Biomedical subjects

A Dye

Publications and source records attributed to A Dye.

6 recordsLinked to original sources

PubMed2000

Effects of morphine glucuronides on the function of opioid receptors in human SK-N-SH cells.

Morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) are active metabolites of morphine. The effects of M3G and M6G on the opioid receptor transduction system has not yet been fully elucidated. Formation of cAMP after treatment with various doses of morphine, M3G, and M6G was studied. M6G and morphine, but not M3G, showed a dose dependent inhibition of cAMP accumulation. Naloxone blocked the inhibitory effect of M6G, M3G, and morphine. Pretreatment with M3G did not change the effects of morphine and M6G. The G-protein inhibitor PTX, prevented morphine, M3G, and M6G effects on cAMP. M3G and M6G vary in their ability to interact with the opioid receptor effector system. Inhibition of cAMP evoked by activation of opioid receptors and inhibitory G-proteins may play a role in the actions of M6G and M3G.

Alprostadil↗

PubMed1985

Systemic absorption of lignocaine ointment from tracheal tubes.

Arterial plasma concentrations of lignocaine were studied in fifteen adult patients following insertion of a tracheal tube whose cuff area was smeared with 5% lignocaine ointment. Twelve patients had 2 ml of ointment (114 mg) and samples were taken every 5 minutes until 30 minutes and in eight of the 12 patients at 40, 50 and 60 minutes after insertion and inflation of the tracheal tube and cuff. Three patients had 1 ml of ointment on the tube and were studied over 60 minutes. Plasma concentrations were determined using gas liquid chromatography. In the 2 ml lignocaine group mean plasma lignocaine levels were 1.9 (SD 0.9) micrograms/ml at 10 minutes, 2.3 (SD 0.8) micrograms/ml at 20 minutes, 2.3 (SD 0.8) micrograms/ml at 30 minutes and 1.7 (SD 1.0) micrograms/ml at 60 minutes. After 1 ml of lignocaine, levels were 1.2 (SD 0.1) micrograms/ml at 10 minutes, 1.1 (SD 0.7) micrograms/ml at 20 minutes, 0.8 (SD 0.3) micrograms/ml at 30 minutes and 0.75 (SD 0.1) micrograms/ml at 60 minutes.

Absorption↗

PubMed1984

Ventilatory effects of nitrous oxide during continuous infusion of fentanyl or alfentanil.

Two groups of eight patients received infusions of either fentanyl at 3 micrograms kg-1 h-1 or alfentanil at 20 micrograms kg-1 h-1 as supplements to 66% N2O in oxygen anaesthesia, during and after body surface surgery. At the end of surgery, the N2O was reduced to 50% and after measurement of ventilatory frequency, minute ventilation, and the ventilatory response to carbon dioxide, N2O was discontinued. The opioid infusions were continued for a further hour and the ventilatory measurements repeated. Both sets of measurements were compared with preoperative values. Minute ventilation (P less than 0.01), frequency (P less than 0.01) and the response to carbon dioxide (P less than 0.01) were reduced during the infusion of fentanyl with N2O; with fentanyl alone, minute ventilation (P less than 0.05) and the response to carbon dioxide (P less than 0.01) were reduced but to a lesser degree. The elimination of nitrous oxide from the inspired gas mixture produced an increase in frequency (P less than 0.05) and increases in the slope (P less than 0.01) and ventilation at 7.3 kPa (P less than 0.025) of the carbon dioxide response curve. Minute ventilation (P less than 0.01) frequency (P less than 0.05) and response to carbon dioxide (P less than 0.01) were all reduced during the infusion of alfentanil with nitrous oxide; with alfentanil alone, minute ventilation (P less than 0.01), tidal volume (P less than 0.05), the slope (P less than 0.025) and the ventilation at 7.3 kPa (P less than 0.01) of the carbon-dioxide response curve were still reduced.(ABSTRACT TRUNCATED AT 250 WORDS)

Adjuvants, Anesthesia↗

PubMed1983

Hepatic function after anaesthesia for major vascular reconstructive surgery.

Three groups of patients received Althesin, minaxolone or di-isopropyl phenol to supplement 67% nitrous oxide in oxygen. A fourth group receiving halothane to supplement nitrous oxide in oxygen acted as a control. Hepatic function tests were measured before operation and on days 1, 3, 5 and 7 after major vascular reconstructive surgery. There were significant increases to a mean value above the upper limit of normal in aspartate amino-transferase activity by day 3 in all groups. Total lactic dehydrogenase activity increased in the patients receiving Althesin, minaxolone and halothane. No change was seen in the alkaline phosphatase in any of the study groups. Gamma glutamyl transpeptidase increased in all groups, but the mean value at day 7 was not greater than the upper limit of normal. The mean activity of ornithine carbamoyl transpeptidase showed no change in any group throughout the study period. Two of the patients receiving minaxolone suffered cholestatic jaundice during the first month. These results suggest that anaesthesia with Althesin or di-isopropyl phenol results in enzyme changes similar to those seen in a comparable group of patients receiving halothane to supplement nitrous oxide in oxygen anaesthesia.

Aged↗

PubMed1983

Ventilatory depression related to plasma fentanyl concentrations during and after anesthesia in humans.

Twenty-four patients were allocated randomly into four groups for the study of the pharmacokinetics of, and effects on postoperative ventilation of, two doses of fentanyl (10 micrograms/kg or 25 micrograms/kg) administered at the start of general anesthesia in which ventilation was controlled at a fixed volume, but arterial PCO2 was adjusted to a range of either 38-42 torr, or 20-25 torr. During the first 2 hr after anesthesia, ventilatory depression (CO2 responsiveness decreased to less than 50% of awake values, PaCO2 greater than 48 torr) occurred only in patients who had received 25 micrograms/kg fentanyl, and was more marked in patients who were hyperventilated to a low PaCO2 during anesthesia. Plasma fentanyl concentrations associated with 50% depression of CO2 responsiveness were in the range 1.5-3.0 ng/ml, the lower values found in patients hyperventilated to a low PaCO2. Whole-body clearance of fentanyl was significantly decreased by hypocapnic hyperventilation.

Adult↗

PubMed1983

Ventilatory effects during and after continuous infusion of fentanyl or alfentanil.

The opioid drugs fentanyl and alfentanil were infused at a constant rate as supplements to nitrous oxide in oxygen anaesthesia throughout the period of surgery. These infusions were continued into the period after operation for 1 h after the discontinuation of anaesthesia. Continuous infusion of alfentanil 20 micrograms kg-1 h-1 and fentanyl 3 micrograms kg-1 h-1 resulted in depression of the carbon dioxide response curve with a lesser effect on frequency and minute ventilation. One hour after discontinuing the infusions the degree of ventilatory depression was only marginally less with fentanyl, but considerably less with alfentanil, reflecting the shorter terminal half-life of that drug.

Adult↗