Background: Pseudocholinesterase (PChE) polymorphism has been a subject of several pharmacogenetic studies worldwide. The patients with atypical homozygous genotype do not only have reduced serum cholinesterase activities but also their elimination rate for some pharmacologically potent drugs decrease drastically. This study was designed to evaluate the PChE polymorphism in Mazandaran province (northern Iran) for the first time.
Methods: About 5 ml plasma samples were collected from 200 healthy volunteers who visited "Iran Blood Transfusion Organization" centers all across Mazandaran province for blood donation. The PChE activity in presence or absence of dibucain was measured and based on obtained dibucain number (DN) volunteers were categorized to normal homozygous (Eu,u), atypical heterozygous (Eu,a), and atypical homozygous (Ea,a).
Results: The average (±SD) of the PChE activity among the blood donors was 9.14±1.93 IU (ranging from 4.1 to 16.6 IU). Only 2 persons (1%) had DN between 60 to 70 (Eu,a) and no one was categorized in 20
Conclusion: According to the findings, only 1% of the sample population had atypical heterozygous phenotype taking into account the experiment precision, the frequency of Ea,u is less than 4%. These findings suggest that the atypical allele frequency in northern Iran's population is probably less than the other regions of Iran and some other countries.
Pseudocholinesterase; Polymorphism; Succinylcholine; Mivacurium
In Pseudomonas aeruginosa, the antibiotic dihydroaeruginoate (Dha) and the siderophore pyochelin are produced from salicylate and cysteine by a thiotemplate mechanism involving the peptide synthetases PchE and PchF. A thioesterase encoded by the pchC gene was found to be necessary for maximal production of both Dha and pyochelin, but it was not required for Dha release from PchE and could not replace the thioesterase function specified by the C-terminal domain of PchF. In vitro, 2-aminobutyrate, a cysteine analog, was adenylated by purified PchE and PchF proteins. In vivo, this analog strongly interfered with Dha and pyochelin formation in a pchC deletion mutant but affected production of these metabolites only slightly in the wild type. Exogenously supplied cysteine overcame the negative effect of a pchC mutation to a large extent, whereas addition of salicylate did not. These data are in agreement with a role for PchC as an editing enzyme that removes wrongly charged molecules from the peptidyl carrier protein domains of PchE and PchF.
Anesthesiologists perceive that the ideal muscle relaxant is not yet available, particularly the nondepolarizing one with a rapid onset and a short duration of action. There is also a need for relaxants with different durations of action but which would be free from side effects. During the process of this development several new compounds have been tested and four have reached an advanced state of study; three of these, doxacurium, pipecuronium, and mivacurium are already licensed and rocuronium is likely to be licensed in the near future. Doxacurium and pipecuronium are slow onset and long duration of action compounds but singularly free from cardiovascular side effects. Mivacurium has an onset comparable to that of atracurium and vecuronium but with a duration of action which is intermediate in duration between these drugs and succinylcholine. Rocuronium is a drug with a fast onset of action capable of being used in place of succinylcholine but with a duration of action which is similar to that of vecuronium.
Severe burn injury causes hepatic dysfunction that results in major metabolic derangements including insulin resistance and hyperglycemia and is associated with hepatic endoplasmic reticulum (ER) stress. We have recently shown that insulin reduces ER stress and improves liver function and morphology; however, it is not clear whether these changes are directly insulin mediated or are due to glucose alterations. Metformin is an antidiabetic agent that decreases hyperglycemia by different pathways than insulin; therefore, we asked whether metformin affects postburn ER stress and hepatic metabolism. The aim of the present study is to determine the effects of metformin on postburn hepatic ER stress and metabolic markers. Male rats were randomized to sham, burn injury and burn injury plus metformin and were sacrificed at various time points. Outcomes measured were hepatic damage, function, metabolism and ER stress. Burn-induced decrease in albumin mRNA and increase in alanine transaminase (p < 0.01 versus sham) were not normalized by metformin treatment. In addition, ER stress markers were similarly increased in burn injury with or without metformin compared with sham (p < 0.05). We also found that gluconeogenesis and fatty acid metabolism gene expressions were upregulated with or without metformin compared with sham (p < 0.05). Our results indicate that, whereas thermal injury results in hepatic ER stress, metformin does not ameliorate postburn stress responses by correcting hepatic ER stress.
