Synthesis and biological evaluation of novel salicylidene uracils: Cytotoxic activity on human cancer cell lines and inhibitory action on enzymatic activity

A series of salicylidene uracil (1-18) derived from 5-aminouracil and substituted salicylaldehydes were analyzed for cytotoxic activity and enzyme inhibitory potency. Nine out of eighteen derivatives (6-8, 10, 12-15, 18) are novel molecules synthesized for the first time in this work, and other derivatives were previously synthesized by our group. The compounds were characterized by Proton nuclear magnetic resonance, carbon nuclear magnetic resonance, fourier transform infrared spectroscopy, and elemental analysis. All compounds were tested for their in vitro cytotoxicity against PC-3 (human prostate adenocarcinoma), A549 (human alveolar adenocarcinoma), and SHSY-5Y (human neuroblastoma) cancer cell lines and the nontumorigenic HEK293 (human embryonic kidney cells) cell line. The 3,5-di-tert-butylsalicylaldehyde derived compound (8) was toxic to PC-3 human prostate adenocarcinoma cells, showing a promising IC50 value at 7.05 ± 0.76 μM. The present study also aimed to evaluate the inhibitory effects of the compounds against several key enzymes, namely carbonic anhydrase I and II (CA I and CA II), acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and glutathione reductase (GR), which are implicated in various global disorders, such as Alzheimer's disease, epilepsy, cancer, malaria, diabetes, and glaucoma. The inhibitory profiles of the tested compounds were assessed by determining their Ki values, which ranged from 2.96 to 9.24 nM for AChE, 3.78 to 12.57 nM for BChE, 8.42 to 25.74 nM for CA I, 7.24 to 19.74 nM for CA II, and 0.541 to 1.124 μM for GR. Molecular docking studies were also performed for all compounds. Most derivatives exhibited much more effective inhibitory action compared with clinically used standards. Thus, our findings indicate that the salicylidene derivatives presented in this study are promising drug candidates that need further evaluation.

A new carbonic anhydrase identified in the Gram-negative bacterium (Chromohalobacter sp.) and the interaction of anions with the enzyme

In this study, the characterization and inhibition characteristic of α-class carbonic anhydrase from Chromohalobacter (ChCA) was documented for the first time. The carbonic anhydrase enzyme had 47.77% yield and 54.45-fold purity. The specific activity of the enzyme was determined as 318.52 U/mg proteins. Alternative substrate (4-nitrophenyl trifluoroacetate, 4-nitrophenyl phosphate, 4-nitrophenyl sulphate and 4-nitrophenyl acetate) were tested for the enzyme. K_M and V_max values for 4-nitrophenyl acetate were 4.57 mM and 4.29 EU/mL and for 4-nitrophenyl trifluoroacetate were 2.39 mM and 2.41 EU/mL. The anions, Cl^-, NO₂^-, NO₃^-, Br^-, ClO₃^-, ClO₄^-, I^-, CO₃^2- and SO₄^2-, inhibited the ChCA hydratase activity. Among nine anions, the strongest inhibitor activities were obtained with micro molar concentrations of NO₂^-, NO₃^-, Br^-, I^-, CO₃^2- (K_I values of 160-255 μM). Other four anions tested (Cl^-, ClO₃^-, ClO₄^- and SO₄^2-) showed moderate inhibitory activities (K_I values of 680-813.5 μM). The results obtained demonstrate that the anions we tested inhibit the Chromohalobacter CA (ChCA) enzyme as in other α-CAs in mammals; however, the susceptibility of ChCA resulted from anions differed significantly from that of other organism CAs.

Design, synthesis and molecular modelling studies of some pyrazole derivatives as carbonic anhydrase inhibitors

In this study, newly synthesised compounds 6, 8, 10 and other compounds (1-5, 7 and 9) and their inhibitory properties against the human isoforms hCA I and hCA II were reported for the first time. Compounds 1-10 showed effective inhibition profiles with KI values in the range of 5.13-16.9 nM for hCA I and of 11.77-67.39 nM against hCA II, respectively. Molecular docking studies were also performed with Glide XP to get insight into the inhibitory activity and to evaluate the binding modes of the synthesised compounds to hCA I and II. More rigorous binding energy calculations using MM-GBSA protocol which agreed well with observed activities were then performed to improve the docking scores. Results of in silico calculations showed that all compounds obey drug likeness properties. The new compounds reported here might be promising lead compounds for the development of new potent inhibitors as alternatives to classical hCA inhibitors.

