0.5% levobupivacaine versus 0.5% ropivacaine: Are they different in ultrasound-guided sciatic block?

CONTEXT AND AIMS: Little is known about onset and duration of sciatic block after 0.5% levobupivacaine (Levo) versus 0.5% ropivacaine (Ropi) for ultrasound-guided technique. We assessed these parameters in the ultrasound-guided block, to know for the practice. SETTING AND DESIGN: A comparative randomized double-blind study was conducted in the University Hospital. MATERIALS AND METHODS: Were included 35 adults of ASA I-II, scheduled for foot surgery, presenting clear imaging of their sciatic nerve at mid-thigh. A volume of 20 mL of either 0.5% Levo or 0.5% Ropi were injected around the sciatic nerve at mid-thigh using ultrasound guidance (out of the plane) followed by placement of a catheter to use, if necessary, for perioperative analgesia. A femoral single shot block was systematically performed to block the saphenous nerve. The onset times until complete foot block (primary outcome) and the sensory and motor block duration (secondary outcome) were assessed using Wilcoxon test. Values were expressed as medians (1(st)-3(rd) quartile). RESULTS: Except for two delayed sciatic blocks in each group, the onset time otherwise was 35 min (20-60) in Ropi versus 40 min (30-60) in Levo, P = 0.5. Sensory block lasted longer in Levo, 17 h (14-27) compared with 15 h (10-17) in Ropi, P = 0.04. No significant between-group difference was found with motor block durations, 15 h (12-18) in Levo and 15 h (12-16) in Ropi, P = 0.3. CONCLUSION: No difference of onset times was found in ultrasound-guided sciatic block whether using Levo or Ropi. Levo induced a longer-lasting sensory block.

Evaluation of CellSolutions BestPrep® automated thin-layer liquid-based cytology Papanicolaou slide preparation and BestCyte® cell sorter imaging system.

OBJECTIVE: A double-blind study was conducted to compare the performance of the new BestPrep® (CellSolutions) liquid-based thin-layer Papanicolaou (Pap) test with ThinPrep® (Hologic). STUDY DESIGN: Samples from the study patients (n = 105) were collected twice in the same encounter with the ThinPrep sample always taken first and the BestPrep sample collected second. Slides were prepared according to both manufacturers' protocols and evaluated using manual microscopic review and the BestCyte® cell sorter imaging system (CellSolutions). Diagnostic truth for each case was determined by independent manual review of both slides by multiple pathologists and histology when available. The presence of atypical squamous cells of undetermined significance was the threshold for positive for sensitivity and specificity calculations. RESULTS: BestPrep and ThinPrep, by manual review, had sensitivities for high-grade squamous intraepithelial lesion (HSIL) cases of 100 and 95.6%, respectively. Using the BestCyte cell sorter, both had 100% sensitivity. For the same HSIL cases, the digene HC2 high-risk human papillomavirus DNA test had sensitivities of 100% (BestPrep) and 95.6% (ThinPrep). Specificities were 71.4% (BestPrep) and 54.8% (ThinPrep). CONCLUSIONS: BestPrep was equivalent to ThinPrep for manual review even though BestPrep was always the second sample collected. The BestCyte cell sorter provides a practical alternative to manual review for both BestPrep and ThinPrep slides.

Preoperative moderate renal impairment is an independent risk factor of transfusion in elderly patients undergoing hip fracture surgery and receiving low-molecular-weight heparin for thromboprophylaxis.

