Increased voluntary drive is associated with changes in common oscillations from 13 to 60 Hz of interference but not rectified electromyography

The purpose of this study was to compare the capability of interference and rectified electromyography (EMG) to detect changes in the beta (13–30‐HZ ) and Piper (30–60‐HZ ) bands when voluntary force is increased. Twenty adults exerted a constant force abduction of the index finger at 15% and 50% of maximum. The common oscillations at various frequency bands (0–500 HZ ) were estimated from the first dorsal interosseous muscle using cross wavelets of interference and rectified EMG. For the interference EMG signals, normalized power significantly (P < 0.01) increased with force in the beta (9.0 ± 0.9 vs. 15.5 ± 2.1%) and Piper (13.6 ± 0.9 vs. 21 ± 1.7%) bands. For rectified EMG signals, however, the beta and Piper bands remained unchanged (P > 0.4). Although rectified EMG is used in many clinical studies to identify changes in the oscillatory drive to the muscle, our findings suggest that only interference EMG can accurately capture the increase in oscillatory drive from 13 to 60 HZ with voluntary force. Muscle Nerve, 2010     

Pathogenicity of the enterococcus in surgical infections.

The enterococcus has been relegated to a position of unimportance in the pathogenesis of surgical infections. However the increasing prevalence and virulence of these bacteria prompt reconsideration of this view, particularly because the surgical patient has become increasingly vulnerable to infectious morbidity due to debility, immunosuppression, and therapy with increasingly potent antibiotics. The enterococcus is a versatile opportunistic nosocomial pathogen, causing such diverse infections as wound, intra-abdominal, and urinary tract infections; catheter-associated infection; suppurative thrombophlebitis; endocarditis; and pneumonia. Although surgical drainage remains the cornerstone of therapy for enterococcal infections involving a discrete focus, in the circumstances typified by the compromised surgical patient, specific antibacterial therapy directed against the enterococcus is warranted. Recent evidence indicates that parenteral antibiotic therapy for enterococcal bacteremia is mandatory and that appropriate therapy clearly reduces the number of deaths.     

Selective interactions of cytochromes P-450 with the hydroxymethyl derivatives of 7, 12-dimethylbenz[a]anthracene

Competition between a hydroxylated metabolite and the parentpolycyclic aromatic hydrocarbon (PAH) for metabolism at cytochromesP-450 may result in the generation of hydroxylated dihydrodiolepoxides. The effectiveness of the competition between 7-hydroxymethyI-12-methylbenz[a]-anthracene(7HOMMBA) or 12-hydroxymethyl-1–7-methyl-benz[a]anthracene(12HOMMBA) and 7, 12-dimethylbenz[a]-anthracene (DMBA) is highlydependent on the form(s) of cytochrome P-450 in the microsomes.The inhibitory effects of exogenously added 7HOMMBA or 12HOMMBAon DMBA metabolism were 30- to 50-fold greater in 3-methyl-cholanthrene(MC-induced rat liver microsomes (K_i = 0.4 µM) comparedto either uninduced or phenobarbital (PB-induced liver microsomes(K_i = 14 and 11 µM, respectively). Similarly, productinhibition of total DMBA metabolism by metabolites generatedin situ was significant only in MC-induced liver microsomes(K'_i = 2.5 µM). Metabolism of 7HOMMBA in these microsomeswas strongly restricted by an unusual substrate inhibition derivedfrom the inhibitory binding of a second molecule of 7HOMMBA.This same phenomenon was observed with reconstituted cytochromeP-450c but not with PB-induced or uninduced microsomes. Complexformation by binding of DMBA, 7HOMMBA, and 12HOMMBA to purifiedP-450c reconstituted in phospholipid micelles was determinedby optical spectroscopy and fluorescence quenching. Bindingaffinities of both the 7HOMMBA and 12HOMMBA (K_d = 95 and 110nM, respectively), were 2.5-fold higher compared to that ofDMBA (K_d = 265 nM). These results provide a first demonstrationthat hydroxylation of a PAH can lead to preferential metabolismthrough an increased affinity for cytochrome P-450.     

Metabolic N-hydroxylation of substituted acetophenone imines. I. Evidence for formation of isomeric oximes

A series of chemically stable substituted acetophenone imines and their potential N-hydroxylated metabolites (i.e., oximes) have been synthesized and characterized by spectroscopic methods. The enzymic N-hydroxylation of acetophenone imines in vitro has been demonstrated as a general metabolic pathway in several mammalian species including the guinea-pig. The oxime metabolites were formed as mixtures of two geometric isomers, Z (syn-phenyl) and E (anti-phenyl), wherein the phenyl and hydroxyl group are cis and trans to each other respectively. The E (anti-phenyl) isomer was the quantitatively predominant isomeric form metabolically produced by all species studied. The relative proportions of the E and Z isomers in metabolic mixtures were found to be species dependent.     

