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A Blum

Publications and source records attributed to A Blum.

At least 145 records · Page 8Linked to original sources
PubMed1998

[Evaluation of spiral computed tomography in the demonstration of kidney stones. Ex vivo study].

OBJECTIVES: The objective of this study was to determine, ex vivo, the limitations of spiral computed tomography (CT) in the detection of renal stones. MATERIAL AND METHODS: Twelve fragments of calcium oxalate stones, 1 to 10 millimetres in diameter, were introduced into 3 porcine kidneys. Spiral CT was then performed on these kidneys. RESULTS: All stones, regardless of their dimensions, were detected with a sensitivity and specificity of 100%. Measurement of these stones on spiral CT showed a magnification factor and a distortion phenomenon which varied according to the table speed and collimation. CONCLUSION: In this study, spiral CT demonstrated excellent performances in the detection of renal stones, even for the smallest stones, measuring 1 mm in diameter.

Algorithms↗
PubMed1998

[Comparative value of MR-angiography, helical CT and digital angiography in the preoperative assessment of abdominal aortic aneurysms].

PURPOSE: To compare helical CT with MR angiography in pre-operative assessment of abdominal aortic aneurysm (AAA). MATERIAL AND METHODS: Twenty patients with AAA underwent helical-CT, MR-angiography and digital angiography. All exams were interpreted independently by two groups of observers. Kappa and rho were calculated to assess correlations. Sensitivity and specificity were calculated to compare each method with the "gold standard" digital angiography. RESULTS: Inter-observer correlation was excellent. There was a very good agreement between both methods in the assessment of the maximal diameter and the proximal neck of the aneurysm. There was no significant difference in the assessment of stenoses of the visceral and iliac arteries, the number of renal arteries, and iliac extension. CONCLUSION: Helical CT and MR angiography are equivalent in pre-operative assessment of AAA.

Aged↗
PubMed1997

Fc gammaRII (CD32) is linked to apoptotic pathways in murine granulocyte precursors and mature eosinophils.

Murine granulocytes and precursors express low-affinity IgG Fc receptors (Fc gammaR). We investigated the effects of FcyR ligation on the development of eosinophils in cultures of normal murine bone marrow. Eosinophilopoiesis was induced by culture of bone marrow cells in the presence of cytokines (granulocyte-macrophage colony-stimulating factor [GM-CSF], interleukin-3 [IL-3], and IL-5). Addition to the cultures of 2.4G2, a rat monoclonal antibody (mAb) that reacts with Fc gammaRII (CD32) and Fc gammaRIII (CD16), induced granulocyte apoptosis within 24 hours. Granulocytes in cultures that contained 2.4G2 showed chromatin condensation, binding of Annexin-V, and fas induction, and by electron microscopy, apoptosis was most commonly observed in cells of the eosinophil lineage. Since murine granulocytes can express both Fc gammaRII (CD32) and Fc gammaRIII (CD16), we investigated the effect of 2.4G2 on cultures of bone marrow obtained from Fc gammaRIII (CD16) gene-disrupted mice and found that the apoptosis induced with 2.4G2 was CD16-independent. Studies with bone marrow cultures from B6MLR-lpr/lpr and C3H/HEJ-gld/gld mice established that the Fc gammaRII (CD32)-triggered apoptosis was fas-fasL-dependent. When mature eosinophils isolated from hepatic granulomas of Schistosoma mansoni-infected mice were cultured in cytokines in the presence of 2.4G2, the eosinophils underwent apoptosis within 24 hours. These findings identify a previously unknown linkage between Fc gammaR on eosinophils and fas-mediated apoptosis, a connection that could be relevant to mechanisms by which eosinophils mediate tissue injury and antibody-dependent cellular cytotoxicity reactions.

Animals↗
PubMed1997

Genetic heterogeneity in sporadic colorectal adenomas.

