Biomedical subjects

James Murray

Publications and source records attributed to James Murray.

33 records · Page 2Linked to original sources

PubMed2003

Oxidative post-translational modification of tryptophan residues in cardiac mitochondrial proteins.

We examined the distribution of N-formylkynurenine, a product of the dioxidation of tryptophan residues in proteins, throughout the human heart mitochondrial proteome. This oxidized amino acid is associated with a distinct subset of proteins, including an over-representation of complex I subunits as well as complex V subunits and enzymes involved in redox metabolism. No relationship was observed between the tryptophan modification and methionine oxidation, a known artifact of sample handling. As the mitochondria were isolated from normal human heart tissue and not subject to any artificially induced oxidative stress, we suggest that the susceptible tryptophan residues in this group of proteins are "hot spots" for oxidation in close proximity to a source of reactive oxygen species in respiring mitochondria.

Amino Acid Sequence↗

PubMed2003

The subunit composition of the human NADH dehydrogenase obtained by rapid one-step immunopurification.

Defects of the NADH dehydrogenase complex are predominantly manifested in mitochondrial diseases and are significantly associated with the development of many late onset neurological disorders such as Parkinson's disease. Here we describe an immunocapture procedure for isolating this multisubunit membrane-bound complex from human tissue. Using small amounts of immunoisolated protein, one-dimensional and two-dimensional gel electrophoresis, matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) peptide mass finger printing (PMF), and nanoflow liquid chromatography mass spectrometry/mass spectrometry (LC-MS/MS), we can resolve and identify the human homologues of 42 polypeptides detected so far in the more extensively studied beef heart complex I. These polypeptides include the GRIM-19 protein, which is claimed to be involved in apoptosis, a polypeptide first identified by gene screening as a neuronal protein, as well as a protein thought to be in differentiation linked processes. The concordance of data from human and bovine complex I isolated by different procedures adds to the certainty that these novel proteins of seemingly diverse function are a part of complex I.

Animals↗

PubMed2003

Normal electrocardiography and serum troponin I levels preclude the presence of clinically significant blunt cardiac injury.

BACKGROUND: Uncertainty about the definition and diagnosis of blunt cardiac injury (BCI) leads to unnecessary hospitalization and cost while trying to rule it out. The purpose of this study was to examine whether the combination of two simple tests, electrocardiography (ECG) and serum troponin I (TnI) level, may serve as reliable predictors of BCI or the absence of it. METHODS: Over a period of 30 months (September 1999-February 2002), 333 consecutive patients with significant blunt thoracic trauma were followed prospectively. Serial ECG and TnI tests were performed routinely and echocardiography was performed selectively. Clinically significant BCI (SigBCI) was defined as the presence of cardiogenic shock, arrhythmias requiring treatment, or posttraumatic structural deficits. RESULTS: SigBCI was diagnosed in 44 patients (13%). Of 80 patients with abnormal ECG and TnI, 27 (34%) developed SigBCI. Of 131 with normal serial ECG and TnI, none developed SigBCI. Of patients with abnormal ECG only or TnI only, 22% and 7%, respectively, developed SigBCI. The positive and negative predictive values were 29% and 98% for ECG, 21% and 94% for TnI, and 34% and 100% for the combination of ECG and TnI. The admission ECG or TnI was abnormal in 43 of 44 patients with SigBCI. Only one patient had initially normal ECG and TnI and developed abnormalities 8 hours after admission. Forty-one patients without other significant injuries stayed 1 to 3 days in the hospital only to rule out SigBCI and could have been discharged earlier. Besides ECG and TnI, other independent risk factors of SigBCI were an Injury Severity Score > 15, the presence of significant skeletal trauma, and history of cardiac disease. CONCLUSION: The combination of normal ECG and TnI at admission and 8 hours later rules out the diagnosis of SigBCI. In the absence of other reasons for hospitalization, such patients can be safely discharged.

Adult↗

PubMed2003

Pelvic fractures in pediatric and adult trauma patients: are they different injuries?

