 90 to 150 degrees of flexion and at 30 and 60 degrees of abduction. Slightly different measurements were compared to validate the results. In addition, a 3-D static biomechanical model was used to show whether the estimated shoulder workload matched the measured physical capacity of the shoulder. In conclusion, these results may help ergonomists to identify shoulder angles associated with a relatively high risk of injury, and to match the workload with the physical capacity of the shoulder. Task-specific information on shoulder work capacity is needed in the manufacturing and shipbuilding industries to protect workers from acute injuries and cumulative trauma disorders of the shoulder. Experimental results provide various data on shoulder work capacity during realistic multijoint arm and shoulder lifting, and should help lead to improvements in workplace ergonomic design. © 2003 Wiley Periodicals, Inc. Hum Factors Man 13: 153,163, 2003. [source] Sonographic diagnosis of acute injuries of the ulnar collateral ligament of the metacarpophalangeal joint of the thumbJOURNAL OF CLINICAL ULTRASOUND, Issue 2 2007Takaaki Shinohara Abstract Purpose. To evaluate the significance of the ultrasonographic appearance of the aponeurosis for deciding the best treatment for ulnar collateral ligament (UCL) injuries of the thumb metacarpophalangeal joint. Methods. Fourteen patients (11 men, 3 women; mean age, 41 years; range, 15,66 years) who had an acute UCL tear were included. All patients were examined by ultrasonography (US) with a 7.5-MHz transducer and subsequently underwent surgery. The ultrasonographic findings were compared to the intraoperative findings. Results. UCL injuries were classified into two types by US according to the appearance of aponeurosis and its spatial relationship with the UCL: the intra-aponeurosis type (5 patients) and the extra-aponeurosis type (9 patients). In the 5 patients with intra-aponeurosis, ultrasonographic findings were well consistent with intraoperative findings. In contrast, extra-aponeurosis cases contained two different pathologies: of the 9 patients, 7 had so-called ,Stener lesions', one showed folding of a ruptured capsule, and one showed a ruptured aponeurosis. Conclusions. Because US is highly reliable in differentiating intra-aponeurosis from extra-aponeurosis types of injuries, the aponeurosis is a more reliable reference than Stener lesion for treatment decision by US. © 2006 Wiley Periodicals, Inc. J Clin Ultrasound, 2007. [source] Multi-item outcome measures for lateral ligament injury of the ankle: a structured reviewJOURNAL OF EVALUATION IN CLINICAL PRACTICE, Issue 2 2004K.L. Haywood BSc(Hons) DPhil MCSP Abstract Objective, To identify and review evidence relating to the measurement properties of published multi-item outcome measures for the conservative management of lateral ligament injuries of the ankle. Methods, Systematic literature searches were used to identify measures, which were then assessed against pre-defined criteria relating to development, item content, reliability, validity and responsiveness. Results, Seven disease-specific measures of ankle status [Ankle Joint Functional Assessment Tool, Clinical Trauma Severity Score, Composite Inversion Injury Scale, Kaikkonen Functional Scale (KFS), Karlsson Ankle Function Score (KAFS), Olerud and Molander Ankle Score (OMAS), and the Point System] and two generic measures of health (McGill Pain Questionnaire, Sickness Impact Profile) met the review inclusion criteria. While all measures had been used in acute injuries, only two had also been applied during later stages of recovery (>6 months). The studies covered a comprehensive range of graded ligament injuries. Expert opinion dominated item generation for all measures. All measures lack evidence of test-retest or internal consistency reliability in patients with ankle sprain. Several measures were assessed for validity through comparison with other measures, but there was limited evidence of construct validity and no formal assessment of responsiveness for any measure. Conclusion, The disappointing lack of evidence for measurement properties suggests that any measure should be used with caution until appropriate evidence is provided. On the basis of limited evidence, the KFS offers the most promising approach to a combined clinician- and patient-assessment of ankle function, and the KAFS or OMAS if a patient-assessed evaluation of function is required. [source] Review: Neutrophil gelatinase-associated lipocalin: A troponin-like biomarker for human acute kidney injuryNEPHROLOGY, Issue 4 2010PRASAD DEVARAJAN ABSTRACT Acute kidney injury (AKI) is a common and serious condition, the diagnosis of which currently depends on functional markers such as serum creatinine measurements. Unfortunately, creatinine is a delayed and unreliable indicator of AKI. The lack of early biomarkers of structural kidney injury (akin to troponin in acute myocardial injury) has hampered our ability to translate promising experimental therapies to human AKI. Fortunately, understanding the early stress response