Mechanisms by which small molecules of diverse chemotypes arrest Sec14 lipid transfer activity

Phosphatidylinositol (PtdIns) transfer proteins (PITPs) enhance the activities of PtdIns 4-OH kinases that generate signaling pools of PtdIns-4-phosphate. In that capacity, PITPs serve as key regulators of lipid signaling in eukaryotic cells. Although the PITP phospholipid exchange cycle is the engine that stimulates PtdIns 4-OH kinase activities, the underlying mechanism is not understood. Herein, we apply an integrative structural biology approach to investigate interactions of the yeast PITP Sec14 with small-molecule inhibitors (SMIs) of its phospholipid exchange cycle. Using a combination of X-ray crystallography, solution NMR spectroscopy, and atomistic MD simulations, we dissect how SMIs compete with native Sec14 phospholipid ligands and arrest phospholipid exchange. Moreover, as Sec14 PITPs represent new targets for the development of next-generation antifungal drugs, the structures of Sec14 bound to SMIs of diverse chemotypes reported in this study will provide critical information required for future structure-based design of next-generation lead compounds directed against Sec14 PITPs of virulent fungi.

An international multidisciplinary consensus statement on fasting before procedural sedation in adults and children

The multidisciplinary International Committee for the Advancement of Procedural Sedation presents the first fasting and aspiration prevention recommendations specific to procedural sedation, based on an extensive review of the literature. These were developed using Delphi methodology and assessment of the robustness of the available evidence. The literature evidence is clear that fasting, as currently practiced, often substantially exceeds recommended time thresholds and has known adverse consequences, for example, irritability, dehydration and hypoglycaemia. Fasting does not guarantee an empty stomach, and there is no observed association between aspiration and compliance with common fasting guidelines. The probability of clinically important aspiration during procedural sedation is negligible. In the post-1984 literature there are no published reports of aspiration-associated mortality in children, no reports of death in healthy adults (ASA physical status 1 or 2) and just nine reported deaths in adults of ASA physical status 3 or above. Current concerns about aspiration are out of proportion to the actual risk. Given the lower observed frequency of aspiration and mortality than during general anaesthesia, and the theoretical basis for assuming a lesser risk, fasting strategies in procedural sedation can reasonably be less restrictive. We present a consensus-derived algorithm in which each patient is first risk-stratified during their pre-sedation assessment, using evidence-based factors relating to patient characteristics, comorbidities, the nature of the procedure and the nature of the anticipated sedation technique. Graded fasting precautions for liquids and solids are then recommended for elective procedures based upon this categorisation of negligible, mild or moderate aspiration risk. This consensus statement can serve as a resource to practitioners and policymakers who perform and oversee procedural sedation in patients of all ages, worldwide.

Pulmonary aspiration during procedural sedation: a comprehensive systematic review

Background

Although pulmonary aspiration complicating operative general anaesthesia has been extensively studied, little is known regarding aspiration during procedural sedation.

Methods

We performed a comprehensive, systematic review to identify and catalogue published instances of aspiration involving procedural sedation in patients of all ages. We sought to report descriptively the circumstances, nature, and outcomes of these events.

Results

Of 1249 records identified by our search, we found 35 articles describing one or more occurrences of pulmonary aspiration during procedural sedation. Of the 292 occurrences during gastrointestinal endoscopy, there were eight deaths. Of the 34 unique occurrences for procedures other than endoscopy, there was a single death in a moribund patient, full recovery in 31, and unknown recovery status in two. We found no occurrences of aspiration in non-fasted patients receiving procedures other than endoscopy.

Conclusions

This first systematic review of pulmonary aspiration during procedural sedation identified few occurrences outside of gastrointestinal endoscopy, with full recovery typical. Although diligent caution remains warranted, our data indicate that aspiration during procedural sedation appears rare, idiosyncratic, and typically benign.

Brief report: symmetricity of radiographic and MRI-detected structural joint damage in persons with knee pain--the Joints on Glucosamine (JOG) Study

OBJECTIVE

Most MRI-based osteoarthritis (OA) studies have focused on a single knee per person and thus, data on bilaterality is sparse. Study aim was to describe symmetricity of MRI-detected OA features in a cohort of subjects with knee pain.

DESIGN

Participants were 169 subjects with chronic knee pain who had 3 T MRI of both knees using the same protocol as in the Osteoarthritis Initiative. Knees were read for cartilage damage, bone marrow lesions (BMLs), and meniscal damage according to the Whole-Organ Magnetic Resonance Imaging Score (WORMS) system. Chi(2) tests were used to compare the proportion of knees with unilateral tissue pathology to the proportion what would be expected if both knees were independent. We further used percent agreement and linear weighted kappa statistics to describe agreement of cartilage damage and BMLs in the same articular plates.

RESULTS

51.2% of participants were men, mean age was 52.1 (±6.2), mean BMI was 29.0 kg/m(2) (±4.1). All plates showed a significant higher degree of symmetricity for cartilage damage as evidenced by weighted kappas ranging from 0.32 to 0.59. For BMLs the degree of symmetricity was higher for the patella, trochlea, medial tibia, lateral femur, and medial femur; for meniscal damage the degree of unilaterality was lower for all medial meniscal subregions but not all lateral. Kappas ranged between 0.52 and 0.68 for cartilage and 0.30 and 0.55 for BMLs for the four subregions with highest agreement.

CONCLUSION

A higher degree of symmetricity of tissue damage than expected by chance was observed in this cohort of subjects with knee pain.

Susceptibility artifacts detected on 3T MRI of the knee: frequency, change over time and associations with radiographic findings: data from the joints on glucosamine study

OBJECTIVE

To determine the prevalence of intraarticular susceptibility artifacts and to detect longitudinal changes in the artifacts, on 3T magnetic resonance imaging (MRI) of the knee in a cohort of patients with knee pain, and to assess the association of susceptibility artifacts with radiographic intraarticular calcifications.

DESIGN

Three hundred and forty-six knees of 177 subjects aged 35-65 were included. 3T MRI was performed at baseline and at 6 months. Baseline radiographs were assessed for presence/absence of linear/punctate calcifications within the tibiofemoral joint (TFJ) space. Corresponding MRIs were assessed for susceptibility artifacts (i.e., linear/punctate hypointensities) in the TFJ space on coronal dual-echo steady-state (DESS) sequences. Kappa statistics were applied to determine agreement between findings on baseline DESS and radiography. Changes in artifacts over time were recorded.