STUDY OBJECTIVE: To define the risk factors of allogeneic erythrocyte transfusion in patients older than 65 years of age who underwent hip fracture surgery. DESIGN: Retrospective, single-center study. SETTING: Orthopedic unit of a university hospital. MEASUREMENTS: The records of 413 consecutive patients undergoing hip fracture surgery over a 12-month period and receiving low-molecular-weight heparin (LMWH) for thromboprophylaxis were retrospectively reviewed. Preoperative independent predictors of transfusion were determined by multivariate analysis, from which a model of individual probability of transfusion was derived using creatinine clearance calculated by Cockroft-Gault (CG) and the Modification of Diet in Renal Disease (MDRD) formulas. MAIN RESULTS: Using the CG and MDRD formulas, 56.9% and 50.1% of patients had moderate renal impairment that was an independent factor associated with transfusion, with adjusted odds ratios of 2.44 (1.49 - 4.02) and 2.35 (1.32 - 4.18), respectively. Other factors were fracture with trochanteric extension, preoperative hemoglobin (Hb) < 12 g/dL, and weight. The observed transfusion rate and probability of transfusion calculated with the regression logistic model were well correlated: y = 0.9534x + 0.0287, P < 0.0001, Pearson coefficient 0.988, goodness of fit, χ(2), P = 1 with CG; y = 0.9197x + 0.0504, P < 0.0001, Pearson coefficient 0.956, goodness of fit, χ(2), P = 1 with MDRD). CONCLUSION: This predictive model may be useful to identify those elderly patients undergoing hip fracture repair who are at risk of blood transfusion.

Improving diagnostic criteria for Propionibacterium acnes osteomyelitis: a retrospective analysis.

The identification of Propionibacterium acnes in cultures of bone and joint samples is always difficult to interpret because of the ubiquity of this microorganism. The aim of this study was to propose a diagnostic strategy to distinguish infections from contaminations. This was a retrospective analysis of all patient charts of those patients with >or=1 deep samples culture-positive for P. acnes. Every criterion was tested for sensitivity, specificity, and positive likelihood ratio, and then the diagnostic probability of combinations of criteria was calculated. Among 65 patients, 52 (80%) were considered truly infected with P. acnes, a diagnosis based on a multidisciplinary process. The most valuable diagnostic criteria were: >or=2 positive deep samples, peri-operative findings (necrosis, hardware loosening, etc.), and >or=2 surgical procedures. However, no single criterion was sufficient to ascertain the diagnosis. The following combinations of criteria had a diagnostic probability of >90%: >or=2 positive cultures + 1 criterion among: peri-operative findings, local signs of infection, >or=2 previous operations, orthopaedic devices; 1 positive culture + 3 criteria among: peri-operative findings, local signs of infection, >or=2 previous surgical operations, orthopaedic devices, inflammatory syndrome. The diagnosis of P. acnes osteomyelitis was greatly improved by combining different criteria, allowing differentiation between infection and contamination.

The local antinociceptive effects of paracetamol in neuropathic pain are mediated by cannabinoid receptors.

Paracetamol analgesic mechanism of action is still poorly defined but mainly involves central inhibition of cyclooxygenases. Here we tested the peripheral antinociceptive effects of paracetamol (intraplantar injections) in a rat model of neuropathic pain. Paracetamol dose-dependently decreased mechanical allodynia and lowered nociceptive scores associated with hyperalgesia testing. These effects were inhibited by the administration of cannabinoid CB(1) (AM251) and CB(2) (AM630) receptor antagonists. The participation of the peripheral cannabinoid system in paracetamol analgesia is suggested.

Is there any need for expanding the perineural space before catheter placement in continuous femoral nerve blocks?

BACKGROUND AND OBJECTIVE: There is debate regarding the benefit of perineural space expansion before catheter placement in continuous femoral nerve block. This question is addressed in this prospective, comparative, and randomized study. METHODS: Sixty patients scheduled for total knee replacement were randomly assigned to receive continuous femoral nerve block with or without perineural space expansion using 10 mL dextrose 5% in water (D5W) flush before stimulation-guided catheter placement. Femoral block was initiated with a 5-mL bolus followed by an infusion of 5 mL/h ropivacaine 0.2% during the 2-hour surgery. The number of attempts before successful placement of the stimulating catheter and the resistance during its insertion were assessed. Patients also received obturator nerve blocks by using ropivacaine 0.75% (10 mL) and sciatic nerve blocks (20 mL). The number of boluses of ropivacaine 0.2% needed to achieve zero VAS scoring was recorded in the postanesthesia care unit during the 2-hour stay. Images of the contrast spread were also studied. RESULTS: There were 30 patients in each group. The number of successful catheter placements at the first attempt was higher with expansion than without (22 vs. 8, P = .007). The resistance felt during insertion was lower with than without expansion (P = .01). More boluses of ropivacaine were required postoperatively without expansion (P = .03). No difference between groups was found regarding the images of the contrast spread. CONCLUSION: Expansion of the perineural space with D5W is useful for catheter placement in continuous femoral nerve block.