Synthesis of N-phenylsulfonamide derivatives and investigation of some esterase enzymes inhibiting properties

In this study, synthesis of nine N-phenylsulfonamide derivatives was designed by starting from aniline, which is the simplest aromatic amine. These compounds were obtained in yields between 69 and 95%. Inhibitory properties of synthesized compounds on carbonic anhydrase I (CA I), CA II isoenzymes, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes were investigated. Inhibitors of CA isoenzymes are important therapeutic targets, particularly due to their preventive/activation potential in the treatment of diseases such as edema, glaucoma, cancer and osteoporosis. Cholinesterase inhibitors are valuable compounds that can be used in many different therapeutic applications, including Alzheimer's disease. The compound 8 for CA I, AChE and BChE, 2 for CA II showed a very active inhibition profile (K_I 45.7 ± 0.46 for CA I, 33.5 ± 0.38 nM for CA II, 31.5 ± 0.33 nM for AChE and 24.4 ± 0.29 nM for BChE). The results indicate that these N-phenyl-sulfonamide derivatives are potent CA and cholinesterases and new potential drugs.

Integrated Binary QSAR-Driven Virtual Screening and In Vitro Studies for Finding Novel hMAO-B-Selective Inhibitors

The increased activity of monoamine oxidase (MAO) enzymes may lead to serious consequences since they reduce the level of neurotransmitters and are associated with severe neurodegenerative diseases. The inhibition of this enzyme, especially the B isoform, plays a vital role in the treatment of Parkinson's disease (PD). This study is aimed to find novel human MAO-B (hMAO-B) selective inhibitors. A total of 256.750 compounds from the Otava small molecules database were virtually screened gradually by employing several screening techniques for this purpose. Initially, a high-throughput virtual screening (HTVS) method was employed, and 10% of the molecules having high docking scores were subjected to binary QSAR models for further screening of their therapeutic activities against PD, Alzheimer's disease (AD), and depression as well as for their toxicity and pharmacokinetic properties. Then, enzyme selectivity of the ligands towards the A and B forms that passed through all the filters were studied using the induced-fit docking method and molecular dynamics simulations. At the end of this exhaustive research, we identified two hit molecules ligand 3 (Otava ID: 7131545) and ligand 4 (Otava ID: 7566820). Based on the in vitro results, these two compounds (ligands 3 and 4) together with ligands 1 and 2 found in our previous study showed activity at the nanomolar (nM) level, and the results indicated that these four ligands inhibit hMAO-B better than the FDA-approved drug selegiline.

Design, synthesis, characterization of peripherally tetra-pyridine-triazole-substituted phthalocyanines and their inhibitory effects on cholinesterases (AChE/BChE) and carbonic anhydrases (hCA I, II and IX)

In this study, phthalocyanine precursors (5and9) and 1,2,3-triazole-substituted metal-free and metallo phthalocyanines (9a–c) were designed and synthesized for the first time and evaluatedin vitrofor key molecular targets.

Comparison of blood carbonic anhydrase activity of athletes performing interval and continuous running exercise at high altitude

The effects of high-intensity interval and continuous exercise on erythrocytes carbonic anhydrase (CA, EC 4.2.1.1) activity levels were scarcely investigated up until now. Here we present a study focused on the CA activity from erythrocytes of athletes experiencing interval and continuous training for 6 weeks, during cold weather and at high altitude (> 1600 m). We observed a 50% increase in the blood CA activity at the second week after initiation of the training in both interval and continuos running groups, whereas the control group did not experience any variation in the enzyme activity levels. In the trained individuals a mild decrease in their body mass, BMI and an increased [Formula: see text] were also observed. The CA activity returned at the basal values after 4-6 weeks after the training started, probably proving that a metabolic compensation occurred without the need of an enhanced enzyme activity. The unexpected 50% rise of activity for an enzyme which acts as a very efficient catalyst for CO2 hydration/bicarbonate dehydration, such as the blood CA, deserves further investigations for better understanding the physiologic basis of this phenomenon.