RESULTS

In the medial compartment, 13 (4%) of the knees showed susceptibility artifacts at baseline. Six knees had persistent artifacts and six knees had incident artifacts at follow-up. Agreement between DESS and radiography was κ = 0.18 (-0.15, 0.51) in the medial compartment. Frequency of artifacts in the lateral compartment was low (2%).

CONCLUSION

Susceptibility artifacts detected on knee MRI are not frequent, and likely correspond to vacuum phenomena as they commonly change over time and are not associated with intraarticular calcifications. Radiologists should be aware of these artifacts as they can interfere with cartilage segmentation.

Changing epidemiology of Clostridium difficile infection following the introduction of a national ribotyping-based surveillance scheme in England

BACKGROUND

Marked increases in Clostridium difficile infection (CDI) incidence, driven by epidemic strain spread, is a global phenomenon.

METHODS

The Clostridium difficile Ribotyping Network (CDRN) was established in 2007 as part of enhanced CDI surveillance in England, to facilitate the recognition and control of epidemic strains. We report on changes in CDI epidemiology in England in the first 3 years of CDRN.

RESULTS

CDRN received 12,603 fecal specimens, comprising significantly (P < .05) increasing numbers and proportions of national CDI cases in 2007-2008 (n = 2109, 3.8%), 2008-2009 (n = 4774, 13.2%), and 2009-2010 (n = 5720, 22.3%). The C. difficile recovery rate was 90%, yielding 11,294 isolates for ribotyping. Rates of 9 of the 10 most common ribotypes changed significantly (P < .05) during 2007-2010. Clostridium difficile ribotype 027 predominated, but decreased markedly from 55% to 36% and 21% in 2007-2008, 2008-2009, and 2009-2010, respectively. The largest regional variations in prevalence occurred for ribotypes 027, 002, 015, and 078. Cephalosporin and fluoroquinolone use in CDI cases was reported significantly (P < .05) less frequently during 2007-2010. Mortality data were subject to potential reporting bias, but there was a significant decrease in CDI-associated deaths during 2007-2010, which may have been due to multiple factors, including reduced prevalence of ribotype 027.

CONCLUSIONS

Access to C. difficile ribotyping was associated with significant changes in the prevalence of epidemic strains, especially ribotype 027. These changes coincided with markedly reduced CDI incidence and related mortality in England. CDI control programs should include prospective access to C. difficile typing and analysis of risk factors for CDI and outcomes.

Wear analysis of failed acetabular polyethylene: a comparison of analytical methods

There are many methods for analysing wear volume in failed polyethylene acetabular components. We compared a radiological technique with three recognised ex vivo methods of measurement. We tested 18 ultra-high-molecular-weight polyethylene acetabular components revised for wear and aseptic loosening, of which 13 had pre-revision radiographs, from which the wear volume was calculated based upon the linear wear. We used a shadowgraph technique on silicone casts of all of the retrievals and a coordinate measuring method on the components directly. For these techniques, the wear vector was calculated for each component and the wear volume extrapolated using mathematical equations. The volumetric wear was also measured directly using a fluid-displacement method. The results of each technique were compared. The series had high wear volumes (mean 1385 mm(3); 730 to 1850) and high wear rates (mean 205 mm(3)/year; 92 to 363). There were wide variations in the measurements of wear volume between the radiological and the other techniques. Radiograph-derived wear volume correlated poorly with that of the fluid-displacement method, co-ordinate measuring method and shadowgraph methods, becoming less accurate as the wear increased. The mean overestimation in radiological wear volume was 47.7% of the fluid-displacement method wear volume. Fluid-displacement method, coordinate measuring method and shadowgraph determinations of wear volume were all better than that of the radiograph-derived linear measurements since they took into account the direction of wear. However, only radiological techniques can be used in vivo and remain useful for monitoring linear wear in the clinical setting. Interpretation of radiological measurements of acetabular wear must be done judiciously in the clinical setting. In vitro laboratory techniques, in particular the fluid-displacement method, remain the most accurate and reliable methods of assessing the wear of acetabular polyethylene.

Social patterns of food sharing in monogamous owl monkeys

Captive owl monkeys (Aotus nancymaae, A. azarai) share food frequently within both families and pairs. In this study food sharing was observed in seven mated pairs and four families (i.e., four mated pairs and their offspring). Patterns of food sharing were examined with respect to age class, sex, and the presence or absence of dependent offspring. Within families, most food transfers were from adult males to developing offspring. Adult males and females transferred food to their mates in caged pairs as well as in family units. Food interactions between adults are as likely to result in food transfers as those between adults and offspring. This pattern of food sharing between mates in a monogamous species may serve both nutritional and social functions that differ from those in polygamous species.

Opsonization of polyethylene wear particles regulates macrophage and osteoblast responses in vitro

The cellular reaction to wear debris may result in the failure of an artificial joint's fixation to the skeleton. The influence of debris opsinization on cell activity has received little attention. This study seeks to establish whether different proteinaceous culture environments may invoke variant cellular responses to debris challenge. Consideration of the zeta potential of a low density polyethylene particle group and an ex vitro ultrahigh molecular weight polyethylene particle group revealed that the nature of the protein adsorbants is related to the concentration of the proteins in solution. Furthermore, the composition of the adsorbed layer was shown to vary with the spectra of proteins in solution. In standard cell culture conditions zeta potential approached zero, indicating the high probability of particle agglomeration. Cell challenge studies with U937 macrophages showed that BSA and FCS protein adsorption mediated increased cell adhesion, while bovine IgG showed little change over control values. No changes in behavior of osteoblastic cells were observed in similar experiments.

Dynamic creep and mechanical characteristics of SmartSet GHV bone cement

The restrained dynamic creep behaviour and mechanical properties of SmartSet GHV bone cement have been investigated at both room temperature and body temperature. It was found that the bone cement behaves significant differently at room temperature from that at body temperature. The test temperature had a strong effect on the creep performance of the bone cements with a higher creep rate observed at body temperature at each loading cycle. For both temperatures, two stages of creep were identified with a higher creep rate during early cycling followed by a steady state creep rate. The relationship between creep deformation and loading cycle can be expressed by a Hyperb 1 model. As a visco-elastic material, the sensitivity of bone cement to the temperature change was evident during mechanical testing. Compared to the mechanical strength at room temperature, a decreased value was demonstrated at body temperature. The bending modulus was very sensitive to the change in testing temperature, where a reduction of 52% was recorded. A significant reduction in compressive and bending strength, 31 and 23% were recorded respectively. The effect of temperature on bending strength was less apparent, where only 13% reduction was exhibited at body temperature compared to room temperature.

