bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative Architecture of the Brachial Plexus and Surrounding Compartments, and Their Possible Significance for Plexus Blocks
Authors: Moayeri Nizar , Bigeleisen Paul E. , Groen Gerbrand J.
Published: March 2009

Background

Nerve injury after regional anesthesia of the brachial plexus (BP) is a relatively rare and feared complication that is partly attributed to intraneural injection. However, recent studies have shown that intraneural injection does not invariably cause neural injury, which may be related to the architecture within the epineurium. A quantitative study of the neural components and the compartment outside BP was made.

Methods

From four frozen shoulders, high-resolution images of sagittal cross-sections with an interval of 0.078 mm were obtained using a cryomicrotome to maintain a relatively undisturbed anatomy. From this data set, cross-sections perpendicular to the axis of the BP were reconstructed in the interscalene, supraclavicular, midinfraclavicular, and subcoracoid regions. Surface areas of both intraepineurial and connective tissue compartments outside the BP were delineated and measured.

Results

The nonneural tissue (stroma and connective tissue) inside and outside the BP increased from proximal to distal, being significant between interscalene/supraclavicular and midinfraclavicular/subcoracoid regions (P < 0.001 for tissue inside BP, P < 0.02 for tissue outside BP). The median amount of neural tissue remained approximately the same in the four measured regions (41.1 +/- 6.3 mm; range, 30-60 mm). The ratio of neural to nonneural tissue inside the epineurium increased from 1:1 in the interscalene/supraclavicular to 1:2 in the midinfraclavicular/subcoracoid regions.

Conclusion

Marked differences in neural architecture and size of surrounding adipose tissue compartments are demonstrated between proximal and distal parts of the brachial plexus. These differences may explain why some injections within the epineurium do not result in neural injury and affect onset times of BP blocks.
Propofol Restores Brain Microvascular Function Impaired by High Glucose via the Decrease in Oxidative Stress
Authors: Nakahata Katsutoshi , Kinoshita Hiroyuki , Azma Toshiharu , Matsuda Naoyuki , Hama-Tomioka Keiko , Haba Masanori , Hatano Yoshio
Published: March 2009

Background

Vascular dysfunction induced by hyperglycemia has not been studied in cerebral parenchymal circulation. The current study was designed to examine whether high glucose impairs dilation of cerebral parenchymal arterioles via nitric oxide synthase, and whether propofol recovers this vasodilation by reducing superoxide levels in the brain.

Methods

Cerebral parenchymal arterioles in the rat brain slices were monitored using computer-assisted videomicroscopy. Vasodilation induced by acetylcholine (10 to 10 m) was obtained after the incubation of brain slices for 60 min with any addition of l-glucose (20 mm), d-glucose (20 mm), or propofol (3 x 10 or 10 m) in combination with d-glucose (20 mm). Superoxide production in the brain slice was determined by dihydroethidium (2 x 10 m) fluorescence.

Results

Addition of d-glucose, but not l-glucose, reduced arteriolar dilation by acetylcholine, whereas the dilation was abolished by the neuronal nitric oxide synthase inhibitor S-methyl-l-thiocitrulline (10 m). Both propofol and the superoxide dismutase mimetic Tempol (10 m) restored the arteriolar dilation in response to acetylcholine in the brain slice treated with d-glucose. Addition of d-glucose increased superoxide production in the brain slice, whereas propofol, Tempol, and the nicotinamide adenine dinucleotide phosphate (NAD[P]H) oxidase inhibitor apocynin (1 mm) similarly inhibited it.

Conclusions

Clinically relevant concentrations of propofol ameliorate neuronal nitric oxide synthase-dependent dilation impaired by high glucose in the cerebral parenchymal arterioles via the effect on superoxide levels. Propofol may be protective against cerebral microvascular malfunction resulting from oxidative stress by acute hyperglycemia.
Protein Requirements of Very Low Birth Weight Infants
Authors: Ziegler Ekhard E
Published: March 2009

Objective:

To review existing information regarding protein (and energy) requirements of very low birth weight infants, and to determine whether revisions may be indicated in view of the commonly observed postnatal growth failure, or in view of adverse consequences of accelerated growth.

Results:

Nutrient requirements of very low birth weight infants have been estimated by the factorial method and by empirical methods. These approaches yield similar estimates of nutrient requirements. The factorial method provides estimates of requirements for protein and energy, including those of extremely small infants. Empirical methods yield estimates of protein requirements but tend to exclude extremely small infants. They also provide estimates of protein intakes that lead to catch‐up growth. Reports of actual nutrient intakes received by very low birth weight infants show that intakes are generally less than estimated requirements.

Conclusions:

Growth failure is adequately explained by insufficient nutrient intakes. Upward revision of requirements is not indicated until it can be shown that growth failure occurs despite intakes that match current estimates of requirements. Downward revision also is not indicated because accelerated growth, in spite of some adverse effects later in life, is associated with improved neurocognitive outcome.
Mutation Analysis of Endothelin‐B Receptor Gene in Patients With Hirschsprung Disease in Taiwan
Authors: Lin Yu‐Cheng , Lai Hong‐Shiee , Hsu Wen‐Ming , Lee Ping‐Ing , Chen Huey‐Ling , Chang Mei‐Hwei
Published: March 2009

Background:

Endothelin‐B receptor (EDNRB) signaling pathway is associated for Hirschsprung disease (HSCR). The aim of this study was to investigate the EDNRB gene mutation in patients with HSCR in Taiwan and correlate the genotype and phenotype.

