ABSTRACT
INTRODUCTION: There is a clear clinical need to reliably detect residual cholesteatoma after canal wall up mastoid surgery. Ideally, this would be achieved through non-invasive radiological means rather than second-look surgery, thus preventing morbidity in those patients in whom no residual disease is found. CASE REPORT: We describe a case in which non-echo-planar, diffusion-weighted magnetic resonance imaging sequences were used pre-operatively, and compared with subsequent surgical findings. This case highlights both the potential of this increasingly popular magnetic resonance technique and also its current limitations. DISCUSSION: Various magnetic resonance sequencing types have been employed to try to reliably detect residual cholesteatoma, each with varying success. Non-echo-planar, fast-spin echo, diffusion-weighted sequences currently appear to be the most reliable at detecting even the smallest pearl of cholesteatoma, down to 2 mm in diameter. In our unit, a propeller, diffusion-weighted image sequence is employed on a GE Signa scanner. However, both this case study and other reports show that the accuracy of the technique is not 100 per cent. This begs the question of how much one can rely on the findings of such techniques when deciding whether second-look surgery is indicated. Scan-negative patients will require continued follow up as, at the time of imaging, residual disease may not have reached a detectable size.
Subject(s)
Cholesteatoma, Middle Ear/diagnosis , Magnetic Resonance Imaging/methods , Otitis Media, Suppurative/surgery , Adult , Cholesteatoma, Middle Ear/surgery , Chronic Disease , Ear Canal/surgery , False Negative Reactions , Female , Hearing Loss, Mixed Conductive-Sensorineural/etiology , Hearing Loss, Mixed Conductive-Sensorineural/surgery , Humans , Mastoid/surgery , Otologic Surgical Procedures/methods , Predictive Value of Tests , Recurrence , Second-Look SurgeryABSTRACT
Intracranial calcifications may represent calcified cerebral emboli. Calcified emboli may be overlooked even though cerebral CT is widely used as a stroke assessment. We report 4 cases of calcified cerebral emboli and demonstrate the value of CT in the diagnosis and temporal evaluation of such emboli.
Subject(s)
Calcinosis/diagnostic imaging , Cerebral Angiography , Infarction, Middle Cerebral Artery/diagnostic imaging , Infarction, Posterior Cerebral Artery/diagnostic imaging , Intracranial Embolism/diagnostic imaging , Tomography, X-Ray Computed , Aged , Aged, 80 and over , Carotid Artery, Internal/diagnostic imaging , Carotid Artery, Internal/drug effects , Carotid Stenosis/diagnostic imaging , Carotid Stenosis/drug therapy , Cerebral Cortex/drug effects , Cerebral Cortex/pathology , Dominance, Cerebral/physiology , Female , Follow-Up Studies , Humans , Infarction, Middle Cerebral Artery/drug therapy , Infarction, Posterior Cerebral Artery/drug therapy , Male , Middle Aged , Middle Cerebral Artery/drug effects , Middle Cerebral Artery/pathology , Myocardial Infarction/complications , Recurrence , Thrombolytic TherapyABSTRACT
Balo concentric sclerosis is a rare demyelinating disease. Pathognomonic features have been previously described. Diffusion-wighted imaging findings have not been previously described in Balo concentric sclerosis. We describe the diffusion-weighted imaging findings in a 45-year-old lady with Balo concentric sclerosis. Diffusion-weighted imaging offers insight into the possible pathophysiology of this rare disease.
Subject(s)
Diffuse Cerebral Sclerosis of Schilder/diagnosis , Female , Humans , Magnetic Resonance Imaging/methods , Middle AgedABSTRACT
In summary the Institute hopes that implementing the provisions of the new Code of Practice will result in a reduction in doses to patients and an improvement in image quality. Further information regarding the licensing of dental X-ray units may be obtained from the Regulatory Service of the Radiological Protection Institute of Ireland, tel. 01-2697766.
Subject(s)
Radiography, Dental/instrumentation , Radiography, Dental/standards , Humans , Ireland , Radiation Dosage , Radiation ProtectionABSTRACT
Interleukin-2 produced from a recombinant E. coli was found to contain as much as 19% norleucine in place of methionine in a minimal medium fermentation. Medium supplementation experiments and use of a leucine-requiring mutant host strain indicated the origin of norleucine to be de novo biosynthesis by reactions involving the enzymes of the leucine biosynthetic pathway. The misincorporation was highly suppressed by addition of either L-leucine or L-methionine to the fermentation and completely suppressed by adding both amino acids.
Subject(s)
Aminocaproates/metabolism , Escherichia coli/metabolism , Interleukin-2/biosynthesis , Norleucine/metabolism , Recombinant Proteins/biosynthesis , Cyanogen Bromide , Escherichia coli/drug effects , Feedback , Fermentation , Interferon Type I/metabolism , Leucine/metabolism , Leucine/pharmacology , Methionine/metabolism , Methionine/pharmacology , Mutation , Norleucine/biosynthesisABSTRACT
The isolation of bacterially synthesized, recombinant-DNA-derived, bovine growth hormone (r-bGH) with native structure is described. The r-bGH is found in insoluble form, in a pellet fraction, after cell breakage and centrifugation. Cell envelope components (protein, lipid, endotoxin) and nucleic acids are selectively removed from the pellet fraction by an EDTA/lysozyme/deoxycholate extraction. We demonstrate that the r-bGH is largely reduced until solubilized using 6 M guanidine/HCl. Air oxidation is then carried out, in the presence of the guanidine/HCl. The oxidation results in a mixture of about one-third disulfide-linked oligomers and two-thirds oxidized monomer. The latter may include some incorrectly oxidized material, but appears to be mostly correctly oxidized. The oxidized monomer is isolated by gel filtration in the presence of guanidine/HCl. Subsequent guanidine/HCl removal leads to refolded, oxidized r-bGH. All steps in the procedure, in particular the oxidation and refolding steps, can be carried out at relatively high protein concentrations.