Pre-heating of components in cemented total hip arthroplasty

Fatigue fractures which originate at stress-concentrating voids located at the implant-cement interface are a potential cause of septic loosening of cemented femoral components. Heating of the component to 44 degrees C is known to reduce the porosity of the cement-prosthesis interface. The temperature of the cement-bone interface was recorded intra-operatively as 32.3 degrees C. A simulated femoral model was devised to study the effect of heating of the component on the implant-cement interface. Heating of the implant and vacuum mixing have a synergistic effect on the porosity of the implant-cement interface, and heating also reverses the gradients of microhardness in the mantle. Heating of the implant also reduces porosity at the interface depending on the temperature. A minimum difference in temperature between the implant and the bone of 3 degrees C was required to produce this effect. The optimal difference was 7 degrees C, representing a balance between maximal reduction of porosity and an increased risk of thermal injury. Using contemporary cementing techniques, heating the implant to 40 degrees C is recommended to produce an optimum effect.

N+ ion implantation of Ti6Al4V alloy and UHMWPE for total joint replacement application

Multidirectional pin-on-plate tribological wear tests were performed to evaluate and compare the tribological behavior of N+ ion-implanted and unmodified Ti6Al4V/ultra high molecular weight polyethylene (UHMWPE) sliding couples, for total joint replacement (TJR) applications. Knoop microhardness indentations were measured and an increase in surface hardness of more than twofold and up to four times, respectively, was observed for the Ti6Al4V alloy and UHMWPE after N+ ion implantation, at a load of 1 gf. Increase in hardness was attributed to the formation of TiN precipitates and cross-linking in the alloy and polymer, respectively. Wear test results showed that N+ ion implantation reduced surface wear of the Ti6Al4V alloy and, in turn, significantly reduced the wear of the mating UHMWPE. Atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), non-contacting interferometry and optical microscopy were used to characterize both modified and unmodified material surfaces prior to and after tribological wear tests. The results indicated that N+ ion-implanted Ti6Al4V/UHMWPE sliding couples were distinctly superior to the unmodified sliding couples, and demonstrated a definite potential for the use of N+ ion-implanted Ti6Al4V and implanted UHMWPE as load bearing surfaces in TJR prostheses. (Journal of Applied Biomaterials & Biomechanics 2003; 1:164-71).

A preliminary hip joint simulator study of the migration of a cemented femoral stem

A hip joint simulator that can be used to evaluate the outcome of the cemented total hip replacement has been designed, manufactured and evaluated. The simulator produces motion of a cemented hip construct in the extension/flexion plane, with a socket to rotate internal/externally. At the same time a dynamic loading cycle is applied to the construct. A validation test was performed on a cemented femoral stem within a novel composite femur. The study demonstrates the value of using a hip joint simulator to evaluate the outcome of the cemented hip construct. A complex migration pattern of the cemented hip prosthesis with respect to load cycling was observed, demonstrated in vitro comparable prosthesis migration behaviour, both the stem migration and migration patterns, to that found clinically.

Creep behavior comparison of CMW1 and palacos R-40 clinical bone cements

The restrained dynamic creep behaviors of two clinical bone cements, Palacos R-40 and CMW1 have been investigated at room temperature and body temperature. It was found that the two cements demonstrated significantly different creep deformations, with Palacos R-40 bone cement demonstrating higher creep strain than CMW1 bone cement at each loading cycle. For both cements, two stages of creep were identified with a higher creep rate during early cycling followed by a steady-state creep rate. The test temperature had a strong effect on the creep performance of the bone cements with higher creep rate observed at body temperature. The relationship between creep deformation and loading cycles can be expressed by single logarithmic model. The SEM examinations revealed that CMW1 bone cement is more sensitive to defects within the specimen especially to the defects at the edges of the specimen than Palacos R-40 bone cement. However, in the absence of micro-cracks or defects within the inner surface layer, the dynamic loading (at less than 10.6 MPa) is unlikely to produce micro-cracks in the CMW1 bone cement. The different behaviors between the two bone cements may be attributed to differences in chemical compositions and molecular weight distributions.

The wear of metal-on-metal total hip prostheses measured in a hip simulator

New generation metal-on-metal prostheses have been introduced to try and overcome the problem of osteolysis often attributed to the wear particles of the polyethylene component of conventional metal-on-ultra-high molecular weight polyethylene (UHMWPE) joints. The wear rates of four metal-on-metal joints (two different clearances) were assessed along with that of a conventional metal-on-UHMWPE joint. Friction measurements of the metal-on-metal joints were taken before and after the wear test and compared. Two distinct wear phases were discernible for all the metal-on-metal joints: an initial wear phase up to 0.5 x 10(6) cycles and then a lower steady state wear phase. The steady state wear rate of the 22 microm radial clearance metal-on-metal joint was lower than that for the 40 microm radial clearance joint, although this difference was not found to be significant (p > 0.15). The wear rates for all the joints tested were consistent with other simulator studies. The friction factors produced by each joint were found to decrease significantly after wear testing (p < 0.05).

Some failure modes of four clinical bone cements

The fracture or failure behaviours of four commercial acrylic-based bone cements have been examined in tensile, bending and compression modes, and their mechanical properties are reviewed. It was found that Palacos R-40 bone cement had high radiopaque agent concentration, with high surface hardness. It exhibited a much lower bending strength and bending modulus compared with the other three bone cements (CMW1, CMW2000 and Simplex P). The textures of tensile fracture surfaces produced were similar for the four bone cements studied. The fracture surface was fragmented by crevices, which developed through the matrix and around large undissolved polymethylmethacrylate (PMMA) beads. Three bands with different features existed on the bending fracture surfaces, with an abrupt transition between them. It appears that the agglomerates of zirconium dioxide particles are implicated in Palacos R-40 bone cement fracture surface. The examination of compressive failed specimens revealed that a 'yielded crack band' existed across the transverse section. Plastic deformation resulted in the PMMA beads being squashed in the longitudinal direction and dilated in the transverse direction.

