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Biomedical subjects

J W Burke

Publications and source records attributed to J W Burke.

16 recordsLinked to original sources
PubMed1996

Contrast-enhanced magnetization transfer saturation imaging improves MR detection of herpes simplex encephalitis.

Cranial MR imaging was performed in three patients in whom herpes simplex encephalitis was subsequently proved. In all cases, the postcontrast T1 weighted MR images obtained with magnetization transfer saturation showed greater central nervous system involvement than was apparent on the conventional MR images. Specifically, the postcontrast magnetization transfer images were superior at delineating generalized meningeal enhancement as well as focal areas of brain involvement not seen on noncontrast T2-weighted images orconventionalpostcontrast T1-weightedimages.

Brain↗
PubMed1990

Meninges: benign postoperative enhancement on MR images.

In a group of 20 postcraniotomy patients who underwent magnetic resonance imaging performed with gadopentetate dimeglumine, 16 (80%) had nonneoplastic meningeal enhancement. This was seen as either enhancement of a local dural membrane or generalized meningeal enhancement. In a control group of 23 patients, only three (13%) had similar findings. The authors believe that postcraniotomy meningeal enhancement is most likely the result of a local inflammatory process or a diffuse chemical arachnoiditis caused by bleeding into the subarachnoid space at the time of surgery. The finding does not necessarily indicate leptomeningeal tumor spread or infection.

Arachnoiditis↗
PubMed1989

Inhibition of human platelet aggregation and secretion by ant venom and a compound isolated from venom.

Venom from the tropical ant, Pseudomyrmex triplarinus, has activity against rheumatoid arthritis. Since platelets are involved in inflammatory responses, they were employed to study the effects of venom on prostaglandin-dependent human platelet aggregation and secretion. The assay is very sensitive and uses microliter volumes, which makes it useful as a screen during isolation and characterization of venom components. Whole venom inhibited arachidonic acid- and U46619-induced platelet aggregation with IC50s of 45 and 39 micrograms/ml, respectively. This suggested that venom prevented the action of prostaglandins. Pure venom was fractionated by gel filtration and at least three materials with antiplatelet activity were detected. The smallest component (factor F) was most active and was purified by additional molecular filtration and characterized by UV absorbance, thin-layer chromatography, nuclear magnetic resonance spectra, and activity to platelets. Factor F was identified as adenosine, which is known to stimulate platelet adenylate cyclase and has not been previously reported to be a component of insect venom.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1988

"Idiopathic" cerebellar calcifications: association with hypothyroidism?

During a 3-year period, unexplained intracerebellar calcifications were seen at computed tomographic (CT) examination in six patients. A surprisingly high association with hypothyroidism was seen, with two-thirds of these patients showing the abnormality. Although an uncommon finding at CT, the presence of cerebellar calcification may indicate hypothyroidism.

Aged↗
PubMed1986

Pseudoaneurysms complicating pancreatitis: detection by CT.

Complications of pancreatitis such as pseudocyst formation and abscess are well known to radiologists. Secondary formation of pseudoaneurysms has not been emphasized in the radiologic literature. The great morbidity and mortality associated with pseudoaneurysms emphasize the importance of early detection. Three patients are described whose angiographically proved pseudoaneurysms were demonstrated on contrast material-enhanced abdominal CT scans obtained for evaluation of pancreatitis. A homogeneously enhancing structure within or adjacent to a pancreatic pseudocyst or contiguous with a vascular structure should be considered highly suspicious for an associated pseudoaneurysm.

Aneurysm↗
PubMed1936

Transilluminator.

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Journal Article↗
PubMed1935

Luminous Dial.

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Journal Article↗
PubMedDate not supplied

High field 1H- and 13C-nmr assignments of grayanotoxins I, IV, and XIV isolated from Kalmia angustifolia.

Grayanotoxins I [2], IV [3], and XIV [4] were isolated from Kalmia angustifolia var. caroliniana, a North American member of the Ericaceae. Their structures were established from physical and spectral data (mp, ir, [alpha]D, uv, cd, ms, 1H and 13C nmr). High field 1H- and 13C-nmr assignments were made for each compound using 1D and 2D nmr techniques including extensive 1H single-frequency spin-decoupling and nOe difference experiments, one-bond and long-range (COLOC) carbon-hydrogen correlations, and the INADEQUATE carbon-carbon correlation experiment. This is the first report of the presence of grayanotoxins IV and XIV in this source, of complete high field (500 MHz) 1H-nmr assignments for any grayanoid, and of 13C-nmr assignments for grayanotoxins IV and XIV. For grayanotoxin I, ambiguities in the literature 13C-nmr assignments have been removed by definitive assignments made through the use of the INADEQUATE experiment.

Diterpenes↗
PubMedDate not supplied

CT appearance of cervical lipoblastoma.

We describe a case of lipoblastoma causing respiratory symptoms in an infant, where CT was useful in establishing the diagnosis and demonstrating the extent of involvement so that complete surgical resection could be planned.

Female↗
PubMedDate not supplied

The "notch" sign: meniscal contour deformities as indicators of tear in MR imaging of the knee.

Conventional magnetic resonance (MR) criteria for meniscal tearing emphasize intrameniscal signal and its communication with the articular surface. In this retrospective study, the value of a focal contour deformity of the meniscal articular surface, termed a "notch," as an additional MR sign of meniscal tearing was assessed. One hundred fifty-four menisci were evaluated. Twenty-three of 24 notches correlated with the site of tear at arthroscopy. Seven notches improved the reading confidence from possible to definite tear; in eight notches, the diagnosis of tear would otherwise not have been considered. Five tears occurred without intrameniscal signal, four following recent trauma. The notch sign improved the sensitivity from 79.8 to 87.8%. Notches are useful additional signs of meniscal tearing, increasing the confidence of a reading when occurring near grade 1 or 2 meniscal signal, and are the only MR sign present in some tears.

False Negative Reactions↗