Search

The scalp nerve block, created by injecting local anesthetics around the scalp nerves, is reported to effectively reduce pain after surgery. In this study, we evaluated the efficacy of scalp nerve block in patients with hemifacial spasm (HFS) undergoing microvascular decompression (MVD). Seventy-four patients who underwent MVD for HFS were enrolled. The block group received scalp nerve block with 0.5% ropivacaine before surgery. The primary outcome was cumulative dose of rescue analgesics 24 h postoperatively. The secondary outcomes were included pain scores, postoperative antiemetic consumption, and Quality of Recovery-15 scale. The cumulative dose of rescue analgesics at 24 h postoperatively was not significantly different between the two groups (4.80 ± 3.64 mg vs. 5.92 ± 3.95 mg, p = 0.633). However, the pain score was significantly reduced in the block group at 6, 12, and 24 h postoperatively. Postoperative antiemetic consumption was lower in the block group than the control group at 12 h. There were no significant differences between the two groups for other secondary outcomes. In MVD for HFS, a preoperative scalp nerve block might reduce postoperative pain in the early postoperative period, but a larger study using a multimodal approach is needed to confirm the efficacy of a scalp block. [ABSTRACT FROM AUTHOR]

Pumpkin (Cucurbita moschata Duchesne ex Poir.) is a multipurpose cash crop rich in antioxidants, minerals, and vitamins; the seeds are also a good source of quality oils. However, pumpkin is susceptible to the fungus Podosphaera xanthii, an obligate biotrophic pathogen, which usually causes powdery mildew (PM) on both sides of the leaves and reduces photosynthesis. The fruits of infected plants are often smaller than usual and unpalatable. This study identified a novel gene that involves PM resistance in pumpkins through a genome-wide association study (GWAS). The allelic variation identified in the CmoCh3G009850 gene encoding for AP2-like ethylene-responsive transcription factor (CmoAP2/ERF) was proven to be involved in PM resistance. Validation of the GWAS data revealed six single nucleotide polymorphism (SNP) variations in the CmoAP2/ERF coding sequence between the resistant (IT 274039 [PMR]) and the susceptible (IT 278592 [PMS]). A polymorphic marker (dCAPS) was developed based on the allelic diversity to differentiate these two haplotypes. Genetic analysis in the segregating population derived from PMS and PMR parents provided evidence for an incomplete dominant gene-mediated PM resistance. Further, the qRT-PCR assay validated the elevated expression of CmoAP2/ERF during PM infection in the PMR compared with PMS. These results highlighted the pivotal role of CmoAP2/ERF in conferring resistance to PM and identifies it as a valuable molecular entity for breeding resistant pumpkin cultivars. [ABSTRACT FROM AUTHOR]

Researchers used the bar gene as a marker for selecting expression plasmids in multivalent Salmonella vaccines. This gene confers resistance to the herbicide DL-phosphinothricin. It eliminates the problem of using plasmids that have antibiotic resistance genes.

A study was conducted to analyze the expression of the 19 kDa carboxy-terminal domain of Plasmodium yoelii merozoite surface protein in Salmonella vaccine strains as a carboxy-terminal fusion to fragment C of tetanus toxin. The design of live multivalent bacterial vaccines against eukaryotic pathogens was also examined. Experimental results indicated that the lack of protection correlated with the antibody response.

A design method of nonuniform CMF banks is presented which is derived in association with a uniform CMF bank. In this derived nonuniform CMF bank, each constituent nonuniform filter is formed by merging the relevant uniform filters in the associated uniform CMF bank. The validity of the derived design is investigated in terms of the band selectivity of the nonuniform filters, the alias cancellation among the nonuniform analysis and synthesis filters, and the distortion function of the overall filter bank. The investigations are done in a rigorous manner via three proved properties, which provide the criterion that the proposed design method is applicable if, and only if, the upper band edge frequency of each nonuniform filter is an integral multiple of the bandwidth of the corresponding band. Design and implementation aspects are considered for the proposed nonuniform CMF bank, which reveals that the design procedure and the structure of the uniform CMF bank are mostly preserved in the nonuniform implementation.

