Bacteria are implicated in endodontic infections. They not only infect the root canal lumen but also invade the dentinal tubules where they may remain untouched by contemporary chemomechanical preparation during root canal therapy. The contentious issue is whether the bacteria within these tubules contribute to secondary infections. Many studies have shown that clinicians fail to completely eradicate them during root canal therapy. At present there are no techniques available to detect the effectiveness of the current chemomechanical treatment regime within dentinal tubules. It is difficult to detect bacteria within the dentinal tubules. Culturing techniques have been used routinely as they are versatile and easy to use. However, they are unable to show the distribution of the bacteria within the dentinal tubules. Scanning electron microscopy, on the other hand, shows detailed surface structure in association with bacteria. Histological examination of root dentine specimens under the light microscope also shows the distribution of bacteria within the specimen but not viability. The dilemma posed by these existing techniques is that the results offer limited information; either demonstrating bacterial viability or bacterial distribution within specimens. No techniques able to show both the viability and the distribution of bacteria within the dentinal tubules have been reported to date. Fluorescent stains, in particular SYTO�9 and propidium iodide (LIVE/DEAD� Baclight[TM] viability kit, Molecular Probes Inc., Eugene, Oregon), have made it possible not only to stain bacteria but to differentiate live and dead bacteria. The combination of these two stains has yet to be applied to dental hard tissue in situ and they provide the basis for this investigation. The aim of this study was to evaluate the potential of the LIVE/DEAD� Baclight[TM] stains in conjuction with confocal laser scanning microscopy in the development of a technique to evaluate the viability and distribution of bacteria within dentinal tubules. This was extended to demonstrate the application of this technique by examining three different means of root canal disinfection both qualitatively and quantitatively. An important aspect of this study was to maintain bacterial viability, as well as to get maximum bacterial invasion into dentinal tubules. Results indicated that when the root canals were instrumented with Protaper� files and then irrigated with sodium hypochlorite (NaOCl) and ethylene diaminetetraacetic acid with cetrimide (EDTAC), there was more bacterial invasion into the dentinal tubules than when the root canals were only irrigated with NaOCl and EDTAC. Daily replenishments of nutrients resulted in deeper bacterial invasion into the dentinal tubules. Bacteria colonized the dentinal tubules up to a distance of 594 � 133 [mu]m from the canal. In the untreated tubules, 96 � 4 % of bacteria remained viable (green-fluorescent), whereas the Amoxicillin-treated tubules contained 94 � 6 % dead (red-fluorescent) bacteria. The calcium hydroxide-treated tubules resulted in 92 � 7 % bacterial death while the laser-treated tubules contained 81 � 12 % dead cells, frequently displaying an inner zone of dead cells surrounded by an outer zone of viable cells. The application of the fluorescent stains combined with confocal microscopy offers a new method for assessing the in vitro efficacy of root canal disinfection regimens.

