Imipenem resistance in Pseudomonas aeruginosa is due to diminished expression of outer membrane proteins.
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Anti-Bacterial Agents↗
Biomedical subjects
W Dick
Publications and source records attributed to W Dick.
Comparison of blood gases of ventilated patients during transport.
Three modes of ventilation during the transport of 30 ventilator-dependent patients were compared using blood gas variables. Ten were ventilated with a manually operated, ventilation bag (group C) and ten with a tidal volume meter at the exhalation valve of the ventilation bag (group V). Another ten patients (group O) were ventilated with a portable ventilator set to the minute volume (VE) given in ICU. VE was measured by volumetry as described above. Blood gases were analyzed in the ICU before and at the end of transport. In group C, significant decreases occurred in arterial (p less than .01) and central venous (p less than .05) PCO2, as well as in central venous PO2 (p less than .01). Arterial (p less than .05) and central venous (p less than .01) pH increased. Group V showed no statistically significant changes. In group O, arterial (p less than .01) and central venous (p less than .05) PCO2 decreased whereas arterial (p less than .01) and central venous (p less than .05) pH increased. We conclude that VE should be monitored during transport of ventilated patients.
Blood Gas Analysis↗
The "fixateur interne" as a versatile implant for spine surgery.
The "fixateur interne" is a new device for posterior spine surgery. It consists of long Schanz screws which are inserted from a posterior approach through the pedicles into the vertebral bodies, and of connecting threaded longitudinal rods, carrying mobile clamps which can be fixed in every position by nuts. The long leverarms of the Schanz screws facilitate manual reduction. They are removed at the end of operation. As the device is stable against flexion and rotation by itself, it does not act on the four-point bending principle. Thus, the fixation can be restricted to the immediately adjacent vertebrae of a lesion, leaving the rest of the spine mobile. In fracture treatment instrumentation is combined with a direct repair of the anterior loss of bone stock by a transpedicular bone grafting procedure from the same dorsal approach. This report presents and discusses 183 instrumentations in fresh fractures, posttraumatic deformities, degenerative diseases, tumors, and severe spondylolistheses. The main advantage is the short fixation area and the ease of after treatment.
Adolescent↗
Imipenem resistance in Pseudomonas aeruginosa resulting from diminished expression of an outer membrane protein.
The mechanism of Pseudomonas aeruginosa resistance to imipenem in five imipenem-susceptible clinical isolates and in their resistant counterparts was investigated. The frequency for selecting imipenem-resistant variants ranged from 2.7 X 10(-5) to 2.1 X 10(-8) and was comparable to those for other beta-lactams. Cross-resistance between imipenem and other beta-lactam compounds was not observed. In all imipenem-resistant variants, induction of chromosomal beta-lactamase by imipenem was markedly diminished compared with that in the susceptible parent strain. This was not the case for other inducers such as ampicillin or cefoxitin, suggesting an impaired uptake of imipenem as an explanation for resistance. Analysis of the outer membrane proteins revealed a marked decrease of either a 46- or a 45-kilodalton protein. The lipopolysaccharide of the outer membrane in the imipenem-resistant variants was not altered.
Anti-Bacterial Agents↗
Selection frequency of resistant variants by various beta-lactam antibiotics in clinical Enterobacter cloacae isolates.
The frequency of selection of resistant variants by 10 different broad-spectrum beta-lactam derivatives was evaluated for 10 clinical Enterobacter cloacae isolates. With respect to most penams or cephems, resistant variants could be selected up to 8- or 32-fold the MIC, respectively. However, with cefpirome as the selecting agent resistant variants were obtained only at twice the MIC, whereas resistant variants were barely detectable with temocillin and not detectable in any case with imipenem. The variants exhibited cross-resistance between penams and cephems including aztreonam, but not to temocillin and imipenem regardless of the beta-lactamase amount produced. Enzyme production of the variants ranged from 0.2 U to 19.0 U beta-lactamase/mg protein of the cell-free supernatants. Moreover, analysis of the outer membrane protein composition did not reveal marked alterations between wild strains and the corresponding variants. It is evident that 'overproduction of the chromosomal beta-lactamase' cannot explain entirely phenotypic resistance to broad-spectrum beta-lactam compounds, but a lack of porin production, i.e., major outer membrane proteins, cannot provide an explanation for the above findings.
Anti-Bacterial Agents↗
[Bupivacaine-CO2 and bupivacaine-HCl at various injection temperatures in peridural anesthesia for extracorporeal shock wave lithotripsy].
