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Biomedical subjects

R M Jones

Publications and source records attributed to R M Jones.

At least 145 records · Page 8Linked to original sources
PubMed1992

Colon carcinoma immunoscintigraphy by monoclonal anti-CEA antibody labeled with gallium-67-aminooxyacetyldeferroxamine.

Previous experimental results in nude mice showing that radiolabeling the monoclonal antibody anti-CEA 35 with 67Ga-aminooxyacetyldeferroxamine could give better tumor localization than radioiodination prompted us to initiate the present clinical study. The 67Ga-labeled antibody anti-CEA 35 (185 MBq, 0.7-1.7 mg) was injected preoperatively into 14 patients for colorectal carcinoma imaging. The same antibody labeled with 125I (3.7 MBq, 0.25 mg) was injected simultaneously to compare the 67Ga and 125I dose recoveries in surgical specimens. Twelve of 14 primary tumors gave a positive 67Ga scintigraph. The mean %ID/g recovered in all tumors 3-9 days after injection was significantly higher for 67Ga (0.019%) than for 125I (0.005%) (p < 0.001, paired t test). The tumor-to-normal tissue ratios were generally higher for 67Ga, with the exception of liver. We conclude that 67Ga-aminooxyacetyldeferroxamine improved immunoscintigraphy outside the liver, particularly in the pelvic region. We also show that deferroxamine infusion accelerates the excretion of 67Ga in eight patients and propose that this could lead to further improvement of immunoscintigraphy.

Aged↗
PubMed1992

Preconditioning of heart by repeated stunning. Adaptive modification of antioxidative defense system.

Previous studies demonstrated that preconditioning of a heart by repeated stunning can reduce the cellular injury to the heart from subsequent acute ischemic insult. To examine the possible biochemical mechanism for such myocardial preservation afforded by preconditioning, swine heart was subjected to four episodes of 5 min. stunning by occluding the left anterior descending coronary artery (LAD), followed by 10 min. of reperfusion after each stunning. Heart was then made regionally ischemic for 60 min. by LAD occlusion, followed by 6 hrs. reperfusion. Control heart was perfused for 60 min., followed by 60 min. ischemia and 6 hrs. reperfusion. The results of our studies indicated the stimulation of a number of antioxidative enzymes, including Mn-superoxide dismutase (Mn-SOD), catalase, glutathione peroxidase, and glutathione reductase, after repeated stunning and reperfusion. In addition, a number of new proteins were expressed after preconditioning the heart, including some oxidative-stress related proteins and 72 kDa heat-shock protein. These results suggest that preconditioning of a heart by repeated stunning may lead to strengthening of the oxidative defense system of the heart, which is likely to play a role in myocardial preservation during subsequent ischemic and reperfusion injury.

Adaptation, Physiological↗
PubMed1991

Prostaglandin E1 for the treatment of primary non-function of the donor organ in liver transplantation.

OBJECTIVE: To present a case in which acute failure of a liver graft was treated with an infusion of prostaglandin E1 (PGE1). CLINICAL FEATURES: A nine-year-old girl underwent liver transplantation for Wilson's disease. Her course was complicated by primary non-function of the graft as evidenced by poor bile production, rising bilirubin and liver enzyme levels and a severe coagulopathy. INTERVENTION AND OUTCOME: PGE1 was infused and there was recovery of graft function. The need for urgent re-transplantation was avoided. CONCLUSIONS: PGE1 may have an important role in liver transplantation considering the logistic difficulties of obtaining donor livers for urgent transplantation in Australia.

Alprostadil↗
PubMed1991

Release of fatty acid-binding protein from ischemic-reperfused rat heart and its prevention by mepacrine.

In an attempt to resolve the issue of whether there is a loss of fatty acid binding protein (H-FABP) from heart during ischemia and reperfusion, and to further examine the role of this protein in ischemic-reperfusion injury, the amount of H-FABP of heart was monitored during ischemia and reperfusion. Excellent correlation was obtained between the loss of H-FABP from heart and its appearance in the perfusate buffer when examined by Western blot using the specific antibody to H-FABP. Further quantitation was achieved by densitometric scanning of the Western blot and rocket electrophoresis. Maximum release of H-FABP was observed within 20 min of reperfusion, the total release being 10% of the H-FABP content of the heart. Mepacrine, a membrane stabilizer and a phospholipase inhibitor, reduced the release of H-FABP from the heart and prevented the accumulation of nonesterified fatty acids in the tissue during ischemia and reperfusion. In view of the established role of H-FABP in the preservation of membrane phospholipids by either scavenging free radicals during ischemia and reperfusion or by modulating the enzymes of phospholipid synthesis, it seems likely that the loss of H-FABP may have some contribution towards the ischemic-reperfusion injury.

Animals↗
PubMed1991

Protection from nonfreezing cold injury by quinacrine, a phospholipase inhibitor.

