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Biomedical subjects

M Borg

Publications and source records attributed to M Borg.

At least 19 recordsLinked to original sources
PubMed2007

Feasibility study on the MammoSite in early-stage breast cancer: initial experience.

The aims of this study were to evaluate the feasibility, practicality, efficacy and safety of the delivery of accelerated partial breast irradiation using the MammoSite for the boost phase. Six patients aged 53-69 years with stage T1N0, T2N0, Grade I-II invasive ductal carcinoma received 9-10 Gy prescribed at 1 cm from the MammoSite balloon surface in two fractions of 4.5-5 Gy 6 h apart. The MammoSite was inserted 20-37 days postoperatively. External beam radiation therapy to the whole breast commenced 1-5 days after accelerated partial breast irradiation. The maximum skin dose ranged from 3 to 9 Gy. The skin-cavity distance ranged from 7 to 19 mm. Local discomfort resolved as the scar healed spontaneously within 3-5 days. No Grade III or higher acute toxicity or local infection was recorded. The ease of insertion and accuracy of dosimetry makes the MammoSite suitable for use in properly selected women with early-stage breast cancer in a trial setting.

Aged↗
PubMed2006

Orbital rhabdomyosarcoma: multidisciplinary treatment experience.

Orbital rhabdomyosarcoma (RMS) accounts for 10% of childhood RMS and has a relatively good prognosis of up to 85% 5-year survival. Improved survival has led to increased interest in late effects of treatment. The objective of this study was to review the results of treating orbital RMS with multidisciplinary treatment at Women's and Children's Hospital and Royal Adelaide Hospital with emphasis on late effects of treatment. A retrospective review was carried out of all patients with orbital RMS treated with multidisciplinary treatment including radiation therapy and chemotherapy in the two institutions between 1982 and 2002. A total of five patients (age range 5.5-12 years) satisfied the eligibility requirements. Late effects were significant and included facial bone hypoplasia, cataract formation and growth hormone deficiency. Overall survival was 80% (4/5) with mean follow up of 8 years (range 3-13 years). Given the high cure rates achieved, future treatments must aim to maintain the good results but to reduce the high incidence of late effects of treatment. Standardised rating of late toxicity, long-term follow-up clinics, and implementation of modern radiation techniques (3-D conformal radiotherapy, intensity modulated radiotherapy, proton therapy) for patients with orbital RMS are important to improving outcome.

Child↗
PubMed2006

Outcome of post-prostatectomy radiotherapy in one institution.

We present a retrospective study to evaluate the outcome of postoperative radiotherapy for biochemical or clinical recurrent prostate cancer. Twenty-six patients (median age 60 years) underwent radiotherapy after radical prostatectomy between January 1997 and January 2004. Seven patients received adjuvant radiotherapy and 19 received salvage radiotherapy. The median prostate-specific antigen at diagnosis was 8.6 (0.9-89) and most (23 patients) presented with T(3)N(0) disease. The median follow up was 19.5 months (5-84 months). All patients received a dose of 61.2 Gy at 1.8 Gy per fraction, 20 initially receiving 45 Gy to the lesser pelvis. The median dose to the bladder, rectum and left femoral head were 55.6, 57.5 and 33.8 Gy, respectively. All patients were managed radiotherapeutically by the first author. Twenty-four patients are alive. Two patients have died, one from oesophageal cancer and the second from metastatic prostate cancer. Two other patients also developed metastatic disease. Four asymptomatic patients with a rising prostate-specific antigen are under observation. None of the 26 patients has developed a local recurrence. Seven patients have developed grade 1 late bowel effects and three a grade 2 late effect. Eight patients suffer from grade 1 late genitourinary effects and two from grade 2 effects. One patient developed impotence, whereas 23 patients were rendered impotent postoperatively. There were no grade 3/4 late effects. Postoperative radiotherapy is well tolerated and provides effective local control.

Aged↗
PubMed2005

One-dimensional PtO2 at Pt steps: formation and reaction with CO.

Using core-level spectroscopy and density functional theory we show that a one-dimensional (1D) oxide structure forms at the steps of the Pt(332) surface after exposure. The 1D oxide is found to be stable in an oxygen pressure range, where bulk oxides are only metastable, and is therefore argued to be a precursor to the Pt oxidation. As an example of the consequences of such a precursor exclusively present at the steps, we investigate the reaction of CO with oxygen covered Pt(332). Albeit more strongly bound, the oxidic oxygen is found to react more easily with CO than oxygen chemisorbed on the Pt terraces.