INTRODUCTION: The effect of different injection temperatures on carbonated anesthetics has been controversial since 1965. The current study was undertaken to determine onset times of sensory and motor blockade after epidural anesthesia with 0.5% bupivacaine-CO2 and 0.5% bupivacaine-HCl at various injection temperatures. MATERIALS AND METHODS: The study was performed on 90 ASA class I-II urologic patients during extracorporeal shock wave lithotripsy. The patients were randomized in six groups to receive either 0.5% bupivacaine-CO2 or 0.5% bupivacaine-HCl at temperatures of 4 degrees, 20 degrees, or 36 degrees C. The six groups were comparable in age, height, and weight. Epidural anesthesia was performed at the L2-3 interspace with an 18-gauge Tuohy needle using loss of resistance. A catheter was advanced 4 cm in the epidural space and 4 ml 0.5% bupivacaine with adrenaline 1:200,000 was given as a test dose. After 4 min the full anesthetic dose, based on body size, was injected with the patient supine. Sensory blockade was determined by the pinprick method and motor blockade by the Bromage method at 2-min intervals for the first 20 min, at 5-min intervals for the next 10 min, and then every 15 min to a total of 240 min. Statistical analysis was done by the Mann-Whitney test, with P less than 0.05 considered significant. RESULTS: Spread of sensory blockade was significantly faster with bupivacaine-CO2 and -HCl at a temperature of 36 degrees C as compared to 4 degrees or 20 degrees C (P less than 0.05) (Figs. 1, 2 and Table 2).(ABSTRACT TRUNCATED AT 250 WORDS)
Analgesia↗
[Postoperative disorders of cardiovascular function].
Cardiovascular instability is the cause of almost 50% of postoperative complications and raises postoperative mortality far above that intraoperatively. The aged patient with pre-existing heart disease represents a high postoperative risk. These patients are very susceptible to hypoxia, anemia, hypovolemia, the negative inotropic effects of certain anesthetics, and increased oxygen consumption due to shivering. The reversal of anesthetic agents is also rather debatable in these cases. Hypertension and arrhythmias are common phenomena in the recovery room. They may be aggravated by a number of factors such as metabolic and respiratory imbalances, incorrect fluid substitution, pain, or excitation. The frequency of postoperative myocardial infarction (MI) depends upon pre-existing coronary artery disease and hypertension. A medical history of heart failure or previous MI also plays an important role hemodynamic course as do the surgical procedure and the intraoperative. Postoperative hemodynamic monitoring should be performed according to the standards suggested by the American Society of Anesthesiologists. Medical treatment basically consists of symptomatic therapy and the avoidance of risk factors. Specific treatment is rarely required.
Cardiovascular Diseases↗
[Comparative clinical studies of the hemodynamic parameters by anesthesia combination with Nalbuphin (Nubain) and Fentanyl].
UNLABELLED: The narcotic agonist-antagonist nalbuphine is reported to act as a strong analgesic with only minor respiratory depressant side-effects. Even in the postoperative period, the pain-relieving properties of analgesic drugs are reported to continue if the respiratory side-effects are being antagonized by administering nalbuphine. It was the aim of this study to investigate the analgesic properties of nalbuphine as compared to those of fentanyl, in suppressing the hemodynamic responses due to endotracheal intubation and skin incision. Furthermore, we are interested in studying postoperative analgesia and respiratory depression after using the two drugs during anesthesia. PATIENTS AND METHODS: Forty-one patients undergoing general surgical procedures were randomly assigned to two groups in a double-blind study. The patients were between 18 and 70 years old and belonged to ASA classes I-III. Patients with chronic obstructive pulmonary disease, cerebral vascular disorders, hepatic or renal failure, or those treated with monoamine oxidase inhibitors and tricyclic antidepressants were excluded from the study, as were patients with a drug dependency. All patients were premedicated with 25-50 mg each promethazine and pethidine. Anesthesia was induced with either 60-70 mg nalbuphine or 0.3-0.35 mg fentanyl, 2 mg alcuronium, 0.01 mg/kg flunitrazepam, and 1-2 mg/kg thiopental. All patients were intubated following 1-2 mg/kg succinylcholine. Five minutes following intubation they received another 30-40 mg nalbuphine or 0.15-0.2 mg fentanyl intravenously. Anesthesia was maintained with N2O:O2 2:1, alcuronium, and either nalbuphine or fentanyl and enflurane up to 1 vol.% or halothane up to 0.5 vol.%. Blood pressure, pulse rate, and arterial blood gases were measured at certain intervals.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
[Neurogenic and anaphylactic shock].