A hallmark of the disease state following severe burn injury is decreased liver function, which results in gross metabolic derangements that compromise patient survival. The underlying mechanisms leading to hepatocyte dysfunction post-burn are essentially unknown. The aim of the present study was to determine the underlying mechanisms leading to hepatocyte dysfunction and apoptosis post-burn. Rats were randomized to either control (no burn) or burn (60% total body surface area burn) and sacrificed at various time points. Liver was either perfused to isolate primary rat hepatocytes, which were used for in vitro calcium imaging, or liver was harvested and processed for immunohistology, transmission electron microscopy, mitochondrial isolation, mass spectroscopy, or Western blotting to determine the hepatic response to burn injury in vivo. Thermal injury leads to severely depleted endoplasmic reticulum (ER) calcium stores and consequent elevated cytosolic calcium concentrations in primary hepatocytes in vitro. Burn-induced ER calcium depletion causes depressed hepatocyte responsiveness to signaling molecules that regulate hepatic homeostasis, such as vasopressin and the purinergic agonist ATP. In vivo, thermal injury results in activation of the ER stress response and major alterations in mitochondrial structure and function; effects which may be mediated by increased calcium release by inositol 1,4,5-trisphosphate receptors. Our results reveal that thermal injury leads to dramatic hepatic disturbances in calcium homeostasis and resultant ER stress leading to mitochondrial abnormalities contributing to hepatic dysfunction and apoptosis after burn injury.
thermal injury; liver; ER stress; unfolded protein response; apoptosis; calcium
Burn induces a hypermetabolic state characterized by alterations in protein metabolism which is associated with increased morbidity and mortality. Eukaryotic elongation factor 2 (eEF2) plays a crucial role in regulating protein synthesis in many diseases, but whether it participates in burn-induced hypermetabolism is unclear. The aim of this study was to determine the expression of eEF2 and the upstream eEF2-inactivating kinase, eEF2K, in severely burned pediatric patients.
Eight pediatric patients (> 40% TBSA) and three non-burned pediatric volunteers were enrolled in this study. Muscle and skin biopsies were collected at early (0–10 days post burn [dpb]), middle (11–49dpb), and late (50–365dpb) time points. Resting energy expenditure (REE), body composition, and muscle protein synthesis rate (FSR) were measured. Proteins were extracted and analyzed by Western blotting. To further investigate the protein synthesis pathway, microarray data from muscle and skin were examined from 22 non-burned and 20 burned children.
Burn patients exhibited a profound hypermetabolic response, as seen by a significant increased in REE (p<0.05) and a loss of lean body mass (LBM) without altered muscle FSR, indicating a shift to catabolism after thermal injury. In muscle, the phosphorylation of eEF2K-dependent eEF2 was down-regulated early and middle post-burn. Similar changes in eEF2K and eEF2 levels occurred in skin at the early time point. Total amounts of eEF2 and eEF2K were not altered.
Burn induces prolonged activation of eEF2K and eEF2. Alterations in these mediators may contribute to profound hypermetabolism seen in severely burned patients.
burn; muscle; skin; protein synthesis; hypermetabolism
Burn induces a sustained catabolic response which causes massive loss of muscle mass after injury. A better understanding of the dynamics of muscle wasting and its impact on muscle function is necessary for the development of effective treatments. Male Sprague-Dawley rats underwent either a 40% total body surface area (TBSA) scald burn or sham burn, and were further assigned to subgroups at four time points after injury (days 3, 7, 14 and 21). In situ isometric contractile properties were measured including twitch tension (Pt), tetanic tension (Po) and fatigue properties. Body weight decreased in burn and sham groups through day 3, however, body weight in the sham groups recovered and increased over time compared to burned groups, which progressively decreased until day 21 after injury. Significant differences in muscle wet weight and protein weight were found between sham and burn. Significant differences in muscle contractile properties were found at day 14 with lower absolute Po as well as specific Po in burned rats compared to sham. After burn, the muscle twitch tension was significantly higher than the sham at day 21. No significant difference in fatigue properties was found between the groups. This study demonstrates dynamics of muscle atrophy and muscle contractile properties after severe burn; this understanding will aid in the development of approaches designed to reduce the rate and extent of burn induced muscle loss and function.
