Impaired oxygen utilization in skeletal muscle of CRPS I patients.

BACKGROUND: The purpose of this study was to evaluate oxygen extraction and utilization in end stage chronic complex regional pain syndrome type I (CRPS I) patients undergoing amputation and to relate these to muscle histology of the amputated limb. MATERIALS AND METHODS: In 25 patients with severe CRPS I requiring amputation of the affected limb venous blood samples and in 11 patients skeletal muscle specimens were analyzed. RESULTS: The mean venous oxygen saturation (S(v)O(2)) value (94.3% ± 4.0%) of the affected limb was significantly higher than S(v)O(2) values found in healthy subjects (77.5% ± 9.8%) pointing to a severely decreased oxygen diffusion or utilization within the affected limb. Histologic analysis showed a significant decrease of type I fibers and a significant increase of type IIB fibers. Ultrastructural investigations of soleus skeletal muscle capillaries revealed thickened endothelial cells and thickened basement membranes. Muscle capillary densities were decreased in comparison with literature data. High venous oxygen saturation levels were partially explained by impaired diffusion of oxygen due to thickened basement membrane and decreased capillary density. CONCLUSION: This study shows that venous oxygen saturation is significantly increased in chronic end stage CRPS I patients corresponding with impaired oxygen diffusion. The abnormal skeletal muscle findings points to severe disuse but only partially explain the impaired diffusion of oxygen; mitochondrial dysfunction seems a likely explanation in addition.

The oxidative response in the chronic constriction injury model of neuropathic pain.

BACKGROUND: In the chronic constriction injury model of rat neuropathic pain, oxidative stress as well as antioxidants superoxide dismutase and reduced glutathione (GSH) are important determinants of neuropathological and behavioral consequences. Studies of the chronic constriction injury model observed (indirect) signs of inflammation. We, therefore, investigated the level of oxidative stress and antioxidant enzymes in skeletal muscle tissue of the rat hind paw and (jugular vein) plasma at d 7 after nerve injury. MATERIALS AND METHODS: The level of reactive oxygen and nitrogen species (RONS) was determined as a measure of oxidative stress. Reduced GSH levels and the ceruloplasmin/transferrin ratio were determined as measures of overall antioxidant activity. RONS and overall antioxidant activity were measured in skeletal muscle tissue of the hind paw and jugular vein plasma. The level of RONS in muscle was determined using spin trapping combined with electron paramagnetic resonance spectroscopy. Using electron paramagnetic resonance spectroscopy, we also determined plasma levels of transferrin and ceruloplasmin. GSH levels were determined using high-performance liquid chromatography. RESULTS: In skeletal muscle tissue, the level of RONS was lower in nerve-injured hind paws than in controls. The plasma level (jugular vein) of RONS did not differ between nerve-injured and control rats. In skeletal muscle tissue, the level of GSH was higher in nerve-injured hind paws than in controls. The ceruloplasmin/transferrin ratio tended to be higher in (jugular vein) plasma of nerve-injured rats as compared to controls. CONCLUSIONS: This study shows that, at d 7 after nerve injury, oxidative stress-induced changes are present also in skeletal muscle tissue of the rat hind paw. Our findings of a decreased level of RONS in combination with an increased level of the antioxidant GSH suggest that an overshoot of antioxidant activity overrules initial oxidative stress.

Zymosan-induced generalized inflammation: experimental studies into mechanisms leading to multiple organ dysfunction syndrome.

Patients suffering from multiple organ dysfunction syndrome (MODS) comprise a heterogeneous population, which complicates research in its pathogenesis. Elucidation of the mechanisms involved in the development of MODS will ultimately necessitate the collection of tissue samples and the performance of invasive procedures. These requirements greatly reduce the possibilities for research in human subjects. Therefore, an animal model for MODS is a necessary and valuable tool. In the mid 1980s, the zymosan-induced generalized inflammation (ZIGI) model was introduced. Intraperitoneal injection of zymosan in mice or rats leads, in the course of 1 to 2 weeks, to increasing organ damage and dysfunction. The ZIGI model has been recognized as the one that best resembles human MODS and it has been used widely to study systemic inflammation in relation to organ failure. This review describes the ZIGI model and gives an overview of the results obtained.