Crystal structure of Staphylococcus aureus tyrosyl-tRNA synthetase in complex with a class of potent and specific inhibitors

SB-219383 and its analogues are a class of potent and specific inhibitors of bacterial tyrosyl-tRNA synthetases. Crystal structures of these inhibitors have been solved in complex with the tyrosyl-tRNA synthetase from Staphylococcus aureus, the bacterium that is largely responsible for hospital-acquired infections. The full-length enzyme yielded crystals that diffracted to 2.8 A resolution, but a truncated version of the enzyme allowed the resolution to be extended to 2.2 A. These inhibitors not only occupy the known substrate binding sites in unique ways, but also reveal a butyl binding pocket. It was reported that the Bacillus stearothermophilus TyrRS T51P mutant has much increased catalytic activity. The S. aureus enzyme happens to have a proline at position 51. Therefore, our structures may contribute to the understanding of the catalytic mechanism and provide the structural basis for designing novel antimicrobial agents.

Iatrogenic cardiopulmonary arrest during pediatric sedation with meperidine, promethazine, and chlorpromazine

The pediatric sedative combination of meperidine, promethazine, and chlorpromazine (MPC) has been widely used for more than 40 years. Despite its relatively poor efficacy and questionable safety profile, many emergency departments (EDs) continue to stock specially formulated mixtures of these three agents. We report a case of iatrogenic cardiac arrest in a 2-month-old infant in whom a consulting resident administered too much MPC (10 times the expected dose) by the wrong route (intravenous instead of intramuscular). The child was successfully resuscitated with no apparent neurologic deficit. Subsequently, we have removed MPC entirely from our ED and instituted a policy restricting ED procedural sedation privileges to emergency physicians. We urge other EDs to do likewise.

Ketamine sedation for pediatric critical care procedures

OBJECTIVES

To describe our experience using ketamine sedation to facilitate pediatric critical care procedures, and to document the safety profile of ketamine in this setting.

DESIGN

Retrospective consecutive case series.

SETTING

Pediatric intensive care unit of a tertiary children's hospital.

PATIENTS

Children receiving ketamine for procedural sedation over a 5-year period.

INTERVENTIONS

We reviewed patient records to determine indication, dosing, adverse events, inadequate sedation, and recovery time for each sedation.

OUTCOME MEASURES

Descriptive features of sedation including adverse events.

RESULTS

During the study period, children in our pediatric intensive care unit received ketamine at total of 442 times to facilitate a wide variety of critical care procedures, most commonly central line placement, esophagogastroduodenoscopy, and wound debridement. Most study children had substantial underlying illness (ASA > or = 3 in 88%; ASA > or = 4 in 39%). Inadequate sedation was noted in only nine (2%) procedures. Adverse effects included transient laryngospasm (n = 9), transient partial airway obstruction (n = 5), apnea with bradycardia (n = 1), emesis during the procedure (n = 2), emesis during recovery (n = 9), mild recovery agitation (n = 10), moderate-to-severe recovery agitation (n = 1), and excessive salivation (n = 4). There were no adverse outcomes attributable to ketamine.

CONCLUSION

Pediatric intensivists skilled in ketamine administration can safely and effectively administer this drug to facilitate critical care procedures. Despite the ill nature of our patient sample, adverse effects were uncommon.

Do published guidelines predict pneumonia in children presenting to an urban ED?

OBJECTIVES

In 1997, a Canadian task force published evidence-based guidelines for diagnosing pediatric pneumonia, concluding that the absence of each of four signs (ie, respiratory distress, tachypnea, crackles, and decreased breath sounds) accurately excludes pneumonia. The study was performed to evaluate the accuracy of these guidelines in predicting pneumonia in young children.

METHODS

This was an observational study conducted over a 4-month period at an urban emergency department with 80,000 annual visits, approximately 20% of which were children < or =5 years old. Consecutive children < or =5 years old who underwent chest radiography were enrolled. Prior to ordering radiographs, treating physicians were required to enter specific patient signs and symptoms into a computerized database. World Health Organization criteria were used to define tachypnea. Sensitivity, specificity, and predictive values of the task force guidelines in predicting pneumonia were calculated.

RESULTS

Three hundred twenty-nine children, including 67 (20%) with pneumonia, were enrolled. Guidelines were 45% sensitive (95% confidence interval (CI) = 33-58) and 66% specific (95% CI = 60-72) for diagnosing pneumonia. Positive and negative predictive values were 25% (95% CI = 18-34) and 82% (95% CI = 77-87), respectively.

CONCLUSION

Previously published evidence-based guidelines for excluding pediatric pneumonia were found unreliable in this study.

Immunohistochemical localization of trichloroacylated protein adducts in tetrachloroethene-treated mice

Tetrachloroethene (PCE), a common industrial solvent and environmental contaminant, is primarily used in the dry-cleaning industry. The toxicity of PCE has been linked to vision disorders, renal and hepatic cancer, and autoimmune diseases. Although the mechanism of toxicity is not fully understood, PCE forms trichloroacylated protein adducts in tissues where toxicity is known to occur. These adducts may be responsible for toxicity by altering the function of cellular proteins. Using Western blot analysis, formation of trichloroacylated protein adducts has been reported. To determine the localization of the adducts in a specific zone of a tissue, immunohistochemical staining was used in the study. An antiserum to trichloroacylated proteins was raised in rabbits and its specificity was established by enzyme-linked immunosorbent assay (ELISA). Female MRL-lpr/lpr and MRL +/+ mice were treated with PCE using a single 5-mmol/kg dose over 24 h or on every fourth day for 6 wk (total 20 doses). Formation of trichloroacylated protein adducts was observed in the liver, and localized to the centrilobular zones. Intensity and circumference of the staining around the central vein were much greater in subchronically treated mice than in acutely treated mice. No immunochemical reactivity was observed in any of the other tissues examined. This study shows that hepatic trichloroacylated protein adducts are localized in a region of the liver where PCE-mediated toxicity is known to occur. Immunohistochemical localization of these adducts and its association with PCE-induced toxicity support the contention that adducts may contribute to toxicity.