Inhibitory Effects and Kinetic-Docking Studies of Xanthohumol FromHumulus lupulusCones Against Carbonic Anhydrase, Acetylcholinesterase, and Butyrylcholinesterase

Xanthohumol is an essential prenyl flavonoid of Humulus lupulus L. cones, and the taste of beer is due to this compound. Lately, xanthohumol has earned significant interest due to its potential anticancer, antigenotoxic, and adipogenesis effects. In this paper, the inhibitory effects of xanthohumol on human carbonic anhydrase isozymes (hCAI and hCAII), acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) were studied. Also, molecular docking studies were used to investigate ligand interaction diagrams of xanthohumol at the binding cavities of hCAI and II. Xanthohumol was isolated from hop cones by silica gel column chromatography. Carbonic anhydrase enzyme activities were determined spectrophotometrically. In addition, molecular modeling approaches were used for the hCAI and hCAII isoenzymes. Ellman’s method was used for the inhibitor activities of AChE and BChE. The KIvalues of xanthohumol were detected as 0.085 µM for hCAI, 0.049 µM for hCAII, 95.5 nM for AChE, and 124.9 nM for BChE. In conclusion, xanthohumol can pleiotropically exert health promoting effects. It has antiglaucoma, anticonvulsant, antiepileptic, and anticancer activities due to its potent inhibitory effects on hCAI and hCAII. These findings may open new avenues for the design and development of novel hCAI, hCAII, AChE, and BChE inhibitors compared with sulfonamide/sulfamate.

Triazole substituted metal-free, metallo-phthalocyanines and their water soluble derivatives as potential cholinesterases inhibitors: Design, synthesis and in vitro inhibition study

In this study, 1,2,3-triazole substituted metal-free and metallo phthalocyanines (4, 5, 6) and their water soluble derivatives (4a, 5a, 6a) were designed, synthesized for the first time and tested in vitro on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. Most phthalocyanines exhibited good inhibitory activities on these enzymes. Among the six phthalocyanines and starting compounds, 4a showed the most interesting profile as a submicromolar selective inhibitor of AChE (IC₅₀ = 0.040 µM) and 5a showed the most effective inhibitor of BChE (IC₅₀ = 0.1198 µM).

Effect of Intraoperative High Positive End-Expiratory Pressure (PEEP) With Recruitment Maneuvers vs Low PEEP on Postoperative Pulmonary Complications in Obese Patients: A Randomized Clinical Trial

IMPORTANCE

An intraoperative higher level of positive end-expiratory positive pressure (PEEP) with alveolar recruitment maneuvers improves respiratory function in obese patients undergoing surgery, but the effect on clinical outcomes is uncertain.

OBJECTIVE

To determine whether a higher level of PEEP with alveolar recruitment maneuvers decreases postoperative pulmonary complications in obese patients undergoing surgery compared with a lower level of PEEP.

DESIGN, SETTING, AND PARTICIPANTS

Randomized clinical trial of 2013 adults with body mass indices of 35 or greater and substantial risk for postoperative pulmonary complications who were undergoing noncardiac, nonneurological surgery under general anesthesia. The trial was conducted at 77 sites in 23 countries from July 2014-February 2018; final follow-up: May 2018.

INTERVENTIONS

Patients were randomized to the high level of PEEP group (n = 989), consisting of a PEEP level of 12 cm H2O with alveolar recruitment maneuvers (a stepwise increase of tidal volume and eventually PEEP) or to the low level of PEEP group (n = 987), consisting of a PEEP level of 4 cm H2O. All patients received volume-controlled ventilation with a tidal volume of 7 mL/kg of predicted body weight.

MAIN OUTCOMES AND MEASURES

The primary outcome was a composite of pulmonary complications within the first 5 postoperative days, including respiratory failure, acute respiratory distress syndrome, bronchospasm, new pulmonary infiltrates, pulmonary infection, aspiration pneumonitis, pleural effusion, atelectasis, cardiopulmonary edema, and pneumothorax. Among the 9 prespecified secondary outcomes, 3 were intraoperative complications, including hypoxemia (oxygen desaturation with Spo2 ≤92% for >1 minute).

RESULTS

Among 2013 adults who were randomized, 1976 (98.2%) completed the trial (mean age, 48.8 years; 1381 [69.9%] women; 1778 [90.1%] underwent abdominal operations). In the intention-to-treat analysis, the primary outcome occurred in 211 of 989 patients (21.3%) in the high level of PEEP group compared with 233 of 987 patients (23.6%) in the low level of PEEP group (difference, -2.3% [95% CI, -5.9% to 1.4%]; risk ratio, 0.93 [95% CI, 0.83 to 1.04]; P = .23). Among the 9 prespecified secondary outcomes, 6 were not significantly different between the high and low level of PEEP groups, and 3 were significantly different, including fewer patients with hypoxemia (5.0% in the high level of PEEP group vs 13.6% in the low level of PEEP group; difference, -8.6% [95% CI, -11.1% to 6.1%]; P < .001).