of the kidney to acute injuries has revealed a number of potential biomarkers. The discovery, translation and validation of neutrophil gelatinase-associated lipocalin (NGAL), possibly the most promising novel AKI biomarker, is reviewed. NGAL is emerging as an excellent stand-alone troponin-like structural biomarker in the plasma and urine for the early diagnosis of AKI, and for the prediction of clinical outcomes such as dialysis requirement and mortality in several common clinical scenarios. The approach of using NGAL as a trigger to initiate and monitor therapies for AKI, and as a safety biomarker when using potentially nephrotoxic agents, is also promising. In addition, it is hoped that the use of sensitive and specific biomarkers such as NGAL as endpoints in clinical trials will result in a reduction in required sample sizes, and hence the cost incurred. Furthermore, predictive biomarkers like NGAL may play a critical role in expediting the drug development process. However, given the complexity of AKI, additional biomarkers (perhaps a panel of plasma and urinary biomarkers) may eventually need to be developed and validated for optimal progress to occur. [source] Protective effect of curcumin, a Curcuma longa constituent, in early colonic inflammation in rats,DRUG DEVELOPMENT RESEARCH, Issue 6 2009Juan Manuel Sánchez-Calvo Abstract Curcumin, a polyphenol derived from the plant, Curcuma longa, has a variety of pharmacological effects, including chemotherapeutic, anti-inflammatory, antiangiogenic, and antioxidant activities. To gain a better understanding of the effects and mechanisms of action of curcumin on the acute injury caused by intra-colonic administration of acetic acid (AA) in rats, inflammation was assessed by histology and myeloperoxidase activity (MPO; an index of neutrophil infiltration in the mucosa); Th1 and Th2 cytokine production; histological and histochemical analysis of the lesions; nitrite production in colon mucosa; and the expression of iNOS, COX-1 and -2 using Western blotting and inmmunohistochemistry. We also studied the involvement of the p38 MAPK/JNK signalling pathway in the protective effect of curcumin in acute colonic inflammation. Curcumin (50,100,mg/kg/day) reduced the degree of colonic injury, the index of neutrophil infiltration and Th1 cytokine secretion, and increased IL-10 production, reduced colonic levels of nitrites, and reduced COX-2 and iNOS overexpression. A reduction in the activation of p38 and JNK MAPKs was also observed. Thus, we show that the widely used food additive, curcumin reduced the development of AA-induced colitis and alleviated the inflammatory response. Inhibition of MAPK signalling by curcumin could explain the changes on the cytokine Th1/Th2 profile, the reduction of COX-2 and iNOS signaling, as well as the decreased nitrite production in colonic mucosa, suggesting that curcumin may be useful in the treatment of ulcerative colitis. Drug Dev Res, 2009. © 2009 Wiley-Liss, Inc. [source] The impact of joint bleeding and synovitis on physical ability and joint function in a murine model of haemophilic synovitisHAEMOPHILIA, Issue 1 2008C. MEJIA-CARVAJAL Summary., Haemophilia is a congenital disorder that commonly results in musculoskeletal bleeding and orthopaedic complications. After an acute joint haemorrhage, an increase in intra-articular pressure and inflammation cause pain, swelling and limited motion. Blood in the joint space provokes a proliferative disorder known as haemophilic synovitis. Overgrowth of the synovial membrane causes mechanical dysfunction. Eventually, there is destruction of the articular surface and underlying bone. The aim of this project was to test the hypothesis that a minimum number of haemarthroses negatively impacts on joint function and that this would be reflected by decreased physical performance of experimental animals. Mice deficient in factor VIII coagulant activity were trained to ambulate on a rotating rod then injured three times at weekly intervals. Their ability to walk was then compared to a group of uninjured mice. Cohorts of mice were killed after 1, 2 or 3 months and the knee joints examined by gross and histological methods. The results supported the following conclusions: (i) haemophilic mice can be trained to ambulate on a rotating rod; (ii) acute hemarthrosis temporarily impairs their ability to ambulate and (iii) following recovery from acute injury, mice developing synovitis demonstrated inferior physical ability compared to mice not developing synovitis. This is the first description of a quantitative assay to monitor joint function in experimental animals and should be useful to evaluate the efficacy of new therapies developed to prevent and treat bleeding and to test strategies to counter the devastating effects of synovitis. [source] Hepatic progenitor cells, stem cells, and AFP expression in models of liver injuryINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 5 2006Wolf D. Kuhlmann Abstract Adult hepatocytes and liver-cell progenitors play a role in restoring liver tissue after injury. For the study of