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Anaphylaxis↗
[Therapy of bacterial spondylitis and spondylodiscitis].
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Arthritis, Infectious↗
[Treatment of spondylolisthesis].
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Adolescent↗
[Future working conditions of anesthesiologists. Attempt at an analysis].
The present conditions of the anaesthesiologist's workplace are characterized by completely unacceptable circumstances, incompatibilities, inflexibility and unsafeness. Like inadequate cockpit conditions in airplanes, these workplace conditions pose considerable risks to the safety of patients and personnel. Taking into consideration the literature and our own views, we have proposed some changes which are essential for improving the working conditions of anesthesiologists: Ergonomic improvements of the anaesthesiological workplace in order to facilitate the anesthetist's performance, to provide him with adequate space, and to automatize repeated and relatively unimportant activities. Vital information about the patient's condition must be located in a position where they will dominate the anesthetist's attention. Information about medications, infusions, transfusions, etc. can be located on the left-hand side of the anesthetist. All other devices can be located beside the anesthetist or even behind him, as they are of minor importance. The most useful alternative to the present conditions would be to locate the information panels of primary and secondary monitoring devices to the immediate right, or on the right- und left-hand sides of the anesthetist at an angle of 15 degrees-30 degrees each. Furthermore, these information panels should be arranged so that they can be monitored using moving and slightly tilted screens. The most important of the patients, clinical parameters as well as the functions of the equipment should be monitored by alarms, warning devices, or simply indicators, which can easily be separated.(ABSTRACT TRUNCATED AT 250 WORDS)
Anesthesiology↗
[Effects of intubation anesthesia on the temporomandibular joint].
Hardly any attention has so far been paid to temporomandibular joint (TMJ) dysfunction after endotracheal intubation. We examined perioperative lesions of the TMJ in 100 patients who underwent operations in areas other than the head and neck. Fifty of these patients were anesthetized with orotracheal intubation; the other 50 were operated under spinal or peridural anesthesia. The orotracheal intubations were carried out with Macintosh laryngoscopes (blatesize 3). Size 32 Kuhn tubes or Magill tubes were used in 25 patients each. Preoperatively and daily for the first 4 postoperative days, we repeated the history and examined the minimal distance between the occlusal edges of upper and lower incisors (SKD), deviations of the mandible during opening and closing movements, and snapping or grinding of the TMJ. We further measured the duration of intubation, technical difficulties, and the number of years of training of the anesthetist. Age, body length, and preoperative findings were compatible in both patient groups. Operating time was 25% longer in the spinal or peridural anesthesia group. Of the 50 patients with orotracheal intubation, 33 demonstrated a reduced ability of maximal oral opening of up to 35% on the 1st postoperative day. Snapping of the TMJ was observed in 80% of the orotracheally intubated patients on the 1st postoperative day, which was 20% above the preoperative value. TMJ grinding showed no significant changes. Two of the 50 intubated patients complained of TMJ pain, another two had occlusal disturbances, and two had a reduced SKD. There were no detectable differences within the group of intubated patients regarding type of tube or experience of the anesthetist.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
[Clinical experiences with a new reusable pressure transducer].
Invasive blood pressure monitoring is increasing in anesthesia and intensive care. Compared to noninvasive methods, it has some decisive advantages: (1) blood pressure trends can be assessed beat by beat, which is important especially in situations of cardiac arrhythmia; (2) respiratory changes in blood pressure as one sign of hypovolemia can be detected easily; and (3) pressure changes induced by the autonomic nervous system become apparent. We studied a new, reusable pressure transducer system, the Medex Novatrans-MX800 in routine intra- and postoperative monitoring of patients undergoing cardiac surgery using the following criteria: (1) handling; (2) accuracy of measurement; (3) durability; and (4) costs. The system is easy to use and has a low susceptability to breakdown. In 29 of 31 transducers tested, the error of measurement over a range of 0-150 mmHg was less than 2% as reported by the manufacturer. Two transducers showed errors of measurement over 5% after 60 times of reuse. The mean reusability rate until the transducer became defective was 75.8 +/- 17.3 in the operating room (19 transducers tested) and 59.7 +/- 29 in the intensive care unit (12 transducers tested, 11 still in use). A comparison of costs shows that the Novatrans-MX800 system is the cheapest system for invasive pressure monitoring available at this time.