Introduction: This prospective observational study compared the postoperative analgesic effectiveness of intrathecal morphine (ITM) and surgical-site infusion (SSI) of ropivacaine as adjuncts to intravenous (IV) patient-controlled analgesia (PCA) (fentanyl) in living-donor kidney transplant recipients.Methods: Patients undergoing living-donor kidney transplantation who received ITM or SSI in addition to IV PCA were included. Rescue analgesia was achieved with IV meperidine as required. The primary outcome, measured using the Numeric Pain Rating Scale (NRS), was pain at rest and when coughing. Patients were assessed for 48 hours after surgery.Results: A total of 53 patients (32 ITM, 21 SSI) were included in the study. The ITM group showed significantly lower NRS scores, at rest and when coughing, for up to 12 and eight hours. NRS scores were comparable between the groups at other times. The ITM group had significantly less postoperative systemic opioid requirement in the first 24 hours, but there was no significant difference between the systemic opioid consumption of the groups on postoperative Day 2. In the ITM group, 3 (9.4%) patients presented with bradypnoea and 1 (3.1%) with excessive sedation in the first 12 postoperative hours. More patients in the ITM group developed pruritus requiring treatment during the first 24 hours. There were no differences between the groups in other outcomes (e.g. nausea/vomiting, change in pulmonary or kidney functions).Conclusion: Compared with SSI, ITM reduced immediate postoperative pain and IV opioid consumption on postoperative Day 1 after living-donor kidney transplantation, but at the cost of increased pruritus and respiratory depression. [ABSTRACT FROM AUTHOR]

Abstract: Background: The effect of opioids on inflammation and immune responses is an important subject of investigation because immunoregulatory cytokines are produced in the central nervous system and opioid receptors are widespread in these cells. Objectives: The aim of this study was to evaluate the immunomodulatory effect of morphine on the C3 expression (both constitutive and proinflammatory cytokine-induced C3 expression) in primary rat astrocytes. Methods: Primary rat astrocytes were untreated or treated with morphine in different concentrations (10–6 to 10–2 M) before incubation without or with 5 U/mL tumor necrosis factor-α (TNF-α), and C3 protein and mRNA expressions were measured. Similarly, astrocytes were treated with 10–3 M morphine and stimulated with other proinflammatory cytokines, including 10 ng/mL interleukin-8 (IL-8) and 5 U/mL IL-1β. Astrocytes were exposed to 10–5 M naloxone for 2 hours before adding morphine, and TNF-α and C3 protein was measured. Tumor growth factor-β (TGF-β) was measured from the supernatants of each proinflammatory cytokine. Results: All results are expressed as mean percentages of C3 production by normalizing C3 without morphine or any cytokine treatment as 100%. Constitutive C3 protein production was decreased at morphine 10–3 M (57.2%) and 10–2 M (30.1%). Pretreatment with morphine suppressed induction of C3 expression at both the protein and mRNA levels in astrocytes stimulated with TNF-α, IL-8, and IL-1β (P < 0.05) in a dose-dependent manner. The inhibition of C3 protein production by morphine (10–3 M; 33%) was partially attenuated by naloxone (52.0%) (P < 0.05). The pretreatment of astrocytes with morphine (10–3 M) before stimulation with TNF-α, IL-8, and IL-1β increased by 33% (P < 0.05), decreased by 15.2% (P < 0.05), and did not change the production of TGF-β protein, respectively. Conclusions: Morphine downregulated both constitutive and proinflammatory cytokine-induced C3 expression of astrocytes at the transcriptional level, but not in a cytokine-specific manner. [Copyright &y& Elsevier]

Intraoperative hypothermia occurs frequently, but hyperthermia is relatively rare during general anesthesia. We experienced a case of hyperthermia during living donor liver transplantation that appeared to be significantly associated with biliary obstruction. A 65-year-old male patient was diagnosed with intrahepatic cholangiocarcinoma, and living donor liver transplantation was planned after confirmation of no metastasis via intraoperative frozen biopsy. Following resection of a segment of common bile duct for frozen biopsy, the surgeon clamped the common bile duct, and the patient's body temperature increased gradually to 39.5°C. As the congested bile was drained, the body temperature decreased to the normal range. This case report suggests that when a patient develops unexplained hyperthermia during hepatobiliary surgery or in a chance of biliary obstruction, clinicians should consider bile congestion as a possible reason for hyperthermia.