atrophy; thermal injury; skin; tetanic tension
Introduction. The key element of a safe workplace for employees is the maintenance of fire safety. Thermal, chemical, and electrical burns are common types of burns at the workplace. This study assessed the epidemiology of work-related burn injuries on the basis of the workers treated in a regional burn centre. Methods. Two years’ retrospective data (2005-2006) from the Trauma Registry of the American College of Surgeons of the Joseph M. Still Burn Center at Doctors Hospital in Augusta, Georgia, were collected and analysed. Results. During the time period studied, 2510 adult patients with acute burns were admitted; 384 cases (15%) were work-related. The average age of the patients was 37 yr (range, 15-72 yr). Males constituted the majority (90%) of workrelated burn injury admissions. The racial distribution was in accordance with the Centre’s admission census. Industrial plant explosions accounted for the highest number of work-related burns and, relatively, a significant number of patients had chemical burns. The average length of hospital stay was 5.54 days. Only three patients did not have health insurance and four patients (1%) died. Conclusion. Burn injuries at the workplace predominantly occur among young male workers, and the study has shown that chemical burns are relatively frequent. This study functions as the basis for the evaluation of work-related burns and identification of the causes of these injuries to formulate adequate safety measures, especially for young, male employees working with chemicals.
WORKPLACE; BURNS; EPIDEMIOLOGY; AETIOLOGICAL FACTORS; INDUSTRIAL PLANT EXPLOSION
Arsenic is a potent pollutant that has caused an environmental catastrophe in certain parts of the world including Bangladesh where millions of people are presently at risk due to drinking water contaminated by arsenic. Chronic arsenic exposure has been scientifically shown as a cause for liver damage, cancers, neurological disorders and several other ailments. The relationship between plasma cholinesterase (PChE) activity and arsenic exposure has not yet been clearly documented. However, decreased PChE activity has been found in patients suffering liver dysfunction, heart attack, cancer metastasis and neurotoxicity. Therefore, in this study, we evaluated the PChE activity in individuals exposed to arsenic via drinking water in Bangladesh.
A total of 141 Bangladeshi residents living in arsenic endemic areas with the mean arsenic exposure of 14.10 ± 3.27 years were selected as study subjects and split into tertile groups based on three water arsenic concentrations: low (< 129 μg/L), medium (130-264 μg/L) and high (> 265 μg/L). Study subjects were further sub-divided into two groups (≤50 μg/L and > 50 μg/L) based on the recommended upper limit of water arsenic concentration (50 μg/L) in Bangladesh. Blood samples were collected from the study subjects by venipuncture and arsenic concentrations in drinking water, hair and nail samples were measured by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). PChE activity was assayed by spectrophotometer.
Arsenic concentrations in hair and nails were positively correlated with the arsenic levels in drinking water. Significant decreases in PChE activity were observed with increasing concentrations of arsenic in water, hair and nails. The average levels of PChE activity in low, medium and high arsenic exposure groups were also significantly different between each group. Lower levels of PChE activity were also observed in the > 50 μg/L group compared to the ≤50 μg/L group. Moreover, PChE activity was significantly decreased in the skin (+) symptoms group compared to those without (-).
We found a significant inverse relationship between arsenic exposure and PChE activity in a human population in Bangladesh. This research demonstrates a novel exposure-response relationship between arsenic and PChE activity which may explain one of the biological mechanisms through which arsenic exerts its neuro-and hepatotoxicity in humans.
Endotracheal intubation in the neonate is painful and is associated with adverse physiological effects. Some premedication regimens have been shown to reduce these effects, but the optimal regimen is not yet determined.
Data on semi‐elective intubations were prospectively collected in the neonatal intensive care unit over a six month period. Patients received 20 μg/kg atropine, 200 μg/kg mivacurium (a non‐depolarising muscle relaxant) followed by 5 μg/kg fentanyl.