CONCLUSIONS AND RELEVANCE

Among obese patients undergoing surgery under general anesthesia, an intraoperative mechanical ventilation strategy with a higher level of PEEP and alveolar recruitment maneuvers, compared with a strategy with a lower level of PEEP, did not reduce postoperative pulmonary complications.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02148692.

Protective ventilation with high versus low positive end-expiratory pressure during one-lung ventilation for thoracic surgery (PROTHOR): study protocol for a randomized controlled trial

BACKGROUND

Postoperative pulmonary complications (PPC) may result in longer duration of in-hospital stay and even mortality. Both thoracic surgery and intraoperative mechanical ventilation settings add considerably to the risk of PPC. It is unclear if one-lung ventilation (OLV) for thoracic surgery with a strategy of intraoperative high positive end-expiratory pressure (PEEP) and recruitment maneuvers (RM) reduces PPC, compared to low PEEP without RM.

METHODS

PROTHOR is an international, multicenter, randomized, controlled, assessor-blinded, two-arm trial initiated by investigators of the PROtective VEntilation NETwork. In total, 2378 patients will be randomly assigned to one of two different intraoperative mechanical ventilation strategies. Investigators screen patients aged 18 years or older, scheduled for open thoracic or video-assisted thoracoscopic surgery under general anesthesia requiring OLV, with a maximal body mass index of 35 kg/m2, and a planned duration of surgery of more than 60 min. Further, the expected duration of OLV shall be longer than two-lung ventilation, and lung separation is planned with a double lumen tube. Patients will be randomly assigned to PEEP of 10 cmH2O with lung RM, or PEEP of 5 cmH2O without RM. During two-lung ventilation tidal volume is set at 7 mL/kg predicted body weight and, during OLV, it will be decreased to 5 mL/kg. The occurrence of PPC will be recorded as a collapsed composite of single adverse pulmonary events and represents the primary endpoint.

DISCUSSION

PROTHOR is the first randomized controlled trial in patients undergoing thoracic surgery with OLV that is adequately powered to compare the effects of intraoperative high PEEP with RM versus low PEEP without RM on PPC. The results of the PROTHOR trial will support anesthesiologists in their decision to set intraoperative PEEP during protective ventilation for OLV in thoracic surgery.

TRIAL REGISTRATION

The trial was registered in clinicaltrials.gov ( NCT02963025 ) on 15 November 2016.

Inhibition of acetylcholinesterase and butyrylcholinesterase with uracil derivatives: kinetic and computational studies

Acetylcholinesterase (AChE) and Butyrylcholinesterase (BuChE) inhibitors are interesting compounds for different therapeutic applications, among which Alzheimer’s disease. Here, we investigated the inhibition of these cholinesterases with uracil derivatives. The mechanism of inhibition of these enzymes was observed to be due to obstruction of the active site entrance by the inhibitors scaffold. Molecular docking and molecular dynamics (MD) simulations demonstrated the possible key interactions between the studied ligands and amino acid residues at different regions of the active sites of AChE and BuChE. Being diverse of the classical AChE and BuChE inhibitors, the investigated uracil derivatives may be used as lead molecules for designing new therapeutically effective enzyme inhibitors.

Effects of aryl methanesulfonate derivatives on acetylcholinesterase and butyrylcholinesterase

There is a dire need for new treatments for Alzheimer's disease (AD). Principal drugs have reached maturity, and the number of people affected by AD is growing at a rapid rate. After years of research and many clinical trials, only symptomatic treatments are available. An effective disease-modifying drug for AD needs to be discovered. The research presented in this paper aims to facilitate in the discovery of new potential targets that could help in the ongoing AD research. Aryl methanesulfonate derivatives were screened for their acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activities. IC₅₀ values between 0.660 and 3.397 µM against AChE and 0.885 and 2.596 µM against BuChE were obtained.

