Microg Ml-1 Research Articles

English

This study aimed to determine a possible correlation between oral mucosal disease and salivary concentrations of the antimicrobial peptides human beta-defensin-1 (hbetaD-1) and human beta-defensin-2 (hbetaD-2). The present work focussed on the establishment of a reversed phase-high performance liquid chromatography (RP-HPLC) procedure to quantify human beta-defensins (hbetaD-1 and hbetaD-2) in saliva samples of patients with oral diseases such as lichen planus (n = 10), Behçet (n = 10) and recurrent apthous stomatitis (n = 10). Linear calibration range for hbetaD-1 and hbetaD-2 defensins was 1.67-200 microg mL-1 and 3.13 -100 PG mL-1 with R2 values of 0.9998 and 0.996, correspondingly. The concentration of beta-defensins in saliva was determined by comparing the peak areas of eluted hbetaD-1 and hbetaD-2 with that of their standards. The variation of the amount of beta-defensins was evaluated by comparisons of the results obtained from the patients with oral mucosal diseases before and after treatments and the control subjects. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 1.62 microg mL-Sand 5.39 microg mL-1 for hbetaD-1 and 0.94 mig mL-1 and 3.13 microg mL-1 for hbetalD-2, respectively. The salivary beta-defensin concentration was significantly higher in patients with oral mucosal diseases than in healthy volunteers; furthermore, in patients with oral mucosal diseases, the concentration was significantly higher before treatment than after treatment.

Caloxanthones O and P: Two New Prenylated Xanthones from Calophyllum inophyllum

Chemical investigation of the EtOH extract of the twigs of Calophyllum inophyllum collected in Hainan Province of China resulted in the isolation of two new prenylated xanthones, caloxanthone O (1) and caloxanthone P (2). Their structures were elucidated by a study of their physical and spectral data. Compound 1 exhibited cytotoxicity against human gastric cancer cell line (SGC-7901), with an IC50 value of 22.4 μg mL−1.

Synthesis and Antistaphylococcal Activity of N‐Substituted‐1H‐benzimidazole‐sulphonamides

A series of N-substituted-1H-benzimidazole-5(6)-sulfonamides and 3-(5,6-dichloro-1H-benzimidazol-2-yl)-N-substituted benzensulfonamides were synthesized and evaluated for antibacterial activity against Staphylococcus aureus and methicillin-resistant S. aureus (MRSA). Certain compounds inhibit bacterial growth with low MIC (microg/mL) values. The most active compounds 30, 31, and 32 have the lowest MIC values with 0.39 to 0.19 microg/mL. Among the compounds having sulfonamido moities, 16, 23, and 24 exhibited the strongest antibacterial activity with 1.56 microg/mL MIC values.

In vitro Antioxidative Activities and Polyphenol Content of Eugenia polyantha Wight Grown in Indonesia

Antioxidative activities of three bark extracts (methanol, methanol-water and water) from Eugenia polyantha Wight grown in Indonesia were evaluated using various in vitro assays; 2, 2-diphenyl-1-picrylhydrazyl radical-scavenging, hydrogen peroxide-scavenging and beta-carotene bleaching assays. From the assays, Eugenia polyantha bark extracts were found to be potential antioxidative activities. The methanol-water extract showed the highest level of free radical-scavenging activity (Effective dose (ED50) = 0.18 mg mL-1) and protection from beta-carotene bleaching (85.7% at 100 microg mL-1). The methanol-water extracts showed the highest total phenolic content (856 mg gallic acid equivalent (GAE)/g and 161 mg catechin equivalent (CE)/g) and total antioxidative capacity (449 mg ascorbic acid equivalent (AAE)/g). Furthermore, it exhibited dose-dependent antioxidative activities. A relationship between total antioxidative capacity and total phenolic content was recognized in the three extracts from Eugenia polyantha bark.

Wild-type MIC distributions and epidemiological cutoff values for the echinocandins and Candida spp.