Effects of a negative pressure venom extraction device (Extractor) on local tissue injury after artificial rattlesnake envenomation in a porcine model

OBJECTIVES

To determine if a commercially available negative-pressure venom extraction device (Extractor) reduces local tissue injury after artificial rattlesnake envenomation in a porcine model.

METHODS

We prospectively studied 10 pigs using a crossover design. After the pigs were anesthetized, 25 mg Crotalus atrox venom was injected obliquely with a 22-gauge needle 7 mm deep into subcutaneous tissues proximal to the ventral hind hoof. Pigs were randomized to receive either the Extractor (applied 3 minutes following envenomation and left in place for 30 minutes) or no Extractor. The protocol was repeated 14 days later by using the alternate treatment group and opposite hind leg for each animal. We measured leg circumference at standardized locations on the hoof, foreleg, and thigh at baseline and then 1, 2, 3, 4, 5, 6, 24, 48, 72, and 96 hours following venom injection. Maximal changes in circumference at 6 hours were compared using the paired t test. Minimum residual swelling at up to 96 hours was similarly compared.

RESULTS

Maximal 6-hour swelling was similar with and without the Extractor: the hoof difference with the Extractor was -0.1% (95% CI = -3.4% to 3.2%, P = .95), foreleg difference was 0.3% (95% CI = -4.1% to 4.7%, P = .88), and thigh difference was -2.8% (95% CI = -10.0% to 4.4%, P = .40). Minimum residual swelling at up to 96 hours was also similar with and without the Extractor: hoof difference with the Extractor was 1.2% (95% CI = -5.6% to 8.0%, P = .70), foreleg difference was 0.6% (95% CI = -3.7% to 4.9%, P = .76), and thigh difference was 0.3% (95% CI = -2.4% to 3.0%, P = .81). A circular lesion identical in size and shape to the Extractor suction cup, which later necrosed and resulted in tissue loss, developed where the device had been applied in 2 animals. No such lesions occurred in legs not treated with the Extractor.

CONCLUSION

No benefit was demonstrated from Extractor use for artificial rattlesnake envenomation in our animal study. The skin necrosis noted in 2 Extractor-treated extremities suggests that an injury pattern may be associated with the device.

Ketamine sedation for pediatric gastroenterology procedures

BACKGROUND

Although the dissociative sedative ketamine is used commonly for pediatric procedural sedation in other settings, the safety of this agent in pediatric gastroenterology is not well-studied. A 5-year experience with ketamine sedation for pediatric gastroenterology procedures was reviewed to document the safety profile of this agent and to identify predictors of laryngospasm during esophagogastroduodenoscopy (EGD).

METHODS

The study was a retrospective consecutive case series of children receiving ketamine administered by pediatric gastroenterologists skilled in basic airway management to facilitate pediatric gastrointestinal procedures during a 5-year period. Patient's records were reviewed to determine indication, dosage, adverse effects, drugs, inadequate sedation, and recovery time for each sedation. A multiple logistic regression analysis was performed to identify predictors of laryngospasm during EGD. Outcome measures were descriptive features of sedation, including adverse effects and predictors of laryngospasm during EGD.

RESULTS

During the study period pediatric gastroenterologists administered ketamine 636 times, primarily for EGD (86%) and primarily by the intravenous route (98%). The median loading dose and total dose were 1.00 mg/kg and 1.34 mg/kg, respectively. Inadequate sedation was noted in seven (1.1%) procedures. Adverse effects included transient laryngospasm (8.2%), emesis (4.1%), recovery agitation (2.4%), partial airway obstruction (1.3%), apnea and respiratory depression (0.5%), and excessive salivation (0.3%). There were no adverse outcomes attributable to ketamine. Nearly half (46%) the subjects had severe underlying illness (American Society of Anesthesiologists (ASA] class > or =3). All instances of laryngospasm occurred during EGD (9.5% incidence), and the only independent predictor of laryngospasm in this sample was decreasing age. The incidence of laryngospasm was 13.9% in preschool-aged (< or =6 years) children and was 3.6% in school-aged (>6 years) children (difference 10.3%, 95% confidence intervals 5.5-14.9%). No dose relationship was noted with laryngospasm, and the risk did not increase with underlying illness.

CONCLUSION

Pediatric gastroenterologists skilled in ketamine administration and basic airway management can effectively administer this drug to facilitate gastrointestinal procedures. Transient laryngospasm occurred in 9.5% of children receiving ketamine for EGD, and its incidence was greater in preschool than in school-aged children.

Analysis and purification of nucleic acids by ion-pair reversed-phase high-performance liquid chromatography

Sizing of DNA fragments is a routine analysis traditionally performed on agarose or polyacrylamide gels. Electrophoretic analysis is labor-intensive with only limited potential for automation. Recovery of DNA fragments from gels is cumbersome. We present data on automated, size-based separation of DNA fragments by ion-pair reversed-phase high performance liquid chromatography (IP RP HPLC) - DNA chromatography - on the WAVE DNA Fragment Analysis System with the DNASep cartridge. This system is suitable for accurate and rapid sizing of double-stranded (ds) DNA fragments from 50 to ca. 2000 base pairs (bp). Fluorescently labeled DNA fragments are compatible with the technology. Length-dependent separation of dsDNA fragments is sequence independent and retention times are highly reproducible. The resolving capabilities of DNA chromatography are illustrated by the analysis of multiple DNA size markers. Resolved dsDNA fragments are easily collected and are suitable for downstream applications such as sequencing and cloning. DNA chromatography under denaturing conditions with fluorescently labeled DNA fragments offers a means for the separation and purification of individual strands of dsDNA. Analysis of DNA fragments on the WAVE System is highly automated and requires minimal manual intervention. DNA chromatography offers a reliable and automated alternative to gel electrophoresis for the analysis of DNA fragments.

Intratendinous rupture of a flexor tendon graft many years after staged reconstruction: a report of three cases

Three cases of rupture of a flexor tendon graft many years after surgery are presented. Two cases occurred 12 years after reconstruction and the third case occurred 21 years after reconstruction. Each rupture was intratendinous, just proximal to the flexor tendon sheath in 2 cases and at the proximal edge of the transverse carpal ligament in the third case. Active digital flexion was restored by transfer of the flexor digitorum superficialis from an adjacent finger to the distal tendon stump or by direct end-to-end repair of the rupture site reinforced with an onlay autogenous patch graft. Patients undergoing tendon grafting should be alerted to the possibility of rupture, even many years later.