Leukocytes in Complex Regional Pain Syndrome type I.

OBJECTIVE: The pathophysiology of Complex Regional Pain Syndrome type I (CRPS I) is unclear. An inflammatory reaction may cause the syndrome in which leukocytes may play an important role. MATERIALS AND METHODS: In this pilot study of six patients with acute warm CRPS I, we performed radiolabeled autologous leukocyte scans of both hands, in order to assess leukocyte accumulation. Comparison was made with the unaffected limb, and with three control patients with a Colles fracture without CRPS I. RESULTS: Images of the CRPS I patients obtained 4 h after leukocyte injection provided the clearest results. At 4 h post-injection, there was clear, asymmetrical leukocyte accumulation in the affected extremity with a mean ratio of 1.49+/-0.19. In control patients, no asymmetry was observed between hands (mean ratio 1.09+/-0.06), indicating the absence of specific leukocyte accumulation. There was a statistically significant difference between CRPS I and control subjects 4 h post injection (p=0.012). CONCLUSION: We found a significantly increased accumulation of leukocytes in patients with CRPS I. This is the first study to show a possible role for leukocytes in the pathophysiology of acute CRPS I.

Improved survival of TNF-deficient mice during the zymosan-induced multiple organ dysfunction syndrome.

The purpose of the study was to investigate the course of the zymosan-induced multiple organ dysfunction syndrome (MODS) in the absence of tumor necrosis factor (TNF) in a murine model. Tumor Necrosis Factor-alpha-lymphotoxin-a knockout (TNF/LT-/-) mice (n = 36) and wild-type (TNF/LT+/+) mice (n = 36) received 40 microg of lipopolysaccharide (LPS) intraperitoneally followed by zymosan at a dose of 1 mg/g body weight 6 days later (day 0). Animals were monitored daily for body weight and temperature and clinical symptoms. At day 22, most of the surviving mice were killed to examine organ weight and histology. A small number of animals were followed until day 48. In all animals, zymosan induced an acute sterile peritonitis phase followed by an apparent recovery. From day 8 onwards the TNF/LT+/+ mice entered a third-MODS-like-phase, characterized by loss of body weight, decreased body temperature, and significant mortality. At day 22, survival in the TNF/LT-/- mice (92%) was significantly (P = 0.01) higher than in the TNF/LT+/+ mice (60%). In addition, average body temperature and average relative (vs. weight at day 0) body weight were higher in the TNF/LT-/- mice than in the TNF/LT+/+ mice (35.9 degrees C and 100% vs. 33.3 degrees C and 84%, respectively). However, at this time point, surviving animals from both groups showed similar and significant organ damage, indicated by an increase in absolute and relative (vs body weight) weight of lung, spleen, and liver (liver only in the TNF/LT-/- mice). Moreover, histopathological examination of organs from the surviving animals showed a similar degree of microscopic damage in both groups. Interestingly, besides mononuclear cells, inflammatory infiltrates in lungs and livers of TNF/LT+/+ but not of TNF-/- mice contained neutrophils. In conclusion, TNF-deficient mice exhibit significantly improved morbidity and mortality during zymosan-induced MODS. However, the absence of TNF does not completely protect against MODS in this murine model.

Intra-arterial tert-Butyl-hydroperoxide infusion induces an exacerbated sensory response in the rat hind limb and is associated with an impaired tissue oxygen uptake.