progenitor cells in liver repair, experimental models included (a) surgical removal of liver tissue by partial hepatectomy; (b) acute injury by carbontetrachloride; (c) acute injury by d -galactosamine (GalN) and N -nitrosomorpholine (NNM); and (d) chemical hepatocarcinogenesis by feeding NNM in low and high doses. Serological and immunohistological detection of alpha-fetoprotein gene expression served to follow pathways of cellular differentiation. Stem cells were not required in models of surgical removal of parenchyma and in carbon tetrachloride intoxication of adult hepatocytes. In contrast, regeneration of liver occurred through biliary epithelial cells in injuries induced by GalN and NNM. These biliary epithelial cells, collectively called oval cells, are most probably derived from the canals of Hering. Proliferating bile duct cells reached a level of differentiation with reactivation of foetal genes and significant alpha-1-fetoprotein (AFP) synthesis signalling a certain degree of retrodifferentiation with potential stemness. Due to the same embryonic origin of bile ducts and hepatocytes, biliary epithelium and its proliferating progeny (oval cells) have a defined role in liver regeneration as a transit and amplification compartment. In their early proliferation stage, oval cells were heavily engaged in DNA synthesis ([3H]thymidine labelling). Pulse-chase experiments during experimental hepatocarcinogenesis exhibited their development into hepatocytes with high risk for transformation and leading to foci of altered hepatocytes. Hepatocellular carcinomas may arise either from proliferating/differentiating oval cells or from adult hepatocytes; both cell types have stem-like properties. AFP-positive and AFP-negative carcinomas occurred in the same liver. They may represent random clonal origin. The heterogeneity of phenotypic marker (AFP) correlated with a process of retrodifferentiation. [source] Posttraumatic Stress Symptoms in the Pediatric Intensive Care UnitJOURNAL FOR SPECIALISTS IN PEDIATRIC NURSING, Issue 2 2007Wendy Ward-Begnoche PURPOSE.,Children who experience acute injury or illness severe enough to result in a pediatric intensive care unit (PICU) stay are at risk for posttraumatic stress symptoms, as are their parents. A distinction is made between injury-related traumatic events, illness-related traumatic events, and treatment-related traumatic events, all of which contribute to this risk. CONCLUSIONS.,This paper reviews what the PICU experience is like for children and their parents, the emerging literature on posttraumatic stress symptoms in PICU patients and their parents, and current knowledge regarding risk and resiliency factors for these children. PRACTICE IMPLICATIONS.,Children hospitalized in the PICU should be monitored for posttraumatic stress disorder during and after their stay. Risk and resiliency factors are a focus for practice and for future research. [source] The complement cascade: Yin,Yang in neuroinflammation , neuro-protection and -degenerationJOURNAL OF NEUROCHEMISTRY, Issue 5 2008Jessy John Alexander Abstract The complement cascade has long been recognized to play a key role in inflammatory and degenerative diseases. It is a ,double edged' sword as it is necessary to maintain health, yet can have adverse effects when unregulated, often exacerbating disease. The contrasting effects of complement, depending on whether in a setting of health or disease, is the price paid to achieve flexibility in scope and degree of a protective response for the host from infection and injury. Loss or even decreased efficiency of critical regulatory control mechanisms can result in aggravated inflammation and destruction of self-tissue. The role of the complement cascade is poorly understood in the nervous system and neurological disorders. Novel studies have demonstrated that the expression of complement proteins in brain varies in different cell types and the effects of complement activation in various disease settings appear to differ. Understanding the functioning of this cascade is essential, as it has therapeutic implications. In this review, we will attempt to provide insight into how this complex cascade functions and to identify potential strategic targets for therapeutic intervention in chronic diseases as well as acute injury in the CNS. [source] Is the modulation of retinoid and retinoid-associated signaling a future therapeutic strategy in neurological trauma and neurodegeneration?JOURNAL OF NEUROCHEMISTRY, Issue 3 2008Andrea Malaspina Abstract The complex molecular pathways that mediate the effects of vitamin A and its derivatives, are increasingly recognized as a component of the repair capacity that could be activated to induce protection and regeneration in the mature nervous tissue. Retinoid and retinoid-associated signaling plays an essential role in normal neurodevelopment and appears to remain active in the adult CNS. In this paper, we review evidence which supports the hypothesis of an activation of retinoid-associated signaling molecular pathways in the mature nervous tissue and its