Thesis (MNurs)--University of South Australia, 1997

Background: The 12-lead electrocardiogram (ECG) is a pivotal clinical investigation for evaluations of disorders of myocardial electrophysiology and function. Myocardial ischemia is generally diagnosed on the basis of clinical history, combined with ST segment shifts and T wave changes on resting 12-lead ECG. The ECG is also used as a monitoring tool for assessment of resolution of transmural ischemia following emergency treatment. Because this technology is easy, noninvasive, and inexpensive, it represents a convenient central investigative modality. On the other hand, the 12-lead ECG exhibits very low predictive accuracy for the diagnosis of ischemia in the absence of concurrent symptoms. Even if ECG monitoring is combined with treadmill exercise, the sensitivity and positive predictive accuracy for detection of myocardial ischemia are only around 50% - 75%. Therefore, information from the ECG, combined with exercise test, does not usually have a large influence on clinical decision-making. A number of imaging techniques may be combined with pacing-induced tachycardia or pharmacological stress in order to improve the diagnostic accuracy of such provocative tests for ischemia beyond the level provided by continuous ECG monitoring alone. These include echocardiography, nuclear imaging with single photon emission computed tomography (SPECT) or positron emission tomography (PET) and magnetic resonance imaging. All add to the diagnostic accuracy of the provocative tests performed, but involve considerably incremental costs. The question therefore arises: is it possible to refine continuous ECG analysis during provocative testing in such a way that the diagnostic accuracy of the procedure can be improved? The majority of clinical studies has examined the accuracy or otherwise of the diagnosis of myocardial ischemia utilizing fluctuation of the ST segments during either “spontaneous” ischemia or during provocative manoeuvres (e.g. exercise). As previously stated, the diagnostic accuracy of such analyses tends to be mediocre; when subjected to utility evaluation under Bayesian considerations, they often add little to history/physical examination. However, a number of potential refinements of 12-lead ECG analysis have been proposed, in order to improve both detection and as well as localization and quantitation of ischemia. These include evaluation of a variety of the component waveforms of both the QRS complex and the ST segment of the ECG. Current experiments The currently described series of investigations arose from preliminary findings that myocardial ischemia in a canine model was associated with transient fluctuations in QRS entropy. Both evaluations performed related to the hypothesis that reversible myocardial ischemia causes transient increases in entropy within QRS complexes and ST segments of the human 12-lead ECG. A series of preliminary experiments suggested that such changes did indeed occur, mainly within the ST segment. The first series of experiments performed compared conventional continuous ST segment analysis within the 12-lead ECG is vs. continuous evaluation of entropy-derived parameters for the localization of ischemia induced by balloon inflation during non-emergency coronary angioplasty. In a series of 103 patients, localization of ischemia was similarly accurate for the entropy-based method and the ST segment assessment method. Ischemic zones were correctly localized by these approaches in 88% and 80% of cases, respectively (p not significant). There was poor concordance between the extent of ST elevation and changes in ST segment entropy. In a small subset of patients with complete bundle branch block and/or ST depression on resting ECG (n=22), entropy-based localization of ischemia was possible in 55% of cases compared with 41% via ST segment assessment (difference not significant). Post hoc analysis revealed that entropy fluctuations arose throughout the ST segment rather than predominantly at the J-point. The second series of experiments was carried out on patients undergoing pacing-induced provocation of possible myocardial ischemia, with scanning via myocardial perfusion imaging (SPECT) examination. As with the first series, 12-lead ECG recording and ST trend monitoring were performed during the pacing procedure. The ST segment deviation and the entropy-based analyses were used for localization of possible ischemia. Data analyses were correlated with myocardial perfusion imaging results. A total 43 patients were studied. Categorization of ischemia via ST segment assessment had only 30% concordance with myocardial perfusion imaging results, while entropy-based analyses had 58% concordance. Therefore neither “conventional” (i.e. ECG-based ST segment analysis) nor novel entropy-based analyses are currently of clinical utility for detection of tachycardia-induced ischemia. / Thesis (M.Med.Sc.) - University of Adelaide, School of Medicine, 2008

Although Australian epidemiology of HBV and HCV has been well described for populations groups at higher risk, but the information available for groups generally considered to be lower risk is much more limited. An understanding of the prevalence of these infections and their risk factors in antenatal women is important to guide testing policy and practice. A study was therefore conducted of the epidemiology of hepatitis B and hepatitis C infection in women. In addition, women were asked about their experience with antenatal testing. A total of 516 women participated in the survey, of these 479 (95%) women had been tested for HCV antibodies .The prevalence of HCV antibodies was 4% overall, and 2% among women who were unaware of their HCV status prior to their antenatal test. A history of injecting drug use and residing with a HCV positive person were significantly associated with HCV infection in multivariate analyses. HBV testing was conducted in 468 (99.6%) of women, and the overall prevalence was 2%. Risk factors identified were birthplace in countries of South East Asia. Women were asked about their perception of antenatal testing and pre-test information. Nearly a third (143, 30.5%) of women who had been tested for HCV infection either said that they did not know whether they had been tested, or said that they had declined testing. The corresponding proportion for HBV infection was 28.8% (135). Over 65% and 66% of women said that had not received any information about testing for HCV and HBV respectively. The finding that virtually all antenatal women were being tested for HCV was in contrast to government and non-government organisation policies of ???selective??? screening in place during the study period. Of concern was the substantial proportion of women who were tested despite reporting that they had declined their clinician???s offer to test for HCV and HBV, and the large number of women who reported an absence of pre-test information. Women who said they had received information reported the delivery and quality of information varied according to the antenatal clinician group, but perceived the overall quality as poor.

Diagnosis of paediatric HIV infection presents a spectrum of challenges particularly in countries where resources are constrained. This program of research aims to illuminate epidemiological and clinical aspects of HIV diagnosis in resource limited settings focusing in particular on the nation of Papua New Guinea (PNG). This body of work commences with an exploration of current literature pertaining to diagnosis of HIV infection in resource constrained settings. This exploration encompasses the current epidemiological data available on HIV infection in the paediatric population worldwide, currently available methods of diagnosis and other aspects of diagnosis of paediatric HIV infection in developing nations including sampling considerations, breast feeding, health services, human resources and the relationship between early diagnosis and early treatment. The next chapter presents an epidemiological analysis of the HIV epidemic in PNG and a description of the paediatric services at Port Moresby General Hospital (PMGH) the site for most of the research presented in the thesis. The original research presented in the thesis begins with a report (Chapter 3) of a survey of paediatric diagnosis and treatment services in PNG in comparison to other countries in the Asia Pacific region. This is followed by an exploratory retrospective study elucidating factors associated with HIV testing and HIV positive serostatus in children admitted to PMGH. Selection for testing was found to be significantly associated with age, length of hospital stay and diagnoses of diarrhoea, malnutrition and oral candidiasis. Tuberculosis was associated with HIV positive serostatus. In advance of a prospective study to ascertain clinical predictors of HIV infection, a study to evaluate acceptability of HIV testing amongst carers of children admitted to PMGH was undertaken. Testing was acceptable to the majority of carers interviewed. This program of research concludes with a prospective cross-sectional study revealing low weight for age, persistent fever, lymphadenopathy and oral candidiasis to be independent predictors of HIV infection in children admitted to PMGH. An algorithm for clinically directed screening of children for HIV infection in a hospital setting was subsequently developed. Finally evidence based clinical recommendations and suggestions for the direction of future research efforts were made.