Patients and Methods:

Using polymerase chain reaction amplification and direct sequencing, we screened for mutations in the coding regions and intron/exon boundaries of the EDNRB gene in 39 isolated HSCR cases and compared them with those in 400 control chromosomes.

Results:

In 3 cases, heterozygous variations in exon 1 and 2 of the EDNRB gene predicted missense mutations of the first cytosolic (M132I), second transmembrane (I157V), second exoplasmic (M173T), and third transmembrane (V185M) domains of the EDNRB protein. Three of the 4 mutations in our study have not been reported previously. For total 39 unrelated cases, the mutation rates were estimated to be 10% (3 of 30) for short‐segment HSCR and 7.7% (3 of 39) for all HSCR cases.

Conclusions:

We did not detect a significant genotype–phenotype correlation. In conclusion, this study identified 4 mutations within the EDNRB gene associated with HSCR. Because HSCR is a multifactorial and multigene disorder, the higher mutation rate of 10% for short‐segment HSCR suggests the important role that the EDNRB gene plays in the pathogenesis of short‐segment HSCR in Taiwan.
Magnitude of the Second Gas Effect on Arterial Sevoflurane Partial Pressure
Authors: Peyton Philip J. , Horriat Maryam , Robinson Gavin J. B. , Pierce Robert , Thompson Bruce R.
Published: March 2009

Background

A number of studies have demonstrated a faster rate of increase in end-expired partial pressure as a fraction of inspired (Pa/Pi) for volatile agents in the presence of high concentrations of nitrous oxide, consistent with the second gas effect. However, no study has demonstrated a similar effect on arterial blood concentrations.

Methods

The authors compared arterial and end-tidal partial pressures of sevoflurane (Pa/Pisevo and Pa/Pisevo) in 14 patients for 30 min after introduction of either 70% nitrous oxide or nitrous oxide-free gas mixtures to determine the magnitude of the second gas effect. Blood partial pressures were measured using a double headspace equilibration technique.

Results

Both Pa/Pisevo and Pa/Pisevo were significantly higher in the nitrous oxide group than in the control group (P < 0.001 on two-way analysis of variance). This difference was significantly greater (P < 0.05) for Pa/Pisevo (23.6% higher in the nitrous oxide group at 2 min, declining to 12.5% at 30 min) than for Pa/Pisevo (9.8% higher in the nitrous oxide group at 2 min) and was accompanied by a significantly lower Bispectral Index score at 5 min (40.7 vs. 25.4; P = 0.004).

Conclusion

Nitrous oxide uptake exerts a significant second gas effect on arterial sevoflurane partial pressures. This effect is two to three times more powerful than the effect on end-expired partial pressures. The authors explain how this is due to the influence of ventilation-perfusion scatter on the distribution of blood flow and gas uptake in the lung.
Young Age as a Risk Factor for Impaired Cerebral Autoregulation after Moderate to Severe Pediatric Traumatic Brain Injury
Authors: Freeman Serena S. , Udomphorn Yuthana , Armstead William M. , Fisk Dana M. , Vavilala Monica S.
Published: March 2009

Background

Little is known about age and cerebral autoregulation in children with traumatic brain injury (TBI). The authors compared cerebral autoregulation between young (aged <4 yr) and older (aged > or =4 yr) children with TBI.

Methods

After University of Washington's institutional review board approval, a retrospective analysis of prospectively collected data (May 2002 and June 2007) was performed. Eligibility criteria included age 16 yr or younger, moderate to severe (admission Glasgow Coma Scale score <13) TBI, TBI on computed tomography scan, and tracheal intubation. Cerebral autoregulation testing was performed within 72 h after TBI, and autoregulation was quantified using the autoregulatory index. An autoregulatory index less than 0.4 represents impaired cerebral autoregulation. The 12-month Glasgow outcome score was measured. Data are presented as mean +/- SD or range.

Results

Thirty-seven children (8.9 +/- 5.1 yr; 0.8-16 yr) were enrolled. Children younger than 4 yr had a higher incidence of impaired cerebral autoregulation (8 of 10 vs. 7 of 27; P = 0.006) and worse 12-month outcome (Glasgow outcome score 3.0 +/- 1.0 vs. 4.0 +/- 1.0; P = 0.02) than older children. Age less than 4 yr (adjusted odds ratio, 12.2; 95% confidence interval, 1.5-98.5) and low Glasgow Coma Scale score (adjusted odds ratio for higher Glasgow Coma Scale, 0.53; 95% confidence interval, 0.30-0.96) were independently associated with impaired cerebral autoregulation.

Conclusions

Age less than 4 yr was a risk factor for impaired cerebral autoregulation, independent of TBI severity. Age-related factors may play a role in the mechanisms maintaining or worsening cerebral autoregulation in children after TBI.
Ambulatory Continuous Femoral Nerve Blocks Decrease Time to Discharge Readiness after Tricompartment Total Knee Arthroplasty
Authors: Ilfeld Brian M. , Le Linda T. , Meyer R Scott , Mariano Edward R. , Vandenborne Krista , Duncan Pamela W. , Sessler Daniel I. , Enneking F Kayser , Shuster Jonathan J. , Theriaque Douglas W. , Berry Linda F. , Spadoni Eugene H. , Gearen Peter F.
Published: March 2009

Background

The authors tested the hypotheses that, compared with an overnight continuous femoral nerve block (cFNB), a 4-day ambulatory cFNB increases ambulation distance and decreases the time until three specific readiness-for-discharge criteria are met after tricompartment total knee arthroplasty.