Pyridazinone substituted benzenesulfonamides as potent carbonic anhydrase inhibitors

A series of sulfonamide derivatives (2a-l) incorporating substituted pyridazinone moieties were investigated for the inhibition of two human cytosolic carbonic anhydrase isoforms, hCA I and hCA II. All these compounds, together with the clinically used sulfonamide acetazolamide were investigated as inhibitors of the physiologically relevant isozymes I and II. These sulfonamides showed very strong inhibition against all these isoforms with K(I)'s in the range of 0.98-8.5 nM which makes such molecules possible to be used as leads for discovery of novel effective CA inhibitors targeting other isoforms with medicinal chemistry applications.

Assessment of left atrial functions in cardiac syndrome X

OBJECTIVE

Cardiac syndrome X (CSX) affects left ventricular functions due to myocardial ischaemia. In this study our aim was to determine the changes in left atrial functions in patients with CSX.

PATIENTS AND METHODS

One-hundred patients (M/F; 57/43) diagnosed with CSX in whom ischaemia was detected at exercise test and myocardial perfusion scintigrapghy with normal coronary angiogram and control group of 80 subjects (M/F; 40/40) were recruited into the study. In transthoracic echocardiography and tissue doppler echocardiography, left ventricular and atrial functions were recorded.

RESULTS

As compared to control group,left ventricular diastolic functions were impaired (E/A; 0.95 ± 0.18 vs 1.11 ± 0.29 p < 0.001), left ventricular end-diastolic pressures were increased (E/Em; 8.1 ± 1.85 vs 6.9 ± 1.74 p < 0.05), and left atrial maximum volume, left atrial pre-A volume,left atrial minimum volume were increased in patients with CSX. Left atrial conduit volume was significantly decreased in patients with cardiac syndrome. Left atrial passive emptying volume (LAPEV), left atrial active emptying volume (LAAEV) and left atrial total emptying volume (LATEV) were significantly increased in patients with cardiac syndrome X. Left atrial passive ejection fration (LAPEF) was found similar between the study groups.Left atrial active ejection fraction (LAAEF) was found significantly increased (37.85 ± 11.89 vs 33.60 ± 9.21; p = 0.009) in patients with CSX. Left atrial total ejection fraction (LATEF) was increased in the group with cardiac syndrome X but it didn't reach statistical significance (60.85 ± 8.73 vs 58.36 ± 8.29; p = 0.054).

CONCLUSIONS

Left atrial active contractile pump function increase in response to impaired left ventricular diastolic functions in CSX. Increased left atrial pump function represents a compensatory mechanism in patients with CSX. These results point out the importance of maintaining sinus rythm in patients with CSX.

Discovering novel carbonic anhydrase type IX (CA IX) inhibitors from seven million compounds using virtual screening and in vitro analysis

Carbonic anhydrase type IX (CA IX) enzyme is mostly over expressed in different cancer cell lines and tumor tissues. Potent CA IX inhibitors can be effective for adjusting the pH imbalance in tumor cells. In the present work, we represented the successful application of high throughput virtual screening (HTVS) of large dataset from ZINC database included of ∼7 million compounds to discover novel inhibitors of CA IX. HTVS and molecular docking were performed using consequence Glide/standard precision (SP), extra precision (XP) and induced fit docking (IFD) molecular docking protocols. For each compound, docking code calculates a set of low-energy poses and then exhaustively scans the binding pocket of the target with small compounds. Novel CA IX inhibitor candidates were suggested based on molecular modeling studies and a few of them were tested using in vitro analysis. These compounds were determined as good inhibitors against human CA IX target with Ki in the range of 0.85-1.58 μM. In order to predict the pharmaceutical properties of the selected compounds, ADME (absorption, distribution, metabolism and excretion) analysis was also carried out.

The effects of subfascial wound versus epidural levo-bupivacaine infusion on postoperative pain following hysterectomy

BACKGROUND

Local analgesia through wound catheters is used as a part of multimodal analgesia. The efficacy of continuous subfascial wound infusion compared to epidural analgesia is unknown for abdominal hysterectomy and bilateral salpingo-oophorectomy (TAH-BSO) via Pfannenstiel incision. The aim of this study was to compare the aforementioned two methods in this type of surgery for postoperative morphine consumption, acute and persistent postsurgical pain.

METHODS

Fifty patients enrolled in the study were randomly allocated to receive continuous 10 mL/h levobupivacaine either via subfascial (Group S) or epidural (Group E) catheter for 48 h postoperatively. In Group S 0.25% levobupivacaine was used for the first six hours and 0.125% thereafter, whereas Group E received 0.125% levobupivacaine throughout the study period. Cumulative morphine consumption, static and dynamic pain, gastrointestinal recovery, ambulation, patient satisfaction, hospital stay, as well as pain at 2nd and 6th months were evaluated.

