Biomedical subjects
Publications and source records attributed to T Bieganski.
We report two patients with Robinow syndrome, review the published literature and stress the importance and limitations of radiographic examination in the diagnosis of this disorder, which shows extreme clinical and radiographic variability. The radiographic differential diagnosis of Robinow syndrome is discussed.
The use of magnetic resonance imaging as a readout method for polymer gel dosimetry commonly involves long imaging sessions, particularly when high spatial resolution is required in all three dimensions, for the investigation of dose distributions with steep dose gradients and stringent dose delivery specifications. In this work, a volume selective turbo spin echo (TSE) pulse sequence is compared to the established Carr-Purcell-Meiboom-Gill (CPMG) multiecho acquisition with regard to providing accurate dosimetric results in significantly reduced imaging times. Polyethylene glycol diacrylate based (PABIG) gels were irradiated and subsequently scanned to obtain R2 relaxation rate measurements, using a CPMG multiecho sequence and a dual echo TSE utilizing an acceleration (turbo) factor of 64. R2 values, plotted against corresponding Monte Carlo dose calculations, provided calibration data of PABIG gels dose response over a wide dose range. A linear R2 versus dose relationship was demonstrated for both sequences with TSE results presenting reduced dose sensitivity. Although TSE data were found to deviate from linearity at lower doses compared to CPMG data, a relatively wide dynamic dose range of response extending up to approximately 100 Gy was observed for both sequences. The TSE and CPMG sequences were evaluated with a brachytherapy irradiation using a high dose rate 192Ir source and a gamma knife stereotactic radiosurgery irradiation with a single 4 mm collimator helmet shot. Dosimetric results obtained with the TSE and CPMG are shown to compare equally well with the expected dose distributions for these irradiations. The 60-fold scan time reduction achieved with TSE implies that this sequence could prove to be a useful tool for the introduction of polymer gel dosimetry in clinical radiation therapy applications involving high doses and steep dose gradients.
Spondyloepipmetaphyseal dysplasias (SEMDS) are characterized by flattening of the vertebral bodies and epi-metaphyseal involvement of all the tubular bones. We report a 13 year-old boy with a novel variant of SEMD that presents with rhizomelic/mesomelic shortening of the extremities and normal head, hands and feet. Variable metaphyseal involvement and relatively large proximal humeral and knee epiphyses are further distinctive radiographic features in this patient.
The cases of two sisters with severe diastrophic dysplasia who showed some unusual radiographic features (kyphosis secondary to hypoplasia/dysplasia of the lumbar spine and a 'monkey wrench' appearance of the proximal femur) are reported here. Absent patellae were another feature that has not previously been reported in diastrophic dysplasia.
Two patients with a unique generalised bone dysplasia demonstrating severe distinctive platyspondyly are reported. This group of crippling disorders defies metabolic and histological classification. The radiographic examination is, at present, the only practical method of documentation of these rare disorders.
UNLABELLED: A new X-linked variant of spondylo-epimetaphyseal dysplasia with distinctive phenotype and severe mental retardation in three boys of one family is reported. The children were normal at birth. After several months of normal development progressive physical disability and slow mental deterioration were observed. Extensive biochemical tests were normal. CONCLUSION: These patients represent a new form of X-linked spondylo-epimetaphyseal dysplasia.
A case is reported here of a boy with brachytelephalangic chondrodysplasia punctata. This is the first case of this disorder reported in the Australian literature.
We have suggested previously that the histamine-diamine oxidase system is involved in cell proliferation. Therefore, the diamine oxidase activity and the histamine content were studied during mucosal proliferation induced by 70% resection of the small intestine of the rat with and without aminoguanidine (AG), a specific inhibitor of diamine oxidase (DAO). The DAO activity underwent a marked alteration during the period of mucosal proliferation, probably as an expression of an antiproliferative regulation mechanism. The histamine content decreased in the proliferating mucosa. No influence of AG on mucosal proliferation could be found, which might be due to a compensatory activity of the interconversion pathway.
Tissues of mice killed 2.5 or 30 min after injection of 14C-putrescine, contained 14C-gamma-aminobutyric acid, an unidentified 14C-compound, and unchanged 14C-putrescine. In mice pretreated with aminoguanidine, a powerful inhibitor of diamine oxidase, and then with 14C-putrescine, tissue levels of the radioactive catabolites, gamma-aminobutyric acid and the unidentified compound were markedly reduced. The data suggest that diamine oxidase is involved in the first step of putrescine metabolism and that intestine is the main site for this step. This and other aspects of putrescine metabolism are discussed.