significance in the context of neurodegenerative, trauma-induced and psychiatric disorders, at spinal and supra-spinal levels. Finally, we summarize the potential therapeutic avenues based on the modulation of retinoid targets undergoing reactivation under conditions of acute injury and chronic degeneration in the central nervous system, and discuss some of the unresolved issues linked to this treatment strategy. [source] Pathophysiology of renal disease associated with liver disorders: Implications for liver transplantation.LIVER TRANSPLANTATION, Issue 2 2002Part I Renal and hepatic function are often intertwined through both the existence of associated primary organ diseases and hemodynamic interrelationships. This connection occasionally results in the chronic failure of both organs, necessitating combined liver-kidney transplantation (LKT). Since 1988, more than 850 patients in the United States have received such transplants, with patient survival somewhat less than that for patients receiving either organ alone. Patients with renal failure caused by acute injury or hepatorenal syndrome have classically not been included as candidates for combined transplantation because of the reversibility of renal dysfunction after liver transplantation. However, the rate and duration of renal failure before liver transplantation is increasing in association with prolonged waiting list times. Thus, the issue of acquired permanent renal damage in the setting of hepatic failure continues to confront the transplant community. The following article and its sequel (Part II, to be published in vol 8, no 3 of this journal) attempt to review the problem of primary and secondary renal disease in patients with end-stage liver disease, elements involved in renal disease progression and recovery, the impact of renal disease on liver transplant outcome, and results of combined LKT; outline the steps in the pretransplantation renal evaluation; and provide the beginnings of an algorithm for making the decision for combined LKT. [source] In vivo MRI using real-time production of hyperpolarized 129XeMAGNETIC RESONANCE IN MEDICINE, Issue 1 2008Bastiaan Driehuys Abstract MR imaging of hyperpolarized (HP) nuclei is challenging because they are typically delivered in a single dose of nonrenewable magnetization, from which the entire image must be derived. This problem can be overcome with HP 129Xe, which can be produced sufficiently rapidly to deliver in dilute form (1%) continuously and on-demand. We demonstrate a real-time in vivo delivery of HP 129Xe mixture to rats, a capability we now routinely use for setting frequency, transmitter gain, shimming, testing pulse sequences, scout imaging, and spectroscopy. Compared to images acquired using conventional fully concentrated 129Xe, real-time 129Xe images have 26-fold less signal, but clearly depict ventilation abnormalities. Real-time 129Xe MRI could be useful for time-course studies involving acute injury or response to treatment. Ultimately, real-time 129Xe MRI could be done with more highly concentrated 129Xe, which could increase the signal-to-noise ratio by 100 relative to these results to enable a new class of gas imaging applications. Magn Reson Med 60:14,20, 2008. © 2008 Wiley-Liss, Inc. [source] Iatrogenic tracheal rupture in children: A retrospective studyTHE LARYNGOSCOPE, Issue 3 2009Eva-Maria Schedlbauer MD Abstract Objectives: Iatrogenic injuries to the trachea are rare, but life-threatening complaints. Causes and treatment methods have been described for adults, but there is no literature on aetiology and treatment in children. We performed a retrospective study to examine the frequency, aetiology, and treatment of iatrogenic injuries to the trachea in children and to develop guidelines for their treatment and prevention. Methods: Retrospective study from 2000,2007 at a level I trauma centre. All iatrogenic injuries to the trachea between the cricoid cartilage and the level of the carina in children (ages 0,16) were included in the study. Results: Between 2000 and 2007, 18 tracheal injuries were treated, four of them in children (22%). The primary symptom in all cases was emphysema. Diagnosis was confirmed using flexible endoscopy. In all cases, the cause of the injury was intubation. Two cases of acute injury were treated conservatively by bridging the injury with a tube. Two cases were treated surgically by means of end-to-end anastomosis. In all cases, healing by first intention occurred. No stenoses were observed during follow-up endoscopy. Conclusions: Acute tracheal ruptures in children can be treated conservatively by bridging the rupture with a tube. Injuries to the trachea in which the mucosa is damaged or in which other complications, such as fistulae, are present must be treated surgically. The prognosis for such injuries is good. Laryngoscope, 2009 [source] Neutrophils and B lymphocytes in ANCA-associated vasculitisAPMIS, Issue 2009VÉRONIQUE WITKO-SARSAT The pathogenesis of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is unknown but is most consistent with a primary role for