Methods

Preoperatively, all patients received a cFNB (n = 50) and perineural ropivacaine 0.2% from surgery until the following morning, at which time they were randomly assigned to either continue perineural ropivacaine or switch to perineural normal saline. Primary endpoints included (1) time to attain three discharge criteria (adequate analgesia, independence from intravenous analgesics, and ambulation of at least 30 m) and (2) ambulatory distance in 6 min the afternoon after surgery. Patients were discharged with their cFNB and a portable infusion pump, and catheters were removed on postoperative day 4.

Results

Patients given 4 days of perineural ropivacaine attained all three discharge criteria in a median (25th-75th percentiles) of 25 (21-47) h, compared with 71 (46-89) h for those of the control group (estimated ratio, 0.47; 95% confidence interval, 0.32-0.67; P <0.001). Patients assigned to receive ropivacaine ambulated a median of 32 (17-47) m the afternoon after surgery, compared with 26 (13-35) m for those receiving normal saline (estimated ratio, 1.21; 95% confidence interval, 0.71-1.85; P = 0.42).

Conclusions

Compared with an overnight cFNB, a 4-day ambulatory cFNB decreases the time to reach three important discharge criteria by an estimated 53% after tricompartment total knee arthroplasty. However, the extended infusion did not increase ambulation distance the afternoon after surgery. (ClinicalTrials.gov No. NCT00135889.).
Success of Tracheal Intubation with Intubating Laryngeal Mask Airways
Authors: Liu Eugene H. , Goy Raymond W. , Lim Yvonne , Chen Fun-Gee
Published: March 2009

Background

The LMA CTrach system (The Laryngeal Mask Company, Singapore) is a development of the LMA Fastrach system (The Laryngeal Mask Company, Singapore), with integrated fiberoptic bundles and a detachable liquid crystal display viewer. This randomized study of 271 patients compared tracheal intubation with these two systems.

Methods

In both groups, ventilation was optimized after insertion of the laryngeal mask conduit before proceeding further: intubation with the LMA Fastrach, and optimizing the conduit placement and view and then intubation with the LMA CTrach. The first-attempt and overall success rates of tracheal intubation, and the times required, were recorded.

Results

Tracheal intubation was successful on the first attempt in 93.3% of patients with the LMA CTrach and 67.9% of patients with the LMA Fastrach (P < 0.001). The success rates within three attempts were 100% with the LMA CTrach and 96.4% with the LMA Fastrach (P = 0.06). The median (interquartile range) time for the complete tracheal intubation process was 116 (82-156) s with the LMA CTrachand 100 (74-121) s with the LMA Fastrach (P = 0.002). There was no correlation between the grade of conventional laryngoscopy and success of intubation with either system.

Conclusions

The ability to view the glottis and optimize placement of the LMA CTrach under vision enabled a higher first-attempt success rate of tracheal intubation with the LMA CTrach. However, more time is required with the LMA CTrach, there are failed views in some patients, and its cost effectiveness remains unclear.
Remifentanil Inhibits Rapid Eye Movement Sleep but Not the Nocturnal Melatonin Surge in Humans
Authors: Bonafide Christopher P. , Aucutt-Walter Natalie , Divittore Nicole , King Tonya , Bixler Edward O. , Cronin Arthur J.
Published: March 2009

Background

Postoperative patients are sleep deprived. Opioids, commonly administered for postoperative pain control, are often mistakenly considered inducers of naturally occurring sleep. This study describes the effect of the opioid remifentanil on nocturnal sleep in healthy volunteers. In addition, this study tests the hypothesis that opioid-induced sleep disturbance is caused by a circadian pacemaker disturbance, reflected by suppressed nocturnal plasma concentration of melatonin.

Methods

Polysomnography was performed in 10 volunteers from 11:00 pm to 7:00 am for four nights at 6-day intervals. On two nights, remifentanil (0.01-0.04 microg x kg x min) was infused from 10:30 pm to 7:00 am, and either a placebo capsule or 3.0 mg melatonin was administered at 10:30 pm. On two additional nights, saline was infused, and the placebo or melatonin capsules were administered at 10:30 pm. Blood was drawn at 12:00 am, 3:00 am, and 6:00 am to measure the plasma concentration of melatonin and cortisol. A repeated-measures analysis of variance model was used to determine the effect of remifentanil on sleep stages, the effect of remifentanil on the plasma concentration of melatonin, and the effect of exogenous melatonin on remifentanil-induced sleep disturbance.

Results

Remifentanil inhibited rapid eye movement sleep (14.1 +/- 7.2% to 3.9 +/- 6.9%). The amount of slow wave sleep decreased from 6.8 +/- 7.6% to 3.2 +/- 6.1%, but this decrease was not statistically significant. Remifentanil did not decrease melatonin concentration. Melatonin administration did not prevent remifentanil-induced sleep disturbance.

Conclusions

An overnight constant infusion of remifentanil inhibits rapid eye movement sleep without suppressing the nocturnal melatonin surge.
Adverse Effects of Methylene Blue on the Central Nervous System
Authors: Vutskits Laszlo , Briner Adrian , Klauser Paul , Gascon Eduardo , Dayer Alexandre G. , Kiss Jozsef Z. , Muller Dominique , Licker Marc J. , Morel Denis R.
Published: March 2009

Background

An increasing number of clinical observations suggest adverse neurologic outcome after methylene blue (MB) infusion in the setting of parathyroid surgery. Hence, the aim of the current study was to investigate the potentially neurotoxic effects of MB using a combination of in vivo and in vitro experimental approaches.