Operative vs percutaneous drainage of intra-abdominal abscesses. Comparison of morbidity and mortality

This retrospective case-controlled study compares the morbidity and mortality of 27 percutaneously drained (PD) abscesses with 27 that were surgically drained (SD). Patients were matched for age, sex, diagnosis, and abscess etiology and location. There was no difference in severity of illness (acute physiology score [APS] = 8.3 vs 10.2), comparable morbidity (29.6% vs 40.7%), or mortality (11.0% vs 7.4%) between PD and SD groups. Duration of drainage was significantly longer in the PD group; however, this is explained in part by the 48% vs 18.5% difference in associated fistulae. Failures of the SD group had a higher mean APS (15) than both failures of the PD group (APS = 9.3) and successes of the SD group (APS = 8.6). All three PD group deaths and half of the SD group deaths were related to ongoing sepsis. Surgical drainage of intra-abdominal abscess is as successful as PD. Percutaneous drainage is reasonable initial treatment for intra-abdominal abscess; however, early assessment of clinical status and frequent reassessment are mandatory to ensure that failures are dealth with early. We present a drainage algorithm.     

Lung injury and bronchopulmonary dysplasia in newborn infants

Bronchopulmonary dysplasia is the most common morbidity among surviving premature infants. Injury to the developing lung is the result of the interaction between a susceptible host and a number of contributing factors such as mechanical ventilation and infection. The resulting persistent impairment of pulmonary function and need for ongoing therapy are the underlying characteristics of bronchopulmonary dysplasia. Important insights into the pathogenesis of bronchopulmonary dysplasia have led to numerous therapies and preventive approaches. Although significant progress has been made, in order to further affect the incidence and severity of the disease, we need to further study (a) the genetically determined predisposing factors, (b) the relative contribution of the various pathogenetic pathways, and, most important, (c) how to best translate the knowledge gained from these studies into effective clinical approaches.     

Reactive Oxygen Metabolites (ROMs) as an Index of Oxidative Stress in Obstructive Sleep Apnea Patients

Study Objectives: Obstructive sleep apnea syndrome (OSA) is accompanied by oxygen desaturation and arousal from sleep. Free oxygen radicals are highly reactive molecules which could be produced by the OSA phenomenon of hypoxia/reoxygenation: cyclical alterations of arterial oxygen saturation with oxygen desaturation developing in response to apneas followed by resumption of oxygen saturation during hyperventilation. On the basis of these considerations, it was hypothesized that OSA may be linked to increased oxidative stress. Materials and methods: Twenty-six participants gave an interview during which a physician asked them about their age, smoking habits, and symptoms such as excessive daytime sleepiness and snoring. Physical examination and polysomnography were performed during their hospitalization. Reactive oxygen metabolites (ROMs) were measured in blood samples by the diacron reactive oxygen metabolites (D-ROM) test. Results: Twenty-one out of 26 subjects had an apnea/hypopnea index greater than 5 (OSA group). The measurement of free radicals was high in OSA patients. Furthermore, ROMs values in OSA patients were linearly correlated with the apnea/hypopnea index (R = 0.426; p = 0.042). The predictive value of a positive D-ROM test is 81%. Conclusions: ROMs were elevated in patients with OSA. When OSA was severe, similarly the value of ROMs in blood samples was enhanced, and the probable underlying mechanism for these events is the hypoxia/reoxygenation phenomenon.     

Predicting septic related mortality of the individual surgical patient based on admission host-defence measurements

In order to assign a numerical probability of septic related death for a given patient, the following data were recorded for 461 patients on admission to the Royal Victoria Hospital in Montreal for major surgical treatment: age; delayed-type hypersensitivity (DTH) skin-test score; total serum protein level; serum albumin level; circulating hemoglobin level; neutrophil adherence; polymorphonuclear chemotaxis; and sex. Logistic regression was used to generate a predictive equation of the form: (formula; see text) (where P is the probability of death and exp is the exponential function) that could be used to calculate the actual probability of septic related death for an individual patient. The predictive accuracy of this equation was tested on a separate, prospectively collected data base of 625 surgical patients. There was an excellent fit of the model. There were 68 septic related deaths where 67.2 were predicted. It is now possible to calculate precisely the probability of a septic related death of a given surgical patient upon admission to the hospital. This should prove useful in clinical decision-making.