BACKGROUND: Many aspects of pediatric trauma are considerably different from adult trauma. Very few studies have performed comprehensive comparisons between pediatric and adult pelvic fractures. The purpose of this study was to compare the incidence of pelvic fracture, the epidemiologic characteristics, type of associated abdominal injuries, and outcomes between pediatric (age </= 16 years) and adult (age > 16 years) patients. METHODS: This was a trauma registry study that included all blunt trauma admissions at a Level I trauma center during an 8-year period. The incidence and severity of pelvic fractures, associated abdominal injuries, need for blood transfusion, and mortality in the two age groups were compared with the two-sided Fisher's exact test. Stepwise logistic regression analysis was used to identify independent risk factors for associated abdominal injuries in pelvic fractures in the two age groups. RESULTS: The incidence of pelvic fractures was 10.0% (1,450 of 14,568) in the adult group and 4.6% (95 of 2,062) in the pediatric group (p < 0.0001). In motor vehicle and pedestrian injuries, adults were twice as likely and in falls from heights > 15 ft seven times as likely as children to suffer pelvic fractures. However, age group was not a significant predictor of the severity of pelvic fracture. Only 9.5% of pediatric fractures and 8.8% of adult fractures had a pelvis Abbreviated Injury Scale (AIS) score >/= 4. The incidence of associated abdominal injuries was high but similar in the two age groups (16.7% in adults and 13.7% in children, p = 0.48). Motor vehicle crash, pelvis AIS score >/= 4, and fall from height > 15 ft were significant predictors of associated abdominal injuries in the adult but not the pediatric group. The incidence of associated gastrointestinal injuries was similar in the two age groups (5.3% in children and 3.3% in adults, p = 0.37). The incidence of solid organ injuries was nearly identical in both groups (11.6% in children and 11.5% in adults). The need for blood transfusions and angiographic intervention was not significantly different between the two age groups. Exsanguination because of bleeding related to the pelvic fracture was responsible or possibly responsible in 42 deaths (2.9%) in the adult group and no deaths in the pediatric group. CONCLUSION: Pediatric trauma patients are significantly less likely than adults to suffer pelvic fractures, although the age group is not a significant risk factor for the severity of pelvic fracture. The incidence of associated abdominal injuries is high and similar in the two age groups. Motor vehicle crash, fall from a height, and pelvis AIS score >/= 4 were significant predictors of associated abdominal injuries in the adult but not the pediatric patients. The need for blood transfusion is similar in both groups irrespective of Injury Severity Score and pelvis AIS score. The mortality resulting from exsanguination related to pelvic fractures is very low, especially in pediatric patients.

Abdominal Injuries↗

PubMed2003

Operative management and outcomes in 103 AAST-OIS grades IV and V complex hepatic injuries: trauma surgeons still need to operate, but angioembolization helps.

BACKGROUND: American Association for the Surgery of Trauma (AAST) Organ Injury Scale (OIS) grades IV and V complex hepatic injuries are highly lethal. Our objectives were to review experience and identify predictors of outcome and to evaluate the role of angioembolization in decreasing mortality. METHODS: This was a retrospective 8-year study of all patients sustaining AAST-OIS grades IV and V hepatic injuries managed operatively. Statistical analysis was performed using univariate and multivariate logistic regression. The main outcome measure was survival. RESULTS: The study included 103 patients, with a mean Revised Trauma Score of 5.61 +/- 2.55 and a mean Injury Severity Score of 33 +/- 9.5. Mechanism of injury was penetrating in 80 (79%) and blunt in 23 (21%). Emergency department thoracotomy was performed in 21 (25%). AAST grade IV injuries occurred in 51 (47%) and grade V injuries occurred in 52 (53%). Mean estimated blood loss was 9,414 mL. Overall survival was 43%. Adjusted overall survival rate after emergency department thoracotomy patients were excluded was 58%. Results stratified to AAST-OIS injury grade were as follows: grade IV, 32 of 51 (63%); grade V, 12 of 52 (23%); grade IV versus grade V (p < 0.001) odds ratio, 2.06; 95% confidence interval, 2.72 (1.40-3.04). Logistic regression analysis identified as independent predictors of outcome Revised Trauma Score (adjusted p < 0.0002), angioembolization (adjusted p < 0.0177), direct approach to hepatic veins (adjusted p < 0.0096), and packing (adjusted p < 0.0013). CONCLUSION: Improvements in mortality can be achieved with an appropriate operative approach. Angioembolization as an adjunct procedure decreases mortality in AAST-OIS grades IV and V hepatic injuries.

Embolization, Therapeutic↗

PubMed2003

The first-generation whole-genome radiation hybrid map in the horse identifies conserved segments in human and mouse genomes.