We tested a global collection of Candida sp. strains against anidulafungin, caspofungin, and micafungin, using CLSI M27-A3 broth microdilution (BMD) methods, in order to define wild-type (WT) populations and epidemiological cutoff values (ECVs). From 2003 to 2007, 8,271 isolates of Candida spp. (4,283 C. albicans, 1,236 C. glabrata, 1,238 C. parapsilosis, 996 C. tropicalis, 270 C. krusei, 99 C. lusitaniae, 88 C. guilliermondii, and 61 C. kefyr isolates) were obtained from over 100 centers worldwide. The modal MICs (in microg/ml) for anidulafungin, caspofungin, and micafungin, respectively, for each species were as follows: C. albicans, 0.03, 0.03, 0.015; C. glabrata, 0.06, 0.03, 0.015; C. tropicalis, 0.03, 0.03, 0.015; C. kefyr, 0.06, 0.015, 0.06; C. krusei, 0.03, 0.06, 0.06; C. lusitaniae, 0.05, 0.25, 0.12; C. parapsilosis, 2, 0.25, 1; and C. guilliermondii, 2, 0.5. 05. The ECVs, expressed in microg/ml (percentage of isolates that had MICs that were less than or equal to the ECV is shown in parentheses) for anidulafungin, caspofungin, and micafungin, respectively, were as follows: 0.12 (99.7%), 0.12 (99.8%), and 0.03 (97.7%) for C. albicans; 0.25 (99.4%), 0.12 (98.5%), and 0.03 (98.2%) for C. glabrata; 0.12 (98.9%), 0.12 (99.4%), and 0.12 (99.1%) for C. tropicalis; 0.25(100%), 0.03 (100%), and 0.12 (100%) for C. kefyr; 0.12 (99.3%), 0.25 (96.3%), and 0.12 (97.8%) for C. krusei; 2 (100%), 0.5 (98.0%), and 0.5 (99.0%) for C. lusitaniae; 4 (100%), 1 (98.6%), and 4 (100%) for C. parapsilosis; 16 (100%), 4 (95.5%), and 4 (98.9%) for C. guilliermondii. These WT MIC distributions and ECVs will be useful in surveillance for emerging reduced echinocandin susceptibility among Candida spp. and for determining the importance of various FKS1 or other mutations.

Crystal structure of Bacillus anthracis dihydrofolate reductase with the dihydrophthalazine-based trimethoprim derivative RAB1 provides a structural explanation of potency and selectivity.

Bacillus anthracis possesses an innate resistance to the antibiotic trimethoprim due to poor binding to dihydrofolate reductase (DHFR); currently, there are no commercial antibacterials that target this enzyme in B. anthracis. We have previously reported a series of dihydrophthalazine-based trimethoprim derivatives that are inhibitors for this target. In the present work, we have synthesized one compound (RAB1) displaying favorable 50% inhibitory concentration (54 nM) and MIC (< or =12.8 microg/ml) values. RAB1 was cocrystallized with the B. anthracis DHFR in the space group P2(1)2(1)2(1), and X-ray diffraction data were collected to a 2.3-A resolution. Binding of RAB1 causes a conformational change of the side chain of Arg58 and Met37 to accommodate the dihydrophthalazine moiety. Unlike the natural substrate or trimethoprim, the dihydrophthalazine group provides a large hydrophobic anchor that embeds within the DHFR active site and accounts for its selective inhibitory activity against B. anthracis.

Chemical composition, antioxidant, anti-elastase, and anti-inflammatory activities of Illicium anisatum essential oil

The essential oil of air-dried Illicium anisatum (Illiciaceae), obtained by hydrodistillation was analyzed by gas chromatography-mass spectrometry (GC-MS). Fifty-two components were identified in the essential oil and the main component was eucalyptol (21.8 %). The antioxidant and anti-elastase activities of the essential oil were also investigated; the essential oil exhibited moderate DPPH scavenging and anti-elastase activities. To clarify the mechanism of the anti-inflammatory activities of I. anisatum essential oil (IAE), we evaluated whether it could modulate the production of nitric oxide (NO) and prostaglandin E2 (PGE2) by activated macrophages. The results indicate that IAE is an effective inhibitor of LPS-induced NO and PGE2 production in RAW 264.7 cells. These inhibitory activities were accompanied by dose-dependent decreases in the expression of iNOS and COX-2 proteins and iNOS and COX-2 mRNA. In order to determine whether IAE can be safely applied to human skin, the cytotoxic effects of IAE were determined by colorimetric MTT assays in human dermal fibroblast and keratinocyte HaCaT cells. IAE exhibited low cytotoxicity at 100 microg mL-1. Based on these results, we suggest that IAE may be considered an anti-aging and anti-inflammatory candidate for cosmetic materials, but additional in vitro and in vivo tests have to be performed to prove its safety and efficacy.