Methods

Isoflurane-anesthetized adult rats were used to evaluate the impact of a single bolus intravascular administration of MB on systemic hemodynamic responses and on the minimum alveolar concentration (MAC) of isoflurane using the tail clamp test. In vivo, MB-induced cell death was evaluated 24 h after MB administration using Fluoro-Jade B staining and activated caspase-3 immunohistochemistry. In vitro, neurotoxic effects of MB were examined in hippocampal slice cultures by measuring excitatory field potentials as well as propidium iodide incorporation after MB exposure. The impact of MB on dendritic arbor was evaluated in differentiated single cell neuronal cultures.

Results

Bolus injections of MB significantly reduced isoflurane MAC and initiated widespread neuronal apoptosis. Electrophysiologic recordings in hippocampal slices revealed a rapid suppression of evoked excitatory field potentials by MB, and this was associated with a dose-dependent effect of this drug on cell death. Dose-response experiments in single cell neuronal cultures revealed that a 2-h-long exposure to MB at non-cell-death-inducing concentrations could still induce significant retraction of dendritic arbor.

Conclusions

These results suggest that MB exerts neurotoxic effects on the central nervous system and raise questions regarding the safety of using this drug at high doses during parathyroid gland surgery.
Perioperative Use of Dobutamine in Cardiac Surgery and Adverse Cardiac Outcome
Authors: Fellahi Jean-Luc , Parienti Jean-Jacques , Hanouz Jean-Luc , Plaud Benoît , Riou Bruno , Ouattara Alexandre
Published: March 2009

Background

Catecholamines, mainly dobutamine, are often administered without institutional guidelines or prespecified algorithms in cardiac surgery. The current study assessed the consequences on clinical outcome of catecholamines simply based on the clinical judgment of the anesthesiologists after cardiopulmonary bypass in adult cardiac surgery.

Methods

Consecutive patients were enrolled in a nonrandomized cohort study. Factors associated with perioperative use of catecholamines and with outcomes were recorded prospectively to conduct bias adjustment, including propensity scores. Major cardiac morbidity (i.e., ventricular arrhythmia, use of an intraaortic balloon pump and postoperative myocardial infarction) and all-cause intrahospital mortality were the primary and secondary endpoints, respectively. Results are expressed as odds ratio (OR) [95% confidence interval].

Results

During the study, 84 of 657 patients (13%) received catecholamines, most often dobutamine (76 of 84, 90%). A higher incidence of both major cardiac morbidity (30 vs. 9%; P < 0.001; OR, 4.2 [2.5-7.3]) and all-cause intrahospital mortality (8 vs. 1%; P < 0.001; OR, 12.9 [3.7-45.2]) was observed in the catecholamine group compared with the control group. After adjusting for channeling bias and confounding factors, catecholamine administration remained significantly associated with major cardiac morbidity after propensity score stratification (OR, 2.1 [1.0-4.4]; P < 0.05), propensity score covariance analysis (OR, 2.3 [1.0-5.0]; P < 0.05), marginal structural models (OR, 1.8 [1.3-2.5]; P < 0.001), and propensity score matching (OR, 3.0 [1.2-7.3]; P < 0.02), but not with all-cause intrahospital mortality.

Conclusions

These results suggest that dobutamine should only be administered when the benefit is judged to outweigh the risks.
Cardiac Surgery Fast-track Treatment in a Postanesthetic Care Unit
Authors: Ender Joerg , Borger Michael Andrew , Scholz Markus , Funkat Anne-Kathrin , Anwar Nadeem , Sommer Marcus , Mohr Friedrich Wilhelm , Fassl Jens
Published: March 2009

Background

The authors compared the safety and efficacy of a newly developed fast-track concept at their center, including implementation of a direct admission postanesthetic care unit, to standard perioperative management.

Methods

All fast-track patients treated within the first 6 months of implementation of our direct admission postanesthetic care unit were matched via propensity scores and compared with a historical control group of patients who underwent cardiac surgery prior to fast-track implementation.

Results

A total of 421 fast-track patients were matched successfully to 421 control patients. The two groups of patients had a similar age (64 +/- 13 vs. 64 +/- 12 yr for fast-track vs. control, P = 0.45) and European System for Cardiac Operative Risk Evaluation-predicted risk of mortality (4.8 +/- 6.1% vs. 4.6 +/- 5.1%, P = 0.97). Fast-track patients had significantly shorter times to extubation (75 min [45-110] vs. 900 min [600-1140]), as well as shorter lengths of stay in the postanesthetic or intensive care unit (4 h [3.0-5] vs. 20 h [16-25]), intermediate care unit (21 h [17-39] vs. 26 h [19-49]), and hospital (10 days [8-12] vs. 11 days [9-14]) (expressed as median and interquartile range, all P < 0.01). Fast-track patients also had a lower risk of postoperative low cardiac output syndrome (0.5% vs. 2.9%, P < 0.05) and mortality (0.5% vs. 3.3%, P < 0.01).

Conclusion

The Leipzig fast-track protocol is a safe and effective method to manage cardiac surgery patients after a variety of operations.
Lack of Analgesia by Oral Standardized Cannabis Extract on Acute Inflammatory Pain and Hyperalgesia in Volunteers
Authors: Kraft Birgit , Frickey Nathalie A. , Kaufmann Rainer M. , Reif Marcus , Frey Richard , Gustorff Burkhard , Kress Hans G.
Published: March 2009

Background

Cannabinoid-induced analgesia was shown in animal studies of acute inflammatory and neuropathic pain. In humans, controlled clinical trials with Delta-tetrahydrocannabinol or other cannabinoids demonstrated analgesic efficacy in chronic pain syndromes, whereas the data in acute pain were less conclusive. Therefore, the aim of this study was to investigate the effects of oral cannabis extract in two different human models of acute inflammatory pain and hyperalgesia.