The majority of colorectal cancers develop from adenomatous polyps under the influence of factors that are still poorly understood. Tumourigenesis is generally considered a multistep process in which multiple genetic alterations occur, eventually reflected in abnormalities of the cellular DNA content. Macroscopical features such as tumour size and tumour architecture (tubular, tubulovillous, or villous) are correlated wit the chance of malignancy in the lesion. Grade of dysplasia can be considered an indicator for the level of progression of the adenoma towards invasive carcinoma. These characteristics were correlated with the presence or absence of K-ras mutations and the DNA ploidy in a prospective study performed on 46 large sporadic colorectal adenomas resected by endoscopy. DNA ploidy and K-ras mutations were analysed in two samples taken at distant sites in the adenomas. Aneuploidy was present in 12 adenomas (26 per cent) and K-ras mutations occurred in 26 (57 per cent). A highly significant correlation was found between aneuploidy and adenoma size, architecture, and grade of dysplasia. The presence of K-ras mutations was significantly correlated only with the size of the adenomas. The proportion of adenomas with aneuploidy and/or a K-ras mutation increased when two samples were analysed instead of one. This observation suggests that the prevalence of genetic mutations and of aneuploidy is probably underestimated, as generally only one sample is investigated. No correlation was observed between K-ras mutations and ploidy. This study demonstrates the presence of genetic heterogeneity in colorectal adenomas and supports the notion that K-ras mutation is an early event, while aneuploidy is a late event in the adenoma-carcinoma sequence.

Adenoma↗
PubMed1997

The effects of right-hemisphere brain damage on patients' use of terms of personal reference.

Successful communication depends on social as well as linguistic factors. In conversation, for example, a speaker must often refer to another person. Choosing an appropriate term of personal reference requires a speaker to consider several features of the discourse context, including properties of the persons being referred to and what knowledge is shared between the speaker and his or her addressee. In a pair of similar studies, we examined how right-hemisphere brain-damaged (RHD) patients and nonbrain-damaged control subjects use these different kinds of information in choosing formal (e.g., "Mr. Harding") versus informal ("Oliver") terms of reference for an absent third person. Stimulus vignettes manipulated three variables: the occupational status of the referent, the speaker's familiarity with the referent (i.e., the degree to which the speaker and referent were personally acquainted), and the addressee's familiarity (i.e., the degree to which the addressee and referent were personally acquainted). Relative to the control subjects, the RHD patients showed decreased use of both familiarity variables when choosing formal over informal labels, but apparently preserved sensitivity to the status variable. These results suggest how decreased use of the knowledge shared between a speaker and addressee disrupts RHD patients' discourse and thus contributes to these patients' aberrant interpersonal behavior. In addition. In addition, the results from the second study demonstrated an asymmetry in how female versus male subjects responded to the status manipulation.

Aged↗
PubMed1997

[Bullous pemphigoid as a paraneoplastic syndrome. A case report in renal-cell carcinoma].

Paraneoplastic markers in tumor patients may occur at various stages of the disease. While some disorders almost invariably herald an underlying malignancy (obligative marker), most only occasionally do so (facultative marker). The association of bullous pemphigoid with malignancy is controversial. There are only a few reports of bullous pemphigoid associated with a renal cell carcinoma. We diagnosed a renal cell carcinoma in a 74 year old female patient, admitted to the hospital because of bullous pemphigoid. Multiple metastases were found in her lymph nodes, liver, lung and skeleton. The patient died eleven weeks after the first symptoms of bullous pemphigoid appeared.

Aged↗
PubMed1997

Immunohistochemical localization of muscarinic acetylcholine receptors in primary and metastatic malignant melanomas.

In embryos morphogenetically active cells transiently express the cholinergic system comprising cholinesterase activity and muscarinic acetylcholine receptors. Malignant melanomas develop from melanocytes, which are derived from the neural crest. Neural crest cells express the embryonic muscarinic system during migration. Using the monoclonal antibody M35, we now show that normal melanocytes carry no muscarinic receptors, whereas malignant melanoma cells express them again. In primary melanomas and metastatic melanomas, we identified muscarinic receptors in solid strands or groups of atypical cells. In all primary malignant melanomas studied we found inhomogeneous distributions of M35-immunoreactivity subdividing the tumors into three different zones. In the tumor center, groups or single cells often showed only little or even no immunofluorescence. In contrast, pericentrally we detected strong immunostaining in the conglomerations of atypical melanocytes. In the peripheral infiltration zone, intensely fluorescent cells in clusters or single, were spreading into the normal tissue, leading to a more patchy staining pattern. Melanocytes of nevi also possess muscarinic receptors, showing similar distribution patterns as in the melanoma. We suggest that in malignant melanomas muscarinic receptors might play a regulative role in infiltrative growth and metastasis.

Hair Follicle↗
PubMed1997

Three-dimensional CT-scan reconstruction of renal calculi. A new tool for mapping-out staghorn calculi and follow-up of radiolucent stones.