Master of Dental Surgery / History has recorded the antiquity of serious infections in the region of the head and neck. Today, our community still experiences major life-threatening infections in these anatomical locations, which pose significant management difficulties to the oral and maxillofacial surgeon. The aim of this thesis is to review the aetiology, diagnosis and treatment of some bacterial infections involving structures of the head and neck. Such infections may spread, causing serious complications with severe morbidity and occasionally death. This theses deals only with infections of bacterial origin and does not attempt to cover viral, or fungal agents or the chronic specific diseases of tuberculosis and syphilis, and makes no attempt to address the old question of focal infection. The literature review relates especially to Ludwig’s Angina which was first described so dramatically in 1836. To this day it remains as a clinically potentially lethal disease despite the progress of modern medicine. Numerous descriptions in the literature warn of the rapid appearance of symptoms and the danger of respiratory obstruction when management of the airway is not satisfactorily undertaken. Both odontogenic and non-odontogenic causes of orofacial and neck infections are reviewed. Odontogenic problems are given special emphasis as they are now of major concern. The significance of the potential fascial spaces in the face and neck which allow the spread of dental infections is also highlighter. A thorough knowledge of these anatomical relationships is still of the utmost importance to the surgeon if he is to be successful in treatment. The principle of surgical drainage of pus is as important in 1990 as it was 150 years ago. The biological basis for the onset and progress of such fulminating infections in the head and neck region is still poorly understood. One constant need is that the bacteria, both aerobic and anaerobic, be correctly identified. Microbiological techniques are constantly improving and provide an important adjuvant investigation, which then allows the surgeon to provide the most appropriate antimicrobial therapy. Principal to the many aspects of treatment is the ability to maintain the airway of the patient and to provide the depth of anaesthesia necessary to undertake the required surgery. Major bacterial orofacial infections may have severe local and far-reaching systemic effects. Such complications are discussed in all their ramifications. It should be realised that the presentation of these patients at a late stage, when complications have already supervened, may make diagnosis difficult. There is always a necessity to ensure that the underlying cause of the disease is accurately defined and that complication are not allowed to progress further. Finally, a retrospective study of the management of 90 patients with major bacterial orofacial infections who have been treated at Westmead Hospital is presented. The outcome of this study of some major bacterial orofacial infections of the head and neck is the need to stress the importance of urgent surgical management and maintenance of the airway, together with the microbiological determination of the causative organisms and their sensitivities, so that other than empirical antibiotics can be instituted early. This must be combined with an upgrading of the patients’ medical and dental status. It was demonstrated that, in the majority of these patients, ignorance and fear combined with a lack of routine dental care resulted in major infections arising from relatively simple odontogenic causes such as dental caries, periodontal disease and pericoronal infection related to impacted teeth. Without doubt, the immediate care of these patients demanded intensive management. However, it is important to recognise that dental education forms an integral part not only of the recovery programme for the afflicted patient, but also as a community health preventive measure of profound significance.

