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Biomedical subjects

A Hamilton

Publications and source records attributed to A Hamilton.

At least 91 records · Page 5Linked to original sources
PubMed1994

Immunohistochemical detection of a novel 22- to 25-kilodalton glycoprotein of Paracoccidioides brasiliensis in biopsy material and partial characterization by using species-specific monoclonal antibodies.

Two murine monoclonal antibodies (MAbs) specific to Paracoccidioides brasiliensis (as determined by enzyme-linked immunosorbent assay [ELISA] and Western blot [immunoblot]) were produced by using a modification of standard hybridization protocols, with cyclophosphamide included as an immunomodulator to abolish responses to highly cross-reactive immunodominant epitopes. MAbs PS14 and PS15 are two different clones which exhibit similar characteristics by ELISA and Western blot. They are directed against a 22- to 25-kDa antigen which is present in P. brasiliensis and which could not be identified in other dimorphic fungi by ELISA or Western blot. Partial purification of the antigen was accomplished by isoelectric focusing, and deglycosylation studies suggested that the 22- to 25-kDa antigen is a glycoprotein with a pI of between 4.5 and 5 and that O-linked sugars may be part of the recognized epitope. The MAbs stained the cytoplasm of P. brasiliensis yeast and hyphal cells in cryostat sections of fresh cultures of the fungus. In addition, the MAbs stained the wall of paracoccidioidomycotic granulomas, as well as the cytoplasm of the fungus, as determined by the use of immunofluorescence, immunoperoxidase, and immuno-alkaline phosphatase staining techniques in paraffin-embedded sections of human biopsy material, and they failed to stain granulomas resulting from other clinical conditions. These findings suggest that these MAbs have potential use in the immunohistochemical identification of P. brasiliensis.

Adrenal Glands↗
PubMed1994

Cost reduction in cardiac surgery.

OBJECTIVE: To reduce surgical waiting lists at the University of Alberta Hospitals. A cost reduction program was initiated, allowing more cases to be performed on the same budget. Reducing the cost of delivering health care services has become necessary as demands upon the system increase. METHODS: Data were retrospectively gathered on patients having open heart surgery at the University of Alberta Hospitals between March 1, 1991 and February 29, 1992. Group 1 were patients operated on before the start of the cost reduction program (September 1, 1991) and group 2 were those operated on after. Student's t test and logistic regression were use to compare population characteristics and to correlate dependent variables. RESULTS: Demographic features and severity indices were not different. Operating time decreased from 4.5 +/- 1.5 to 4 +/- 1 h, P < 0.002. Preoperative, intensive care unit (ICU) and postoperative ward length of stay were reduced (P < 0.002). Total length of stay went from 19.3 +/- 22.7 to 13.8 +/- 10.7 days, P < 0.001. Operating room, nursing and x-ray costs decreased, P < 0.002. Hospital costs declined from $14,182 +/- 16,464 to $10,710 +/- 7,332, P < 0.001. Multiple regression showed hospital stay, ICU, operating room time, severity of illness and age to be significant determinants of cost, P < 0.03 for each. Waiting time and number of patients on the waiting list declined significantly as surgical lists increased. Mortality and rate of readmission following discharge were not different between the two groups. CONCLUSIONS: Substantial cost savings can be made by changing practice patterns, without adverse consequences. ICU and hospital length of stay are the most important cost determinants.

Alberta↗
PubMed1994

The role of anterior surgery for vertebral fractures with and without cord compression.

The indications for anterior surgery are well defined in the upper and lower cervical spine if one accepts the importance of early restoration of stability for improved patient rehabilitation. Cannulated screw fixation of Type II fractures of the odontoid peg is a highly specialized procedure that requires technical expertise still only available at a limited number of orthopaedic centers. The engineering improvements in internal fixation for the anterior cervical spine, allied with an increasing expertise in instrumentation, have increased the tendency toward anterior stabilization for all unstable lower cervical fractures, except irreducible dislocations, irrespective of the mechanism of injury. Most thoracolumbar fractures with less than 50% to 60% canal compromise can be adequately dealt with by posterior surgery, largely because of the powerful correction inherent in the short segment, pedicle crew systems available. Anterior surgery continues to have a role in the correction of severe disruption, late deformity, and chronic anterior cord compression. No ideal anterior internal fixation system exists, but the Kaneda device is undoubtedly the strongest. The timing and indications for intervention for acute cord compression remain controversial in the absence of neurologic deterioration, although the route is undisputedly anterior in view of the usual site of compression.

