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Biomedical subjects

J E Pedersen

Publications and source records attributed to J E Pedersen.

At least 19 recordsLinked to original sources
PubMed1992

Halothane 2% for caesarean section.

During the induction-delivery interval for Caesarean section delivery, 2% halothane in pure oxygen was administered. The technique was compared to a 0.5% halothane in 50% oxygen/50% nitrous oxide anaesthesia. When a continuous infusion of oxytocin was administered, no excessive haemorrhage was seen. No maternal reminiscence was seen using 2% halothane, but awareness was recorded using 0.5% halothane in 50% nitrous oxide in 15% of the mothers. When there were no signs of preoperative fetal distress, the neonates were unaffected by the halothane concentration provided the induction-delivery interval was short. In cases of fetal distress, the administration of 2% halothane further aggravated the condition of the neonates, as indicated by lowered 1-min Apgar scores, umbilical oxygen tensions, pH and base excess values.

Adult↗
PubMed1991

Sensitive and specific radioimmunoassays for opiates using commercially available materials. I: Methods for the determinations of morphine and hydromorphone.

Sensitive and specific radioimmunoassay (RIA) methods for the analysis of morphine and hydromorphone in human plasma samples using commercially available materials were developed. The limit of quantitation was 0.3 ng/mL of plasma for morphine and 50 pg/mL of plasma for hydromorphone. An extraction step preceding the RIA quantitatively removed morphine, leaving 99% morphine-3-glucuronide (M3G) and 95% hydromorphone-3-glucuronide (H3G) in the aqueous phase. The specificity of the morphine RIA method for the analysis of clinical samples was confirmed by HPLC quantitation. The antiserum used in the hydromorphone RIA method cross reacted slightly with H3G at 0.66%. However, analysis of clinical samples using the direct versus the extraction RIA showed that the extraction step was necessary for the specific determination of hydromorphone in pharmacokinetic studies. After extraction, only 0.033% of the H3G present in plasma samples would be observed as interference for the free hydromorphone. The RIA methods were shown to be accurate and reproducible with almost 100% recovery of morphine and hydromorphone. They offer convenient alternatives to chromatographic methods for pharmacokinetic studies.

Antibody Specificity↗
PubMed1991

Iridium-192 brachytherapy in the treatment of cancer of the prostate.

Aggressive radiotherapy was used in 170 patients with advanced localized carcinoma of the prostate. After pelvic lymphadenectomy, 192Ir brachytherapy was used to deliver 3500 cGy to the prostate within 2 days. External-beam therapy (4500 cGy) was then given to a total of 8000 cGy. Random biopsies 18 months afterward were negative for residual cancer in 62 of 83 patients (75%), and 37 of 45 patients (82%) with pathologically proved localized disease remain without evidence of disease. Morbidity was significantly reduced in the most recent 70 patients by improvements in technique. The authors believe such therapy should be considered for patients with advanced stage B2 or C disease in particular.

Adenocarcinoma↗
PubMed1990

Real-time signal processing in speech recognition and its potential use within the development of hearing aids.

Acoustic-phonetic features necessary for rule-based speech recognition are described. The selection of feature algorithms is based on their robustness to variability of dynamics in speech signals and to influence of environmental noise, and their suitability for real-time implementation using speech production or speech perception modelling. Features are estimated in real-time, using a 32-bit floating point signal processor DSP32. The features described are pitch, formants, segmentation and labelling. The paper indicates the potential use of these features in connection with future experiments leading to development of new hearing aids.

Algorithms↗
PubMed1986

Peroperative buprenorphine: do high dosages shorten analgesia postoperatively?

Fifty-two patients undergoing biliary surgery were investigated in a prospective randomized study, in which they received buprenorphine 10, 20, 30, and 40 micrograms X kg-1, respectively, as sole intravenous analgesic as a bolus 15 min before induction of anaesthesia. The anaesthetic was uneventful in all four groups, although when receiving 10 and 20 micrograms X kg-1 almost two-thirds of the patients needed supplemental analgesics during the operation. When receiving buprenorphine in the dosage of 30 and 40 micrograms X kg-1, 50% of the patients requested an analgesic within 5 min of extubation. In contrast, when receiving 10 and 20 micrograms X kg-1 none of the patients requested an analgesic within 1 h of the operation. These findings accord to a certain extent with the presence of a bell-shaped dose-response curve for buprenorphine in humans.

Biliary Tract Surgical Procedures↗
PubMed1985

Postoperative pain relief with naloxone. Severe respiratory depression and pain after high dose buprenorphine.

Buprenorphine 30 and 40 micrograms/kg was given as the sole intravenous analgesic in balanced anaesthesia to 12 patients undergoing cholecystectomy. Significant and severe respiratory depression was found 15 minutes after preoperative loading with buprenorphine. In the immediate postoperative period six patients were in pain. They were treated with naloxone 0.08-0.4 mg leading to a long lasting period of pain relief (median 22 hours).

Adult↗
PubMed1979

Distribution and tumour cytotoxicity of the radiosensitizer misonidazole (Ro-07-0582) in C57 mice.

The distribution and clearance of misonidazole (MIS = Ro-07-0582) were studied in C57 mouse tissues and in transplants of Lewis lung tumour. The half life of the drug in blood after a dose of 1 mg/g i.p. was 3 h. Some tissues, such as liver, were found to have consistently low MIS levels, and this was found to be due to degradation of the drug after removal of the tissues from the host. The in vivo cytotoxicity of MIS to Lewis lung tumour cells was studied using an in-vitro colony assay. After half of the tumours had been irradiated with 10 Gy to kill most of the oxic cells, the mice received i.p. injections of MIS. To simulate the longer drug exposure of human tumour cells (due to the longer half life in man) a repeated injection regime was used in some mice. There was no significant cell kill after a single dose, but with a prolonged exposure to the drug in the multiply injected animals, cell survival was reduced to 50% of control in both the irradiated and unirradiated tumours. Since the hypoxic fraction of the unirradiated tumour is probably not more than 30%, it would appear that MIS is not selectively cytotoxic to hypoxic cells. However, MIS had a much greater cytotoxic effect upon hypoxic Lewis lung tumour cells in vitro, with very little or no effect on cells grown in air. This would support the theory that the presence of hypoxic cells is essential for the expression of MIS cytotoxicity.

Animals↗
PubMed1978

Fresh autotransfusion in major surgery.

The purpose of this study was to investigate whether 600-800 ml of fresh autologous blood, withdrawn just before anesthesia and retransfused at the end of the operation, would reduce early postoperative anemia. Thirty-nine patients undergoing abdominal hysterectomy were autotransfused, while 44, submitted to the same operation, served as controls. Appropriate amounts of lactated Ringer solution were infused during phlebotomy and operation. The cardiovascular system remained stable and diuresis high. Postoperative complications were few and did not prolong hospitalization. The mean peroperative blood loss per patient was 680 ml. Fresh autotransfusion did not improve early postoperative anemia.

Anemia↗
PubMed1977

An attachment for delivery of humidified gas.

A new attachment, to either endotracheal or trachestomy tubes, is described which ensures delivery of gas to the spontaneously breathing patient without significant loss of heat or water vapour. Problems of traction and pressure are minimised when the device is used.

Aerosols↗