The objective of this study was to investigate oxidative stress and oxygen extraction mechanisms in an animal model of continuous intra-arterial infusion of a free radical donor and in an in vitro model using isolated mitochondria. tert-Butyl-hydroperoxide (tert-BuOOH, 25 mM) was infused for 24 h in the left hind limb of rats to induce soft tissue damage (n = 8). After 7 days, we assessed local sensory response, tissue oxygen consumption, oxygen radicals, and antioxidant levels. In vitro mitochondrial function was measured after stimulation of isolated mitochondria of skeletal muscle cells with increasing doses of tert-BuOOH. tert-BuOOH infusion resulted in an increased skin temperature (p = 0.04), impaired function, and a significantly increased pain sensation (p = 0.03). Venous oxygen saturation levels (p = 0.01) and the antioxidant ceruloplasmin (p = 0.04) were increased. tert-BuOOH inhibited mitochondrial function in vitro. Induction of free radical formation in the rat hind limb results in an exacerbated sensory response and is associated with impaired oxygen extraction, which likely results from mitochondrial dysfunction caused by free radicals.

Mitochondrial dysfunction in muscle tissue of complex regional pain syndrome type I patients.

Reactive oxygen species (ROS) are known to be involved in the pathophysiology of complex regional pain syndrome type I (CRPS I). Since the mitochondrial respiratory chain is a major source of ROS, we hypothesized that mitochondria play a role in the pathophysiology of CRPS I. The hypothesis was tested by studying mitochondrial energy metabolism in muscle tissue from amputated limbs of CRPS I patients. We observed that mitochondria obtained from CRPS I muscle tissue displayed reduced mitochondrial ATP production and substrate oxidation rates in comparison to control muscle tissue. Moreover, we observed reactive oxygen species evoked damage to mitochondrial proteins and reduced MnSOD levels. It remains to be established if the mitochondrial dysfunction that is apparent at the end-stage of CRPS I is also present in earlier stages of the disease, or are secondary to CRPS I. The observation of a reduced mitochondrial energy production combined with reactive oxygen species induced damage in muscle tissue from CRPS I patients warrants further studies into the involvement of mitochondrial dysfunctioning in the pathophysiology of CRPS I.

Complex regional pain syndrome type I in children.

BACKGROUND: Complex Regional Pain Syndrome type I (CRPS I) is a potentially incapacitating syndrome which can occur after a minor injury or operation to a limb. It is a disorder characterized by pain, sensory and motor disturbances. CRPS I is well known in adults, but a relatively new diagnostic entity in children. The clinical presentation of CRPS I in children is, to some extent, different from adults and therefore sometimes not recognized early. The aim of this study was to search for differences in patient characteristics between children and adults with CRPS I. METHODS: We have performed a retrospective chart review of 78 children (age

Revision of the multiple organ failure score.

BACKGROUND AND AIM: The multiple organ failure (MOF) score published by Goris et al. in 1985 was one of the first attempts to quantify severity of organ dysfunction and failure based on expert opinion in surgical intensive care unit patients. Fifteen years later a reassessment of this score is mandatory. PATIENTS AND METHODS: Daily MOF scores were documented in patients admitted to the surgical ICUs in Nijmegen (NL) and Cologne (D). Patients with an ICU stay < or = 3 days were excluded. Organ dysfunction (1 point) and organ failure (2 points) were recorded for the following organ systems: lung, heart, kidney, liver, blood, gastrointestinal tract (GI), and central nervous system (CNS). Maximum scores were computed, and logistic regression analysis was used to optimize point weights for each organ system. Predictive power was analyzed using receiver operating characteristic (ROC) curves. RESULTS: In all, 147 patients, mean age 56 years, were included with a total of 2,354 observation days. Hospital mortality was 30.6%. GI failure was present on only 3.3% of days, without impact on mortality. Valid evaluation of CNS was impossible in most cases due to sedation and ventilation. Reweighting of the score items revealed only marginal improvements in prediction. Mortality consistently increased with increase in number of failed organs. This phenomenon was even more pronounced in older patients, e.g., 55% mortality (age > or = 60) versus 0% (age < 60) with two failing organs. CONCLUSION: Due to problems in definition and assessment (reliability) CNS and GI should not be considered in future assessments of the MOF score. The original point weights in the remaining five organ systems provide a valid and reliable risk stratification, at least in surgical ICU patients.

Tissue- and time-dependent upregulation of cytokine mRNA in a murine model for the multiple organ dysfunction syndrome.

