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Biomedical subjects

J M Gibbs

Publications and source records attributed to J M Gibbs.

At least 55 records · Page 3Linked to original sources
PubMed1983

In vivo disturbance of the oxidative metabolism of glucose in human cerebral gliomas.

Abnormalities in the oxidative metabolism of glucose in human cerebral gliomas have been studied in seven patients using positron emission tomography. Measurements of regional cerebral blood flow and oxygen consumption were obtained using the oxygen-15 steady-state inhalation technique. Values of regional cerebral glucose consumption were obtained using fluorine 18-labeled 2-fluoro-2-deoxy-D-glucose and a simplification of the method of Sokoloff. Functional values were obtained for regions of tumor and brain tissue in the middle cerebral artery territory of the contralateral cortex. Values of regional glucose consumption were calculated for both regions using a value of the lumped constant quoted for normal brain tissue (0.42). Tumor regional cerebral blood flow was comparable to that in the contralateral cortex, whereas regional cerebral oxygen consumption was depressed. This depression resulted in low tumor values of the fractional oxygen extraction ratio (0.21 +/- 0.07), indicating that oxygen supply exceeded the metabolic demand. In contrast, tumor regional cerebral glucose consumption was not depressed and regional glucose extraction ratios were similar for tumor and brain tissue. The metabolic uncoupling between regional oxygen consumption and regional glucose consumption (CMRO2/CMRGlu = 0.24 +/- 0.07 ml of oxygen per milligram of glucose) is indicative of increased aerobic glycolysis.

Adult↗
PubMed1983

Disturbance of oxidative metabolism of glucose in recent human cerebral infarcts.

Eight patients with recent cerebral hemispheric infarction were studied with positron emission tomography and the oxygen-15 steady-state inhalation and [18F]deoxyglucose techniques to obtain values of regional cerebral blood flow, oxygen consumption, and glucose metabolism. The Sokoloff equation, used to calculate glucose metabolism, was simplified to exclude the exponential terms containing the rate constants. A value of the lumped constant quoted for normal brain (0.42) was used for infarcted regions and contralateral hemisphere. Mean regional cerebral blood flow, oxygen consumption, and glucose metabolism were all significantly depressed within the infarcts compared with the mirror regions in the contralateral cerebral hemisphere. The mean fractional extraction of oxygen was low, indicating an adequate supply of oxygen for residual oxidative metabolism. Regional oxygen consumption and glucose metabolism were significantly correlated within the infarcts, but with a relationship of 2 moles of oxygen per mole of glucose--one-third that in the contralateral hemisphere and in normal brain. Although these results suggest that the metabolizing tissue of a recent cerebral infarct utilizes aerobic glycolysis, caution about the validity of this pathophysiological observation is dictated by limitations in current positron emission tomographic tracer methodology.

Adult↗
PubMed1983

Correction for the presence of intravascular oxygen-15 in the steady-state technique for measuring regional oxygen extraction ratio in the brain: 2. Results in normal subjects and brain tumour and stroke patients.

Values of regional cerebral oxygen extraction ratio and oxygen utilisation obtained with the oxygen-15 steady-state inhalation technique have been found to be overestimated due to the signal from intravascular oxygen-15. A previously described method to correct for this intravascular component has been applied to a series of studies on normal subjects, and on brain tumour and stroke patients. With this correction the regional cerebral oxygen extraction ratio in normals becomes comparable to the global values previously reported with arteriovenous sampling techniques. Within the lesions of brain tumour and stroke patients, the corrections have been found to be variable and often substantial. It is concluded that failure to apply this correction may result in major errors in the values for regional oxygen extraction ratio and oxygen utilisation. This is especially true when the regional blood flow and oxygen extraction ratio of a tissue is low and regional blood volume is high.

Blood Volume↗
PubMed1983

Narcotics and spasm of the sphincter of Oddi. A retrospective study of operative cholangiograms.

The operative cholangiograms of 112 patients undergoing elective cholecystectomy were reviewed independently and retrospectively by two radiologists who were not aware of the anaesthetic technique used. Fifty four patients who received opioid drugs either pre- and/or intra-operatively comprised one study group whilst 58 patients who received no opioids comprised the other. Spasm of the sphincter of Oddi was observed in two patients in the opioid group and in one patient in the non-opioid group. The use of opioid drugs as part of the anaesthetic management for cholecystectomy did not appear to interfere with the radiological interpretation of operative cholangiography nor to increase the low incidence of spasm of the sphincter of Oddi.

Adolescent↗
PubMed1982

Pain relief.

Explore the source record for details and available documents.

Buprenorphine↗
PubMed1982

Patient administration of I.V. buprenorphine for postoperative pain relief using the "Cardiff" demand analgesia apparatus.

In 51 patients undergoing elective abdominal surgery, analgesia was provided for the first 24 h after surgery by bolus injections of buprenorphine 0.1 or 0.2 mg given i.v. on patient demand using a patient-operated syringe driver (the "Cardiff" palliator). Excellent analgesia was reported by 47 patients. Four elderly patients had difficulty in operating the demand apparatus. In two other patients, clinically significant ventilatory depression necessitated abandoning the trial. Although there was a high degree of patient and staff acceptance of the method, the potential for ventilatory depression emphasizes the need for close observation of patients receiving i.v. opioids by this technique.