neutrophils in the acute injury. Thus, neutrophils are cardinal cells in the pathophysiological process in AAV because they are both effector cells responsible for endothelial damage and targets of autoimmunity. In addition, because of their capacity to synthesize a wide variety of cytokines and chemokines, neutrophils can be considered as important modulators of the inflammatory and potentially of the autoimmune process. ANCA directed against two main autoantigens, namely proteinase 3 and myeloperoxidase, are likely to play a modulatory role in the inflammatory process. Interestingly, neutrophils are an important source of lymphocyte stimulator (BLy), a cytokine that plays a fundamental role in B-cell physiology, including differentiation, proliferation and immunoglobulin production. The issue of B-cell activation and/or dysregulation in vasculitis will be discussed. [source] Gastric mucosal resistance to acute injury in experimental portal hypertensionBRITISH JOURNAL OF PHARMACOLOGY, Issue 1 2001Sara Calatayud The gastric mucosa of portal hypertensive rats exhibits important microvascular changes and a nitric oxide (NO)-dependent hyperemia. This study analyses whether portal hypertensive mucosa exhibits changes in its ability to withstand aggression. Portal hypertension was induced by partial portal vein ligation (PPVL) or common bile duct ligation (CBDL) and gastric damage was induced by oral administration of ethanol or aspirin. Experiments were performed in conscious or anaesthetized rats and some animals were pre-treated with the NO-synthesis inhibitor L -NAME. Conscious PPVL or CBDL rats showed an increased resistance to the damaging effects of ethanol. Oral administration of aspirin produced less gastric damage in PPVL conscious rats than in the control group. The protective effects of portal hypertension were maintained in animals anaesthetized with ketamine and absent when pentobarbital was employed. Pre-treatment with L -NAME restored the damaging effects of ethanol and aspirin in PPVL rats without modifying the level of damage in control animals. Gastric bleeding induced by oral aspirin, as measured by the luminal release of 51Cr-labelled erythrocytes, was significantly greater in PPVL rats than in control animals. Semi-quantitiative analysis by RT , PCR of the mRNA for endothelial NO-synthase (eNOS), neuronal NOS (nNOS) and inducible NOS (iNOS) levels showed that the expression of iNOS was slightly increased in both the gastric mucosa and smooth muscle of PPVL rats. No changes were observed in eNOS and nNOS expression. Conscious portal hypertensive rats exhibit an enhanced resistance to acute gastric damage which is absent under the influence of some types of anaesthesia and seems related to an increased synthesis of nitric oxide. However, mucosal lesions in these animals show an augmented bleeding per area of injury. British Journal of Pharmacology (2001) 132, 309,317; doi:10.1038/sj.bjp.0703785 [source] Iatrogenic vertebral artery injuryACTA NEUROLOGICA SCANDINAVICA, Issue 6 2005J. Inamasu Iatrogenic vertebral artery injury (VAI) results from various diagnostic and therapeutic procedures. The objective of this article is to provide an update on the mechanism of injury and management of this potentially devastating complication. A literature search was conducted using PubMed. The iatrogenic VAIs were categorized according to each diagnostic or therapeutic procedure responsible for the injury, i.e., central venous catheterization, cervical spine surgery, chiropractic manipulation, diagnostic cerebral angiography, percutaneous nerve block, and radiation therapy. The incidence, mechanisms of injury, and reparative procedures were discussed for each type of procedure. The type of VAI depends largely on the type of procedure. Laceration was the dominant type of acute injury in central venous catheterization and cervical spine surgery. Arteriovenous fistulae and pseudoaneurysms were the delayed complications. Arterial dissection was the dominant injury type in chiropractic manipulation and diagnostic cerebral angiography. Inadvertent arterial injection caused seizures or stroke in percutaneous nerve block. Radiation therapy was responsible for endothelial injury which in turn resulted in delayed stenosis and occlusion of the vertebral artery (VA). The proximal VA was the most vulnerable portion of the artery. Although iatrogenic VAIs are rare, they may actually be more prevalent than had previously been thought. Diagnosis of iatrogenic VAI may not always be easy because of its rarity and deep location, and a high level of suspicion is necessary for its early detection. A precise knowledge of the surgical anatomy of the VA is essential prior to each procedure to prevent its iatrogenic injury. [source] Validation Set Correlates of Anogenital Injury after Sexual AssaultACADEMIC EMERGENCY MEDICINE, Issue 3 2008Peter Drocton MD Abstract Objectives:, Forensic investigators remain unsure exactly why some sexual assault victims display acute injury while others do not. This investigation explores potential reasons for these