Blood Pressure Determination↗
Use of the acetabular reamer to harvest autogeneic bone graft material: a simple method for producing bone paste.
In comparison with solid bone grafts, the particulate form as a paste-like material offers several advantages. The method reported for harvesting a homogeneous mixture of ground cortical and cancellous bone has proven to be simple, time-saving, and productive. A normal acetabular reamer is used to procure the graft from the outer surface of the posterior iliac wing, transforming it simultaneously into paste-like material.
Acetabulum↗
Inducible beta-lactamases are principally responsible for the naturally occurring resistance towards beta-lactam antibiotics in Proteus vulgaris.
The role of inducible chromosomally mediated beta-lactamases was studied in 22 Proteus vulgaris isolates by monitoring enzyme induction in the presence of various inducers such as ampicillin, cefalothin, cefuroxime, cefsulodin, 6-aminopenicillanic acid (6-APS), and imipenem. 20 of the isolates exhibited resistance to ampicillin, cefalothin, and cefuroxime, whereas 2 isolates were susceptible to these compounds. In all resistant isolates marked inoculum effects could be observed. Enzyme production proved to be transient, i.e. maximum of enzyme production was achieved after 2 or 3 h. In both sensitive isolates enzyme production did not exceed 0.021 U beta-lactamase/mg protein of the cell-free supernatant even after induction with 6-APS or imipenem, whereas it ranged from 0.46 to 6.3 U in the resistant ones. Moreover, enzyme induction was found to be concentration-dependent, as revealed by the extensive study of one of the isolates (No. 4917). Three different enzymes could be distinguished by means of isoelectric focusing with isoelectric points at 7.4, 8.8, and approximately 9.5. In the presence of 2.5 mg/l clavulanic acid even strains known to be strong enzyme producers became as susceptible as the sensitive ones: moreover, the inocolum effect was markedly reduced. These findings make it apparent that it is above all the production of inducible enzymes that is responsible for resistance to beta-lactam antibiotics in P. vulgaris.
Anti-Bacterial Agents↗
[A simple enzyme assay for the simultaneous determination of penicillin derivatives and clavulanic acid in biological fluids].
A simple enzymatic assay for simultaneous determinations of amino-/ureidopenicillins and clavulanic acid concentrations in various body fluids is described; no pretreatment of the samples is required. The assay is based on the competitive inhibition of the chromogenic compound Padac by clavulanic acid in the presence of Proteus vulgaris beta-lactamase. Detection limit for clavulanic acid amounts 0.02 mg/l. Interferences with other antibiotics such as aminoglycosides, macrolides, quinolones etc. can be ruled out.
Binding, Competitive↗
Inactivation of general acyl-CoA dehydrogenase from pig kidney by 2-alkynoyl coenzyme A derivatives: initial aspects.
Pig kidney general acyl-CoA dehydrogenase is rapidly, stoichiometrically, and irreversibly inactivated by the acetylenic thio ester 2-octynoyl coenzyme A (2-octynoyl-CoA). The inhibitor binds initially to the dehydrogenase with a 10-nm red shift and increased resolution of the flavin chromophore, followed by the generation of a charge-transfer complex between some form of the bound inhibitor and oxidized flavin (lambda max 800 nm; epsilon app = 4.5 mM-1 cm-1; k1 = 1.07 min-1, at pH 7.6, 25 degrees C). The rate of formation of the long wavelength band is increased markedly with increasing pH (pKapp = 7.9). This intermediate then decays with release of about 0.6 mol of CoASH at pH 7.6, yielding a final form with a spectrum typical of bound oxidized flavin. Both irreversible inactivation and covalent modification of the protein occur prior to the decay of the long wavelength species. The modified dehydrogenase is not reduced on prolonged anaerobic incubation with the substrate octanoyl-CoA. The inactive enzyme is unusually resistant to dithionite reduction but may be readily photoreduced via the blue semiquinone to the dihydroflavin form. This reduced enzyme is rapidly reoxidized by electron-transferring flavoprotein, the physiological electron acceptor of the dehydrogenase. General acyl-CoA dehydrogenase is also inactivated by 2-pentynoyl- and 2-pentadecynoyl-CoA with formation of an 800-nm band of lower intensity and by propiolyl-CoA, phenylpropiolyl-CoA, and 2-octynoylpantetheine without the appearance of detectable intermediate species. These data are compared with the behavior of acyl-CoA dehydrogenases toward mechanism-based inactivators carrying an acetylene function at C-3, e.g., 3-butynoyl-CoA.
Acyl Coenzyme A↗