Thirty three patients were electively intubated during this time period. The primary reason for intubation was surfactant administration (53%). Median (range) birth weight, gestational age, and age at intubation were 1360 g (675–4200), 29 weeks (25–38), and 33 hours (1–624) respectively. Twenty two of the infants were intubated on the first attempt. Median duration from initial insertion of the laryngoscope to successful intubation was 60 seconds (15 seconds to 20 minutes). In 18 cases, the first attempt was by a trainee with no previous successful intubation experience, 10 of whom intubated within two attempts. Muscle relaxation occurred at a mean (SD) of 94 (51) seconds, and mean (range) time to return of spontaneous movements was 937 seconds (480–1800). Intubation conditions were scored as excellent using a validated intubation scale.
Effective analgesia can be administered and intubation performed with some brief desaturations, even when junior personnel are being taught their first intubation. In this first report of mivacurium for intubation in the newborn, effective bag and mask ventilation was easily achieved during muscle relaxation and was associated with excellent intubation conditions, permitting a high success rate for inexperienced personnel.
premedication; intubation; mivacurium
Severe burn injuries lead to a prolonged hyper-catabolic state resulting in dramatic loss of skeletal muscle mass. Post-burn muscle loss is well documented, but the molecular signaling cascade preceding atrophy is not. Our purpose was to determine the response to burn injury of signaling pathways driving muscle inflammation and protein metabolism.
Muscle biopsies were collected in the early flow phase after burn injury from the vastus lateralis of a non-injured leg in patients with 20–60% total body surface area burns and compared to uninjured, matched controls. Circulating levels of pro-inflammatory cytokines were also compared. Immunoblotting was performed to determine protein levels of key signaling components for translation initiation, proteolysis, and TNF/NFκB and IL-6/STAT3 signaling.
Burn subjects had significantly higher levels of circulating pro-inflammatory cytokines, but no difference in muscle STAT3 activity and lower NFκB activity. No differences were found in any translational signaling components. Regarding proteolytic signaling in burn, calpain-2 was 47% higher, calpastatin tended to be lower, and total ubiquitination was substantially higher.
Surprisingly, a systemic pro-inflammatory response 3–10 d post-burn did not lead to elevated muscle STAT3 or NFκB signaling. Signaling molecules governing translation initiation were unaffected while indices of calcium-mediated proteolysis and ubiquitin-proteasome activity were up-regulated. These novel findings are the first in humans to suggest the net catabolic effect of burn injury in skeletal muscle (i.e. atrophy) may be mediated, at least during the early flow phase, almost entirely by increased proteolytic activity in the absence of suppressed protein synthesis signaling.
Skeletal muscle atrophy; Burn injury; Inflammation; Cytokines
The treatment and hospitalization policies in various hospitals in Israel are influenced by injury severity and by the existence or non-existence of a designated burn treatment body. Severely injured burn victims requiring designated burn treatment are referred to one of Israel's five major burn units located in the highest level trauma centres that have an advanced burn treatment infrastructure. This national distribution of burn centres ensures designated treatment availability in various areas according to Israeli demographics, geography, and security threats. Israel does not have an obligatory burn report policy. Implementation of a national burn repository such as that in the USA will be able to give burn treatment specialists in our country a basis for comparison of treatment standards and allow for better care for burn victims. The Israeli Burn Association has a major role in the processes discussed in the manuscript.
burn treatment; Israel; funding; multidisciplinary approach
Significance: Nutrition has been recognized as a critical component of acute burn care and ultimate wound healing. Debate remains over the appropriate timing of enteral nutrition and the benefit of supplemental trace elements, antioxidants, and immunonutrition for critically ill burn patients. Pharmacotherapy to blunt the metabolic response to burn injury plays a critical role in effective nutritional support.
Recent Advances: Further evidence is demonstrating long-term benefits from pharmacologic immunomodulation given the prolonged metabolic response to injury that may last for over a year following the initial insult.