β-Lactam Effects on Mixed Cultures of Common Respiratory Isolates as an Approach to Treatment Effects on Nasopharyngeal Bacterial Population Dynamics

Background Streptococcus pneumoniae, Streptococcus pyogenes and Haemophilus influenzae are bacteria present in the nasopharynx as part of normal flora. The ecological equilibrium in the nasopharynx can be disrupted by the presence of antibiotics.Methodology/Principal FindingsA computerized two-compartment pharmacodynamic model was used to explore β-lactam effects on the evolution over time of a bacterial load containing common pharyngeal isolates by simulating free serum concentrations obtained with amoxicillin (AMX) 875 mg tid, amoxicillin/clavulanic acid (AMC) 875/125 mg tid and cefditoren (CDN) 400 mg bid regimens over 24 h. Strains and MICs (µg/ml) of AMX, AMC and CDN were: S. pyogenes (0.03, 0.03 and 0.015), S. pneumoniae (2, 2 and 0.25), a β-lactamase positive H. influenzae (BL+; >16, 2 and 0.06) and a β-lactamase positive AMC-resistant H. influenzae (BLPACR, >16, 8 and 0.06). Mixture of identical 1∶1∶1∶1 volumes of each bacterial suspension were prepared yielding an inocula of ≈4×106 cfu/ml. Antibiotic concentrations were measured both in bacterial and in bacteria-free antibiotic simulations. β-lactamase production decreased AMX concentrations and fT>MIC against S. pneumoniae (from 43.2% to 17.7%) or S. pyogenes (from 99.9% to 24.9%), and eradication was precluded. The presence of clavulanic acid countered this effect of co-pathogenicity, and S. pyogenes (but not BL+ and S. pneumoniae) was eradicated. Resistance of CDN to TEM β-lactamase avoided this co-pathogenicity effect, and CDN eradicated S. pyogenes and H. influenzae strains (fT>MIC >58%), and reduced in 94% S. pneumoniae counts (fT>MIC ≈25%).Conclusions/SignificanceCo-pathogenicity seems to be gradual since clavulanic acid countered this effect for strains very susceptible to AMX as S. pyogenes but not for strains with AMX MIC values in the limit of susceptibility as S. pneumoniae. There is a potential therapeutic advantage for β-lactamase resistant cephalosporins with high activity against streptococci.

Plasma and Tissue Depletion of Florfenicol and Florfenicol-amine in Chickens

Chickens were used to investigate plasma disposition of florfenicol after single intravenous (i.v.) and oral dose (20 mg kg-1 body weight) and to study residue depletion of florfenicol and its major metabolite florfenicol-amine after multiple oral doses (40 mg kg-1 body weight, daily for 3 days). Plasma and tissue samples were analyzed using a high-performance liquid chromatography (HPLC) method. After i.v. and oral administration, plasma concentration-time curves were best described by a two-compartment open model. The mean [ +/- standard deviation (SD)] elimination half-life (t1/2beta) of florfenicol in plasma was 7.90 +/- 0.48 and 8.34 +/- 0.64 h after i.v. and oral administration, respectively. The maximum plasma concentration was 10.23 +/- 1.67 microg mL-1, and the interval from oral administration until maximal concentration was 0.63 +/- 0.07 h. Oral bioavailability was found to be 87 +/- 16%. Florfenicol was converted to florfenicol-amine. After multiple oral dose (40 mg kg-1 body weight, daily for 3 days), in kidney and liver, concentrations of florfenicol (119.34 +/- 31.81 and 817.34 +/- 91.65 microg kg-1, respectively) and florfenicol-amine (60.67 +/- 13.05 and 48.50 +/- 13.07 microg kg-1, respectively) persisted for 7 days. The prolonged presence of residues of florfenicol and florfenicol-amine in edible tissues can play an important role in human food safety, because the compounds could give rise to a possible health risk. A withdrawal time of 6 days was necessary to ensure that the residues of florfenicol were less than the maximal residue limits or tolerance established by the European Union.