Methods

The authors conducted a double-blind, crossover study in 18 healthy female volunteers. Capsules containing Delta-tetrahydrocannabinol-standardized cannabis extract or active placebo were orally administered. A circular sunburn spot was induced at one upper leg. Heat and electrical pain thresholds were determined at the erythema, the area of secondary hyperalgesia, and the contralateral leg. Intradermal capsaicin-evoked pain and areas of flare and secondary hyperalgesia were measured. Primary outcome parameters were heat pain thresholds in the sunburn erythema and the capsaicin-evoked area of secondary hyperalgesia. Secondary measures were electrical pain thresholds, sunburn-induced secondary hyperalgesia, and capsaicin-induced pain.

Results

Cannabis extract did not affect heat pain thresholds in the sunburn model. Electrical thresholds (250 Hz) were significantly lower compared with baseline and placebo. In the capsaicin model, the area of secondary hyperalgesia, flare, and spontaneous pain were not altered.

Conclusion

To conclude, no analgesic or antihyperalgesic activity of cannabis extract was found in the experiments. Moreover, the results even point to the development of a hyperalgesic state under cannabinoids. Together with previous data, the current results suggest that cannabinoids are not effective analgesics for the treatment of acute nociceptive pain in humans.
Influence of Methylenetetrahydrofolate Reductase Gene Polymorphisms on Homocysteine Concentrations after Nitrous Oxide Anesthesia
Authors: Nagele Peter , Zeugswetter Barbara , Wiener Caspar , Burger Hansjörg , Hüpfl Michael , Mittlböck Martina , Födinger Manuela
Published: March 2009

Background

Mutations in the methylenetetrahydrofolate reductase (MTHFR) gene (677C>T, 1298A>C) cause elevated plasma homocysteine concentrations and have been linked to fatal outcomes after nitrous oxide anesthesia. This study tested the hypothesis that patients with common MTHFR 677C>T or 1298A>C mutations develop higher plasma homocysteine concentrations after nitrous oxide anesthesia than wild-type patients.

Methods

In this prospective, observational cohort study with blinded, mendelian randomization, the authors included 140 healthy patients undergoing elective surgery. All patients received 66% nitrous oxide for at least 2 h. The main outcome variable, plasma total homocysteine, and folate, vitamin B12, and holotranscobalamin II were measured before, during, and after surgery. After completion of the study, all patients were tested for their MTHFR 677C>T or 1298A>C genotype.

Results

Patients with a homozygous MTHFR 677C>T or 1298A>C mutation (n = 25) developed higher plasma homocysteine concentrations (median [interquartile range], 14.9 [10.0-26.4] microm) than wild-type or heterozygous patients (9.3 [7.5-15.5] microm; n = 115). The change in homocysteine after nitrous oxide anesthesia was tripled in homozygous patients compared with wild-type (5.6 microm [+60%] vs. 1.8 microm [+22%]). Only homozygous patients reached average homocysteine levels considered abnormal (> 15 microm). Plasma 5-methyl-tetrahydrofolate concentrations increased uniformly by 20% after nitrous oxide anesthesia, indicating the inactivation of methionine synthase and subsequent folate trapping. Holotranscobalamin II concentrations remained unchanged, indicating no effect of nitrous oxide on vitamin B12 plasma concentrations.

Conclusions

This study shows that patients with a homozygous MTHFR 677C>T or 1298A>C mutation are at a higher risk of developing abnormal plasma homocysteine concentrations after nitrous oxide anesthesia.
Differential Role of Calcium/Calmodulin-dependent Protein Kinase II in Desflurane-induced Preconditioning and Cardioprotection by Metoprolol
Authors: Lange Markus , Smul Thorsten M. , Redel Andreas , Lotz Christopher , Jazbutyte Virginija , Schnupp Verena , Roewer Norbert , Kehl Franz
Published: March 2009

Background

Anesthetic preconditioning is mediated by beta- adrenergic signaling. This study tested the hypotheses that desflurane-induced preconditioning is dose-dependently blocked by metoprolol and mediated by calcium/calmodulin-dependent protein kinase II (CaMK II).

Methods

Pentobarbital-anesthetized New Zealand White rabbits were instrumented for measurement of systemic hemodynamics and subjected to 30 min of coronary artery occlusion followed by 3 h of reperfusion. Rabbits were assigned to receive vehicle (control), 0.2, 1.0, 1.75, or 2.5 mg/kg metoprolol for 30 min, or the CaMK II inhibitor KN-93 in the absence or presence of 1.0 minimum alveolar concentration desflurane. Protein expression of CaMK II, phospholamban, and phospho-phospholamban was measured by Western blotting. Myocardial infarct size and area at risk were measured with triphenyltetrazolium staining and patent blue, respectively.

Results

Baseline hemodynamics were not different among groups. Infarct size was 60 +/- 3% in control and significantly (* P < 0.05) decreased to 33 +/- 2%* by desflurane. The CaMK II inhibitor KN-93 did not affect infarct size (55 +/- 4%) but blocked desflurane-induced preconditioning (57 +/- 3%). Metoprolol at 0.2 and 1.0 mg/kg had no effect on infarct size (55 +/- 3% and 53 +/-3%), whereas metoprolol at 1.75 and 2.5 mg/kg reduced infarct size to 48 +/- 4%* and 39 +/- 5%*, respectively. Desflurane-induced preconditioning was attenuated by metoprolol at 0.2 mg/kg, leading to an infarct size of 46 +/- 5%*, and was completely abolished by metoprolol at 1.0, 1.75, and 2.5 mg/kg, resulting in infarct sizes of 51 +/- 3%, 52 +/- 3%, and 55 +/- 3%, respectively.