OBJECTIVE: We sought to quantitate the course of specific cytokine mRNA expression in tissues that exhibit increasing histopathological changes in time in an animal model for the multiple organ dysfunction syndrome (MODS). SUMMARY BACKGROUND DATA: The development of treatment protocols for MODS requires elucidation of the mechanisms and mediators involved. To devise logical interventions, it is necessary to collect data on cytokine expression at tissue level during the development of MODS. METHODS: Ninety-four C57BL/6 mice were given an intraperitoneal injection of 40 microg of lipopolysaccharide (LPS), followed by zymosan at a dose of 0.8 mg/g body weight 6 days later (day 0). Six additional animals did not receive zymosan and acted as controls. At several time points after zymosan injection, 6 randomly assigned, zymosan-treated animals were killed, and their livers, lungs, spleens, and kidneys were collected. mRNA expression of tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6, macrophage migration inhibiting factor, IL-12, interferon-gamma, and IL-10 was measured using a real-time reverse transcription-polymerase chain reaction assay. RESULTS: The injection of zymosan induced an acute peritonitis, followed by an apparent recovery. From approximately day 6 onwards, animals started to display MODS-like symptoms. During the peritonitis phase, up-regulation of cytokine mRNA was limited. During the period of apparent recovery, cytokine mRNA expression strongly increased, mostly reaching its maximum at day 9 when deterioration of the clinical condition had already set in. The up-regulation of tumor necrosis factor-alpha mRNA was most pronounced, especially in the lungs and liver. CONCLUSIONS: Interventions should preferentially be targeted against multiple cytokines and, at least in this model, there may be a treatment window well after the initial challenge.

Trauma resuscitation time.

Documenting the timing and organisation of trauma resuscitation can be utilised to assess performance standards, and to ensure a high quality of trauma resuscitation procedures. Since there is no European literature available on trauma resuscitation time (TRT) in the emergency room, the aim of this descriptive study is to evaluate TRT in the Netherlands. The introduction of an ATLS-trained prehospital mobile medical team (MMT) in the Nijmegen area initiated the on-site advanced trauma life-support for the prehospital management of trauma patients. We studied TRT in two groups of patients, one with, the other without on-site care by a MMT. In the emergency room the use of videotape recording was chosen to document trauma resuscitation (22 actions) and TRT. A specially flow-chart was used to define the TRT-procedures. We studied 43 patients; 27 without MMT treatment and 16 with MMT treatment. The activities were divided into the ABCDE's of trauma care. Significant more patients of the MMT group were intubated before arrival in the hospital (12/16 (75%) versus 2/27 (2%), P<0.05). Eleven definitive airway management interventions (intubation) and one thoracic drainage in the non-MMT group were demanded by the protocol, but not performed before arrival in the hospital. Sixteen out of 22 actions that were documented were carried out at an earlier stage in the MMT group. There was no significant difference between the resuscitation times; in both groups the recorded median time was approximately 43 min. This prospective analysis demonstrates the timing of resuscitation procedures in a resuscitation room and provides some insight into the timing of ATLS initial assessment.

Advanced trauma life support study: quality of diagnostic and therapeutic procedures.

BACKGROUND: The introduction of the ATLS course in The Netherlands in 1995 provided for an opportunity to compare data of trauma patients between a pre-ATLS and a post-ATLS period. MATERIALS AND METHODS: Over a 3-year period (May 1996 - September 1997 pre ATLS; December 1997-April 1999 post ATLS) 63 trauma patients with an AIS-ISS > or = 16 (n = 31, pre-ATLS and n = 32, post-ATLS) were prospectively studied in two community residency training (ACS Level III) hospitals. All diagnostic and therapeutic procedures were recorded by a video-camera and evaluated by a neutral faculty of six experienced ATLS trained specialists. RESULTS: Ten out of 14 interventions were performed qualitatively better in the post-ATLS group, while also the overall score was highly significantly better (4.2 pre-ATLS and 5.8 post-ATLS, p < 0.0001). CONCLUSION: Using the opinion of an expert team, this study identified a significantly lower number of patients with inadequate management.