differential findings among female victims. Methods:, This cross-sectional analysis examined data from consecutive female sexual assault victims, at least 12 years old, who agreed to a forensic exam between November 1, 2002, and November 30, 2006. Exams utilized colposcopy, anoscopy, macrodigital imaging, and toluidine blue dye to delineate anogenital injury (AGI), which was defined as the presence of recorded anogenital abrasions, tears, or ecchymosis. Demographic variables of the victim, including sexual experience and reproductive parity, and assault characteristics were recorded in the database for bivariate and multivariate analysis with AGI. Results:, Forty-nine percent of the initial 3,356 patients displayed AGI. Of this total, 2,879 cases included complete data for all variables and were included in the multivariate logistic regression model. A statistically significant increased risk for AGI was noted with: educational status (odds ratio [OR] 1.53, 95% CI = 1.25 to 1.87); vaginal or attempted penetration using penis (OR 2.29, 95% CI = 1.74 to 3.01), finger (OR 1.61, 95% CI = 1.88 to 1.94), or object (OR 3.19, 95% CI = 1.52 to 6.68); anal,penile penetration (OR 2.00, 95% CI = 1.57 to 2.54); alcohol involvement (OR 1.25, 95% CI = 1.04 to 1.50); and virgin status of victim (OR 1.38, 95% CI = 1.11 to 1.71). Victims were less likely to display AGI with a longer postcoital interval (OR 0.50, 95% CI = 0.39 to 0.65) and increased parity (OR 0.76, 95% CI = 0.57 to 0.99). Conclusions:, Approximately half the patients displayed AGI. This rate is higher than earlier studies, but consistent with current investigations utilizing similar injury detection methods. The correlates of injury found reinforce the findings of prior studies, while prompting questions for future study. [source] Salvaging The Ischaemic Penumbra: More Than Just Reperfusion?CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 1-2 2002Thanh G Phan SUMMARY 1. The ischaemic penumbra is defined as a moderately hypoperfused region that retains structural integrity but has lost function. In animal models of ischaemic stroke, this region is prone to recurrent anoxic depolarization and will become infarcted if reperfusion does not occur. In the macaque model, an ischaemic penumbra has been identified for up to 3 h after ischaemic stroke onset, whereas in selected human patients it may exist for up to 48 h. 2. Although most definitions of the ischaemic penumbra stress a ,time,brain volume' concept, few incorporate the idea that selective and delayed neuronal injury plays an important role. Thus, in addition to necrotic cell death caused by acute injury, it is important to also consider delayed death mediated by caspase-dependent and -independent apoptotic pathways. 3. ,Salvage' of penumbral tissue is possible if reperfusion (e.g. after thrombolysis) occurs. However, neurons within this ,salvaged' region may be still at risk of further delayed neuronal injury. 4. In the present review, we aim to revisit the concept of the ischaemic penumbra and explore the role of selective and delayed neuronal injury in enlargement of the volume of infarction, as well as pathogenic mechanisms of white matter ischaemia. Both animal and human models of cerebral ischaemia imaged using magnetic resonance and positron emission tomography techniques will be discussed. [source] Maximizing management of patients with decompensated heart failureCLINICAL CARDIOLOGY, Issue S3 2000E. Loh M.D. Abstract Patients with decompensated congestive heart failure can be categorized into those with either acute or chronic presentations. Patients with acute decompensated heart failure most often have an acute injury that affects either myocardial performance (i.e., myocardial infarction) or valvular/chamber integrity (mitral regurgitation, ventricular septal rupture), which leads to an acute rise in left ventricular (LV) filling pressures resulting in pulmonary edema and dyspnea. Therapy for these patients is aimed at treating the underlying cause of the myocardial injury as well as pharmacologic strategies to reduce LV filling pressures and to improve cardiac performance. In contrast, the therapy of patients presenting with decompensated heart failure in the setting of chronic LV systolic dysfunction, treated with angiotensin-converting enzyme inhibitors, digoxin, diuretics, and maybe beta blockers, represent a poorly defined clinical entity that lacks clear guidelines for treatment. These patients can present with symptoms of volume overload and/or low cardiac output without evidence for a volume overloaded state. Potential diagnostic and therapeutic approaches include (1) a pulmonary artery catheter for invasive hemodynamic monitoring, (2) intravenous inotropic therapy, (3) LV mechanical assist device therapy, and (4) cardiac transplantation. This review presents some of the advantages and disadvantages of each of these interventions for patients with chronic systolic dysfunction who present with decompensated symptoms and require specialized management in the hospital setting. [source] | ||||||||||||||||||||||