Alteration and abnormal expression of the c-myc oncogene in human multiple myeloma

Structural alterations of the c-myc oncogene in human Burkitt's lymphoma and mouse plasmacytoma suggest that this oncogene is involved in several B cell neoplasms. The possibility of c-myc alterations in human myeloma has not been explored, probably because the low proliferative activity characteristic of this tumor impairs the propagation of representative cell lines for the performance of adequate cytogenetic studies. This report describes alterations in the c-myc locus with concomitant elevated expression of mRNA in the tumor cells of two of 37 patients with multiple myeloma. In one case, somatic cell hybrid studies revealed that the cloned rearranged DNA was entirely derived from chromosome 8, thus indicating a novel mechanism of c-myc activation different from that in Burkitt's lymphoma. Seven other patients exhibited five- to 12-fold overexpression of c-myc RNA when compared with normal marrow cells. Elevated mRNA expression in about one fourth of our patients suggests that the c-myc oncogene has a pathogenetic role in the evolution of multiple myeloma.     

The genetic basis of immune and autoimmune responses

HLA class I and class II molecules play a major role in the presentation of short, pathogen-derived peptides to T cells, a process that initiates the adaptive cellular and humoral immune responses. However, the factors governing a cell's ability to respond or not to particular peptides are still not completely understood. Taking the example of a viral infection, in tissues infected with a virus, viral particles are taken up by antigen-presenting cells and uncoated. The viral DNA or RNA enters the nucleus, where it replicates. mRNA enters the cytosol and is transcribed into proteins. These proteins are degraded in proteasomes and the resulting peptides (8–10 residues) are loaded onto class I molecules for export to the surface of the cells. In the meantime, the groove of the class II molecules is also preparing to accommodate peptides (12–24 residues) generated by the endocytic protein-processing pathway. The surface of the infected cell then becomes adorned with peptide-loaded human leukocyte antigen (HLA) molecules. CD4⁺ T helper lymphocytes engage class II molecules and elicit responses from B cells, which will ultimately lead to antibody production, whereas CD8⁺ T lymphocytes become cytotoxic T cells. As a consequence, the virus is eliminated from the body. However, certain mysteries and challenges remain. How can, as an exception to this rule, an autoimmune response be the escape from the perfect machinery? This review offers some hypotheses on how to see the problem through to its solution.     

Navigation-guided oral and maxillofacial surgery (reconstructive and plastic, orthognathic, oncology)

Purpose: Advance in the field of compeer assisted surgery enables the surgical procedures to be less invasive and more accurate for the support of diagnosis imaging, pre-operative simulation and intraoperative navigation.     

Characterization of MR spectroscopic imaging of the human head and limb at 2.0 T

Using section-select and phase-encoding gradients, the authors obtained phosphorus chemical shift images of the human head and limb. Phosphorus spectra were acquired from planar sections divided into voxels as small as 7 cm3 in calf muscle and 27 cm3 in brain, with total examination times, including setup and proton locator imaging, of roughly 1 hour. Both spin-echo and free induction decay (FID) methods were employed; the FID gave superior results. Signal-to-noise ratios for the beta-adenosine triphosphate and phosphocreatine resonances were as high as 10:1 and 13:1 from volumes of 27 cm3 in brain.     

Reliability of the Otago photoscreener A study of a thousand cases

The Otago photoscreener is a 35 mm single lens reflex camera in which the flash light comes from a narrow ring around the outer margin of its lens. The margin is also the limiting aperture of the optic system and in the centre of the lens is a flickering fixation light. In a colour photograph taken at a distance of 66 cm from the face of the subject who is accurately focusing on and fixing the camera fixation light with both eyes, the fundus reflex in each pupil is very dark red and the corneal light reflexes are symmetrical. If either or both eyes are not appropriately focused or fixing, the fundus reflex is brighter and yellow or white. This article describes a prospective trial of the performance of the Otago photoscreener in a series of 1000 infants with actual or suspected amblyopia, refractive error or strabismus. In this study photoscreening showed a sensitivity of 94% and a specificity of 79%. Photoscreening also identified some cases of esotropia and of refractive error which were missed on clinical examination. In this series photoscreening passed as normal three children with mild to moderately severe amblyopia. This represents les than 1 % of the clinically abnormal children.     

Neuronal migrational disorders: diffuse cortical dysplasia or the "double cortex" syndrome

We report a 10-year-old girl who presented with a single episode of partial complex seizure. Neurological examination and psychological evaluation were normal. Electroencephalogram showed abnormalities in the left temporo-occipital region. Magnetic resonance imaging revealed a bilateral layer of tissue iso-intense with gray matter, between the wall of the lateral ventricle and the cortex, extending from the frontal to the occipital region, and enlarged left lateral ventricle. The images indicated diffuse cortical dysplasia, also known as band heterotopia or "double cortex", and left cortical hemiatrophy.