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Biomedical subjects

D Armstrong

Publications and source records attributed to D Armstrong.

801 records · Page 45Linked to original sources
PubMedDate not supplied

Evaluation of the infant spine by direct sagittal computed tomography.

Direct sagittal computed tomography (CT) and metrizamide myelography, in addition to standard axial CT, have proven most useful in evaluation of complex anomalies of the infant spine. Direct sagittal CT was performed by placing the entire infant sideways and supine within the gantry after metrizamide was injected. This technique was performed in six infants with diagnoses of lipoma with dysraphism, lipomyelomeningocele, lipomyelocystocele, lumbosacral agenesis with cord regression, capillary hemangioma, and vertebral osteomyelitis. The technique showed the relation and/or extension of lesions in the dorsal ventral plane, particularly the presence or absence of subarachnoid, enteric, or genitourinary communication. Spinal and paraspinal anatomic detail was also demonstrated beautifully.

Hemangioma↗
PubMedDate not supplied

Characterization of laser-induced fluorescence in the canine retinal pigment epithelium.

The adult retinal pigment epithelium (RPE) exhibits fluorescence caused by various cytoplasmic flurophors and by lipofuscin. Microscopic investigations of fluorescence generally utilize continuum excitation sources (xenon, mercury) and varying filter combinations. Consequently, discrepant emission characteristics are often encountered in the literature. In the present study, an epi-fluorescence microscope linked to a laser source with defined excitation characteristics was used to examine fluorescence in normal, adult canine RPE. Excitation at 337 nm produced maximal fluorescence at 450 nm (blue), while excitation at 439 nm induced 550 nm (yellow) fluorescence. Continuous exposure of cells to 439 nm light caused an initial rapid reduction of intensity, with a subsequent slower decrease of the signal. After solvent extraction, fluorescence at 600 and 650 nm showed no major alterations relative to the values recorded at 550 nm. Our findings demonstrate that varying excitation wavelengths produce discrepant fluorescence data from RPE cells and indicate caution in direct comparisons between experiments where different excitation sources and filter combinations are used.

Animals↗
PubMedDate not supplied

Iodine-enhanced CT patterns after cerebral arterial embolization in baboons.

The pathophysiology of iodine-enhanced computed tomography (CT) patterns produced by embolic arterial cerebral infarction in the baboon is reported. The appearance of iodine patterns in zones of nonperfusion, blood-brain barrier damage, loss of autoregulation, and neovascularity is demonstrated. The iodine CT patterns were correlated with stable xenon CT flow studies, regional cerebral blood flow studies, clinical course, and pathology.

Animals↗
PubMedDate not supplied

Cryptococcal bone disease: a manifestation of disseminated cryptococcosis.

In three patients with cryptococcal bone infection, skeletal involvement was sometimes occult, localized (offering a clinically accessible area for the diagnosis of disseminated) or part of a disseminated disease. Cryptococcal bone infection may clinically imitate neoplastic disease. Cryptococcal antigen determinations on bone curettings or serum may be helpful for rapid diagnosis. Although bony disease has been cured with local curettage, systemic amphotericin B is prescribed to eliminate inapparent disseminated disease.

Adolescent↗
PubMedDate not supplied

Prevention of skin colonization and subsequent bacteremia with CDC-JK organisms in patients with cancer.

A 10-year experience with a program designed to reduce the incidence of bacteremias in the cancer patient, specifically those caused by Corynebacterium CDC-JK, is presented. Retrospective chart reviews identified patients at risk and generated the hypothesis that special attention to body hygiene may play a significant role. Implementation of a skin hygiene program resulted in a significant decrease in the incidence of CDC-JK bacteremias in Memorial Hospital patients.

Bacteremia↗
PubMedDate not supplied

In vitro glycosylation in the retina in canine ceroid-lipofuscinosis.

Dolichol-dependent glycoprotein synthesis in the sensory retina of adult dogs with canine ceroid-lipofuscinosis (CCL) has been investigated by studying 3H-mannose uptake in organ culture. Sensory retinal organ cultures were prepared from unaffected littermates and mongrel dogs were used as controls. Morphometric analysis of autoradiographs from dogs without disease showed maximal uptake predominantly into photoreceptors and inner segments, and no abnormalities of incorporation were observed in two affected animals. Tunicamycin blocked the reaction in both samples. Incorporation of 3H-leucine was also normal in CCL retinal tissues. These studies demonstrate that the pathways for addition of mannose residues into dolichol pyrophosphate prior to transfer onto acceptor proteins is similar in normal dogs and those with CCL and does not appear to be the primary lesion in ceroid formation. Its role as a model for lipopigment storage is discussed.

Animals↗