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Biomedical subjects

A Hamilton

Publications and source records attributed to A Hamilton.

At least 19 recordsLinked to original sources
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.

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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↗
PubMed1990

Vibration arthrometry. A preview.

Throughout the ages, physicians have listened to sounds and felt vibrations from human joints in their attempts to diagnose pathology. They have used a wide vocabulary to describe these phenomena, but technology has been slow to provide recording and analytic equipment. Lately, accelerometers have been used with considerable success in a new noninvasive method now known as vibration arthrometry (formerly "arthrography"). The technique has been used in early detection of congenital dislocation of the hip and also in diagnosis of meniscal pathology. More recently, patellar vibration has been used to assess the mechanical properties of articular cartilage. Vibration arthrometry has also yielded new information on a possible damage mechanism associated with shock vibration that arises during cavitation of synovial fluid. Joint vibrations are therefore useful aids to diagnosis and may even be etiologic in orthopedic disease.

Hip Dislocation, Congenital↗
PubMed1979

Upper limb amputees.

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Activities of Daily Living↗
PubMed1978

Isolation of 57Co-cobalamin coenzymes at high specific activity from Streptomyces griseus.

The distribution of radio-labelled cobalamins in Streptomyces griseus grown in medium containing 57Co-cobalt chloride has been estimated by two-dimensional thin-layer chromatography and bioautography. 57Co-Methylocobalamin (Me[57Co]Cbl) was the major form in the mycelium together with smaller amounts of 57Co-adenosylcobalamin (Ado[57Co]Cbl) and 57Co-hydroxocobalamin (OH[57Co]Cbl). The OH[57Co]Cbl was detected in three forms having, respectively, anionic, cationic and neutral properties. A simple technique has been developed to isolate and purify Me[57Co]Cbl and Ado[57Co]Cbl from the mycelium using column chromatography on ion-exchange celluloses. Small quantities of each cobalamin coenzyme have been obtained at 90--96% purity and specific activities of 190--230 muCi/microgram.

Chromatography, DEAE-Cellulose↗