Viridicatumtoxin B, a new anti-MRSA agent from Penicillium sp. FR11

A new tetracycline-type antibiotic named viridicatumtoxin B along with the known compound viridicatumtoxin has been isolated from the mycelium of liquid fermentation cultures of Penicillium sp. FR11. The structure of viridicatumtoxin B was determined on the basis of MS and NMR data. Viridicatumtoxin B inhibited the growth of Staphylococcus aureus including methicillin-resistant S. aureus and quinolone-resistant S. aureus with MIC (microg/ml) of 0.5, which is similar with that of vancomycin, but 8-64 times higher activity than that of tetracycline.

The Clinical Efficacy of Kanamycin for &lt;i&gt;Mycobacterium avium&lt;/i&gt; Complex Disease

No previous reports have compared clarithromycin (CAM), rifampicin (RFP) and ethambutol (EB) containing regimens with and without an aminoglycoside antibiotic kanamycin (KM) for the treatment of pulmonary Mycobacterium avium complex (MAC) disease. We conducted a retrospective study to investigate the clinical efficacy of KM using data from 40 patients who received combined chemotherapy for MAC disease with or without KM in the National Hospital Organization Tokyo Hospital from July, 1999 to December, 2005. All patients were administered CAM, RFP and EB for 6 to 12 months, and 20 of the 40 simultaneously received combined chemotherapy with KM. The difference in the backgrounds of the groups was not statistically significant. The improvement rates of clinical symptoms and radiological findings were significantly higher in the KM-treated group than in the KM-untreated group (75% versus 35% and 80% versus 25%). Moreover, the sputum relapse rate was significantly lower in the KM-treated group (18% versus 75%). However, there were no significant differences in the sputum conversion rate (55% with KM versus 40% without KM). As for adverse reactions, there were no significant differences between the groups. Furthermore, we examined time-kill kinetics of KM and streptomycin (SM) against a clinical isolate of M. avium. Most M. avium was killed by KM and SM at concentrations higher than MIC (8 microg/ml), and concentration- and time-dependent killing by KM and SM were almost identical. These observations indicate that KM is effective for treatment of patients with MAC disease.

Influence of Vancomycin Minimum Inhibitory Concentration on the Treatment of Methicillin-Resistant Staphylococcus aureus Bacteremia

Vancomycin treatment failure in methicillin-resistant Staphylococcus aureus (MRSA) bacteremia is not uncommon, even when MRSA is susceptible to vancomycin. The aim of our study was to evaluate whether vancomycin minimum inhibitory concentration has any influence on the mortality associated with MRSA bacteremia. A total of 414 episodes of MRSA bacteremia were prospectively followed-up from 1991 through 2005. MIC of vancomycin for the first isolate was determined by E-test. Clinical variables recorded were age, comorbidity, prior administration of vancomycin, use of corticosteroids, prognosis of underlying disease, source of bacteremia, the need for mechanical ventilation, shock, and mortality. A "treatment group" variable was created and defined as follows: (1) receipt of empirical vancomycin and an isolate with a vancomycin MIC of 1 microg/mL (38 episodes), (2) receipt of empirical vancomycin and an isolate with a vancomycin MIC of 1.5 microg/mL (90 episodes), (3) receipt of empirical vancomycin and an isolate with a vancomycin MIC of 2 microg/mL (40 episodes), and (4) receipt of inappropriate empirical therapy (246 episodes). Univariate and multivariate analyses were performed. Episodes caused by strains with a vancomycin MIC of 2 microg/mL were independently associated with a lower risk of shock (odds ratio [OR], 0.33; 95% confidence interval [CI], 0.15-0.75). Multivariate analysis selected receipt of empirical vancomycin and an isolate with a vancomycin MIC of 2 microg/mL (OR, 6.39; 95% CI, 1.68-24.3), receipt of inappropriate empirical therapy (OR, 3.62; 95% CI, 1.20-10.9), increasing age (OR, 1.02; 95% CI, 1.00-1.04), use of corticosteroids (OR, 1.85; 95% CI, 1.04-3.29), an ultimately (OR, 10.2; 95% CI, 2.85-36.8) or rapidly (OR, 1.81; 95% CI, 1.06-3.10) fatal underlying disease, high-risk (OR, 3.60; 95% CI, 1.89-6.88) and intermediate-risk (OR, 2.18; 95% CI, 1.17-4.04) sources of bacteremia, and shock (OR, 7.38; 95% CI, 4.11-13.3) as the best predictors of mortality. Mortality associated with MRSA bacteremia was significantly higher when the empirical antibiotic was inappropriate and when vancomycin was empirically used for treatment of infection with strains with a high vancomycin MIC (>1 microg/mL).

