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Biomedical subjects

H Turndorf

Publications and source records attributed to H Turndorf.

At least 91 records · Page 5Linked to original sources
PubMed1989

Sufentanil pharmacokinetics in neurosurgical patients.

The effects of respiratory alkalosis and dehydration on the pharmacokinetics of sufentanil have been determined. Forty neurosurgical patients entered the study: group I (n = 20) had spinal surgery while group II (n = 20) had elective craniotomies. All patients received a single intravenous bolus of sufentanil (2 micrograms/kg) during induction of anesthesia. Patients in group II received furosemide (40 mg) and mannitol (1 g/kg) prior to surgery and were hyperventilated to a PaCO2 below 30 mmHg. The anesthetic management was identical in both groups. Arterial blood samples were collected to determine sufentanil concentrations (RIA), blood gases, pH, hematocrit and electrolytes. Patients in group II had significantly higher blood pH and urinary output when compared to group I (p less than 0.05). Plasma sufentanil concentrations were best fitted to a bi-exponential curve and the pharmacokinetic variables calculated using a curve stripping program (STRIPE). No significant differences were observed between groups regarding plasma sufentanil concentrations or pharmacokinetic parameters. Our results demonstrate that respiratory alkalosis and dehydration do not alter the pharmacokinetics of sufentanil after intravenous bolus administration.

Alkalosis↗
PubMed1989

A computerized anesthesia database.

The collection of anesthesia related information in an organized fashion and the subsequent analysis of the data assist in the maintenance of quality anesthesia care. We have created and implemented a computerized anesthesia database that utilizes an IBM personal computer. We are now able to easily and accurately monitor the anesthesia practices of our large university anesthesia program. We recommend the wide adaptation of systems such as ours to all departments, from the small private hospital to the large university center.

Anesthesia↗
PubMed1988

Stereospecific inhibition of gastrointestinal transit by kappa opioid agonists in mice.

Systemic administration of highly selective kappa opiate agonists, U-50488H and U-69593 (3, 10 and 30 mg/kg i.p.) produced significant inhibition of the gastrointestinal transit in mice as assessed by charcoal meal test. In contrast, the (+) stereoisomer of U-50488H, U-53455E did not inhibit the gastrointestinal motility. Furthermore, the kappa-selective antagonist, Mr 2266 (3 mg/kg) when administered along with the agonists, reversed the effects of the agonists. These results suggest that stereospecific kappa opiate receptors are involved in inhibition of gut motility in mice.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1988

Influence of hypo and hyperthermia on disposition of morphine.

Using morphine as a prototype opiate anesthetic, the dispositional changes and cardiovascular effects during hypothermia (30 degrees C) and hyperthermia (40 degrees C) in dogs under isoflurane anesthesia was assessed. Single intravenous bolus injection of 1 mg/kg morphine resulted in a significant and sustained decrease in mean arterial pressure in hypothermic, but not in hyperthermic or normothermic (37 degrees C) conditions. Hypothermic dogs showed significantly higher levels of morphine both in plasma and in cerebrospinal fluid. In contrast, hyperthermia did not affect these levels. Body temperature did not affect the t1/2 alpha, however t1/2 beta and mean residence time were significantly increased while volume of distribution at steady state and total body clearance were decreased during hypothermia. The results provide evidence that hypothermia is likely to be associated with a sustained increase in opiate levels and might be associated with a enhanced side effects. The results suggests the need for a controlled clinical trial to assess the dose of opiate anesthetics during hypothermia.

Animals↗
PubMed1988

Effects of mu receptor agonists and droperidol on motor coordination in mice.

The effects of morphine, fentanyl, sufentanil and droperidol on motor coordination in mice were studied. Animals were trained to complete successfully the rotarod test before assessing the effects of drugs. Administration of analgesic doses of the mu agonists morphine, fentanyl and sufentanil did not inhibit motor coordination. Droperidol produced a dose related inhibition of motor coordination. When a subthreshold dose of droperidol was administered followed by an opiate, a significant inhibition of motor coordination was observed. The results indicate that although analgesic doses of mu opioid agonists do not affect motor coordination, their combination with droperidol results in motor incoordination. The mechanisms and/or opioid receptor sub-types involved in this in vivo interaction remain to be established.

Animals↗
PubMed1988

Droperidol enhances fentanyl and sufentanil, but not morphine, analgesia.