Introduction: This prospective observational study compared the postoperative analgesic effectiveness of intrathecal morphine (ITM) and surgical-site infusion (SSI) of ropivacaine as adjuncts to intravenous (IV) patient-controlled analgesia (PCA) (fentanyl) in living-donor kidney transplant recipients., Methods: Patients undergoing living-donor kidney transplantation who received ITM or SSI in addition to IV PCA were included. Rescue analgesia was achieved with IV meperidine as required. The primary outcome, measured using the Numeric Pain Rating Scale (NRS), was pain at rest and when coughing. Patients were assessed for 48 hours after surgery., Results: A total of 53 patients (32 ITM, 21 SSI) were included in the study. The ITM group showed significantly lower NRS scores, at rest and when coughing, for up to 12 and eight hours. NRS scores were comparable between the groups at other times. The ITM group had significantly less postoperative systemic opioid requirement in the first 24 hours, but there was no significant difference between the systemic opioid consumption of the groups on postoperative Day 2. In the ITM group, 3 (9.4%) patients presented with bradypnoea and 1 (3.1%) with excessive sedation in the first 12 postoperative hours. More patients in the ITM group developed pruritus requiring treatment during the first 24 hours. There were no differences between the groups in other outcomes (e.g. nausea/vomiting, change in pulmonary or kidney functions)., Conclusion: Compared with SSI, ITM reduced immediate postoperative pain and IV opioid consumption on postoperative Day 1 after living-donor kidney transplantation, but at the cost of increased pruritus and respiratory depression., (Copyright: © Singapore Medical Association)

We retrospectively evaluated the effects of 6% hydroxyethyl starch (HES) 130/0.4 on postoperative blood loss and acute kidney injury (AKI) in patients undergoing off-pump coronary artery bypass grafting (OPCAB).Electronic medical records of 771 patients who underwent OPCAB in our hospital between July 2012 and July 2014 were reviewed, and 249 patients without intraoperative HES-exposure (group NoHES) were matched 1:N with intraoperative HES-exposed 413 patients (group HES) based on propensity score. The effects of intraoperative HES on postoperative cumulative blood loss within the first 24 hours, need for bleeding-related reoperation, and occurrence of postoperative AKI (determined by KDIGO and RIFLE criteria) were analyzed.In our propensity score matched cohort, there were no significant differences between groups for median postoperative 24 hours blood loss (525 mL in group HES vs. 540 mL in group NoHES, P = .203) or need for bleeding-related reoperation (OR, 2.44; 95% confidence interval [CI], 0.64-9.34, P = .19). However, postoperative AKI (assessed by 2 criteria) occurred more frequently in group HES than in group NoHES (by KDIGO criteria: 10.7% vs. 3.6%; OR 3.43 [95% CI, 1.67-7.04]; P < .001 and by RIFLE criteria: 9.6% vs. 2%; OR 3.32 [95% CI, 1.34-8.24]; P = .01). The median volume of infused HES per patient weight was 16 mL/kg in group HES.In the patients undergoing OPCAB, intraoperative 6% HES 130/0.4 did not increase postoperative bleeding. However, renal safety remains a concern. Intraoperative use of HES should be determined cautiously during OPCAB.