This thesis proposes four novel geometric neurodynamical classifier models, namely GBAM, Lie-derivative, Lie-Poisson, and FAM, applied to breast cancer detection. All these models have been published in a paper and/or in a book form. All theoretical material of this thesis (Chapter 2) has been published in my monographs (see my publication list), as follows: 2.1 Tensorial Neurodynamics has been published in Natural Biodynamics (Chapters 3, 5 and 7), Geometrical Dynamics of Complex Systems; (Chapter 1 and Appendix), 2006) as well as Applied Differential Geometry:A Modern Introduction(Chapter 3) 2.2 GBAM Neurodynamical Classifier has been published in Natural Biodynamics (Chapter 7) and Neuro-Fuzzy Associative Machinery for Comprehensive Brain and Cognition Modelling (Chapter 3), as well as in the KES–Conference paper with the same title; 2.3 Lie-Derivative Neurodynamical Classifier has been published in Geometrical Dynamics of Complex Systems; (Chapter 1) and Applied Differential Geometry: A Modern Introduction (Chapter 3); 2.4 Lie-Poisson Neurodynamical Classifier has been published in Geometrical Dynamics of Complex Systems; (Chapter 1) and Applied Differential Geometry: A Modern Introduction (Chapter 3); 2.5 Fuzzy Associative Dynamical Classifier has been published in Neuro-Fuzzy Associative Machinery for Comprehensive Brain and Cognition Modelling (Chapter 4), as well as in the KES-Conference paper with the same title. Besides, Section 1.2 Artificial Neural Networks has been published in Natural Biodynamics (Chapter 7) and Neuro-Fuzzy Associative Machinery for Comprehensive Brain and Cognition Modelling (Chapter 3). Also, Sections 4.1. and 4.5. have partially been published in Neuro-Fuzzy Associative Machinery for Comprehensive Brain and Cognition Modelling (Chapters 3 and 4, respectively) and in the corresponding KES–Conference papers. A. The GBAM (generalized bidirectional associative memory) classifier is a neurodynamical, tensor-invariant classifier based on Riemannian geometry. The GBAM is a tensor-field system resembling a two-phase biological neural oscillator in which an excitatory neural field excites an inhibitory neural field, which reciprocally inhibits the excitatory one. This is a new generalization of Kosko’s BAM neural network, with a new biological (oscillatory, i.e., excitatory/inhibitory)interpretation. The model includes two nonlinearly-coupled (yet non-chaotic and Lyapunov stable) subsystems, activation dynamics and self-organized learning dynamics, including a symmetric synaptic 2-dimensional tensor-field, updated by differential Hebbian associative learning innovations. Biologically, the GBAM describes interacting excitatory and inhibitory populations of neurons found in the cerebellum, olfactory cortex, and neocortex, all representing the basic mechanisms for the generation of oscillating (EEG-monitored) activity in the brain. B. Lie-derivative neurodynamical classifier is an associative-memory, tensor-invariant neuro-classifier, based on the Lie-derivative operator from geometry of smooth manifolds. C. Lie-Poisson neurodynamical classifier is an associative-memory, tensor-invariant neuro-classifier based on the Lie-Poisson bracket from the generalized symplectic geometry. D. The FAM-matrix (fuzzy associative memory) dynamical classifier is a fuzzy-logic classifier based on a FAM-matrix (fuzzy phase-plane). All models are formulated and simulated in Mathematica computer algebra system. All models are applied to breast cancer detection, using the database from the University of Wisconsin and Mammography database. Classification results outperformed those obtained with standard MLP trained with backpropagation algorithm. / Thesis (Ph.D.) -- University of Adelaide, School of Mathematical Sciences, 2008

[Truncated abstract] Pressure ulcers affect a substantial proportion of patients admitted to health care services worldwide imposing considerable physical, social and economic burdens on patients and communities. As largely preventable wounds their prevalence is likely to escalate as the life expectancy and incidence of people living longer with other chronic diseases increases. Clinical practice guidelines are promulgated as evidence-based tools to assist clinicians and patients to determine care strategies, reduce inequities in healthcare provision and lower the burden of illness through improved health outcomes. This prospective multi-centre study evaluated the effectiveness of the Australian Wound Management Association?s Clinical Practice Guidelines for the Prediction and Prevention of Pressure Ulcers within ten selected Australian tertiary hospitals. The data, collected in 2000, examined pressure ulcer prevalence in a subset of five of these hospitals and junior doctors’ and nurses’ knowledge of pressure ulcers in all ten hospitals at two time points, before and after guideline implementation. Pressure ulcer prevalence was ascertained by two surveyors who independently examined the skin of all consenting adult patients on a designated day. ... In addition, it is recommended that all Australian health care facilities providing in-patient, residential aged or domiciliary care services be required to demonstrate compliance with the Australian Council of Health Care Standards framework for pressure ulcers in order to be an accredited healthcare provider. The use, benefits and cost utility of pressure reducing / relieving devices in the prediction and prevention of pressure ulcers in Australian contexts of care, is required to substantiate current guideline recommendations and assist service providers and clinicians in choosing devices according to patient need. A recommendation will be forwarded to the Australian Wound Management Association suggesting the Association develop a toolkit to facilitate implementation and adoption of their guidelines. It is recommended that training of doctors, nurses and allied health personnel in the prediction, prevention and management of pressure ulcers should be of a higher priority within under-and-postgraduate education programs. From a community perspective and with a view to improving the health of the community, it is proposed that pressure ulcers be the subject of ongoing health promotion campaigns aimed at raising patients’, caregivers’ and community awareness of the potential for pressure ulcers due to the secondary effects of lifestyle related chronic diseases and ensuing reduced levels of immobility.

Zugl.: München, University, Diss., 2006.

Zugl.: Lübeck, Univ., Diss., 2006