Critical Issues: The majority of evidence regarding early enteral feeding comes from mixed populations and smaller studies. However, on balance, available evidence favors early feeding. Data regarding immunonutrition does not support the routine use of these products. Limited data regarding use of antioxidants and trace elements support their use.
Future Directions: Further evaluation of anti-inflammatory mediators of the immune response, such as statins, will likely play a role in the future. Further data are needed on the dosing and route of micronutrients as well as the utility of immunonutrition. Finally, little is known about nutrition in the obese burn patient making this an important area for investigation.
Burn injuries in low and middle income countries still remain a significant health problem, even though numbers of burn injuries in high income countries have decreased showing that such events are not “accidents” but are usually preventable. WHO states that the vast majority (over 95%) of fire-related burns occur in low and middle income countries. Burn injuries are a major cause of prolonged hospital stays, disfigurement, disability, and death in Africa Region. Evidence shows that prevention strategies can work. However prevention strategies need to be tailored to the specific environment taking into account local risk factors and available resources. An examination of the patterns and causes of burns should allow site specific recommendations for interventions. This literature review, specific to the United Republic of Tanzania, was conducted by researching PubMed, SafetyLit, and African Journals on Line data bases for primary sources using key words plus . Two sets of student data collected as part of Bachelor’s degree final dissertations at Muhimbili University of Health and Allied Sciences were used. In all, twenty two primary sources were found. Risk factors for burn morbidity in Tanzania are: 1/ a young age, especially years 1-3, 2/ home environment, especially around cooking fires, 3/ epilepsy, during seizures, and 4/ perceived inevitability of the incident. It was expected that ground level cooking fires would be found to be a risk factor, but several studies have shown non-significant results about raised cooking fires, types of fuel used, and cooking appliances. Risk factors for burn mortality are: being male, between 20-30 years of age, and being punished for alleged thieving by community mobs. An important factor in reducing burn morbidity, especially in children, is to educate people that burns are preventable in most cases and that most burns occur in the home around cooking fires. Children need to be kept away from fires. Epileptics should be monitored for medication and kept away from cooking fires as well. Community members need to be encouraged to bring wrong doers to the police.
Burn injury; burn mortality; burn morbidity; Africa; Tanzania
Healing of the burn wound is a critical component of the burn patient's successful recovery. While inflammation is a critical component of the healing process, it is unknown whether the inflammatory response differs between non-burn and burn wounds. To study this, mice were subjected to major burn injury or sham procedure. Wound cells were collected by implantation of polyvinyl alcohol sponges beneath the burn site in injured mice or beneath uninjured skin in sham mice (i.e., non-burn wound). Three days thereafter, skin, wound fluid and infiltrating cells were collected for analysis. Significant levels of tumor necrosis factor (TNF)-α, interleukin (IL-6), monocyte chemoattractant protein (MCP)-1 and keratinocyte-derived chemokine (KC) were observed in burn wound tissue and the wound fluid from both non-burn and burn wounds. Burn injury induced 3-fold higher levels of KC and 50-fold higher levels of IL-6 in the wound fluid as compared to non-burn injury. Significant numbers of the cells from both burn and non-burn wounds were CD11b+, GR1+ and F4/80+, suggestive of a myeloid suppressor cell phenotype, whereas CD3+ T-cells were negligible under both conditions. LPS induced TNF-α, IL-6, IL-10, MCP-1, KC and nitric oxide production in both cell populations, however; IL-6, IL-10, MCP-1 and KC levels were suppressed in burn wound cell cultures. These findings indicate that significant differences in the wound inflammatory response exist between burn and non-burn cutaneous wounds and that the unique characteristics of the inflammatory response at the burn site may be an important contributing factor to post-burn wound healing complications.