RESULTS

Group S was superior to Group E regarding cumulative morphine consumption (16.8±7.2 mg and 28.7±10.3 mg respectively, P<0.001; mean difference -11.9 with 95% CI of the difference -17.1 to -6.7) and pain relief. Patient satisfaction was higher in Group S compared to Group E (P=0.006). Less postoperative vomiting was observed in Group S. No difference was detected in length of hospital stay and persistent postsurgical pain incidence.

CONCLUSION

Wound analgesia via subfascial catheter with continuous levobupivacaine infusion decreases postoperative morphine consumption and increases patient satisfaction compared to epidural analgesia with no difference in persistent postsurgical pain following TAH-BSO via Pfannenstiel incision.

Synthesis and biological activity of novel thiourea derivatives as carbonic anhydrase inhibitors

A new series of chiral thiourea derivatives (5a-5c) and thiourea containing benzimidazole moieties (9b-9e) were synthesized from different amino acids (l-valine, l-isoleucine, l-methionine, l-phenylalanine, and d-phenylglycine). The compounds were characterized and tested against the two most studied members of the pH regulatory enzyme family, carbonic anhydrase (CA, EC 4.2.1.1). KI values of the novel compounds were measured in the range of 3.4-73.6 μM for hCA I isozyme and 8.7-1.44.2 μM for hCA II isozyme, respectively. Phenol was also tested as standard in order to understand the structure activity relationship and the clinically used sulfonamide acetazolamide was tested for comparison reasons. All of the compounds exhibited competitive inhibition with 4-nitrophenylacetate as substrate.

The effects of chemical and radioactive properties of Tl-201 on human erythrocyte glutathione reductase activity

AIM

The aim of the study was to evaluate the inhibitory effects of thallium-201 ((201)Tl) solution on human erythrocyte glutathione reductase (GR) activity.

METHODS

Erythrocyte GR was initially purified by 2',5'-adenosine diphosphate Sepharose-4B affinity and Sephadex G-200 gel filtration chromatography. The purification was monitored by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which showed a single band for the final enzyme preparation. The in vitro and in vivo effects of the (201)Tl solution including Tl(+), Fe(+3) and Cu(+2) metals and the in vitro effects of the radiation effect of the (201)Tl solution and nonradioactive Tl(+), Fe(+3) and Cu(+2) metals on human erythrocyte GR enzyme were studied. Enzyme activity was determined with the Beutler method at 340 nm using a spectrophotometer. All purification procedures were carried out at (+)4 °C.

RESULTS

Glutathione reductase was purified 2033-fold at a yield of 28.17%. (201)Tl solution and radiation exposure had inhibitory effects on the enzyme activity. Besides, effects of nonradioactive Tl(+), Fe(+3) and Cu(+2) were studied on enzyme activity in vitro. Furthermore, seven human patients were also used for in vivo studies of (201)Tl solution.

CONCLUSION

It was detected in in vitro and in vivo studies that the human erythrocyte GR enzyme is inhibited due to the radiation effect of (201)Tl solution.

Comparison of equipotent doses of ropivacaine-fentanyl and bupivacaine-fentanyl in spinal anaesthesia for lower abdominal surgery

The aim of this randomised, double-blind study was to compare equipotent doses of plain ropivacaine and bupivacaine (19.5 mg and 13 mg respectively), both with fentanyl 20 microg, for spinal anaesthesia in lower abdominal surgery. After written informed consent had been obtained, 52 ASA I to II male patients scheduled for lower abdominal surgery were randomly assigned to receive intrathecal plain ropivacaine 19.5 mg with fentanyl 20 microg (group R, n =26) or plain bupivacaine 13 mg with fentanyl 20 microg (group B, n =26) in 3 ml. The level and duration of sensory block, intensity and duration of motor block, time to mobilise and patient satisfaction were recorded. All patients achieved sensory block to T10 or higher The level of sensory block was significantly higher in group B (T4 [T3 to T7] vs T7 [T4 to T9], P <0.05). There was no difference in the onset time of motor block. The duration of motor block (Bromage score >0) was shorter in group R (139+/-39 minutes vs group B 182+/-46 minutes, P <0.05). The duration and intensity of complete motor block (Bromage score=3) were also shorter in group R (90+/-25 minutes vs 130+/-40 minutes, P <0.05). We conclude that plain ropivacaine 19.5 mg plus fentanyl 20 microg is associated with a lower level of sensory block and a shorter duration of motor block when compared to bupivacaine 13 mg plus fentanyl 20 microg for spinal anaesthesia in lower abdominal surgery.

