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Biomedical subjects

H Bray

Publications and source records attributed to H Bray.

9 recordsLinked to original sources
PubMed2000

Local staging of Wilms' tumor--computerized tomography correlation with histological findings.

PURPOSE: The aim of this study was to assess the accuracy of computed tomography (CT) in the local staging of Wilms' tumor. METHODS: Twenty-six patients with unilateral, nonmetastatic Wilms' tumors were accrued over the period of 1990 through 1997. Preoperative CT staging was performed before surgical biopsy or excision. The abdominal CT images were reviewed and staged for local disease according to National Wilms' Tumour Study (NWTS) Group Staging V as either intrarenal disease (Stage I), local extrarenal extension amenable to complete local excision (Stage II), or advanced local disease (Stage III). Patients with metastatic (Stage IV) and bilateral disease (Stage V) were excluded from our study. Results were compared to histological findings. RESULTS: CT scan correctly staged 10 of 26 cases (38%) of Wilms' tumor. CT scan overstaged 12 of 16 (75%) localized renal disease (Stage I) and local extension (Stage II) tumors, and understaged 4 of 10 (40%) localized spread (Stage III) tumors. CONCLUSIONS: CT scan appears to have poor correlation to histological staging. Therefore, basing therapy solely on radiological imaging may lead to some patients receiving more intense therapy than necessary, whereas others do not receive sufficient therapeutic regimens. Histological assessment of the excised mass should remain the standard for staging Wilms' tumors.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1995

Wavelet variations on the Shannon sampling theorem.

The Shannon sampling theorem asserts that a continuous square-integrable function on the real line which has a compactly supported Fourier transform is uniquely determined by its restriction to a uniform lattice of points whose density is determined by the support of the Fourier transform. This result can be extended to the wavelet representation of functions in two ways. First, under the same type of conditions as for the Shannon theorem, the scaling coefficients of a wavelet expansion will determine uniquely the given square-integrable function. Secondly, for a more general function, there is a unique extension from a given set of scaling coefficients to a full wavelet expansion which minimizes the local obstructions to translation invariance in a variational sense.

Fourier Analysis↗
PubMed1994

Comparison of stimulable phosphor technology and conventional screen-film technology in pediatric scoliosis.

One hundred consecutive patients being investigated for scoliosis were studied using a double cassette containing a conventional film screen and a stimulable phosphor plate. The images were separated, randomised and scored thrice by three radiologists for anatomic structure visualisation. The exposure to the plate and film and repeat rate were measured. Scoliosis angles were comparable on both sets of images, however, visualisation of vertebrae, vertebral end plates, pedicles, spinous processes and other structures were significantly improved (p < 0.0001). Intra- and inter-observer reliability was high with good intraclass correlation. There was a 40% potential exposure reduction, and retakes were decreased from 3 to 0%. We conclude that stimulable phosphor images give better anatomic structure visualisation with potential radiation exposure reduction and lower repeat rate.

Child↗
PubMed1987

Nitrous oxide and cerebrospinal fluid markers of ischaemia following cardiopulmonary bypass.

Twenty patients with good ventricular function undergoing coronary artery bypass surgery were studied to determine whether the pre-bypass use of nitrous oxide resulted in any differences in cerebrospinal fluid markers indicative of cerebral ischaemia. All patients were anaesthetised with diazepam, fentanyl and pancuronium, after which ten patients received 50-60% nitrous oxide in oxygen until commencement of bypass, and the remaining patients 100% oxygen. Because of the known effect of nitrous oxide in expanding gaseous bubbles, any neurological dysfunction of gaseous microembolic origin may be worsened in the presence of nitrous oxide. Patients were lumbar punctured 24 hours after cardiopulmonary bypass and cerebrospinal fluid analysed for the following markers of central nervous system ischaemia: creatine kinase, lactate, total protein, noradrenaline, adrenaline and adenylate kinase. There was a statistically significant difference in cerebrospinal fluid lactate between the two groups. There were no statistically significant differences in the other cerebrospinal fluid markers of ischaemia.

Adenylate Kinase↗
PubMed1976

Prevalence and distribution of four serotypes of SMSV serum neutralizing antibodies in wild animal populations.

Serum neutralizing antibodies to four serotypes of San Miguel Sea Lion Virus (SMSV) were demonstrated in a variety of marine and terrestrial species. These results show a wide geographic distribution of SMS viruses in the marine environment and indicate that certain terrestrial mammals have been infected with these so-called marine viruses. Evidence is presented supporting the theory that unidentified submammalian marine species are a reservoir for SMSV.

Animals↗