Gradient HPLC analysis of raloxifene hydrochloride and its application to drug quality control

A rapid, sensitive and selective method for the determination of raloxifene hydrochloride (RLX) in pure drug and in tablets was developed using gradient high performance liquid chromatography (HPLC). The devised method involved separation of RLX on a reversed phase Hypersil ODS column and determination with UV detection at 284 nm. The standard curve was linear (R = 0.999) over the concentration range of 50-600 microg mL-1 with a detection limit of 0.04 microg mL-1 and a quantification limit of 0.16 microg mL-1. Intra-day and inter-day precision and accuracy of the method were established according to the current ICH guidelines. Intra-day RSD values at three QC levels (250, 450 and 550 microg mL-1) were 0.2-0.5%, based on the peak area. The intra-day relative error (er) was between 0.2 and 0.5%. The developed method was successfully applied to the determination of RLX in tablets and the results were statistically compared with those obtained by a literature method. Accuracy, evaluated by means of the spike recovery method, was the excellent with percent recovery in the range 97.7-103.2 with precision in the range 1.6-2.2%. No interference was observed from the co-formulated substances. The method was economical in terms of the time taken and the amount of solvent used.

Comparativein vitroactivities of posaconazole, voriconazole, itraconazole, and amphotericin B againstAspergillusandRhizopus, and synergy testing forRhizopus

We compared the in vitro activities of posaconazole, voriconazole, itraconazole, and amphotericin B against clinical isolates of Aspergillus spp. and Rhizopus spp., and explored the in vitro interaction between posaconazole and amphotericin B against Rhizopus spp. Clinical strains of 82 Aspergillus spp. (43 Aspergillus fumigatus, 29 A. flavus, 7 A. niger, 2 A. terreus, 1 A. nidulans) and 11 Rhizopus oryzae isolates were tested in accordance with CLSI M38-A microdilution guidelines. In vitro activity of posaconazole against Aspergillus spp. was also investigated with the Etest. The combination of posaconazole and amphotericin B against R. oryzae isolates was investigated by the checkerboard methodology. Voriconazole was the most active drug in vitro against Aspergillus spp., followed by posaconazole, itraconazole, and amphotericin B, in order of decreasing activity. In studies with R. oryzae isolates, posaconazole was found to be the most potent drug followed by itraconazole and amphotericin B. Voriconazole had no meaningful activity against Rhizopus. Posaconazole Etest MICs (microg/ml) with Aspergillus spp. were found to be considerably lower than those obtained with the CLSI microdilution method (4-9 and 3-7 two-fold lower than CLSI MICs at 24 and 48 h, respectively). The interaction between posaconazole and amphotericin B was indifferent for all R. oryzae isolates tested; importantly no antagonism was observed.

Antimicrobial Lexitropsins Containing Amide, Amidine, and Alkene Linking Groups

The synthesis and properties of 80 short minor groove binders related to distamycin and the thiazotropsins are described. The design of the compounds was principally predicated upon increased affinity arising from hydrophobic interactions between minor groove binders and DNA. The introduction of hydrophobic aromatic head groups, including quinolyl and benzoyl derivatives, and of alkenes as linkers led to several strongly active antibacterial compounds with MIC for Staphylococcus aureus, both methicillin-sensitive and -resistant strains, in the range of 0.1-5 microg mL-1, which is comparable to many established antibacterial agents. Antifungal activity was also found in the range of 20-50 microg mL-1 MIC against Aspergillus niger and Candida albicans, again comparable with established antifungal drugs. A quinoline derivative was found to protect mice against S. aureus infection for a period of up to six days after a single intraperitoneal dose of 40 mg kg-1.