A first-generation radiation hybrid (RH) map of the equine (Equus caballus) genome was assembled using 92 horse x hamster hybrid cell lines and 730 equine markers. The map is the first comprehensive framework map of the horse that (1) incorporates type I as well as type II markers, (2) integrates synteny, cytogenetic, and meiotic maps into a consensus map, and (3) provides the most detailed genome-wide information to date on the organization and comparative status of the equine genome. The 730 loci (258 type I and 472 type II) included in the final map are clustered in 101 RH groups distributed over all equine autosomes and the X chromosome. The overall marker retention frequency in the panel is approximately 21%, and the possibility of adding any new marker to the map is approximately 90%. On average, the mapped markers are distributed every 19 cR (4 Mb) of the equine genome--a significant improvement in resolution over previous maps. With 69 new FISH assignments, a total of 253 cytogenetically mapped loci physically anchor the RH map to various chromosomal segments. Synteny assignments of 39 gene loci complemented the RH mapping of 27 genes. The results added 12 new loci to the horse gene map. Lastly, comparison of the assembly of 447 equine genes (256 linearly ordered RH-mapped and additional 191 FISH-mapped) with the location of draft sequences of their human and mouse orthologs provides the most extensive horse-human and horse-mouse comparative map to date. We expect that the foundation established through this map will significantly facilitate rapid targeted expansion of the horse gene map and consequently, mapping and positional cloning of genes governing traits significant to the equine industry.

Animals↗

PubMed2003

Intubation after cervical spinal cord injury: to be done selectively or routinely?

Patients with cervical spinal cord injuries (CSCIs) often develop acute respiratory failure and require intubation. It is unknown if intubation should be offered preemptively in all CSCI patients or selectively based on signs of acute respiratory failure. The purpose of this study was to evaluate the role of routine early intubation in CSCI patients. The medical records of 68 patients with CSCI were reviewed. Univariate and multivariate analyses were used to identify independent risk factors for the need of intubation. Statistical significance was considered at P < 0.05. Fifty patients (74%) required intubation and 27 (40%) developed pneumonia. Of patients with CSCI above C5, 87.5 per cent required intubation compared with 61 per cent of patients with CSCI at C5-C8 (P = 0.026). Similarly, of patients with complete quadriplegia, 90 per cent required intubation compared to 48.5 per cent of patients with incomplete quadriplegia or paraplegia (P < 0.001). Of 31 patients not presenting with overt signs of acute respiratory failure on admission, 13 (42%) decompensated later and were eventually intubated up to 53 hours after admission. Six of these 13 patients had emergent intubation due to acute desaturation and developed pulmonary complications associated with emergent intubation. There were 3 independent risk factors for the need of intubation: Injury Severity Score > 16, CSCI higher than C5, and complete quadriplegia. The combination of the 2 latter risk factors resulted in intubation in 21 of 22 patients (95%). The majority of patients with CSCI require intubation. In patients with CSCI above C5 and complete quadriplegia, intubation should be offered routinely and early because delays may cause preventable morbidity.

Adult↗

PubMed2002

Whole-genome analysis of animal A- and B-type cyclins.

BACKGROUND: Multiple A- and B-type cyclins have been identified in animals, but their study is complicated by varying degrees of functional redundancy. A non-essential phenotype may reflect redundancy with a known or as yet unknown gene. Complete sequencing of several animal genomes has allowed us to determine the size of the mitotic cyclin gene family and therefore to start to address this issue. RESULTS: We analyzed the Caenorhabditis elegans, Drosophila melanogaster and Homo sapiens genomes to identify known and novel A- and B-type cyclin genes and distinguish them from related pseudogenes. We find only a single functional A-type cyclin gene in invertebrates but two in vertebrates. In addition to the single functional cyclin A gene, the C. elegans genome contains numerous cyclin A pseudogenes. In contrast, the number and relationship of B-type cyclins varies considerably between organisms but all contain at least one cyclin B1-like gene and a cyclin B3 gene. CONCLUSIONS: There are three conserved families of mitotic cyclins in animals: A-, B3- and B-type. The precise number of genes within the A- and B-type families varies in different organisms, possibly as an adaptation to their distinct developmental strategies.

Amino Acid Sequence↗

PubMed2002

Investigation of possible free-radical scavengers and metrics for radiation damage in protein cryocrystallography.

The introduction of highly intense wiggler and undulator beamlines has reintroduced the problem of X-ray radiation damage in protein crystals even at cryogenic temperatures. Several metrics for monitoring radiation damage are considered and unit-cell volume expansion is systematically investigated using crystals of three different types, but it is found to be too variable to be a useful metric. Radical scavengers of secondary radiation damage are investigated as possible mitigating agents. Styrene is found to be ineffective. A method of spectroscopically measuring the radiation damage with a microspectrophotometer was used and, in conjunction with crystallographic data, provided tentative but suggestive evidence for the efficacy of ascorbate as a free-radical scavenging agent in cryocooled hen egg-white lysozyme crystals.