Effects of apolipoprotein E genotype on spatial attention, working memory, and their interaction in healthy, middle-aged adults: results From the National Institute of Mental Health's BIOCARD study.

The cognitive consequences of the apolipoprotein E-epsilon4 (APOE-epsilon4) allele were examined in middle age, before likely onset of symptoms of Alzheimer's disease. The authors identified 3 cognitive processes--visuospatial attention, spatial working memory, and the effect of visuospatial attention on working memory--and devised "behavioral assays" of the integrity of components of these processes. Redirecting visuospatial attention, retention of memory for location, and attentional modulation of memory of target location were affected by APOE genotype. Visuospatial attention showed additive effects of epsilon4 gene dose; each additional epsilon4 allele inherited further slowed disengagement from invalidly cued space. In contrast, working memory performance was affected only in epsilon4 homozygotes. Effect sizes for the APOE gene were moderate to large, ranging from 14% to 24%. Effects of APOE genotype on component processes of cognition in healthy, middle-aged adults is consistent with the emergence in adulthood of an APOE-epsilon4 cognitive phenotype.

Chronic effects of angiotensin-converting enzyme inhibition on kinin receptor binding sites in the rat spinal cord.

With the use of in vitro receptor autoradiography, this study aims at determining whether the higher level of kinin B(2) receptor density in the spinal cord of the spontaneously hypertensive rat (SHR) is secondary to arterial hypertension and whether chronic treatment with angiotensin I-converting enzyme inhibitors (ACEI) can regulate neuronal B(1) and B(2) receptors. SHR received, from the age of 4 wk, one of the two ACEI (lisinopril or zofenopril, 10 mg x kg(-1) x day(-1)) or for comparison, the selective AT(1) antagonist (losartan, 20 mg x kg(-1) x day(-1)) in their drinking water for a period of 4, 12, and 20 wk. Age-matched untreated SHR and Wistar-Kyoto rats (WKY) were used as controls. B(2) receptor binding sites in most laminae were higher in SHR than in WKY from the age of 8 to 24 wk. Whereas B(1) receptor binding sites were significantly present in young SHR and WKY, they were barely detectable in adult rats. ACEI (16 and 24 wk) and AT(1) antagonist (24 wk) enhanced the number of B(2) without changing B(1) receptor binding sites. However, at 8 wk the three treatments significantly increased B(1) and decreased B(2) receptors in lamina I. It is concluded that 1) the higher density of B(2) receptors in the spinal cord of SHR is not due to hypertension, 2) kinin receptors are regulated differently by ACEI in neuronal and vascular tissues, and 3) aging may have a profound impact on levels of B(1) and B(2) receptors in the rat spinal cord.

EGF receptor transactivation is obligatory for protein synthesis stimulation by G protein-coupled receptors.

The epidermal growth factor receptor (EGFR) was recently identified as a signal transducer of G protein-coupled receptors (GPCRs). In this study, we have examined the contribution of EGFR transactivation to the growth-promoting effect of GPCRs on vascular smooth muscle cells. Activation of the G(q)-coupled ANG II receptor or G(i)-coupled lysophosphatidic acid receptor resulted in increased tyrosine phosphorylation and activation of EGFR. Specific inhibition of EGFR kinase activity by tyrphostin AG-1478 or expression of a dominant-negative EGFR mutant abolished this response. Importantly, inhibition of EGFR function strongly attenuated the global stimulation of protein synthesis by GPCR agonists in vitro in cultured aortic smooth muscle cells and in vivo in the rat aorta and in small resistance arteries. The growth inhibition was associated with a marked reduction of extracellular signal-regulated kinase and phosphoinositide 3-kinase pathway activity and the resulting suppression of eukaryotic translation initiation factor 4E and 4E binding protein 1 phosphorylation. Our results demonstrate that EGFR transactivation is a physiologically relevant action of GPCRs linked to translational control and protein synthesis.