Journal Article↗
PubMed2005

The experience of making treatment decisions for women with early stage breast cancer: a diagrammatic representation.

Women who are making decisions about treatment for early stage breast cancer interact with a number of people when they are considering their treatment options and the impact breast cancer will have on their lives. Previous research has considered patient preferences for involvement in treatment decision-making and proposed factors that may influence breast cancer treatment decisions. However, to date, there has been a paucity of research focusing on the experience of making treatment decisions from the women's perspective. The aim of this paper is to describe the relationships between the women, the medical practitioners and other people, and to consider features that may be influential in the experience of making treatment decisions. Two models are proposed to represent concepts that are linked to the experience of making treatment decisions. The first model proposed has been formulated to represent factors that may influence the treatment decision. The second model highlights aspects of the women's lives that may be affected. This paper discusses concepts that are presented in the conceptual models and makes suggestions for future studies relating to the experience of making treatment decisions for women with breast cancer.

Adaptation, Psychological↗
PubMed2005

Importance of radiation time and dose factors on outcome for childhood medulloblastoma.

The purpose of this study was to investigate the relationship of posterior fossa radiation therapy duration (PFRTD) and relapse-free survival (RFS) following adjuvant craniospinal RT for childhood medulloblastoma. A retrospective audit was performed assessing all children aged <18 years managed with adjuvant craniospinal RT for medulloblastoma in Australia and New Zealand in 1980-1993. Children receiving prolonged (>180 days) pre-RT chemotherapy were excluded. Data were obtained for potential prognostic factors in domains of patient, tumour and treatment factors. Radiation therapy time factors assessed were PFRTD and time interval from surgery to commencement of RT (SRTD). The end-point assessed was RFS and analysis was performed using Cox regression and Kaplan-Meier survival. One hundred and eighty-nine children were identified from 10 oncology units, with data available from 182 children for analysis. Median follow up was 5.3 years. Seventy-three per cent of children presented with disease confined to the cerebellum; 13% had initial neuraxis disease. Macroscopic resection was described in 54%; 42% received adjuvant chemotherapy. Median RT dose and RT duration to PF was 55 Gy and 45 days, respectively. Seventy-eight relapses occurred with a 10-year actuarial RFS of 58.2% (standard error +/- 4%). On univariate analysis, increasing PF dose (P = 0.002), age >5 years (P = 0.006), and more thorough extent of surgical resection (P = 0.043) were associated with improved RFS; PFRTD (P = 0.20) and SRTD (P = 0.51) were not associated with RFS. On multivariate analysis, although both PF dose (P = 0.004) and extent of surgery (P = 0.045) remained strongly significant, RT duration was now associated with RFS (P = 0.049). Other factors assessed that did not reach significance were patient age, local tumour extent, presence of internal shunt and use of chemotherapy. The importance of local treatment factors was confirmed in this audit with established prognostic factors such as primary tumour macroscopic resection and adequate PF RT dose being associated with RFS. A treatment time effect is weakly suggested, although less significant than RT dose delivered.

Adolescent↗
PubMed2004

High-coverage oxygen structures on Rh111: adsorbate repulsion and site preference is not enough.

A new O induced structure on Rh(111) displaying a (2 sqaureroot[3] x 2sqaureroot[3])R30 degrees periodicity with an oxygen coverage of 2/3 has been studied by high resolution core level spectroscopy, scanning tunneling microscopy, and density functional theory. Although O favors fcc hollow sites in all other known phases, it occupies both fcc and hcp sites in this structure, which cannot be explained by pairwise adsorbate repulsion only. Both the (2sqaureroot[3] x 2sqaureroot[3])R30 degrees and (2 x 2)-3O structures also exemplify that density-of-states contrast can lead to oxygen adatoms appearing as protrusions in scanning tunneling microscopy images.

Journal Article↗
PubMed2004

Self-limited growth of a thin oxide layer on Rh(111).

The oxidation of the Rh(111) surface at oxygen pressures from 10(-10) mbar to 0.5 bar and temperatures between 300 and 900 K has been studied on the atomic scale using a multimethod approach of experimental and theoretical techniques. Oxidation starts at the steps, resulting in a trilayer O-Rh-O surface oxide which, although not thermodynamically stable, prevents further oxidation at intermediate pressures. A thick corundum like Rh2O3 bulk oxide is formed only at significantly higher pressures and temperatures.

Journal Article↗
PubMed2004

Clozapine improves dyskinesias in Parkinson disease: a double-blind, placebo-controlled study.