Adult↗
PubMed1982

Teaching the uptake and distribution of halothane. A computer simulation program.

A computer aided learning program for teaching the kinetics of uptake and distribution of the inhalational anaesthetic halothane is described. The program is based on a seven-compartment model which simulates the action of halothane on ventilation and on the cardiovascular system. The program is available to the student in four forms: one with no changes in circulation or respiration, one with the cardiovascular effects of halothane included, one with respiratory effects only, and one with both of these effects combined. The student can study the importance of the influence of halothane on respiration and blood circulation by comparing results from simulations on different models. The simulation is presented as graphs which are continuously displayed on an alphanumeric visual display terminal. Interaction with the program is possible at all times to change the simulation speed, the variables being graphed, the inspired halothane fraction, and the fresh gas flow.

Anesthesia, Inhalation↗
PubMed1982

Evaluation of a computer simulation program for teaching halothane uptake and distribution.

A pilot evaluation of a simulation program used during a tutorial for the teaching of uptake and distribution of the inhalational anaesthetic halothane shows a highly significant improvement in the students' answers after the tutorial using a 'before and after' questionnaire. The students showed an understanding of the program's display and model limitations. This encourages the further use of the program.

Anesthesiology↗
PubMed1982

The computer as a teaching aid: with particular reference to anaesthesia.

Computers have been used by a few anaesthetists for teaching purposes for a number of years. Well constructed programs have the capacity to realistically present material which would not be available by other teaching methods. The advent of small portable computers has made this powerful teaching aid potentially available to a much larger group. It is likely that computer aided learning has a significant future in anaesthetic training and, in particular, for continuing medical education.

Anesthesiology↗
PubMed1980

Is a microfilter necessary in a single unit blood transfusion.

Pulmonary dysfunction may be caused by microaggregates passing through a standard blood filter (170 mu) during transsfusion. In this study a sheep was repeatedly tranfused with a single unit (about 450 ml) of her own blood to compare the effects of 27 mu and 170 mu pore filters on lung function. Lung function was assessed by comparing cardiac output, pulmonary shunt and alveolar-arterial oxygen tension gradient before, during and after transfusion. There were no significant changes in these parameters. So far as these results can be extrapolated from sheep to man, it is considered that the more expensive 27 mu pore filter is not justified in small volume transfusions.

Animals↗
PubMed1980

Comparison of three benzodiazepines for oral premedication in minor gynaecological surgery.

Diazepam 10 and 20 mg, lorazepam 2.5 and 5.0 mg, flunitrazepam 1 and 2 mg, and a placebo, were compared in a randomized double-blind controlled trial as oral premedication for 210 patients undergoing minor gynaecological surgery. Flunitrazepam 1 mg and lorazepam 2.5 mg were superior to placebo (P less than 0.001 and P less than 0.05 respectively) in relieving patient anxiety when assessed by a trained observer 60 min after premedication. Flunitrazepam 1 mg also produced more drowsiness (P less than 0.01) than the placebo. Comparisons of other low-dose benzodiazepine groups with the placebo, and of the large dose with the small dose of each drug revealed no significant changes in anxiolysis or drowsiness. Dizziness and prolonged drowsiness were not apparent with low-dose flunitrazepam. The data suggests that flunitrazepam 1 mg offers advantages over placebo, diazepam 10 mg and lorazepam 2.5 mg for routine oral premedication in minor gynaecological surgery.

Adolescent↗
PubMed1980

A trial of meptazinol for the relief of pain after abdominal surgery.

Meptazinol is an opioid drug having mixed agonist-antagonist properties. Chemically it is a hexahydroazepine derivative. It has been used to provide postoperative analgesia for patients undergoing abdominal surgery but only in single dose studies. The drug is of particular interest in that the clinical impression of minimal ventilatory depression has been confirmed, 60 mg meptazinol showing less ventilatory depression than 10 mg of morphine. To test its efficacy in patients undergoing abdominal surgery and to assess the incidence of side effects, an open study was undertaken in 43 patients.

Abdomen↗
PubMed1978

Preservation of the pulmonary vasoconstrictor response to alveolar hypoxia during the administration of halothane to dogs.

The action of halothane on the pulmonary vasoconstrictor response to unilateral alveolar hypoxia was studied in two groups of dogs. In the first group the redistribution of blood flow between the two lungs was studied with a radioactive isotope method, which provided intermittent measurements, whilst in the second group the distribution of blood flow was observed continuously. In both groups there was no significant alteration of the hypoxic vasoconstrictor response with inspired halothane concentrations varying from 0.5 to 1.5%.

Animals↗
PubMed1978

A case of rhabdomyolysis associated with suxamethonium.

A boy presenting for oesophagoscopy developed myoglobinuria during convalescence from the procedure. A susceptibility to malignant hyperpyerexia was considered in the differential diagnosis but was felt to be unlikely on the basis of in vitro testing of muscle biopsy specimens. A review of relevant papers suggests that rhabdomyolysis of significant degree following suxamethonium administration may be more common than generally appreciated, particularly in children.

Child↗