A recent study from our laboratory indicated additional tissue injury during rewarming of a cooled rabbit leg. Oxygen-derived free radicals were believed to play a role in such "rewarming injury." Since free radicals may attack membrane phospholipids, we analyzed the phospholipid composition in the leg tissue during cooling and rewarming. Our results indicated significant breakdown of membrane phospholipids, particularly phosphatidylcholine and phosphatidylethanolamine, with a corresponding accumulation of lysophosphatidylcholine and nonesterified fatty acids. Quinacrine, a phospholipase inhibitor, was able to preserve membrane phospholipids during rewarming of the cooled leg. Rewarming of cooled tissue was also accompanied by additional tissue injury, as evidenced by the increased release of lactic acid dehydrogenase and creatine kinase, as well as enhanced lipid peroxidation, as evidenced by increased malonaldehyde formation. Quinacrine reduced the release of these intracellular enzymes and decreased lipid peroxidation, suggesting its efficacy as a therapeutic agent against hypothermic injury.

Animals↗
PubMed1991

Release of endothelin from cultured bovine endothelial cells.

Recently discovered endothelin is a powerful vasoconstrictor of vascular smooth muscle in vitro, which also profoundly affects the mechanical function of the heart. An increased level of plasma endothelin in patients with acute myocardial infarction suggests the enhanced release of endothelin from vascular endothelium under pathophysiological conditions of the heart. The reperfusion of ischemic myocardium is associated with the activation of polymorphonuclear leukocytes (PMN) generating oxygen-derived free radicals (OFR), as well as, enhanced responsiveness of myocardial alpha 1-adrenergic receptor. Both OFR and catecholamines are implicated in the modulation of release of endothelium-derived peptides.

Adrenergic alpha-Agonists↗
PubMed1991

Microleakage and shear bond strength of resin and porcelain veneers bonded to cast alloys.

Four resin veneering materials and four methods of retaining the veneer on metal castings were compared with metal ceramic restoration. Variations in microleakage were noted between the four resin materials retained by mechanical retention beads. When mechanical and chemical modes of a resin and porcelain veneer retention were compared, there was no microleakage with one mechanically and two chemically retained resin groups including one metal ceramic group. The resin materials tested understandably produced substantially lower shear bond strengths than the metal ceramic specimens. Higher shear bond strengths were recorded for the retentive beads than for the resins retained by three chemical bonding techniques. There was no direct correlation between microleakage and shear bond strength.

Acrylic Resins↗
PubMed1991

Resistance to atracurium in a patient with an increase in plasma alpha 1 globulins.

We observed that a female patient with a poorly differentiated adenocarcinoma of the stomach undergoing gastrectomy was markedly resistant to the action of the neuromuscular blocking drug atracurium. There was no evidence of tumour metastasis and her liver function tests were normal. Electrophoresis of plasma proteins revealed a marked increase in alpha 1 globulin. Alpha 1 acid glycoprotein is an acute phase reactant that is increased in patients with cancer and is present in the alpha 1 globulin electrophoresis pattern. It is likely that the mechanism for the resistance to neuromuscular block in the patient was an increase in drug binding to alpha 1 acid glycoprotein.

Adenocarcinoma↗
PubMed1991

Induction and recovery characteristics of desflurane in day case patients: a comparison with propofol.

Desflurane is an ether halogenated exclusively with fluorine. It has a blood/gas partition coefficient of 0.42 (cf. isoflurane 1.40 and nitrous oxide 0.46). This characteristic suggests that it should provide both a fast induction of anaesthesia and a rapid recovery from anaesthesia. To assess this, 60 patients were entered into a study and allocated at random to one of four groups receiving either desflurane or propofol for induction and maintenance of anaesthesia. Desflurane caused loss of consciousness in approximately 2 minutes during gaseous inductions. The psychomotor scores in the patients who received propofol for induction and maintenance of anaesthesia were significantly worse compared with those who were given desflurane for either induction and maintenance or for maintenance only. There was also a tendency for other recovery parameters to be faster in the patients receiving desflurane although this did not reach statistical significance. This suggests that desflurane would be a suitable agent for day case anaesthesia providing for a rapid recovery.

Adolescent↗
PubMed1991

A prospective study of liver function in infants and children exposed to daily isoflurane for several weeks.

Eleven infants and children presenting for daily radiotherapy for a period of at least 2 weeks were anaesthetised with isoflurane in 33% oxygen and nitrous oxide. They were unpremedicated and given no other agents to supplement anaesthesia. The average number of exposures was 24 (SD 11; range 10-39) and the total anaesthetic time per exposure varied between 15 and 30 minutes. Liver function was assessed by determining serum total bilirubin, aspartate amino transferase, gamma glutamyl transferase and alkaline phosphatase before the start of treatment and at 5-daily intervals thereafter. There was no measurable change in any of these determinants of liver function. All children accepted daily induction of anaesthesia with isoflurane. Induction, maintenance and recovery from anaesthesia were uncomplicated.

Alkaline Phosphatase↗
PubMed1991

Laparoscopic cholecystectomy: initial experience.

Twenty-five consecutive patients underwent percutaneous laparoscopic cholecystectomy (PCC). The gallbladder was removed successfully in 18 patients. The mean postoperative hospital stay was 1.4 days and patients returned to normal activity at a mean 8 days after operation. Postoperative pain was minimal. Formal laparotomy was performed in 7 patients due to: bleeding (3 patients), stone spillage (3 patients) and exploration of the common bile duct (1 patient). Complications were reduced with experience and strict adherence to the described operative technique. With obvious advantages for the patient, hospitals and the community an increased demand for PCC is inevitable. However, its role in the management of cholelithiasis and overall safety have yet to be determined. There is a significant learning curve and proper training is necessary. The widespread introduction of PCC has immediate implications for surgical training.

Adolescent↗