Long-Wavelength Fluorescence Polarization Immunoassay: Determination of Amikacin on Solid Surface and Gliadins in Solution

The versatility of the fluorescence polarization immunoassay (FPIA) is increased by using two long-wavelength labels, Nile Blue and a ruthenium(II) chelate. The first label has been used to study the potential of FPIA on a solid surface using dry reagent technology. The aminoglycoside antibiotic amikacin has been used as an analyte model, and the method has been applied to the analysis of serum samples. The second label has been used to show the practical application of FPIA to the determination of macromolecules, using gliadins as an analyte model, which have been determined in gluten-free food. Very low amounts of anti-amikacin antibodies and amikacin-Nile Blue tracer were immobilized onto nitrocellulose membranes, for the development of the amikacin method, and the consumption of reagents is lower than in conventional FPIA. Only the addition of the standard or sample extract at an adequate pH is required at the analysis time. The analyte displaces the tracer from the tracer-antibody immunocomplex, obtaining a decrease in the fluorescence polarization proportional to the analyte concentration. The gliadin-Ru(II) chelate tracer shows a relatively long lifetime, which allows the observation of differences in fluorescence polarization values between the tracer-antibody complex and the tracer alone. The dynamic range of the calibration graphs for both analytes is 0.5-10 microg mL-1 and the detection limits are 0.1 and 0.09 microg mL-1 for amikacin and gliadins, respectively. The study of the precision gave values of relative standard deviations lower than 5 and 1.5% for the amikacin and gliadin methods, respectively. Amikacin was determined in human serum samples using a previous deproteinization step with acetonitrile, obtaining recovery values in the range 83.4-122.8%. The gliadin method was applied to the analysis of gluten-free food samples by using a previous extraction step. The recovery study gave values between 94.3 and 105.0%.

Monoclonal Antibody Production Using a New Supermacroporous Cryogel Bioreactor

A supermacroporous cryogel bioreactor has been developed to culture hybridoma cells for long-term continuous production of monoclonal antibodies (mAb). Hybridoma clone M2139, secreting antibodies against J1 epitope (GERGAAGIAGPK; amino acids, 551-564) of collagen type II, are immobilized in the porous bed matrix of a cryogel column (10 mL bed volume). The cells got attached to the matrix within 48 h after inoculation and grew as a confluent sheet inside the cryogel matrix. Cells were in the lag phase for 15 days and secreted mAb into the circulation medium. Glucose consumption and lactic acid production were also monitored, and during the exponential phase (approximately 20 days), the hybridoma cell line consumed 0.75 mM day-1 glucose, produced 2.48 mM day-1 lactic acid, and produced 6.5 microg mL-1 day-1 mAb during the exponential phase. The mAb concentration reached 130 microg mL-1 after continuous run of the cryogel column for 36 days. The yield of the mAb after purification was 67.5 mg L-1, which was three times greater than the mAb yield obtained from T-flask batch cultivation. Even after the exchange of medium reservoir, cells in the cryogel column were still active and had relatively stable mAb production for an extended period of time. The bioreactor was operated continuously for 55 days without any contamination. The results from ELISA as well as arthritis experiments demonstrate that the antibodies secreted by cells grown on the cryogel column did not differ from antibodies purified from the cells grown in commercial CL-1000 culture flasks. Thus, supermacroporous cryogels can be useful as a supporting material for productive hybridoma cell culture. Cells were found to be viable inside the porous matrix of the cryogel during the study period and secreted antibodies continuously. The antibodies thus obtained from the cryogel reactor were found to be functionally active in vivo, as demonstrated by their capacity to induce arthritis in mice.