Cervical Vertebrae↗
PubMed1993

Maori attitudes to diabetes and diabetes health care delivery in north Canterbury.

AIMS: The study aims were as follows: (1) To obtain information regarding Maori attitudes to diabetes and to the services provided by a specialist diabetes clinic in Christchurch; (2) to initiate discussion about local diabetes health care delivery for Maori. METHODS: A questionnaire was designed following advice from professional Maori health researchers, with the aim of assessing Maori attitudes to diabetes and specialist diabetes services, available in Christchurch. RESULTS: The questionnaire was delivered to 51 (77%) of the 66 Maori with noninsulin dependent diabetes (NIDDM), attending a specialist diabetes clinic in Christchurch. Although 47 of the 51 subjects were able to name one or more diabetes complications, only five subjects named heart disease as a complication, despite the fact that heart disease is a major cause of mortality in NIDDM: Subjects were selected on the basis of being hospital specialist clinic attenders and the majority were satisfied with currently available services, yet 10 of the 51 subjects indicated that they would prefer marae-based to hospital-based diabetes health care, if they had a choice. CONCLUSIONS: The process of questionnaire interview and dissemination of results proved to be a cost-effective means of initiating local discussion about future directions for Maori diabetes health care delivery.

Adult↗
PubMed1993

Pulse stream VLSI circuits and systems: the EPSILON neural network chipset.

An analogue CMOS VLSI neural processing chip has been designed and fabricated. The device employs "pulse-stream" neural state signalling and is capable of computing some 360 million synaptic connections per second. In addition to basic characterisation results, the performance of the chip in solving "real-world" problems is also demonstrated. The experience gained from the development of this device has resulted in the design of a second "pulse-stream" chip with improved performance and features. It is anticipated that this second device will be integrated into a standard bus-based system and find early application in robotic control.

Computers, Analog↗
PubMed1993

School nutrition survey.

Food we eat has an important influence on health and well-being. Many eating habits are established in childhood. 456 children aged eight to 12 years participated in this survey of food eaten at school. Of all the food items eaten as a snack, 48.6% were categorised as junk. 75.8% of the sandwiches brought to school for lunch were made with white bread. Of the remaining food items brought for lunch 63.5% were of the junk variety. Compared with those who brought a snack or lunch from home, those given money to buy their own were more likely to eat junk (p < 0.01). Food eaten at school reflects approximately one third of a child's daily food intake but health food practises for even a third of food intake may be of a value for health and long term eating habits. Nutritional education with the reinforcement of high nutritional standards in schools could improve the situation.

Child↗
PubMed1992

Treatment of malignant gliomas with interstitial irradiation and hyperthermia.

A Phase I study of interstitial thermoradiotherapy for high-grade supratentorial gliomas has been completed. The objective of this trial was to test the feasibility and toxicity of hyperthermia induced by ferromagnetic implants in the treatment of intracranial tumors. The patient population consisted of 16 males and 12 females, with a median age of 44 years and a median Karnofsky score of 90. Nine patients had anaplastic astrocytoma while 19 had glioblastoma multiforme. Twenty two patients were treated at the time of their initial diagnosis with a course of external beam radiotherapy (median dose 48.4 Gy) followed by an interstitial implant with Ir-192 (median dose 32.7 Gy). Six patients with recurrent tumors received only an interstitial implant (median dose 40 Gy). Median implant volume for all patients was 55.8 cc and median number of treatment catheters implanted per tumor was eighteen. A 60-minute hyperthermia treatment was given through these catheters just before and right after completion of brachytherapy. Time-averaged temperatures of all treatments were computed for sensors located within the core of (> 5 mm from edge of implant), and at the periphery of the implant (outer 5 mm). The percentage of sensors achieving an average temperature > 42 degrees C was 61% and 35%, respectively. Hyperthermia was generally well tolerated; however, there have been 11 minor toxicities, which resolved with conservative management, and one episode of massive edema resulting in the death of a patient. In addition, there were three major complications associated with the surgical implantation of the catheters. Preliminary survival analysis shows that 16 of the 28 patients have died, with a median survival of 20.6 months from diagnosis. We conclude that interstitial hyperthermia of brain tumors with ferromagnetic implants is feasible and carries significant but acceptable morbidity given the extremely poor prognosis of this patient population.