T-cells; trauma; cytokines; chemokines; nitric oxide
Infection is the most common and most serious complication of a major burn injury related to burn size. Despite improvements in antimicrobial therapies sepsis still accounts for 50–60% of deaths in burn patients. Given the acute onset and unpredictable nature of sepsis, primary prevention was rarely attempted in its management. However, recent studies have demonstrated that statin treatment can decrease mortality is a murine model of sepsis by preservation of cardiac function and reversal of inflammatory alterations. In addition, it has been shown that treatment with statins is associated with reduced incidence of sepsis in human patients. In the current study groups of CD1 male mice (n=12) were anesthetized and subjected to a dorsal 30% TBSA scald burn injury. Starting 2 hours post burn, the animals were divided into a treatment group receiving 0.2 µ/g simvastatin or a sham group receiving placebo. Simvastatin and placebo were administered by intraperitoneal injection with two dosing regimens; once daily and every 12 hours. On Post burn day 7 cecal ligation and puncture with a 21-gauge needle was performed under ketamine/xylazine anesthesia and the two different dosing schedules were continued. A simvastatin dose dependant improvement in survival was observed in the burn sepsis model.
Sepsis; Cecal ligation; Simvastatin; burn; sepsis; survival
Using a mouse model, we tested the hypotheses that severe burn trauma causes metabolic disturbances in skeletal muscle, and that these can be measured and repeatedly followed by in vivo electron paramagnetic resonance (EPR). We used a 1.2-GHz (L-band) EPR spectrometer to measure partial pressure of oxygen (pO2) levels, redox status and oxidative stress following a non-lethal burn trauma model to the left hind limbs of mice. Results obtained in the burned mouse gastrocnemius muscle indicated a significant decrease in tissue pO2 immediately (P=0.032) and at 6 h post burn (P=0.004), compared to the gastrocnemius of the unburned hind limb. The redox status of the skeletal muscle also peaked at 6 h post burn (P=0.027) in burned mice. In addition, there was an increase in the EPR signal of the nitroxide produced by oxidation of the hydroxylamine (CP-H) probe at 12 h post burn injury, indicating a burn-induced increase in mitochondrial reactive oxygen species (ROS). The nitroxide signal continued to increase between 12 and 24 h, suggesting a further increase in ROS generation post burn. These results confirm genomic results, which indicate a downregulation of antioxidant genes and therefore strongly suggest the dysfunction of the mitochondrial oxidative system. We believe that the direct measurement of tissue parameters such as pO2, redox and ROS by EPR may be used to complement measurements by nuclear magnetic resonance (NMR) in order to assess tissue damage and the therapeutic effectiveness of antioxidant agents in severe burn trauma.
electron paramagnetic resonance; oximetry; partial pressure of oxygen; redox; skeletal muscle; burn; trauma; mitochondria; reactive oxygen species; nuclear magnetic resonance; genomics
Persistent and extensive skeletal muscle catabolism is characteristic of severe burns. Whole body protein metabolism, an important component of this process, has not been measured in burned children during the long-term convalescent period. The aim of this study was to measure whole body protein turnover in burned children at discharge (95% healed) and in healthy controls by a non-invasive stable isotope method. Nine burned children (7 boys, 2 girls; 54 ± 14 (SD)% total body area burned; 13 ± 4 yrs; 45 ± 20 kg; 154 ± 14 cm) and 12 healthy children (8 boys, 4 girls; 12 ± 3 yrs; 54 ± 16 kg;150 ± 22 cm) were studied. A single oral dose of 15N-alanine (16 mg/kg) was given, and thereafter urine was collected for 34 hours. Whole body protein flux was calculated from labeling of urinary urea nitrogen. Then, protein synthesis was calculated as protein flux minus excretion, and protein breakdown as flux minus intake. At discharge, total protein turnover was 4.53 ± 0.65 (SE) g kg bodyweight−1 day−1 in the burned children compared to 3.20 ± 0.22 g kg−1 day−1 in controls (P = 0.02). Expressed relative to lean body mass (LBM), the rates were 6.12 ± 0.94 vs. 4.60 ± 0.36 g kg LBM−1 day−1 in burn vs. healthy (P = 0.06). Total protein synthesis was also elevated in burned vs. healthy children, and a tendency for elevated protein breakdown was observed. Conclusion: Total protein turnover is elevated in burned children at discharge compared to age-matched controls, possibly reflecting the continued stress response to severe burn. The oral 15N-alanine bolus method is a convenient, non-invasive, and no-risk method for measurement of total body protein turnover.
burn injury; children; whole body protein kinetics; stable isotope methodology