Antioxidant properties of the essential oil of Eugenia caryophyllata and its antifungal activity against a large number of clinical Candida species

Many essential oils are known to possess an antioxidant activity and antifungal properties and therefore they potentially act as antimycotic agents. Essential oil of clove (Eugenia caryophyllata) was isolated by hydrodistillation. The chemical composition of the essential oil was analysed by gas chromatography and gas chromatography/mass spectroscopy. The antioxidant effect of the tested oil was evaluated by measuring its 2,2-diphenyl-l-1-picrylhydrazil radical scavenging ability and the antiradical dose required to cause a 50% inhibition (IC50) was recorded. The antifungal activity of essential oils was evaluated against 53 human pathogenic yeasts using a disc paper diffusion method. Our results show that the major components present in the clove bund oil were eugenol (88.6%), eugenyl acetate (5.6%), beta-caryophyllene (1.4%) and 2-heptanone (0.9%). The tested essential oil exhibited a very strong radical scavenging activity (IC50 = 0.2 microg ml-1) when compared with the synthetic antioxidant (tert-butylated hydroxytoluene, IC50 = 11.5 microg ml-1). On the other hand, this species displayed an important antifungal effect against the tested strains. It is clear that clove oil shows powerful antifungal activity; and it can be used as an easily accessible source of natural antioxidants and in pharmaceutical applications.

Laparoscopic cholecystectomy under segmental thoracic spinal anaesthesia: a feasibility study

Laparoscopic surgery is normally performed under general anaesthesia, but regional techniques have been found beneficial, usually in the management of patients with major medical problems. Encouraged by such experience, we performed a feasibility study of segmental spinal anaesthesia in healthy patients. Twenty ASA I or II patients undergoing elective laparoscopic cholecystectomy received a segmental (T10 injection) spinal anaesthetic using 1 ml of bupivacaine 5 mg ml-1 mixed with 0.5 ml of sufentanil 5 microg ml-1. Other drugs were only given (systemically) to manage patient anxiety, pain, nausea, hypotension, or pruritus during or after surgery. The patients were reviewed 3 days postoperatively by telephone. The spinal anaesthetic was performed easily in all patients, although one complained of paraesthesiae which responded to slight needle withdrawal. The block was effective for surgery in all 20 patients, six experiencing some discomfort which was readily treated with small doses of fentanyl, but none requiring conversion to general anaesthesia. Two patients required midazolam for anxiety and two ephedrine for hypotension. Recovery was uneventful and without sequelae, only three patients (all for surgical reasons) not being discharged home on the day of operation. This preliminary study has shown that segmental spinal anaesthesia can be used successfully and effectively for laparoscopic surgery in healthy patients. However, the use of an anaesthetic technique involving needle insertion into the vertebral canal above the level of termination of the spinal cord requires great caution and should be restricted in application until much larger numbers of patients have been studied.

Low-dose remifentanil to suppress haemodynamic responses to noxious stimuli in cardiac surgery: a dose-finding study

High-dose remifentanil (1-5 microg kg-1 min-1), commonly used for cardiac surgery, has been associated with muscle rigidity, hypotension, bradycardia, and reduced cardiac output. The aim of this study was to determine an optimal lower remifentanil dose, which should be accompanied by fewer adverse events, that still effectively suppresses haemodynamic responses to typical stressful stimuli (i.e. intubation, skin incision, and sternotomy). Total i.v. anaesthesia consisted of a target-controlled propofol (2 microg ml-1) and a remifentanil infusion. Forty patients were allocated to receive either a constant infusion of remifentanil at 0.1 microg kg-1 min-1 or up-titrations to 0.2, 0.3, or 0.4 microg kg-1 min-1, respectively, 5 min before each stimulus. Subsequently, changes in heart rate and mean arterial blood pressure were recorded for 8 min. Increases exceeding 20% of baseline were considered to be of clinical relevance. Patients who exhibited these alterations were termed responders. The number of responders was less with the two higher remifentanil dosages (P<0.05) while propofol target doses could either be kept at the same level or even be reduced without affecting the plane of anaesthesia. Although single phenylephrine bolus had to be applied more frequently in these two groups (P<0.05), no severe haemodynamic depression was observed. Remifentanil at 0.3 and 0.4 microg kg-1 min-1 in combination with a target-controlled propofol infusion in the pre-bypass period is well tolerated. It appears to mitigate potentially hazardous haemodynamic responses from stressful stimuli equally well as higher doses when compared with data from the literature.