Adult↗
PubMed1992

A prospective randomized trial of chemonucleolysis and conventional disc surgery in single level lumbar disc herniation.

The role of chemonucleolysis as an alternative to disc surgery is still disputed. The authors conducted a prospective randomized controlled trial of chemonucleolysis and conventional disc surgery involving 92 patients with L4-5 or L5-S1 disc herniation who failed to respond to conservative treatment. There were 46 patients in each group, matched for demographic, clinical characteristics, and co-interventions. Independent examiners assessed patients before treatment, at 6 weeks after, 3 months after, and 1 year after treatment. A comprehensive method of outcome assessment involving physiological outcome, functional outcome, cost outcome, and psychological outcome was employed. Nine chemonucleolysis patients and one disc surgery patient required additional surgery for failure of initial treatment (P less than 0.02). The outcomes at 6 weeks and at 3 months were better in the surgical group, but at 1 year the differences were not significant. The authors conclude that chemonucleolysis as a minimally invasive technique produces inferior short-term results and offers no advantage over conventional discectomy.

Adult↗
PubMed1992

RT97- and calcitonin gene-related peptide-like immunoreactivity in lumbar intervertebral discs and adjacent tissue from the rat.

The innervation of rat intervertebral disc and adjacent ligamentous tissue has been investigated using 2 antibodies, RT97 and anti-calcitonin gene-related peptide. Immunoreactivity to the peptide was found in many fibres throughout the long ligaments around the intervertebral discs and in the periosteum, especially associated with vascular channels entering the vertebral bodies. Few of the immunoreactive fibres entered the annular lamellae of the disc tissue. Most of those which terminated did so as fine fibres which lay close to, or in, the interlamellar spaces of the outer annulus fibrosus. Calcitonin gene-related peptide-like immunoreactivity was also found in more complex endings in the longitudinal ligaments and rarely within the annulus fibrosus. RT97-immunoreactivity was also present in the complex endings and associated fibres. Conversely, RT97-immunoreactivity was apparent only in a few fine filamentous fibre endings. This suggested that the majority of fine filamentous, or free, nerve endings were of an unmyelinated sensory origin. Alternatively, those endings of a more complex nature, which were RT97-immunoreactive, were of a myelinated sensory origin. No immunoreactivity to either antibody was seen in the inner annular or nuclear tissue. It was therefore concluded that the sensory innervation of the rat intervertebral disc has both myelinated and unmyelinated components, the latter being more extensive. Both types of innervation appear to be restricted to the outermost rings of the annulus fibrosus.

Animals↗
PubMed1991

The role of magnetic resonance imaging in cystic fibrosis.

Magnetic resonance imaging (MRI) of the chest was performed on eight patients with known cystic fibrosis. Comparison was made with the findings on plain chest radiographs. MRI shows a greater extent of disease than that predicted by the chest films alone and clearly demonstrates peribronchial thickening and mucoid impacted bronchi. It also distinguishes between hilar lymphadenopathy and enlarged proximal pulmonary vessels as the cause of prominent hilar shadows without the need for contrast injection.

Adolescent↗
PubMed1991

The eye in diabetes.

Explore the source record for details and available documents.

Diabetic Retinopathy↗
PubMed1990

An investigation of vanishing bone disease.

Vanishing bone disease is a rare condition producing local deformity and instability. Fibrovascular tissue replaces bone completely but the mechanism of bone destruction and resorption is unknown and there is controversy regarding the presence or absence of osteoclasts in the disease. Radiography, clinical chemistry, light microscopy, transmission electron microscopy (TEM) and cytochemistry were used to investigate the condition of a young woman presenting early in the disease process. We detected atypical ultrastructure in osteoblasts and endothelial cells. The rare osteoclasts, numerous mononuclear phagocytes and vascular endothelium found in the condition reacted positively for the enzyme acid phosphatase. Aggressive local excision of diseased tissue and insertion of a free vascularized bone graft at an advanced stage of the disease, accompanied by subsequent radiotherapy for residual disease only were successful in rehabilitating the affected forearm and hand.

Adult↗