Animals↗

PubMed2002

Quantitative proteomics: the copy number of pyruvate dehydrogenase is more than 10(2)-fold lower than that of complex III in human mitochondria.

Pyruvate dehydrogenase (PDH) and complex III are two key protein complexes in mitochondrial metabolic activity. Using a novel quantitative Western blotting method, we find that PDH and complex III exist at a steady-state ratio of 1:100, 1:128 and 1:202 in HeLa cell extracts, fibroblast mitochondria and heart tissue mitochondria, respectively. This difference in stoichiometry is reflected in the immunogold labeling intensities of the two complexes and by the much more sparse distribution of PDH in fluorescence microscopy. In Rho0 fibroblasts there is a 64% reduction of complex III but the concentration of PDH remains the same as wild-type.

Blotting, Western↗

PubMed2002

A replicating module as the unit of mitochondrial structure and functioning.

The mitochondrion within human cells in tissue culture is pleomorphic and highly dynamic. The organelle mass can exist as thousands of small ovoids or as one continuous reticulum. In either state, the mitochondrial mass is in constant thermal motion, as well as moving in approximately 0.8-microm jumps that are determined by, and related to, attachments with cytoskeletal elements. Many protein complexes, such as the pyruvate dehydrogenase (PDH) complex and DNA containing nucleoids, are dispersed through the mass and as though fixed by attachments to membranes, such that they can become distributed to all of the individual small ovoid mitochondria when the reticulum becomes fragmented. This leads us to propose that a replicating module is the repeating unit of mitochondrial structure. Studies to examine heterogeneity of functioning within the organelle mass are briefly reviewed.

Biosensing Techniques↗

PubMed2002

Dissociation and post-traumatic stress disorder: two prospective studies of road traffic accident survivors.

BACKGROUND: Dissociative symptoms during trauma predict post-traumatic stress disorder (PTSD), but they are often transient. It is controversial whether they predict chronic PTSD over and above what can be predicted from other post-trauma symptoms. AIMS: To investigate prospectively the relationship between dissociative symptoms before, during and after a trauma and other psychological predictors, and chronic PTSD. METHOD: Two samples of 27 and 176 road traffic accident survivors were recruited. Patients were assessed shortly after the accident and followed at intervals over the next 6 months. Assessments included measures of dissociation, memory fragmentation, data-driven processing, rumination and PTSD symptoms. RESULTS: All measures of dissociation, particularly persistent dissociation 4 weeks after the accident, predicted chronic PTSD severity at 6 months. Dissociative symptoms predicted subsequent PTSD over and above the other PTSD symptom clusters. Memory fragmentation and data-driven processing also predicted PTSD. Rumination about the accident was among the strongest predictors of subsequent PTSD symptoms. CONCLUSIONS: Persistent dissociation and rumination 4 weeks after trauma are more useful in identifying those patients who are likely to develop chronic PTSD than initial reactions.

Accidents, Traffic↗

PubMed2002

Pharmacologic and pharmacokinetic profile of repifermin (KGF-2) in monkeys and comparative pharmacokinetics in humans.

Repifermin (truncated, recombinant human keratinocyte growth factor-2, KGF-2) was evaluated in cynomolgus monkeys and healthy humans during a phase 1 trial. Monkeys received vehicle or repifermin at 20, 75, or 200 microg/kg IV or 750 microg/kg subcutaneous (SC) daily for 29 days. Clinical observations were made during the entire dosing period. Gross and microscopic changes were assessed at necropsy. Pharmacokinetic parameters and immunogenicity were evaluated in these monkeys and in humans, following a single or 7 daily IV bolus injections of 1, 5, 25, or 50 microg/kg repifermin. In monkeys, repifermin was well tolerated, and histologic evaluation demonstrated dose-dependent, reversible thickening of the mucosa throughout the alimentary tract, except for the stomach. In the alimentary tract tissues, nonepithelial tissues were not affected, indicating a specificity of repifermin for epithelial cells. Pharmacokinetics in both monkeys and humans were dose proportional, showed lack of drug accumulation with repeated daily dosing, and were characterized by high volumes of distribution and clearance rates, indicating substantial tissue binding and metabolism. Repifermin was not markedly immunogenic following multiple daily IV injections in either species. Serum repifermin concentrations in humans were comparable to those attained in monkeys that produced significant pharmacological effects on epithelial cells in the alimentary tract. These findings provide additional support for the ongoing clinical development of repifermin for diseases involving epithelial injury.