Comparison of high-fat and high-carbohydrate foods in a meal or snack on short-term fat and energy intakes in obese women

The present study aimed to compare the action of high-fat and high-carbohydrate (CHO) foods on meal size (satiation) and post-meal satiety in obese women. A within-subjects design was used; each participant received all four nutritional challenges. Fifteen healthy obese women (age 21-56 years, BMI 35-48 kg/m2) participated; thirteen completed all four test days. On two test days, participants were exposed to a nutritional challenge comprising an ad libitum high-fat or high-CHO lunch. On the other two test days they were exposed to a challenge comprising an ad libitum sweet high-fat or high-CHO mid-afternoon snack. Energy and macronutrient intakes were measured at each eating episode. Visual analogue rating scales were completed periodically to record subjective feelings of appetite. When offered a high-CHO selection of foods at lunch and mid-afternoon participants consumed less energy than when offered a high-fat selection. However, post-meal satiety was similar. Total test-day energy intake was significantly higher when high-fat foods were consumed at lunch, but not as a snack. Consumption of high-fat foods at a lunch and snack increased the amount of fat consumed over the whole test day. In conclusion, energy intake of an eating episode was influenced by nutrient composition in this group of obese women. Consumption of high-fat foods at lunch or as a snack led to overconsumption relative to high-CHO foods. However, high-fat foods at meals may have greater potential to influence daily intake than at snacks, probably because meals are larger eating episodes and therefore give greater opportunity to overconsume.

Compressive radial neuropathies

Radial neuropathy can have one of several clinical presentations, depending on the level of compression: high radial nerve palsy, PIN palsy, radial tunnel syndrome, and Wartenberg's syndrome. Elucidating the history and progression of symptoms with a physical examination directed at testing individual muscles will determine the approximate anatomic level of radial injury. Identification of a Tinel's sign will often locate the site of compression. Electrodiagnostic studies can confirm the diagnosis in a radial motor neuropathy, but are unreliable in radial tunnel syndrome and sensory radial nerve compression. A trial of nonsurgical treatment is warranted in all cases except those with progressive motor weakness or palsy. Patients who do not respond or continue to progress despite conservative treatment are candidates for surgical decompression.

Abdominal trauma in infants and children: prompt identification and early management of serious and life-threatening injuries. Part II: Specific injuries and ED management

Evaluation of children with suspected abdominal trauma could be a difficult task. Unique anatomic and physiologic features render vital sign assessment and the physical examination less useful than in the adult population. Awareness of injury patterns and associations will improve the early diagnosis of abdominal trauma. Clinicians must have a complete understanding of common and atypical presentations of children with significant abdominal injuries. Knowledge of the utility and limitations of available laboratory and radiologic adjuncts will assist in accurately identifying abdominal injury. While other obvious injuries (eg, facial, cranial, and extremity trauma) can distract physicians from less obvious abdominal trauma, an algorithmic approach to evaluating and managing children with multisystem trauma will improve overall care and help to identify and treat abdominal injuries in a timely fashion. Finally, physicians must be aware of the capabilities of their own facility to handle pediatric trauma. Protocols must be in place for expediting the transfer of children who require a higher level of care. Knowledge of each of these areas will help to improve the overall care and outcome of children with abdominal trauma.

A novel technique for the detailed size characterization of wear debris

The accurate and detailed characterization of artificial joint wear debris is important in determining both the wear rate of prostheses and understanding the role that the debris plays in the development and progression of aseptic loosening. The novel application of low angle laser light scattering (LALLS) to the particle size characterization of ultra high molecular weight polyethylene (UHMWPE) wear debris is described. The results demonstrate that both ex vivo and in vitro origin wear debris samples, at concentrations typical of those produced via an alkali-digestion retrieval route, can be reproducibly analyzed via LALLS. Because the LALLS route enables particle size analysis of the entire debris sample to be acquired non-destructively and whilst in suspension, artefacts associated with filtering, drying and agglomeration of debris are avoided, in contrast to currently used techniques such as filtration and scanning electron microscopy (SEM) observation.

Physical fighting in childhood as a risk factor for later mental health problems

OBJECTIVE

The prevalence, persistence, and desistance of boys' physical fighting was examined over a 7-year period. The importance of persistent physical fighting compared with other risk factors in the prediction of later mental health problems was explored.

METHOD

One hundred seventy-seven boys, aged 7 to 12 years, who had been referred to clinics for mental health problems were followed up annually for 7 years, with the boys, their parents, and teachers as informants.

RESULTS

Agreement among different informants about the boys' fighting tended to be low. The prevalence of fighting over time remained quite similar for different age cohorts. Almost 9 of 10 fighters in year 1 continued to fight in one or more successive years, and about one third of the boys could be classified as persistent fighters. Only 13.1% of the boys desisted in fighting. Boys who desisted, compared with those who persisted, had higher intelligence and their mothers scored lower on measures of antisocial personality disorder. At year 7, persistent fighting was significantly associated with impairment. The prevalence of psychiatric diagnoses in year 7 was 3 times higher for persistent fighters than for nonfighters. Using regression analyses with several control variables, conduct disorder was best predicted by earlier oppositional defiant disorder in year 1 and persistent fighting. Global impairment was best predicted by oppositional defiant disorder in year 1, persistent fighting, and low IQ. Finally, the number of diagnoses at year 7 was best predicted by persistent fighting.

CONCLUSION

Physical fighting constitutes a significant mental health risk in referred boys.

Abdominal trauma in infants and children: prompt identification and early management of serious and life-threatening injuries. Part I: injury patterns and initial assessment

Evaluation of children with abdominal trauma can be a difficult process. Unique anatomic features predispose children to specific injuries and potentially make identification of life-threatening injuries difficult. While Part I of this review discusses the initial assessment and diagnostic testing in children with abdominal trauma, Part II will review specific injuries and ED management of children with possible abdominal trauma. Knowledge of each of these factors will improve the ability of general and pediatric emergency physicians to expeditiously identify children with potential serious injury and initiate appropriate treatment.

Does adjunctive midazolam reduce recovery agitation after ketamine sedation for pediatric procedures? A randomized, double-blind, placebo-controlled trial

STUDY OBJECTIVE

Despite widespread use of adjunctive benzodiazepines during ketamine sedation, their efficacy in reducing recovery agitation in children has never been studied. We wished to characterize the nature and severity of recovery agitation after ketamine sedation in children treated in the emergency department and to determine whether the addition of adjunctive midazolam reduces the magnitude of such recovery agitation.