OBJECTIVES: The development of CT scanners (CT scan) with continuous rapid spiral acquisition now allows three-dimensional reconstructions of mobile organs such as kidneys. The aim of this study was to appreciate the merits of this new technique in the field of renal lithiasis. METHOD: This non-invasive technique was applied in 27 renal calculi (23 staghorn and 4 radiolucent stones). The acquisition does not require any injection of contrast material. Reconstruction was carried out by three-dimensional (3D) shaded surface display. RESULTS: 3D reconstruction of calculi permits a precise study of the shape of the stone, and of the number, size and direction of its branches. Therefore, it allows for better planning of the PCNL (number of ports, per-operative pelvi-caliceal exploration ...). Large radiolucent calculi are clearly defined with 3DS, facilitating the follow-up under medical treatment. CONCLUSION: 3D CT scan reconstruction is a noninvasive, cost-effective method which offers high quality 3D images of renal calculi. These results should spur the more widespread use of this technique.

Cost-Benefit Analysis↗
PubMed1997

In vitro magnetic resonance microimaging of experimental osteoarthritis in the rat knee joint.

OBJECTIVE: To visualize articular changes during iodoacetate induced osteoarthritis (OA) of the rat knee using high resolution magnetic resonance imaging (MRI). METHODS: All images were acquired on a 8.5T microimager on ex vivo rat knees. After optimization studies, 3D spin echo sequences were used with TR 1200 ms and TE 15 ms; 40 sagittal images were obtained with a resolution of 400 x 60 x 60 microns. OA lesions were achieved by injecting 3 mg iodoacetate in the right knee joint (Day 0). Progression of OA changes was studied at Days 5, 10, 15, 20, 30, 90 and corresponding radiographs and histological sections were obtained. RESULTS: Spin echo images of the normal rat knee clearly visualized cortical bone, calcified menisci, patella, and cruciate ligaments as dark regions. Cartilage and muscles appeared as intermediate signal. In some cases a trilaminar appearance of cartilage and growth plate was depicted. This appearance persisted at Day 5, although cartilage presented a marked loss of proteoglycans. After Day 10 the menisci appeared irregular and inhomogeneous. After Day 15, MRI showed important alterations of articular cartilage, predominant on weight bearing areas of femoral condyles. Osteophytic remodeling was also seen around the patella. From Day 20 to Day 90 anatomical changes progressively affected epiphyseal bone, leading to subchondral cysts and loss of its regular trabecular structure. CONCLUSION: High field MRI provides a sensitive method for investigating ex vivo focal erosions of cartilage and established osteochondral remodeling in experimental OA in the rat. In this model, microimaging provides more information about early modifications of cartilage and soft tissue than radiographic exploration, in good correlation with histological data.

Animals↗
PubMed1997

Insufficiency fractures of the ilium.

Insufficiency fractures often occur in the sacrum and pubic rami but have rarely been reported in the ilium, where their frequency may be underestimated. We studied a series of 14 patients with insufficiency fractures of the ilium. Six patients had an oblique fracture through the wing of the ilium (which was bilateral in one case) and nine a supraacetabular fracture, with in one case a superomedial extension into the iliac wing. The initial radiographs were normal, making the diagnosis difficult. A linear area of sclerosis along the fracture line was seen after a few weeks. The radionuclide examination provided early detection and often demonstrated multiple insufficiency fractures (mean 2.1 per patient). Computed tomography missed some of the fractures, whereas magnetic resonance imaging proved a reliable diagnostic tool, especially in patients with supraacetabular fractures, showing the fracture as a line of low signal surrounded by an area of edema whose contours were exactly the same as those of the hyperactive focus on the radionuclide scan. Osteoporosis was a causative factor in all 14 patients and vitamin D deficiency in seven. Also, three patients had a history of fluoride therapy.

Acetabulum↗
PubMed1996

Heart transplantation--an update.

Cardiologists caring for heart transplant recipients must be familiar with the pharmacology, drug interactions, and drug toxicity of those agents used extensively in clinical practice (cyclosporine, prednisone, azathioprine, polyclonal and monoclonal anti-T-cell agents) and the newer treatments [methotrexate, FK-506, rapamycin, mycophenolate mofetil (RS61443), deoxyspergualin, anti-CD4 monoclonal antibodies, total lymphoid irradiation, and photophoresis]. Another important aspect of medical follow-up is the detection, differential diagnosis, and treatment of allograft dysfunction. Hemodynamic abnormalities that occur as a result of rejection or a direct drug effect must be differentiated from physiologic changes. Cardiac allograft vasculopathy is the primary impediment to the long-term survival of heart transplant recipients. Immunopathogenesis, prevention, early detection, and treatment of allograft vasculopathy should be the major focus of heart transplantation research.

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