Conclusions

Desflurane-induced preconditioning is dose-dependently blocked by metoprolol and mediated by CaMK II.
Morphine versus Mexiletine for Treatment of Postamputation Pain
Authors: Wu Christopher L. , Agarwal Shefali , Tella Prabhav K. , Klick Brendan , Clark Michael R. , Haythornthwaite Jennifer A. , Max Mitchell B. , Raja Srinivasa N.
Published: March 2009

Background

Stump and phantom pains are debilitating sequelae of amputations that are often resistant to treatment. The efficacy of pharmacologic therapies, including opioids and sodium channel blockers, for postamputation pain is uncertain.

Methods

The authors conducted a double-blind, randomized, placebo-controlled, crossover study in adult patients with postamputation pain of 6 months or longer and greater than 3 on a 0-10 numeric pain rating scale. Each of the three treatment periods (morphine, mexiletine, or placebo) included a 1-week drug-free interval followed by 4-week titration, 2-week maintenance, and 2-week drug-taper phases. The primary outcome measure was change in average pain intensity from the drug-free baseline to the last week of maintenance.

Results

Sixty amputees were enrolled; data were analyzed from 56 subjects for one drug period, 45 subjects for two drug periods, and 35 subjects who completed all three drug periods. The mean morphine and mexiletine dosages were 112 and 933 mg, respectively. Morphine treatment provided lower pain scores compared with placebo and mexiletine (P = 0.0003). The mean percent pain relief during treatment with placebo, mexiletine, and morphine was 19, 30, and 53%, respectively (P < 0.0001, morphine vs. placebo and mexiletine). The numbers needed to treat to obtain 50% and 33% decreases in pain intensity with morphine were 5.6 and 4.5, respectively. Treatment with morphine was associated with a higher rate of side effects.

Conclusions

Therapy with morphine, but not mexiletine, resulted in a decrease in intensity of postamputation pain but was associated with a higher rate of side effects and no improvement in self-reported levels of overall functional activity and pain-related interference in daily activities.
Experimental Forearm Immobilization in Humans Induces Cold and Mechanical Hyperalgesia
Authors: Terkelsen Astrid J. , Bach Flemming W. , Jensen Troels S.
Published: March 2009

Background

Complex regional pain syndrome is a painful condition of unknown etiology. Clinical and experimental observations suggest that limb immobilization may induce symptoms and signs characteristic of complex regional pain syndrome. This study examined the effect of forearm immobilization on regional sensory and autonomic functions in healthy subjects.

Methods

Thermal and mechanical sensitivity, skin temperature, and vasoconstrictor responses were measured in 30 healthy subjects before and 0, 3, and 28 days after scaphoid cast immobilization. Fifteen subjects served as nonimmobilized controls.

Results

At cast removal, 27 subjects experienced pain at joint movement. Cast immobilization induced cold hyperalgesia in glabrous and hairy skin on the immobilized hand and induced significant skin temperature differences between the control and the immobilized hand at cast removal and after 3 days. Immobilization also reduced pain threshold at skin fold testing at all time points after cast removal. All measures except pain threshold at skin fold testing were normalized after 28 days. Immobilization did not affect thermal detection, heat pain, and pressure pain thresholds; resting skin perfusion; or vasoconstrictor responses induced by mental stress or deep inspirations.

Conclusions

Four weeks of forearm immobilization caused transient changes in skin temperature, mechanosensitivity, and thermosensitivity, without alteration in the sympathetically mediated vascular tone.
Neural Mechanisms of Sevoflurane-induced Respiratory Depression in Newborn Rats
Authors: Kuribayashi Junya , Sakuraba Shigeki , Kashiwagi Masanori , Hatori Eiki , Tsujita Miki , Hosokawa Yuki , Takeda Junzo , Kuwana Shun-ichi
Published: March 2009

Background

Sevoflurane-induced respiratory depression has been reported to be due to the action on medullary respiratory and phrenic motor neurons. These results were obtained from extracellular recordings of the neurons. Here, the authors made intracellular recordings of respiratory neurons and analyzed their membrane properties during sevoflurane application. Furthermore, they clarified the role of gamma-aminobutyric acid type A receptors in sevoflurane-induced respiratory depression.

Methods

In the isolated brainstem-spinal cord of newborn rat, the authors recorded the C4 nerve burst as an index of inspiratory activity. The preparation was superfused with a solution containing sevoflurane alone or sevoflurane plus the gamma-aminobutyric acid type A receptor antagonist picrotoxin or bicuculline. Neuronal activities were also recorded using patch clamp techniques.

Results

Sevoflurane decreased C4 burst rate and amplitude. Separate perfusion of sevoflurane to the medulla and to the spinal cord decreased C4 burst rate and amplitude, respectively. Both picrotoxin and bicuculline attenuated the reduction of C4 burst rate. Sevoflurane reduced both intraburst firing frequency and membrane resistance of respiratory neurons except for inspiratory neurons.

Conclusion

Under the influence of sevoflurane, the region containing inspiratory neurons, i.e., the pre-Bötzinger complex, may determine the inspiratory rhythm, because reduced C4 bursts were still synchronized with the bursts of inspiratory neurons within the pre-Bötzinger complex. In contrast, the sevoflurane-induced decrease in C4 burst amplitude is mediated through the inhibition of phrenic motor neurons. gamma-Aminobutyric acid type A receptors may be involved in the sevoflurane-induced respiratory depression within the medulla, but not within the spinal cord.
Early Packed Red Blood Cell Transfusion and Acute Respiratory Distress Syndrome after Trauma
Authors: Chaiwat Onuma , Lang John D. , Vavilala Monica S. , Wang Jin , MacKenzie Ellen J. , Jurkovich Gregory J. , Rivara Frederick P.
Published: March 2009

Background

Transfusion of packed red blood cells (PRBCs) is a risk factor for acute respiratory distress syndrome (ARDS) in trauma patients. Yet, there is a paucity of information regarding the risk of ARDS with incremental PRBCs exposure.