Background: Hemodialysis via the internal jugular vein (IJV) has been widely used for patients with end stage renal disease (ESRD) patients, as they have a higher risk of arterial diseases. We investigated the ultrasonographic findings of the IJV and carotid artery (CA) in recipients of kidney transplantation (KT) and identified factors influencing IJV/CA abnormalities., Methods: We enrolled 120 adult KT recipients. Patients in group A (n = 57) had a history of IJV hemodialysis, while those in group B (n = 63) were not yet on dialysis or undergoing dialysis methods not involving the IJV. The day before surgery, we evaluated the state of the IJV and CA using ultrasonography. We followed patients with IJV stenosis for six months after KT., Results: Ultrasonography revealed that four patients (7%) in group A had IJV abnormalities, while no patients in group B had abnormalities (P = 0.118). Of the four patients with abnormalities, one with 57.4% stenosis normalized during follow- up. However, another patient with 90.1% stenosis progressed to occlusion, while the two patients with total occlusion remained the same. Twenty patients in group A (n = 11) and B (n = 9) had several CA abnormalities (P = 0.462). Upon multivariate analysis with stepwise selection, height and age were significantly correlated with IJV stenosis (P = 0.043, odds ratio = 0.9) and CA abnormality (P = 0.012, odds ratio = 1.1), respectively., Conclusions: IJV abnormalities (especially with a history of IJV hemodialysis) and CA abnormalities may be present in ESRD patients. Therefore, we recommend ultrasonographic evaluation before catheterization.

Background: Although anesthetic-induced inhibition of lipopolysaccharide (LPS)-induced lung injury has been recognized, the underlying mechanism is obscure. Some studies suggest that reactive oxygen species (ROS) by isoflurane play a crucial role for anesthetic-induced protective effects on the brain or the heart; however, it still remains controversial. In this study, we examined the role of isoflurane-derived ROS in isoflurane-induced inhibition of lung injury and nuclear factor κB (NFκB) activation in LPS-challenged rat lungs., Methods: Male Sprague-Dawley rats were subjected to inhalation of 1.0 minimum alveolar concentration of isoflurane for 60 minutes, and intratracheal LPS 0.1 mg was administered 60 minutes later. In some cases, ROS scavenger, 2-mercaptopropinyl glycine or N-acetylcysteine was given 30 minutes before isoflurane. ROS generation was measured by fluorometer before LPS challenge and 4 hours after. Isoflurane's preconditioning effect was assessed by histologic examination, protein content, neutrophil recruitment, and determination of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 levels in bronchoalveolar lavage fluid and lung tissue. Western blotting measured phosphorylation of inhibitory κB α (ser 32/36), NFκB p65, and inducible nitric oxide synthase (iNOS). TNF-α and IL-6 mRNA expression and immunofluorescence staining for iNOS were also assessed., Results: Isoflurane preconditioning reduced inflammatory lung injury and TNF-α, IL-1β, and IL-6 release in the lung. Isoflurane upregulated ROS generation before LPS but inhibited a ROS burst after LPS challenge. ROS scavenger administration before isoflurane abolished the isoflurane preconditioning effect as well as isoflurane-induced inhibition of phosphorylation of inhibitory κBα, NFκB p65, iNOS activation, and mRNA expression of TNF-α and IL-6 in acute LPS-challenged lungs., Conclusions: This study suggests a crucial role of upregulated ROS generation by isoflurane for modification of inflammatory pathways by isoflurane preconditioning in acute inflammation of the lung.

Background: Perioperative lidocaine infusion improves postoperative outcomes, mostly after abdominal and urologic surgeries. Knowledge of the effect of lidocaine on peripheral surgeries is limited. Presently, we investigated whether intraoperative lidocaine infusion reduced anesthetic consumption, duration of ileus, pain intensity, analgesic consumption and hospital stay after breast plastic surgeries., Methods: Sixty female patients, aged 20-60 years, enrolled in this prospective study were randomly and equally divided to two groups. One group (n = 30) received a 1.5 mg/kg bolus of lidocaine approximately 30 min before incision followed by continuous infusion of lidocaine (1.5 mg/kg/h) until skin closure (lidocaine group). The other group (n = 30) was untreated (control group). Balanced inhalation (sevoflurane) anesthesia and multimodal postoperative analgesia were standardized. End tidal sevoflurane concentration during surgery, time to the first flatus and defecation, visual analog pain scale (0-10), analgesic consumption and associated side effects at 24, 48, and 72 h after surgery, hospital stay, and patient's general satisfaction were assessed., Results: Compared to the control group, intraoperative lidocaine infusion reduced by 5% the amount of sevoflurane required at similar bispectral index (P = 0.014). However, there were no significant effects of lidocaine regarding the return of bowel function, postoperative pain intensity, analgesic sparing and side effects at all time points, hospital stay, and level of patient's satisfaction for pain control., Conclusions: Low dose intraoperative lidocaine infusion offered no beneficial effects on return of bowel function, opioid sparing, pain intensity and hospital stay after various breast plastic surgeries.

