Hepatic micrometastases in the rat: ferrite-enhanced MR imaging

A rat tumor model was used to evaluate the ability of ferrite-enhanced magnetic resonance (MR) imaging to demonstrate hepatic metastases smaller than 1 cm. Twenty-eight rat livers were inoculated with 5 X 10(5) mammary carcinoma cells and imaged with a 0.6-T MR system. Non-enhanced and ferrite-enhanced images were analyzed and correlated with autopsy findings for each rat. Lesion detection rates correlated closely with cancer-to-liver contrast-to-noise ratios. Ferrite-enhanced MR imaging demonstrated significantly more lesions than non-enhanced imaging (P less than .05) and decreased the threshold size for lesion detectability (less than 2 mm). Ferrite also enabled more accurate measurements of the lesions (r = .96).     

Anti-My-28, an antigranulocyte mouse monoclonal antibody, binds to a sugar sequence in lacto-N-neotetraose

Anti-My-28 is an IgM kappa monoclonal antibody produced by a hybridoma prepared from spleen cells of a mouse immunized with normal human granulocytes. By immunofluorescence it binds to human granulocytes but not to monocytes and lymphocytes. However, after treating cells with neuraminidase, the antibody also binds to lymphocytes and monocytes and to many leukemic cell lines and patient leukemic blast cells. Anti-My- 28 binds to several neutral glycolipids and desialylated gangliosides of leukocytes and erythrocytes as detected by radioimmunoassay and immunostaining of thin-layer chromatograms. It recognizes a sugar sequence in lacto-N-neotetraose, Gal beta 1-4GlcNAc beta 1-3Gal beta 1- 4Glc. This tetrasaccharide occurs in the glycolipids paragloboside and sialosylparagloboside, and its distal trisaccharide sequence is found in higher glycolipids and in glycoproteins.     

Linear IgA bullous dermatosis in South India

Background A study of five cases of linear IgA dermatosis (LABD) in a referral hospital in South India is presented. Methods A dermatologic examination, skin biopsy, and direct immunofluorescence were carried out on all patients. Patients were then followed up. Results All five cases showed linear IgA deposits at the dermo-epidermal junction. One case in addition showed IgG and C3 deposits. All cases responded to treatment with dapsone. The treatment duration varied from 14 to 16 months and the fifth patient is still on treatment after 37 months. Conclusions Linear IgA bullous dermatosis is a self-limiting bullous disorder. To the best of our knowledge this is the first report of LABD from India.     

von Willebrand factor biosynthesis and partitioning between constitutive and regulated pathways of secretion after thrombin stimulation

The major part of von Willebrand factor (vWf) synthesized in cultured endothelial cells is secreted constitutively without stimulation and consists of all multimeric forms of vWf. In contrast, stimulation with secretagogues such as thrombin results in the release of vWf from the storage pool, the Weibel-Palade bodies which contain only the largest, most biologically potent multimeric forms of vWf. We wished to determine whether the signal for release of vWf might also function as a signal for replenishment of the vWf by enhancing de novo biosynthesis and if replenishment of the vWf storage pool involved a diversion of newly synthesized vWf from the constitutive pathway to the regulated pathway. vWf mRNA and protein levels in unstimulated human umbilical vein endothelial cells were compared with cells that were briefly stimulated with 1 U/mL thrombin for 15 minutes and then incubated without thrombin for periods up to 72 hours. A comparison was also made between unstimulated cells and cells continuously exposed to thrombin for up to 48 hours. Thrombin stimulation, brief or continuous, had no significant effect on subsequent biosynthesis of vWf protein or vWf- specific mRNA. Since thrombin releases vWf only from the storage pool, we examined the possibility of diversion of newly synthesized vWf from the constitutive pathway to the regulated pathway. Cells were pulse- labeled, incubated for 15 minutes with and without thrombin, chased for various periods in unlabeled media, and briefly restimulated with thrombin. No significant redistribution of vWf between the two pathways was observed as a result of thrombin stimulation for the time periods tested.(ABSTRACT TRUNCATED AT 250 WORDS)     

Surface coil MR imaging of abdominal viscera. Part III. The pancreas

Eight healthy volunteers and 11 patients with pancreatic abnormalities were studied using a conventional body coil and a prototype magnetic resonance (MR) surface coil. Final pathologic diagnoses included carcinoma of the head (six), body (one), and tail of the pancreas (two) and chronic pancreatitis (two). In surface coil images of the volunteers, the body and tail of the pancreas was visualized in all cases but one, and the pancreatic duct was seen in five of eight cases. In-plane spatial resolution of 0.9 X 0.9 mm and 5-mm section thickness was obtained. At the same time, pancreatic surface coil images had a twofold improvement in the signal-to-noise ratio (SNR) compared with body coil images. T1-weighted spin-echo images gave greater SNR, reduced motion artifacts, provided superior anatomic detail, and offered more diagnostic information than comparable T2-weighted images. Significant abnormalities detected only by surface coil imaging included a small tumor surrounded by reactive edema and periglandular tumor invasion. This study demonstrates that surface coil imaging of the pancreas not only is feasible but provides an improved method for examining the pancreas by MR.     

Metallic hip implants: CT with multiplanar reconstruction

Thirty consecutive patients with metallic implants in the hip were evaluated with both standard transaxial computed tomography (CT) and multiplanar reconstruction (MPR) to assess the contribution of MPR. The metallic devices included total hip replacements (n = 6), one or more surgical plates with screws (n = 9), acetabular pins or screws (n = 9), and Knowles pins (n = 6). The metallic implants were on the side of interest in 25 hips and in the contralateral hip in five cases. One patient had bilateral hardware. MPR reformats axially acquired data into other planes. The reconstruction program weights the true signal over the randomly distributed artifacts by integrating adjacent axial images. Examination using standard transaxial imaging was graded as excellent in five cases, adequate in 15 cases, and inadequate in ten cases. After MPR, 19 studies were classified as excellent, 11 were classified as adequate, and none were classified as inadequate. It is concluded that MPR significantly reduced artifacts caused by metal present in transaxial images.