In vitro inhibition of salicylic acid derivatives on human cytosolic carbonic anhydrase isozymes I and II

The inhibition of two human cytosolic carbonic anhydrase (hCA, EC 4.2.1.1) isozymes, hCA I and II, with a series of salicylic acid derivatives was investigated by using the esterase method with 4-nitrophenyl acetate as substrate. IC(50) values for sulfasalazine, diflunisal, 5-chlorosalicylic acid, dinitrosalicylic acid, 4-aminosalicylic acid, 4-sulfosalicylic acid, 5-sulfosalicylic acid, salicylic acid, acetylsalicylic acid (aspirin) and 3-metylsalicylic acid were of 3.04 microM, 3.38 microM, 4.07 microM, 7.64 microM, 0.13 mM, 0.29 mM, 0.42 mM, 0.56 mM, 2.71 mM and 3.07 mM for hCA I and of 4.49 microM, 2.70 microM, 0.72 microM, 2.80 microM, 0.75 mM, 0.72 mM, 0.29 mM, 0.68 mM, 1.16 mM and 4.70 mM for hCA II, respectively. Lineweaver-Burk plots were also used for the determination of the inhibition mechanism of these substituted phenols, most of which were noncompetitive inhibitors with this substrate. Some salicylic acid derivatives investigated here showed effective hCA I and II inhibitory activity, and might be used as leads for generating enzyme inhibitors eventually targeting other isoforms which have not been assayed yet for their interactions with such agents.

Purification and characterization of glutathione reductase from rainbow trout (Oncorhynchus mykiss) liver and inhibition effects of metal ions on enzyme activity

Glutathione reductase (E C: 1.8.1.7; GR) was purified from rainbow trout (Oncorhynchus mykiss) liver, and some characteristics of the enzyme were investigated. The purification procedure consisted of four steps: preparation of homogenate, ammonium sulfate fractionation, affinity chromatography on 2',5'-ADP Sepharose-4B and gel filtration chromatography on Sephadex G-200. The enzyme, with a specific activity of 27.45 U/mg protein, was purified 1,654-fold with a yield of 41%. Optimal pH, stable pH, optimal temperature, optimum ionic strength, molecular mass, KM and Vmax values for GSSG and NADPH were also determined for the enzyme. In addition, Ki values and inhibition types were determined for GSH and NADP+. Additionally, inhibitory effects of metal ions (Cd+2, Cu+2, Pb+2, Hg+2, Fe+3 and Al+3) on glutathione reductase were investigated. Ki constants and IC50 values for metal ions were determined by Lineweaver-Burk graphs and plotting activity % vs. [I], respectively. IC50 values of Cd+2,Cu+2, Pb+2, Hg+2, Fe+3 and Al+3 were 0.0655, 0.082, 0.122, 0.509, 0.797 and 0.804 mM, and the Ki constants for Cd+2 and Cu+2 were 0.104+/-0.001, 0.117+/-0.001, respectively.

Prediction of cardiopulmonary morbidity after resection for lung cancer: stair climbing test complications after lung cancer surgery

BACKGROUND

The objective of this study was to assess the role of a modified stair climbing test in predicting postoperative cardiopulmonary complications.

METHODS

A consecutive series of 150 patients who had undergone pulmonary resection for lung carcinoma formed the prospective database of this study. All patients performed a preoperative modified stair climbing test. Univariate and multivariate analyses were performed to identify predictors of postoperative cardiopulmonary complications.

RESULTS

With univariate analysis, the patients with complications had a lower pre-exercise and postexercise percentage of oxygen saturation. PaO (2) levels were found to be lower and a greater change in oxygen desaturation during exercise was noted. Logistic regression analysis showed that the percent of oxygen saturation pre-exercise and the change in percent of oxygen desaturation during exercise were independent and reliable predictors of cardiopulmonary morbidity.

CONCLUSIONS

A modified stair climbing test is a safe, economical and simple test capable of predicting cardiopulmonary complications.