Clinical impact of advanced trauma life support.

The Advanced Trauma Life Support (ATLS) course sponsored by the American College of Surgeons Committee On Trauma (ACSCOT) presents a standardized method of initial trauma care. This study attempted to measure any changes in morbidity and mortality in trauma patients after the introduction of ATLS training. Over a 3-year period (May 1996 to September 1997-pre-ATLS period; December 1997 to April 1999-post-ATLS period), 63 trauma patients with an Injury Severity Scale (ISS) > or =16 (n = 31, pre-ATLS and n = 32, post-ATLS) were prospectively studied in two community teaching hospitals. There was no significant difference in mortality rate between groups (48% [15 of 31] pre-ATLS vs. 30% [10 of 32] post-ATLS; P = .203, Fisher exact test). Mortality rates within the ISS range of 16 to 25 were 64% (nine of 14 pre-ATLS) versus 29% (five of 17 post-ATLS), and for the ISS 26 to 35 subgroup, 40% (four of 10 pre-ATLS) versus 25% (two of eight post-ATLS), and within the ISS 36 to 75 subgroup, 29% (two of seven pre-ATLS) versus 43% (three of seven post-ATLS). There was a significant difference in mortality during the first 60 minutes after admission: 0.0% post-ATLS versus 24.2% pre-ATLS (P = .002, Fisher exact test (95% confidence interval ranged from 12-45% in the pre-ATLS group and 0-11% in the post-ATLS group). According to the TRISS methodology (a worldwide-accepted mathematical method to calculate chances of survival through logistical regression),ATLS improved outcome from sub-"Major Trauma Outcome Study" (MTOS) standard results (z = -2.9 to a MTOS standard result z = -0.49). Our data demonstrate that introduction of the ATLS program significantly improved trauma patient outcome in the first hour after admission, as well as improvement from sub-MTOS standard to MTOS standard levels.

Organ damage in zymosan-induced multiple organ dysfunction syndrome in mice is not mediated by inducible nitric oxide synthase.

OBJECTIVE: To examine the role of inducible nitric oxide synthase (iNOS) in the development of the multiple organ dysfunction syndrome (MODS) in a murine model by using either a selective iNOS inhibitor or iNOS knockout mice. DESIGN: Prospective randomized laboratory study. SETTING: Central animal laboratory and experimental laboratory. SUBJECTS: Fifty inbred C57BL/6 mice, 39 iNOS knockout (-/-) mice, and 30 wild-type (+/+) mice, 7-9 wks old, weighing 20-25 g. INTERVENTIONS: Mice received an aseptic intraperitoneal injection of 40 microg of lipopolysaccharide followed by zymosan at a dose of 1 mg/g of body weight 6 days later (day 0). In experiment 1, C57BL/6 mice additionally received intraperitoneal injections with 5 mg of aminoguanidine or saline every 12 hrs, from 4 days after the injection of zymosan onward. In experiment 2, both iNOS-/- mice and corresponding wild-type (iNOS+/+) mice were treated with lipopolysaccharide and zymosan. MEASUREMENTS AND MAIN RESULTS: In all animals, the injection of zymosan induced an acute peritonitis, followed by an apparent recovery. From approximately day 6 onward, animals entered the third-MODS-like-phase, indicated by weight loss, a decrease in body temperature, and significant mortality rates. Quantitative reverse transcriptase polymerase chain reaction and immunochemistry revealed a strongly increased expression of iNOS messenger RNA and iNOS protein in livers of mice in the last phase. However, neither the in vivo administration of aminoguanidine to C57BL/6 mice nor the complete absence of iNOS enzyme (iNOS-/- mice) had a beneficial effect on survival rate, body temperature, or body weight. In addition, relative lung, liver, and spleen weights and lung scores were not different between experimental groups. CONCLUSIONS: The current results strongly argue against an essential and causative role of iNOS in the development of organ damage in our murine model of MODS.