OBJECTIVE: To investigate the efficacy and safety of clozapine in the treatment of levodopa-induced dyskinesias (LID) in patients with severe Parkinson disease (PD). METHODS: Fifty patients were randomized to treatment in this 10-week, double-blind, parallel-group, placebo-controlled, multicenter trial. The principal measure of outcome was the diurnal change in the "on" time with LID assessed using a self-evaluation of the motor performance fluctuations performed every 2 weeks. An acute levodopa challenge was also performed at the beginning and end of the study. RESULTS: A reduction in the duration of "on" periods with LID was noted in favor of the clozapine group at the end of the study (placebo group day 0: 4.54 +/- 0.53 hours, end: 5.28 +/- 0.70 hours; clozapine group day 0: 5.68 +/- 0.66 hours, end: 3.98 +/- 0.57 hours; p = 0.003). The mean clozapine dosage was 39.4 +/- 4.5 (SEM) mg/day. The maximal LID score at rest during the levodopa challenge was significantly decreased under clozapine treatment, with a variation from day 0 to day 70 in the placebo group of +0.15 +/- 1.01 and in the clozapine group of -2.22 +/- 0.52 (p < 0.05). Five patients receiving clozapine and seven receiving placebo discontinued on account of adverse events. Among them, three patients in the clozapine group developed eosinophilia, which rapidly resolved after withdrawal of the drug. CONCLUSION: Clozapine is effective in the treatment of levodopa-induced dyskinesias in severe PD.

Aged↗
PubMed2004

Clinical and cellular radiosensitivity in inherited human syndromes.

AIMS: It has been proposed that in-vitro measurements of radiosensitivity might allow individualisation of patient radiotherapy schedules, with concomitant increases in the therapeutic ratio between tumours and normal tissues. Most predictive assay research on normal tissues to date has been based on the radiosensitivity of normal lymphocytes and skin fibroblasts as determined by clonogenic cell-survival assays. Studies comparing the radiosensitivity of fibroblasts or lymphocytes with acute or late radiation damage have reported variable results. METHODS: In this study, we measured the radiosensitivity of lymphocytes from three patients displaying clinical radiation hypersensitivity who were known or suspected to carry germline mutations in genes that have been linked to increased radiosensitivity (a BRCA2 mutation carrier, a patient with Bloom's syndrome and a patient with a Fanconi anaemia-like condition), to investigate whether there is a correlation between cellular radiosensitivity and normal tissue response. RESULTS: We found no association between lymphocyte radiosensitivity and the development of adverse radiation reactions in this group of patients, as is observed in the paradigm radiosensitivity syndrome, ataxia-telangiectasia. CONCLUSIONS: Our results, and those of others, show that, at present, the evidence is not strong enough to justify routine clinical use of clonogenic cell survival assays to predict radiation response.

Adult↗
PubMed2003

Identification of step atoms by high resolution core level spectroscopy.

Vicinal Rh(111) surfaces are studied with high resolution core level photoemission. We demonstrate the possibility to distinguish between the different kinds of surface atoms on these surfaces by virtue of their 3d core level binding energies. In particular, the low coordinated step atoms are found to exhibit a clear fingerprint in Rh 3d spectra. We demonstrate how this may be used to show that initial oxygen adsorption occurs on the steps and not on the terraces of the vicinal surfaces.

Journal Article↗
PubMed2003

Prevalence of methicillin-resistant Staphylococcus aureus in eight African hospitals and Malta.

Methicillin-resistant Staphylococcus aureus (MRSA) poses a serious therapeutic problem worldwide, and its frequency in most African countries has not been reported. This study was aimed at determining the prevalence and antibiotic susceptibility patterns of MRSA in eight large hospitals (>500 beds) in Africa and Malta, from 1996 to 1997. Susceptibility to methicillin (oxacillin) and to other drugs was determined by E test (AB Biodisk, Solna, Sweden) on a total of 1440 clinical isolates of S. aureus. Methicillin resistance was detected in 213 (15%) of the 1440 isolates tested. The rate of MRSA was relatively high in Nigeria, Kenya, and Cameroon (21-30%), and below 10% in Tunisia, Malta, and Algeria. All MRSA isolates were sensitive to vancomycin, with MICs 60%) of MRSA strains were multiresistant. There is a need to maintain surveillance and control of MRSA infections in Africa.

Africa↗
PubMed2002

Two-dimensional oxide on Pd(111).