1. The effect of droperidol pre-treatment on the analgesic potency of morphine, fentanyl and sufentanil was assessed in mice. 2. Acetic acid writhing test and tail immersion test were used to measure the analgesic response. 3. The neuroleptic augments the effects of sufentanil and fentanyl. 4. Thus, the dose-response curves for fentanyl and sufentanil were shifted to the left and the ED50 of the analgesics lowered in droperidol pre-treated animals. 5. However, morphine analgesia was not influenced by droperidol. 6. The results suggest that combination of sufentanil or fentanyl with droperidol may be better than morphine to produce neuroleptanalgesia and anesthesia.

Analgesics, Opioid↗
PubMed1988

Synergistic interaction of morphine and halothane in the guinea pig ileum.

The present study describes the effects of halothane on morphine activity in the myenteric plexus-longitudinal muscle preparation of the guinea pig ileum. Morphine and halothane produced a dose-related inhibition of the electrically induced muscle contractions with IC50 of 1.9 X 10(-7) and 1.7 V/V%, respectively. The effects of morphine, but not halothane, were antagonized by naloxone. The IC50 of morphine was decreased in the presence of halothane (0.8-3.0 V/V%). Hill coefficients derived from dose-response curves were less than one for morphine or halothane alone, while it was 1.4 for the combination. The pA2 values (a measure of affinity of the antagonist for the opioid receptor) for naloxone in the absence and presence of halothane (1.6%) were 9.4 and 9.1, respectively. These results indicate that 1) halothane increases the potency of morphine in the guinea pig ileum at clinically relevant concentrations, 2) the interaction between the agents is synergistic, and 3) halothane does not modify the binding of naloxone to opioid receptors, but may affect membrane or intracellular processing of the receptor signal.

Animals↗
PubMed1988

Effects of acute and chronic hyperglycemia on morphine-induced inhibition of gastrointestinal transit in mice.

Using the charcoal meal test, the effects of morphine (3, 5 and 7 mg/kg) on gastrointestinal transit was assessed in normoglycemic as well as in acute and chronic hyperglycemic mice. Acute hyperglycemia was induced by intraperitoneal injection of glucose (5.04 g/kg), while chronic hyperglycemia was induced by streptozotocin injection (200 mg/kg i.p., 7-8 days before). Acute hyperglycemia augmented the inhibitory effect of morphine on gut transit, however, chronic hyperglycemia failed to modify the effects of morphine. The results indicate that hyperglycemia per se may not be the primary mechanism for the altered sensitivity to morphine in experimental models of diabetes.

Acute Disease↗
PubMed1987

Naloxone elicits an excitatory response in the morphine-tolerant mouse vas deferens.

The effects of naloxone on the electrically stimulated vas deferens from mice implanted with morphine (tolerant) or placebo (naive) pellets were studied. In tolerant vas deferens, naloxone produced an 86.6% increase of the twitch contractions when the preparations were stimulated with 15 V, while only a 12% increase was observed with supramaximal voltage (40 V). Naloxone had no effect at either voltage in preparations from naive animals. The effect of morphine in naive vas deferens stimulated with 15 V, was reversed by naloxone without further increase over baseline contractions. The results suggest that opioid receptors other than those located in the neuronal soma and/or coupled to adenylate cyclase may be involved in the development of dependence.

Animals↗
PubMed1987

Effects of temperature on the interaction of morphine with opioid receptors.

The electrically stimulated guinea pig ileum preparation was used to determine the effects of temperature on the affinity of morphine for opioid receptors. The potency of morphine (expressed as the concentration which produces 50% inhibition--IC50) was significantly decreased at 30 degrees C (IC50 41.0 x 10(-8) mol litre-1) and increased at 40 degrees C (IC50 5.1 x 10(-8) mol litre-1) when compared with its potency at 37 degrees C (IC50 8.8 x 10(-8) mol litre-1). Experiments carried out in the presence of naloxone (a competitive opioid antagonist) indicated that the affinity of opioid receptors for this antagonist was not affected by temperature. Further studies using B-funaltrexamine (a mu-specific, non-reversible opioid antagonist) revealed an increase in morphine receptor affinity when temperature was increased from 30 to 37 degrees C. The data demonstrated that the potency of morphine increased with temperature; the affinity of naloxone for opioid receptors was unaltered by temperature; and the affinity of morphine for mu-receptors reached an optimal value within the range 30-37 degrees C.

Animals↗