Dental material artifacts on MR images

Magnetic resonance (MR) imaging of the head and neck is becoming an important aid in evaluating pathologic conditions of the brain, midface, and pharynx. Certain dental materials cause artifacts during MR imaging of the lower midface. These artifacts can obscure the normal anatomy. This study describes the degree of artifact production caused by various materials commonly used in dental restorations. Of the materials tested, those causing artifacts were made of stainless steel, such as orthodontic bands used for braces, and pins or posts that are commonly drilled into teeth to provide structure or stability before filling. Materials used as temporary or permanent fillings or crowns--such as amalgam, gold alloy, aluminum, microfilled resin, and polyvinyl acrylics--did not cause artifacts in the images.     

Effects of surgery on the cell kinetics of residual tumor.

Noncurative excision of a primary sc Lewis lung tumor performed on Day 7 or later results in an increase in the thymidine index and growth rate with minimal changes in the cell cycle parameters of the lung metastases. The stimulation of the lung nodules is accompanied by a small but consistent decrease in median lifespan. Sham surgery performed on Day 3 or later also results in a decrease in median lifespan and an increase in the thymidine index of the undisturbed primary tumor. Artifical metastases (10(6) cells iv) are inhibited by the presence of a second (sc) implant and the median lifespan of the doubly implanted mice exceeds that of mice bearing iv implants only. In mice bearing widely metastasized Lewis lung carcinoma, surgery alone may have a detrimental effect on life expectancy, but the residual tumor foci, stimulated to more rapid growth, should be appropriate targets for adjuvant chemotherapy.     

Proliferation of early human myeloid precursors induced by interleukin- 1 and recombinant soluble CD23

Low affinity Fc epsilon receptors (Fc epsilon RII/CD23) or their soluble fragments have various biologic effects on B- and T-cell lineages. In this study, we have assessed the effect of recombinant soluble CD23 (rsCD23) on the proliferation of human bone marrow (BM)- derived myeloid precursors with or without recombinant interleukin-1 (rIL-1) addition. Non-adherent CD2- or CD34+ BM cell subsets were used as target cells. Our results show that rsCD23 in synergy with rIL-1 displays an interleukin-3-like activity as it promotes the proliferation of multipotential marrow precursors. This effect was abolished by anti-CD23 addition to these cultures, but was not affected by anti-IL-3 monoclonal antibody. Furthermore, sequential study indicates that rIL-1 induces bone marrow cell responsiveness to rsCD23.     

Biallelic expression of the IGF2 gene in human breast disease

We examined the imprinting status of the insulin-like growth factor II gene (IGF2) in a series of 20 human breast disease samples to determine if disrupted imprinting (as evidenced by biallelic expression), was a demonstrable mechanism of altered gene expression. These samples included benign (n = 7) and malignant breast lesions (n = 13). Biallelic expression of IGF2 was detectable in 67% of benign and 60% of malignant informative breast lesions. Three informative reduction mastectomies displayed normal IGF2 imprinting. The presence of this alteration in human breast tissue is a novel finding, and may contribute to tumorigenesis, possibly by favouring an enhanced proliferative milieu, during which additional mutations could occur.      

Global sequence diversity of BRCA2: analysis of 71 breast cancer families and 95 control individuals of worldwide populations [published erratum appears in Hum Mol Genet 1999 Apr;8(4):717-9]

The aim of this study was to evaluate the prevalence of simple sequence variation in the BRCA2 gene. To this end, 71 breast and breast-ovarian cancer (HBC/HBOC) families along with 95 control individuals from a wide range of ethnicities were analyzed by means of denaturing high- performance liquid chromatography (DHPLC) and direct sequence analysis. In the coding (10 257 bp) and non-coding (2799 bp) sequences of BRCA2, 82 sequence variants were identified. Three different, apparently disease-associated BRCA2 mutations were found in six HBC/HBOC families (8%): two splice site mutations in introns 5 and 21, and one frameshift mutation in exon 11. In the coding region, 53 simple sequence variants were found: 35 missense mutations, one 2 bp deletion (CT) resulting in a stop at codon 3364, one nonsense mutation with a stop at codon 3326, one deletion of a complete codon (AAA) resulting in the loss of leucine, and 15 silent mutations. In the non-coding region, 26 polymorphisms were detected. Of the 79 sequence variants that were not obviously disease-associated, eight were detected only in HBC/HBOC families. The remaining 71 variants were identified in both HBC/HBOC families and control individuals. Sixty three sequence variants (80%) were specific for a continent. Forty two percent (33 out of 79) of the sequence variants were detected exclusively in Africa, though only 13% of the 332 chromosomes screened were of African origin. Our data indicate that, in BRCA2, simple sequence variation is frequent [in the coding region 1 in 194 bp (straight theta = 2.2 x 10(-4)), and in the non-coding region 1 in 108 bp (straight theta = 4.4 x 10(-4)), respectively].      

Mesenchymal hamartoma of the liver: radiologic-pathologic correlation

Mesenchymal hamartoma of the liver (MHL) is an uncommon cystic mass of infancy that is a developmental anomaly rather than a neoplasm. Fourteen cases of MHL were retrospectively reviewed. Grossly, MHL is a solitary mass with cystic spaces of variable size. Patients are seen initially with painless progressive abdominal enlargement. On plain films, MHL appears as a large, noncalcified mass in the right upper quadrant. Scintigraphy is helpful in confirming its hepatic origin. Ultrasonography and computed tomography demonstrate a large multiloculated mass with considerable variation in the size of septa and cystic spaces. Angiographically, MHL is avascular or hypovascular. Recognition of these radiographic findings allows a correct diagnosis to be made in many cases. With resection, the prognosis is excellent.