BIS guided sedation with propofol during spinal anaesthesia: influence of anaesthetic level on sedation requirement

BACKGROUND

In this prospective, clinical study we tested the hypothesis whether two different doses of spinal administered bupivacaine and accordingly, two different levels of spinal anaesthesia can affect the dose requirement of propofol during BIS guided sedation.

METHODS

Fifty women undergoing vaginal hysterectomy (high spinal group, HS) or transvaginal tape (TVT) procedure for urinary incontinence (low spinal group, LS) under spinal anaesthesia were enrolled to the study. In group HS, 17.5 mg and in group LS, 7.5 mg of hyperbaric bupivacaine were given intrathecally. After 15 min to obtain the appropriate level of spinal anaesthesia, propofol infusion was started at a rate of 100 microg kg(-1) min(-1) to reach a BIS level of less than 75 (onset time), and titrated to maintain the BIS value between 65 and 75. Propofol infusion was stopped 45 min after placing the spinal to measure the time to reach a BIS level of 90 (recovery time).

RESULTS

Median anaesthetic level was T3 (T1-4) in the HS group and T10 (T9-11) in the LS group. In both the HS and the LS groups, onset time was 226 (47) vs 273 (48) s (P=0.001), recovery time was 234 (47) vs 202 (56) s (P=0.03), total dose of propofol was 2.17 (0.43) vs 3.14 (0.56) mg kg(-1) (P<0.001), respectively.

CONCLUSION

A high spinal block obtained with hyperbaric bupivacaine 17.5 mg was associated with a faster onset, delayed recovery and lower doses of propofol sedation compared with a low spinal block with 7.5 mg of the same drug.

Comparison of Early Postoperative Results of Thymectomy: Partial Sternotomy vs. Videothoracoscopy

BACKGROUND

The aim of this study was to compare the early postoperative results of thymectomy operations after partial sternotomy and videothoracoscopy for myasthenia gravis.

METHODS

A total of 51 thymectomy operations were reviewed. The surgical procedure was simple thymectomy with partial sternotomy in the first 19 patients (Group I) and videothoracoscopic thymectomy (Group II) in the remaining patients. Both groups were compared in terms of preoperative data (age, gender, classification, duration of disease, medications), operative data (operation time, the mean amount of drainage, the duration of chest tube drainage), and postoperative data (duration of hospital stay, complications and pain).

RESULTS

Groups were statistically uniform in terms of preoperative and operative data. Statistically significant differences were noted for the duration of chest tube drainage (48.8 vs. 29.8 hours, p < 0.001), the amount of drainage (264.4 vs. 178.6 ml, p = 0.001), the length of hospital stay (5.6 vs. 2.3 days, p = 0.000), and the visual analogue scale score (4.8 vs. 3.1, p < 0.001).

CONCLUSIONS

Thymectomy with videothoracoscopic surgery demonstrated a more comfortable and faster recovery period without deterioration in myasthenic status.

Effects of intramuscular administration of lidocaine or bupivacaine on induction and maintenance doses of propofol evaluated by bispectral index

BACKGROUND

Interest in combining local and general anaesthesia has lead to studies investigating possible interactions. In a prospective, randomized, double-blind study, we tested whether local anaesthetics administered i.m. potentiate the hypnotic effect of propofol.

METHODS

Sixty patients (three groups, n=20) undergoing lower abdominal surgery with total i.v. propofol anaesthesia were investigated. Patients in Group B received i.m. bupivacaine (5 mg ml(-1)) 1 mg kg(-1), patients in Group L received i.m. lidocaine (100 mg ml(-1)) 2 mg kg(-1) and patients in Group C received i.m. saline 5 ml before operation. Hypnosis was measured with bispectral index (BIS).

RESULTS

The induction (BIS <45), and the maintenance doses of propofol (BIS between 40 and 50) were significantly less in Group B and Group L compared with the control group. Induction doses were 1.58 (SD 0.39), 1.56 (0.24) and 2.03 (0.33) mg kg(-1) respectively; P<0.0001. Maintenance doses were 6.33 (2.06), 7.08 (1.23) and 9.95 (2.02) mg kg(-1) respectively in the first hour; P<0.0001. Groups B and L were associated with an attenuated haemodynamic response to both induction and intubation.

CONCLUSION

I.M. administered local anaesthetics are associated with a decrease in both the induction and maintenance doses of propofol during total i.v. anaesthesia and a reduction in haemodynamic responses.