Adolescent↗

PubMed2002

Wound management after colon injury: open or closed? A prospective randomized trial.

It is unknown whether leaving the skin wound open to heal by secondary intention is associated with a lower rate of wound infections compared with primary skin-wound closure after operations for colon injuries. From June 1998 to December 2000 at our Level I academic trauma center 48 patients entered into a randomized controlled trial (RCT) and were randomized to have their skin wound primarily closed (CLOSED-RCT) or left open (OPEN-RCT). At the same time patients not included in the RCT were followed prospectively. At the discretion of the surgeon their skin wounds were managed by primary closure (CLOSED-nonRCT) or were left open (OPEN-nonRCT). Univariate and multivariate analysis was done to identify independent risk factors of wound infection, wound dehiscence, and necrotizing soft tissue infection. Wound infection developed in 65 per cent of CLOSED-RCT and 36 per cent of OPEN-RCT patients (P = 0.04) and wound dehiscence in 31 per cent and 14 per cent respectively (P = 0.18). No remarkable differences were noted in any other variable including length of hospital stay. Wound infection developed in 29 per cent of CLOSED-nonRCT and 15 per cent of OPEN-nonRCT patients (P = 0.46). There were three independent risk factors of wound infection: primary wound closure [odds ratio (OR) = 5.5, 95% confidence interval (CI) = 1.8-19.4], colectomy (OR = 3.4, 95% CI = 1.2-10.4), and intraabdominal infection (OR = 5.3, 95% CI = 1.3-24.2). There were two independent risk factors for wound dehiscence and/or necrotizing soft tissue infection: wound infection (OR = 20.9, 95% CI = 4.9-152.3) and intra-abdominal infection (OR = 19.3, 95% CI = 4.0-146.9). Primary closure of the wound almost doubles the rate of wound infection compared with leaving the wound open in operations for colon injuries. Primary wound closure is a risk factor for wound infection and wound infection is a risk factor for wound dehiscence or necrotizing soft tissue infection. Because of the complexity of evaluating the real clinical significance of superficial wound infection larger studies on trauma patients are required.

Adult↗

PubMed2001

Penetrating thoracoabdominal injuries: ongoing dilemma-which cavity and when?

The aims of this study were to (1) define characteristics for the thoracoabdominal injury patient population; (2) describe sequences of surgical interventions with combined procedures (i.e., thoracotomy and laparotomy); and (3) describe pitfalls leading to inappropriate sequencing of surgical interventions for thoracoabdominal injuries. It was a retrospective 4-year study (January 1995 to December 1998) conducted at an urban level I trauma center. The study population comprised 254 patients who had sustained thoracoabdominal injuries requiring surgical intervention: 187 (73%) gunshot wounds (GSWs), 64 (25%) stab wounds (SWs), and 3 (2%) shotgun wounds (STWs). The mean revised (RTS) was 6.04; the mean Injury Severity Score (ISS) was 27; the mean estimated blood loss (EBL) was 3000 ml. The overall survival was 175 of 254 (69%). Of the 254, 51 (20%) underwent emergency department (ED) thoracotomy. Altogether, 73 (29%) underwent combined thoracotomy and laparotomy: 59 (81%) GSW, 13 (18%) SW, 1 (1%) STW (mean RTS 5.2, mean ISS 34, mean EBL 6800 ml). Overall survival was 30 of these 73 (41%). A total of 21 of the 73 (29%) underwent ED thoracotomy. In group I (laparotomy then thoracotomy: Lap + Thor, n = 34) the initial procedure was interrupted in 18 (53%). In group II (thoracotomy then laparotomy: Thor + Lap, n = 39) the initial procedure was interrupted in 14 (36%). Pitfalls leading to inappropriate surgical sequencing were persistent hypotension (13/73, 18%) and misleading chest tube output (8/73, 10%). It was concluded that penetrating thoracoabdominal injuries incur high mortality (31%), and the mortality doubles for patients who require combined procedures (59%). Inappropriate surgical sequencing occurred in 32 of 73 (44%) patients undergoing combined procedures. Persistent hypotension, indicating that the wrong cavity was accessed, and misleading chest tube output are the leading pitfalls in thoracoabdominal injury management.

Abdominal Injuries↗