The oxidation of Pd(111) leads to an incommensurate surface oxide, which was studied by the use of scanning tunneling microscopy, surface x-ray diffraction, high resolution core level spectroscopy, and density functional calculations. A combination of these methods reveals a two-dimensional structure having no resemblance to bulk oxides of Pd. Our study also demonstrates how the atomic arrangement of a nontrivial incommensurate surface can be solved by molecular dynamics in a case where experimental techniques alone give no solution.

Journal Article↗
PubMed2002

The apathy inventory: assessment of apathy and awareness in Alzheimer's disease, Parkinson's disease and mild cognitive impairment.

OBJECTIVE: This study was designed to establish the validity and reliability of the apathy inventory (IA), a rating scale for global assessment of apathy and separate assessment of emotional blunting, lack of initiative, and lack of interest. METHOD: Information for the IA can be obtained from the patient or from a caregiver. We evaluated 115 subjects using the IA, consisting of 19 healthy elderly subjects, 24 patients with Mild Cognitive Impairment (MCI), 12 subjects with Parkinson's disease (PD) and 60 subjects with Alzheimer's disease (AD). RESULTS: Internal consistency, item reliability, and between-rater reliability were high. A test-retest reliability study demonstrated that caregiver responses to IA questions were stable over short intervals. A concurrent validity study showed that the IA assesses apathy as effectively as the Neuro Psychiatric Inventory apathy domain. In the caregiver-based evaluation, AD subjects had significantly higher scores than controls, both for global apathy score and for the lack of interest dimension. When the AD patients were subdivided according to diagnostic criteria for apathy, apathetic patients had significantly higher scores than non apathetic patients. With the patient-based evaluations, no differences were found among the AD, MCI and control groups. The scores in the patient-based evaluations were only higher for the PD group versus the control subjects. The results also indicated that AD patients had poor awareness of their emotional blunting and lack of initiative. CONCLUSIONS: The IA is a reliable method for assessing in demented and non-demented elderly subjects several dimensions of the apathetic syndrome, and also the subject's awareness of these symptoms.

Aged↗
PubMed2002

Choosing the right dopamine agonist for patients with Parkinson's disease.

Dopamine receptor agonists (DA) are assuming an increasing importance in the treatment of both early and advanced symptoms of Parkinson's disease (PD). However, choosing the right DA for patients with PD unfortunately remains more a pragmatic medical art than a science. The aim of this review is to provide a realistic point of view on the strengths and weaknesses of five DAs: bromocriptine, ropinirole, pergolide, pramipexole and piribedil. This has been done by analysing their respective: (1) flexibility in PD, i.e. in monotherapy, in early and in late combination with levodopa; (2) safety profile and (3) titration schedule. These five DAs are not evenly matched regarding these three criteria. The differences observed highlight the therapeutic value of piribedil, which has a flexible indication, adapted to all stages of PD, a safer profile and the most simple initiation schedule.

Decision Making↗
PubMed2001

Unusual Multilayer Surface Alloy: Al(100)-c(2 x 2)-2Li.

An unusual multilayer surface alloy is formed by adsorption of one monolayer Li on Al(100). It is shown by low energy electron diffraction that the first three layers consist of a mixed Al-Li layer, a pure Al layer, and a second Al-Li layer. Thus the alloy has the same layer stoichiometry as the (100) surface of the metastable Al(3)Li bulk alloy. However, the relative orientation of the two mixed layers is the same as that in the Al(3)Ti-type structure. These findings are confirmed by total-energy calculations, which lead further to the prediction that the bulk Al(3)Li alloy has a faulted, Al(3)Ti-type surface.

Journal Article↗
PubMed2001

Origin of the mutations in the parkin gene in Europe: exon rearrangements are independent recurrent events, whereas point mutations may result from Founder effects.

A wide variety of mutations in the parkin gene, including exon deletions and duplications, as well as point mutations, result in autosomal recessive early-onset parkinsonism. Interestingly, several of these anomalies were found repeatedly in unrelated patients and may therefore result from recurrent, de novo mutational events or from founder effects. In the present study, haplotype analysis, using 10 microsatellite markers covering a 4.7-cM region known to contain the parkin gene, was performed in 48 families, mostly from European countries, with early-onset autosomal recessive parkinsonism. The patients carried 14 distinct mutations in the parkin gene, and each mutation was detected in more than one family. Our results support the hypothesis that exon rearrangements occurred independently, whereas some point mutations, found in families from different geographic origins, may have been transmitted by a common founder.

Age of Onset↗