Two cases were reported in which severe postoperative laryngeal edema were developed after the operation of diffuse idiopathic skeletal hyperostosis (DISH) of cervical spine. In the first case, sudden airway obstruction was developed in the general ward 6 hour after uneventful decompression surgery for osteophyte. In the second patient, an elective preoperative tracheostomy was performed before surgery but the tube could not be removed for 2 months because of laryngeal edema and decreased vocal cord mobility. It should be emphasized that this airway problem can develop during the postoperative as well as the preoperative period, especially in the case of anterior cervical spine surgery.

Background: Theoretically, L-type calcium channel blockers could modulate anesthetic effects. Nicardipine does not affect the bispectral index (BIS), but nimodipine, which can penetrate the blood-brain barrier, has not been studied. The aim of this study was to evaluate whether a single dose of intravenous nicardipine or nimodipine could affect BIS following rapid sequence intubation., Methods: This study was done in a double-blind, randomized fashion. Anesthesia was induced with fentanyl 2 µg/kg, thiopental sodium 5 mg/kg, and 100% oxygen. After loss of consciousness, patients received rocuronium 1.0 mg/kg and either a bolus of 20 µg/kg nicardipine, nimodipine, or a comparable volume of normal saline (n = 20). Intubation was performed 1 min after study drug administration. BIS, mean blood pressure (MBP), and heart rate (HR) were measured before anesthetic induction, after loss of consciousness, before intubation, during intubation, and 1, 2 and 5 min after intubation., Results: BIS dropped rapidly after induction but increased to 60 before intubation in all groups irrespective of study drug. In nimodipine, the increase in BIS during intubation was not significant compared to pre-intubation, in contrast to the other two groups, but there was no difference in BIS during intubation. HR significantly increased, but MBP just rose to pre-induction values after intubation in nicardipine and nimodipine groups. BIS, MBP, and HR following intubation increased in control group., Conclusions: A single dose of intravenous nicardipine or nimodipine could attenuate blood pressure increases but not affect BIS increases in rapid sequence intubation.

Background: Leukemic cells originate from hypoxic bone marrow, which protects them from anti-cancer drugs. Although many factors that cause drug resistance in leukemic cells have been studied, the effect of hypoxia on drug-induced apoptosis is still poorly understood., Methods: In this study, we examined the effect of hypoxia on anti-leukemic drug resistance in leukemic cell lines treated with cobalt chloride (CoCl(2)), a hypoxia-mimetic agent. Cellular proliferation was evaluated using the methyl thiazolyl tetrazolium (MTT) assay. Flow cytometry analysis and western blots were performed to investigate apoptosis-related proteins., Results: Unlike its previously known apoptotic effect, the expression of HIF-1α increased the survival rate of human promyelocytic leukemia HL-60 cells when these cells were exposed to anti-leukemic drugs; these effects were mediated by heat-shock protein HSP70 and the pro-apoptotic protein Bax., Conclusion: These findings may provide new insights for understanding the mechanisms underlying hypoxia and for designing new therapeutic strategies for acute myeloid leukemia.