Methods

For this retrospective analysis, eligible patients from National Study on Costs and Outcomes of Trauma were included. Our main exposure was defined as units of PRBCs transfused during the first 24 h after admission. The main outcome was ARDS.

Results

A total of 521 (4.6%) of 14070 patients developed ARDS, and 331 patients (63.5%) who developed ARDS received PRBCs transfusion. Injury severity, thoracic injury, polytrauma, and pneumonia receiving more than 5 units of fresh frozen plasma and 6-10 units of PRBCs were independent predictors of ARDS. Patients receiving more than 5 units of PRBCs had higher risk of developing ARDS (patients who received 6-10 units: adjusted odds ratio 2.5, 95% CI 1.12-5.3; patients who received more than 10 units: odds ratio 2.6, 95% CI 1.1-6.4). Each additional unit of PRBCs transfused conferred a 6% higher risk of ARDS (adjusted odds ratio 1.06; 95% CI 1.03-1.10).

Conclusions

Early transfusion of PRBCs is an independent predictor of ARDS in adult trauma patients. Conservative transfusion strategies that decrease PRBC exposure by even 1 unit may be warranted to reduce the risk of ARDS in injured patients.
Prevalence and Characteristics of Immunomediated Neuropathies in a Group of Patients With Autoimmune Diseases
Authors: Servioli Luisa , Pérez Cristina , Consani Sandra , Suárez Alejo , Sehabiaga Gabriel , Collazo Cecilia , Catalá Gaspar
Published: March 2009

Objective:

To determine the prevalence and the clinical-neurophysiological characteristics of immunomediated peripheral neuropathies (PN) in a group of patients with systemic autoimmune diseases.

Method:

Fifty-nine patients with proved systemic autoimmune diseases were included. Patients underwent clinical examination and nerve conduction studies to diagnose the PN.

Results:

Immune PNs were detected in 18 patients (30.5%). Out of the total number of PNs (18), 39% were sensory-motor polyneuropathies, 33% mononeuritis multiplex, 11% pure sensory polyneuropathies, 11% cranial neuropathies, and 6% proximal motor neuropathies, such as the Guillain-Barré syndrome. Nine PNs (50%) appeared at the onset of the connective tissue disorders, and the rest of the cases appeared during the course of the disease. Of the total of PNs detected in this study, only 45% had a previous diagnosis. Vasculitis was the disease that presented more associated PNs. Systemic lupus erythematosus showed the widest range of PN clinical varieties.

Conclusions:

The first national prevalence rate of PNs in patients with systemic autoimmune diseases was provided: 30.5%. No comparative data were found in the international bibliography. Sensory-motor polyneuropathy was the most frequently observed form of PN, followed by mononeuritis multiplex. The NPs appeared with the same frequency both at the onset and during the course of the diseases under study; these predominated at the onset of vasculitis and primary Sjögren syndrome. The compromise of the peripheral nervous system is underdiagnosed.
Anatomical Localization of Motor Endplate Bands in the Human Biceps Brachii
Authors: Amirali Asif , Mu Liancai , Gracies Jean-Michel , Simpson David M
Published: March 2009

Objectives:

Botulinum neurotoxin (BoNT) reduces disabling muscle contraction in numerous disorders with muscle overactivity. While motor endplates are the primary site of action for BoNT, their location is unknown in most human muscles. This study localized the motor endplate bands (MEB) within human biceps brachii (BB) muscles in relation to external landmarks.

Methods:

Five human BB muscles were obtained from autopsy. Three muscles were processed for Sihler's stain, a nerve staining technique, and 2 were processed by whole-mount acetylcholinesterase stain.

Results:

The major MEB in BB is an inverted V-shaped band, 1 cm in width, located 7 cm superior to the olecranon laterally, 11 cm superior to the olecranon in the middle, and 8 cm above the olecranon medially. The ratio of MEB location to total olecranon-acromion length is 0.25 at the lateral edge, 0.39 in the midline, and 0.28 at the medial edge.

Conclusions:

This study localized MEB in human BB in reference to external landmarks. This data should improve the feasibility of endplate targeting when injecting BoNT in BB, which might enhance the clinical efficacy of these injections.
Steroid-Responsive Myopathy: Immune-Mediated Necrotizing Myopathy or Polymyositis Without Inflammation?
Authors: Sadeh Menachem , Dabby Ron
Published: March 2009

Objective:

To describe the clinical course and steroid responsiveness of a patient with subacute proximal symmetric weakness, very high serum creatine kinase activity, and myopathic pattern with fibrillations in the electromyogram, whose muscle biopsy showed necrotizing myopathy, with practically no inflammation.

Design:

Case report.

Setting:

Academic research.

Results:

Diagnosis of muscular dystrophy was suggested; nevertheless, steroid treatment was initiated, and the patient recovered and gained normal strength. However, after a few years he stopped treatment, and all symptoms recurred. He developed severe proximal weakness of all limbs. Another biopsy showed similar findings, with no inflammation; still, he responded favorably to steroids and immunosuppressive medications. Currently on a low dose of prednisone and methotrexate, he has no neurological deficit.