METHODS

The study was a randomized, double-blind, clinical trial of adjunctive midazolam versus placebo during ketamine sedation. We enrolled 104 children aged 12 months to 15 years (median age, 6 years) at a combined university medical center and children's hospital. Subjects received either intravenous midazolam (0.05 mg/kg up to 2 mg) or placebo after intravenous administration of a ketamine loading dose (1.5 mg/kg). Treating physicians and nurses independently noted the presence of crying, hallucinations, and nightmares during recovery and graded recovery agitation by using a 100-mm visual analog scale. Preprocedure agitation and external stimulation during recovery were also graded. The time from ketamine injection until each subject met the recovery criteria was recorded.

RESULTS

Fifty-three subjects received midazolam, and 51 received placebo. Potentially confounding variables were similar between the groups. Sedation efficacy, adverse effects, and recovery time were also similar between groups. Interobserver agreement between physician and nurse assessments was substantial. Median physician assessment of recovery agitation was 4 mm (interquartile range, 2 to 19) in the midazolam group and 5 mm (interquartile range, 3 to 14) in the placebo group (difference -1; 95% confidence interval -3 to 2; P =.705). Recovery agitation was moderately correlated with preprocedure agitation (rho=0.486) but not with external stimulation during recovery (rho=0.147).

CONCLUSION

Recovery agitation is common but generally of very low magnitude after ketamine sedation in children in the ED. We observed a median physician rating of 5 mm on a 100-mm visual analog scale, a score that we believe to be clinically insignificant. The degree of recovery agitation after ketamine sedation is significantly related to the degree of preprocedure agitation. In this study, concurrent midazolam did not diminish such agitation and had no measurably beneficial effect. Use of adjunctive benzodiazepines in pediatric ketamine sedation appears unnecessary.

Findings on disruptive behavior disorders from the first decade of the Developmental Trends Study

The paper summarizes the first decade of the Developmental Trends Study, a prospective longitudinal study of 177 boys. Initially, they were referred to mental health clinics in Pennsylvania (Pittsburgh), and Georgia (Athens and Atlanta). Since 1987, the boys, their parents, and their teachers have been followed up almost annually. The study is unique because the cooperation rate of participants has remained very high over the years, psychiatric diagnoses were derived from structured interviews (especially disruptive behavior disorders), and many risk factors were measured over the years. The present paper summarizes key findings on the development of disruptive behavior, especially Oppositional Defiant Disorder, Conduct Disorder, and Attention Deficit-Hyperactivity Disorder. The paper also highlights results on risk factors and comorbid conditions of disruptive behaviors.

Predictors of adverse events with intramuscular ketamine sedation in children

STUDY OBJECTIVE

Ketamine is a safe and effective sedative for emergency department procedures in children. However, the use of ketamine sometimes is associated with airway complications, emesis, and recovery agitation. We wished to identify predictors of these adverse events that clinicians might use to risk-stratify children who are candidates for ketamine sedation.

METHODS

We analyzed data from 1,021 ED intramuscular ketamine sedations in children 15 years of age or younger at a university medical center and an affiliated county hospital over a 9-year period. Five potential predictor variables (age, gender, American Society of Anesthesiologists' [ASA] risk classification, quantity of first ketamine dose, and number of ketamine doses administered) were compared between children with and without complications. We used multiple logistic regression analyses to determine the association of these 5 variables with emesis and recovery agitation, and validated these analyses with bootstrap resampling techniques. We compared children with and without airway complications using univariate statistics alone, as there were too few patients with airway complications to support a multivariate analysis.

RESULTS

No study variables had significant univariate associations with airway complications (all P values >.40). We found emesis to be associated with increasing age in multivariate analysis (odds ratio [OR] 1.25 per year, bias-corrected 95% confidence interval [CI] 1.17 to 1.34, P<.001). The incidence of emesis was 12. 1% in children aged 5 years or older, and 3.5% in those younger than 5 years (Delta8.6%, 95% CI 4.9% to 12.1%). Recovery agitation was associated with the presence of an underlying medical condition (ie, ASA class > or =2, OR 3.05, bias-corrected 95% CI 1.65 to 7.30, P=.004) and inversely associated with increasing age (OR 0.79 per year, bias-corrected 95% CI 0.69 to 0.89, P<.001). The incidence of recovery agitation was 17.9% in ASA class 1 children and 33.3% in children in ASA class 2 or greater (Delta-15.4%, 95% CI 0.0% to -30. 7%). The incidence of recovery agitation was 12.1% in children aged 5 years or older, and 22.5% in those younger than 5 years (Delta-10. 4%, 95% CI -3.0% to -17.7%). Bootstrap resampling techniques validated the importance of the significant variables identified in the regression analyses.

CONCLUSION

No study variable was predictive of ketamine-associated airway complications. Emesis that occurred after ketamine administration was modestly associated with increasing age. Recovery agitation was modestly associated with decreasing age and the presence of an underlying medical condition. The discriminatory power of these variables was low enough as to be unlikely to alter clinical decisions regarding patient selection for ketamine administration. No evidence of a significant ketamine dose relationship was noted for airway complications, emesis, or recovery agitation.

Inadvertent ketamine overdose in children: clinical manifestations and outcome

STUDY OBJECTIVE

We sought to characterize the clinical manifestations, outcome, and etiology of inadvertent ketamine overdose in the emergency department.

METHODS

We investigated cases of inadvertent ketamine overdose in children seen in the ED solicited through electronic mail subscription lists or reported to the Institute for Safe Medication Practices. The clinical manifestations, outcome, and reported cause for each case are described.

RESULTS

We identified 9 cases of inadvertent ketamine overdose in children treated in the ED. Patients received either 5(n=3), 10(n=5), or 100(n=1) times the intended dose, either by the intramuscular (n=5) or intravenous (n=4) route. All 9 experienced prolonged sedation (3 to 24 hours). Four experienced brief respiratory depression shortly after administration, and assisted ventilation was performed in 2. Two children without respiratory difficulty or hypoxemia were intubated by their physicians as a precaution. In 5 children, the dosing error was not discovered until late in the sedation, often when the child was not waking at the expected time. No adverse outcomes were noted, and all children were normal neurologically on discharge and longer-term follow-up if available.

