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Biomedical subjects

P Downie

Publications and source records attributed to P Downie.

8 recordsLinked to original sources
PubMed2002

Sedation practices for Australian and New Zealand paediatric oncology patients.

OBJECTIVES: Paediatric oncology patients often require repeated bone marrow aspirates and lumbar punctures. These procedures commonly require sedation and analgesia. The Australian and New Zealand College of Anaesthetists and the American Academy of Pediatrics have published guidelines that provide recommendations on monitoring and staffing requirements during sedation of paediatric patients. A survey was conducted of the oncology units in Australia and New Zealand in order to compare current practices with published guidelines. METHODS: Telephone interviews were conducted with nursing or medical staff members. RESULTS: Fourteen oncology units collectively perform approximately 130 procedures each week, of which 74% are performed under general anaesthesia. Of the remainder, most are performed using conscious sedation. Most units adhere to published recommendations regarding equipment and staffing during procedures performed under sedation. Only a minority of units follow guidelines regarding documentation; fasting requirements; observation and documentation of vital signs during and after the procedure; and obtaining informed consent for procedures performed using sedation. CONCLUSION: Sedation practices among paediatric oncology units in Australia and New Zealand vary. None of the units fully adhere to published guidelines on childhood sedation. Paediatric oncology units should be familiar with the content of these guidelines and make an informed decision as to their usefulness, both in directing best clinical practice, and in supporting current practice in the event of medico-legal challenge.

Analgesics↗
PubMed2000

An angle resolved electron-ion recoil vector correlation study of alternate ion dissociation channels in A CF3I+

Electron-ion recoil vector correlations are examined for the ionization and subsequent dissociation of A state CF3I+. The magnitude of the electron and fragment ion recoil vectors permits the energetics of two alternative decays to I+ and CF3+ to be compared, while differences between the angular correlations are interpreted as molecule-frame photoelectron angular distributions which, in the I+ channel, are smeared by molecular rotation between ionization and dissociation. Quantitative estimates of sub-ps I+ decay lifetimes are extracted, indicating very different decay rates for the alternative dissociation channels. Surprisingly, the ka1 and ke photoelectron continua exchange polarization dependence in the I+ channel correlations and vibronic interactions are postulated in explanation. This can also rationalize the non-adiabatic A CF3I+-->I+ decay mechanism and the branching competition between the CF3+ and I+ channels.

Journal Article↗
PubMed1999

Gene transfer of endothelial nitric oxide synthase improves nitric oxide-dependent endothelial function in a hypertensive rat model.

OBJECTIVE: We have shown previously that there is a relative nitric oxide deficiency at the level of vascular endothelium in the stroke-prone spontaneously hypertensive rat (SHRSP), a model of human essential hypertension, as compared to its normotensive reference strain Wistar Kyoto (WKY) rat. The aim of the current study was to investigate whether adenoviral-mediated gene transfer of an endothelial nitric oxide synthase (eNOS) cDNA (AdCMVeNOS) into carotid arteries of the SHRSP may improve endothelial function. METHODS: Enzyme activity of the recombinant eNOS protein encoded by AdCMVeNOS was tested using a Griess assay in endothelial cells in culture. Left carotid arteries of SHRSP were surgically isolated and exposed to either the AdCMVeNOS or control beta-galactosidase-containing virus, (2 x 10(9) pfu/ml) ex vivo and in vivo. The vessels were harvested 24 h after surgery and analysed by Western blotting, immunohistochemistry and by examining endothelial function ex vivo. RESULTS: Cultured endothelial cells showed almost 100% transduction with both viruses and a dose response of eNOS expression showed a five-fold increase in nitrite production for AdCMVeNOS with no change for beta-galactosidase-containing virus. Western blotting demonstrated a significant increase of eNOS expression in vessels infused with AdCMVeNOS when compared to controls. Immunohistochemistry showed highly positive staining with monoclonal antibodies against eNOS in the intact endothelial cells of the AdCMVeNOS infused vessels. The areas under the curve of the concentration responses to phenylephrine (10(-9) to 3 x 10(-6) M) in the absence and presence of NG-nitroarginine methyl ester (100 microM) showed increased basal nitric oxide bioavailability in the carotid arteries infused with AdCMVeNOS compared to the control (n = 6 for each; P = 0.0069; 95% CI, 0.864 to 3.277). CONCLUSIONS: Our results show that AdCMVeNOS is an effective tool for vascular gene transfer and that it can improve endothelial NO availability in the SHRSP, a genetic model of essential hypertension and endothelial dysfunction.

Animals↗
PubMed1999

High incidence of treatment failure with vincristine, etoposide, epirubicin, and prednisolone chemotherapy with successful salvage in childhood Hodgkin disease.

BACKGROUND AND PROCEDURE: In an attempt to further reduce the long-term toxicity of chemotherapy for childhood Hodgkin disease (HD), the Australian and New Zealand Children's Cancer Study Group between 1990 and 1996 enrolled 53 children with biopsy-proven and imaging-staged HD into a chemotherapy-only treatment regimen using 5-6 courses of vincristine, etoposide, epirubicin, and prednisolone (VEEP). RESULTS: There were 23 events in these children with 3 progressive disease (PD), 8 partial remissions (PR), and 12 relapses. In the stage I patients, there were 8 events (35%). There was no association between the number of events and the stage of HD. Massive mediastinal disease at diagnosis was present in 16 patients, 11 of whom had an event with 3 PD, 3 PR, and 5 relapses. For all patients with an event at 6-24-month follow-up, all but two patients were salvaged with either alkylating agent-based chemotherapy alone or with irradiation and chemotherapy. The event-free survival for the whole group with median follow-up of 33 months was 59%, but only 31% for massive mediastinal disease. Disease-free survival was 78% and overall survival at 60 months was 92%, with one death due to drug-induced aplasia and another from acute myeloid leukemia. CONCLUSIONS: We conclude that VEEP chemotherapy in childhood HD used as the only treatment modality has an unacceptably high treatment failure rate in patients with massive mediastinal disease and 35% incidence of treatment failure in stage I disease.

Adolescent↗
PubMed1997

Cancer in children.

Cancer is an uncommon disease in children. The majority of children who develop a malignancy are under the age of 5 years with the commonest tumours being those of the bone marrow, lymphoid systems and central nervous system. Solid tumours in children are almost always sarcomas. Tumours of epithelial origin (or carcinomas) are exceedingly rare. The cause of the various paediatric cancers is largely unknown, and preventive measures are therefore unavailable to combat them. Despite this, there have been significant gains made in the past 20 years, such that 60% of all children who present with a malignancy in the 1990s can expect to be cured.

Central Nervous System Diseases↗
PubMed1997

The ageing face. Stemming the tide with cosmetic surgery.

Over the past decade there has been growing media focus on cosmetic surgery, with greatly increased public acceptance which has spread through all ethnic groups in our society, especially in second and third generation Australians. The acceptance and desire for male cosmetic surgery is also increasing but not at the level of their female counterparts. Increased requests for cosmetic surgery now cover all socioeconomic groups.

Aged↗