Conclusion:

The absence of inflammation in muscle biopsy may lead to misdiagnosis of muscular dystrophy; however, if the clinical impression is that of inflammatory myopathy, an immunomodulatory treatment should be initiated. During the past century, there has been much controversy about the diagnosis of polymyositis (PM). The debate is still ongoing. We present hereby a patient with typical course and clinical features of PM who underwent two muscle biopsies, several years apart, which showed necrotizing myopathy, practically without inflammation, leading to misdiagnosis of muscular dystrophy. This report brings up the dispute regarding the role of muscle biopsy in the diagnosis of PM.
Isolated Head Drop Triggered by Neck Surgery Following Concomitant Chemoradiotherapy
Authors: Luo Jin Jun
Published: March 2009

Dropped head syndrome (DHS) is characterized by severe weakness of neck extension that occurs in isolation or association with a generalized neuromuscular disorder. Multietiologies may be responsible for DHS, including radiotherapy, which may cause a delayed form of DHS. However, DHS acutely triggered by neck surgery after chemoradiotherapy is rare. The author reports a case of acute onset of isolated DHS following selective neck dissection surgery after concomitant chemoradiotherapy for laryngeal cancer.
Organ Preserving Transoral Laser Microsurgery for Cancer of the Hypopharynx
Authors: Martin Alexios , Jäckel Martin C. , Christiansen Hans , Mahmoodzada Mary , Kron Martina , Steiner Wolfgang
Published: March 2009

Objective: To assess the feasibility of transoral laser microsurgery (TLM) in the treatment of hypopharyngeal cancer, with a special focus on piriform sinus carcinomas, and to report the oncologic and functional outcomes.

Study Design: Prospective case‐series study at a single institute, an academic tertiary referral center.

Methods: A total of 172 patients with previously untreated squamous cell carcinoma of the hypopharynx were eligible for this study (1986–2003). The piriform sinus was the most common localization (n = 150). Patients with simultaneous second primaries, distant metastases, or N3 neck disease and cancers of the category pT4b were excluded. Fifteen percent of the patients had stages I and II (according to guidelines from the Union Internationale Contre le Cancer 2002/American Joint Commission on Cancer, 2002), and 85% had stages III and IVa. The median follow‐up period was 45 months. All patients (n = 172) were treated by TLM, mainly by selective neck dissection (93%) and/or postoperative radiotherapy (52%). Overall survival, recurrence‐free survival, organ preservation, and local control were analyzed as end points. Rate of tracheotomies, postoperative complications, and swallowing function (feeding tube dependency) were also analyzed.

Results: Five‐year Kaplan‐Meier local control was 84% for pT1; 70% for pT2; 75% for pT3; and 57% for pT4a. Five‐year Kaplan‐Meier recurrence‐free survival was 73% for stages I and II, 59% for stage III, and 47% for stage IVa. The whole group of 172 hypopharyngeal cancer patients was analyzed, with an additional special focus on the homogenous group of piriform sinus carcinomas (n = 150).

Conclusions: Our data support the conclusion that TLM is a valid option to standard radical surgery or standard conservation treatment. Oncologic and functional results compare favorably, while morbidity and complication rates tend to be lower.
Future Horizons in the Treatment of Enteric Neuropathies
Authors: Thapar Nikhil
Published: March 2009

Enteric neuropathies comprise a vast and disparate array of congenital and acquired disorders of the enteric nervous system (ENS), reflecting both the complexity of its neuronal composition and the many interactions that modulate its function. Although present therapeutic strategies, largely limited to surgery and the provision of artificial nutrition, have transformed the early survival and life of sufferers, levels of morbidity and mortality remain unacceptably high. This highlights the need to develop new treatments for enteric neuropathies. In the last decade, the tremendous advances in molecular biology and genetics have significantly enhanced our understanding of ENS development and function. Coupled with equivalent progress in the fields of pharmacology and stem‐cell biology, this has led to the identification of novel tools and targets for therapy, which either aim to optimise the function of the intrinsic ENS or replace/replenish components of an inadequate or dysfunctional ENS. This article reviews current work on a number of these interventions with a particular focus on the use of ENS stem cells as potential therapeutic tools for enteric neuropathies.
Treatment of Severe Malnutrition in Children: Experience in Implementing the World Health Organization Guidelines in Turbo, Colombia
Authors: Bernal Carlos , Velásquez Claudia , Alcaraz Gloria , Botero Jorge
Published: March 2009

Objective:

To evaluate the implementation of the World Health Organization guidelines for the treatment of children with severe acute malnutrition in a class I hospital.

Paitents and Methods:

Descriptive and prospective study of 335 children under the age of 6, admitted between 2001 and 2005 for severe acute malnutrition (83%) and moderate acute malnutrition associated with illness (17%). The care of the children was provided by clinicians and medical staff trained under World Health Organization guidelines.

Results:

Kwashiorkor was a common result in children with severe acute malnutrition (60.8%); 58% were younger than 1 year old. Complications upon admission were diarrhea (68.4%) and anemia (51.1%), and the most common complication during hospital stay was sepsis (9%). Overall, 61.7% attained −1 standard deviation of weight for height after an average stay of 3 weeks in the hospital; 5.1% were sent to tertiary care hospitals. Overall, mortality during the 5 years was 5.7%, with sepsis the most common cause. In the first year, the mortality rate was 8.7%; it decreased to 4.0% in the last year. The mortality rate was significantly higher in children with edema. Children with moderate acute malnutrition had similar complications and mortality when compared with children with severe acute malnutrition (5.3%).

Conclusions:

Once the World Health Organization guidelines were implemented, low mortality rates were achieved in children with severe acute malnutrition in class I hospitals.