Background and Objectives: Sleep disorders, including sleep-disordered breathing and periodic limb movements during sleep, are associated with an increased risk for cardiovascular diseases, which are the leading causes of death in patients with ESRD. This study investigated the association between sleep disorders and mortality in patients with ESRD., Design, Setting, Participants, & Measurements: Thirty patients on maintenance hemodialysis, who were clinically stable for >2 months, underwent overnight polysomnography to evaluate sleep parameters., Results: All patients were followed for a median of 48 months (range: 14 to 62 months), and 14 of them died during the follow-up period. Among the sleep parameters, the percent of sleep time with arterial oxygen saturation <90% (T <90%), mean arterial oxygen saturation, and periodic limb movement index score were associated with significant increases in the risk of death. However, associations of the apnea-hypopnea index or oxygen desaturation index with mortality were NS. The hazard ratios (95% confidence intervals) for death per one SD increment in the log-transformed T <90% and periodic limb movement index score were 2.10 (1.06 to 4.15) and 2.48 (1.11 to 5.52), respectively, after adjusting for age., Conclusions: We found that nocturnal hypoxemia and periodic limb movement during sleep, rather than apnea itself, were associated with an increased risk for death in patients with ESRD. However, conclusions from this study should be drawn with caution, because they are limited by the small sample size.

Background: The aim of this study was to compare intraoperative and postoperative complications and clinical outcome of endovascular coiling (EVT) with neurosurgical clipping (NST) under general anesthesia in the cerebral aneurysm patients older than 60 years., Methods: We retrospectively reviewed the charts, operative reports of patients who underwent EVT or NST at our hospital between January 2006 and August 2008. A total of 181 patients (EVT = 78, NST = 103) were included in this study., Results: The rate of intraoperative event was higher in EVT than in NST but postoperative complication and Glasgow outcome scale (GOS) at 6 months did not show statically significance in both groups. Preoperative aneurysm rupture, age and the World Federation of Neurological Surgeons grade (WFNS) were the influencing factors for outcome in both groups. Anesthetic agents, body temperature and vasoactive drugs were significantly different between the two groups but the effects of these on the outcome of patients were insignificant., Conclusions: In EVT and NST, the variables related to the postoperative complications were preoperative aneurysm rupture, age and WFNS. When the elderly patients get these procedures, more close care should be considered postoperatively.

Purpose: Arrhythmias after an esophagectomy (most commonly atrial fibrillation) are a significant contributing factor to patient morbidity. However, the significance of an intraoperative arrhythmia is not completely understood. The aim of this retrospective study was to determine the occurrence and risk factors for developing intraoperative arrhythmias in patients undergoing an esophagectomy., Materials and Methods: We reviewed the records of 427 patients who underwent a transthoracic esophagectomy between 2001 and 2005. Variables such as age, sex, hypertension, diabetes, cardiac disease, preoperative pulmonary function test (PFT) results, cancer level, combined radiochemotherapy, intrathoracic cavity adhesions and anastomosis site, hemoglobin, central venous pressure (CVP), fluid balance, serum potassium level, dose of vasopressors, temperature, and combined general and epidural anesthesia were analyzed as risk factors for the occurrence of an arrhythmia. We defined this arrhythmia as one not originating from the sinus node., Results: The incidence of intraoperative arrhythmia in this subset of patients was 17.1%, with a 37.2% reoccurrence rate during the first three postoperative days. Univariate and multivariate analysis revealed the presence of heart disease, poor PFTs, cervical anastomosis, elevated CVP, and higher ephedrine doses to be independent predictors of the development of an intraoperative arrhythmia., Conclusion: The incidence of intraoperative arrhythmia during esophagectomy was 17.1% with a 37.2% of reoccurrence rate.

Background: Individuals with Type O blood have been reported to have a tendency toward reduced Factor VIII and von Willebrand Factor (vWF) levels. If this is true, patients with Type O blood might be vulnerable to coagulopathy during acute normovolemic hemodilution using hydroxyethyl starch (HES), both from hemodilution as well as HES-related coagulopathy., Methods: Thirty non-O and 15 type O ASA 1 or 2 patients scheduled for spinal surgery involving more than two spinal levels were enrolled for the study. After anesthesia induction, 30% of the estimated blood volume was removed, and the volume was simultaneously replaced with 6% HES (130/0.4). Coagulation profiles were measured before (T0) and 30 min after acute normovolemic hemodilution (T30)., Results: Factor VIII activity, vWF antigen levels (vWF:ag), and vWF ristocetin cofactor activity (vWF:RCof) were lower in the O group than in the non-O group before and after acute normovolemic hemodilution, and decreased below the normal range in the O group after acute normovolemic hemodilution. The decrease was beyond that expected from hemodilution alone. Maximum amplitude and coagulation index of the thromboelastogram decreased below the normal range in the O group after acute normovolemic hemodilution. The decrease in vWF:ag was related to the degree of blood loss, and was greater in patients in the O group., Conclusions: Patients with Type O blood may have increased coagulation compromise, and greater dilution of Factor VIII activity, vWF:ag, and vWF:RCof after acute normovolemic hemodilution with HES.