CONCLUSION

No adverse outcomes were noted in 9 healthy children treated in the ED who inadvertently received 5 to 100 times the intended dose of ketamine. Toxicity manifested as prolonged sedation in all 9 and brief respiratory depression in 4. The margin of safety in ketamine overdose may be wide, although less common and more serious outcomes cannot be excluded by this small, self-reported sample.

Fatty acid ethyl and methyl ester synthases, and fatty acid anilide synthase in HepG2 and AR42J cells: interrelationships and inhibition by tri-o-tolyl phosphate

Synthesis of fatty acid ethyl esters (FAEEs), fatty acid methyl esters (FAMEs), and fatty acid anilides (FAAs) in humans and/or experimental animals and in vitro have been reported by us and other investigators. In previous studies, we have demonstrated that fatty acid ethyl ester synthase (FAEES), purified from rat liver microsomes, is structurally and functionally identical to the rat liver microsomal carboxylesterase (pI 6.1) and suggested a role in the conjugation of a variety of xenobiotic alcohols with endogenous fatty acids (B. S. Kaphalia, R. R. Fritz, and G. A. S. Ansari, Chem. Res. Toxicol. 11, 211-218, 1997). However, hepatic FAEES was found to be structurally and functionally different from that of pancreas. Therefore, the present study was undertaken to determine structural and functional interrelationships among the enzyme(s) involved in the synthesis of FAEEs, FAMEs, and FAAs, in HepG2 and AR42J cells using tri-o-tolyl phosphate (TOTP), a specific inhibitor for beta-esterases. Synthesis of FAEEs, FAMEs, and FAAs, studied in the HepG2 cells, was found to be dose- and time-dependent following incubation with methanol, ethanol, or aniline, respectively. Approximately 86-90% inhibition of FAEE, FAME, and FAA synthesizing activities was found in HepG2 cells following exposure to 2.5 microM TOTP. Identical profiles of dose- and time-dependent inhibition of FAEE, FAME, and FAA synthesizing activities by TOTP in HepG2 cells suggest that synthesis of FAEEs, FAMEs, and FAAs is catalyzed by the same enzyme(s). However, FAEE, FAME, and FAA synthesizing activities in AR42J cells could not be inhibited by TOTP under similar experimental conditions. A differential pattern of p-nitrophenyl acetate hydrolyzing activity (a measure of esterase activity) similar to that of fatty acid ester/anilide synthesizing activities was observed in the two cell lines. These results are further substantiated by the presence of approximately 60 kDa (subunit molecular weight) protein in the postnuclear fraction of HepG2 but not in AR42J cells by Western blot analysis using antibodies raised against FAEES, purified from rat liver microsomes or adipose tissue. Therefore, the enzyme responsible for the FAEE, FAME, or FAA synthesizing activities is most probably carboxylesterase in HepG2 cells and is structurally and functionally different than that present in AR42J cells. These studies also indicate the utility of HepG2 and AR42J cell cultures as an alternative to the animal model regarding studies on nonoxidative metabolism of alcohols and amines, in general.

Nutritional intake in community patients with pressure ulcers

Nutritional status has been associated with the development and healing of pressure ulcers. This study aimed to examine the dietary intake of adults who had pressure ulcers (n = 75) and a control group with no pressure ulcers (n = 100), randomly selected from those receiving treatment from community nurses. All participants were considered to be at risk of developing pressure damage. Dietary intake was assessed using a 24-hour recall method (completed by 84 participants) and a nutritional questionnaire (completed by all 175 participants). The mean age of participants was 79 +/- 6 years and 70% were women. Patients who had pressure ulcers had a lower energy intake (mean difference -185 kcal, 95% confidence interval -413 to 43) and intake of protein (mean difference -6.73 g/day, 95% CI -16.20 to 2.74) but neither factor achieved a standard level of statistical significance. However, when protein was categorised into quartiles, a significantly higher proportion of participants with low intake had pressure ulcers on chi-squared analysis (p = 0.043). More participants who had pressure ulcers required assistance with eating (odds ratio 4.55, 95% CI 1.53 to 13.54) and more had experienced recent taste changes (odds ratio 3.28, 95% CI 1.19 to 9.10). While these differences were significant, there were few major differences between those who had pressure ulcers and the control group. A number of participants in both groups had poor nutritional intake and other risk factors for malnutrition were also found. Poor nutrition is a problem for all patients receiving community nursing care, not just those with pressure ulceration. Due to acknowledged difficulties in recording nutritional intake in elderly patients, further assessment of dietary intake in those receiving community nursing services should be undertaken to support these results.

Concert medicine: spectrum of medical problems encountered at 405 major concerts

OBJECTIVES

To identify factors predictive of patient load at major commercial concert first-aid stations, and to characterize the spectrum of presenting injuries and illnesses at such events.

METHODS

This study was a retrospective case series of patients presenting to on-site first-aid stations at five major concert venues in southern California over a five-year period. The authors compared the number of patients per ten thousand attendees (PPTT) with four potential predictors (music type, overall attendance, temperature, and indoor vs outdoor location) using univariate techniques and negative binomial regression. The spectrum of chief complaints observed is described.

RESULTS

There were 1,492 total patients out of 4,638,099 total attendees at 405 separate concerts. The median patient load per concert was 2.1 PPTT, ranging from 0 PPTT at 53 concerts to 71 PPTT at a punk rock festival that turned into a riot. Patient load varied significantly by music category (p = 0.0001) but not with overall attendance, temperature, or indoor vs outdoor location. Median PPTT by music category ranged from 1.3 PPTT for rhythm and blues to 12.6 PPTT for gospel/Christian, with negative binomial regression indicating that rock concerts had 2.5 times (95% CI = 2.0 to 3.0) the overall patient load of non-rock concerts. Music type, however, was able to account for only 4% of the variability observed in the regression model. Trauma-related complaints predominated overall, with similar rates at rock and non-rock concerts. Four cardiac arrests occurred at classical concerts.

CONCLUSION

Rock concert first-aid stations evaluated 2.5 times the patient load of non-rock concerts overall, although there was substantial concert-to-concert variability. Trauma-related complaints predominate at both rock and non-rock events. These data may assist individuals and organizations planning support for such events.