We analyzed the effects of several factors on the serum ethanol levels after alcohol sclerotherapy in the arteriovenous malformations (AVMs) retrospectively. Blood ethanol level, amounts of given alcohol, location of lesions, methods of flow control, and Doppler resistive index (RI) were analyzed. The results of linear regression analysis showed that the amount of alcohol administered was the predictor of serum ethanol level (r2=0.75, p<0.001). The average amount of injected alcohol was 0.89 mL/kg in the patients with the serum levels above the legal intoxication level (>80 mg/dL). Location of the lesions was not related with the serum ethanol level (p=0.643), and other variables such as forms of flow control and RI were not related to the serum ethanol level after controlling for injected amounts of alcohol (analysis of covariance). It is recommended to keep an eye on the possibility of intoxication when using the amounts of alcohol exceeding 0.89 mL/kg in the sclerotherapy of AVMs.

Streptolysin O (SLO) and streptolysin S (SLS) are potent cytolytic toxins produced by almost all clinical isolates of group A streptococci (GAS). Allele-replacement mutagenesis was used to construct nonpolar (in-frame) deletion mutations in the slo and sagB genes of the serotype M5 GAS strain Manfredo, producing isogenic single and double SLO- and SLS-defective mutants. In contrast to recent reports on SLS-defective insertion mutants (I. Biswas, P. Germon, K. McDade, and J. Scott, Infect. Immun. 69:7029-7038, 2001; Z. Li, D. Sledjeski, B. Kreikemeyer, A.Podbielski, and M. Boyle, J. Bacteriol. 181:6019-6027, 1999), none of the mutants described here had notable pleiotropic effects on the expression of other virulence factors examined. Comparison of isogenic parent and mutant strains in various virulence models revealed no differences in their abilities to multiply in human blood or in their 50% lethal doses (LD(50)s) upon intraperitoneal infection of BALB/c mice. A single log unit difference in the LD(50)s of the parent and SLS-defective mutant strains was observed upon infection by the subcutaneous (s.c.) route. Comparisons over a range of infective doses showed that both SLO and SLS contributed to the early stages of infection and to the induction of necrotic lesions in the murine s.c. model. Individually, each toxin made an incremental contribution to virulence that was not apparent at higher infective doses, although the absence of both toxins reduced virulence over the entire dose range examined. Interestingly, in some cases, the contribution of SLO to virulence was clear only from an analysis of the double-mutant strain, highlighting the value of not confining virulence studies to mutant strains defective in the expression of only single virulence factors.

Bacterial superantigens are potent T-cell stimulatory protein molecules produced by Staphylococcus aureus and Streptococcus pyogenes. Their superantigenic activity can be attributed to their ability to cross-link major histocompatibility complex class II molecules with T-cell receptors (TCRs) to form a tri-molecular complex. Each superantigen is known to interact with a specific V(beta) element of TCR. Staphylococcal enterotoxin B (SEB, a superantigen), a primary cause of food poisoning, is also responsible for a significant percentage of non-menstrual associated toxic shock syndrome in patients with a variety of staphylococcal infections. Structural studies have elucidated a binding cavity on the toxin molecule essential for TCR binding. To understand the crucial residues involved in binding, mutagenesis analysis was performed. Our analysis suggest that mutation of a conserved residue Thr(112) to Ser (T112S) in the binding cavity induces a selective reduction in the affinity for binding one TCR V(beta) family and can be attributed to the structural differences in the native and mutant toxins. We present a detailed comparison of the mutant structure determined at 2.0 A with the previously reported native SEB and SEB-TCR V(beta) complex structures.