Citations

ABSTRACT A 300-bp plasmid fragment of the hemagglutinin gene was used as target DNA to develop a rapid real-time LightCycler (Roche Applied Science, Indianapolis, Ind.) PCR assay for laboratory detection of smallpox virus. PCR primers and probes were designed specifically for detection of smallpox virus DNA, but all viruses of the genus Orthopoxvirus tested could be detected by use of the hemagglutinin gene target sequence. Base pair mismatches in the 204-bp amplicon allowed discrimination of cowpox virus (melting temperature [ T m ], 56.40°C), monkeypox virus ( T m , 56.24°C), and vaccinia virus ( T m , 56.72°C), including the Dryvax vaccine strain, from smallpox virus ( T m , 62.45°C) by melting curve analysis. The analytical sensitivity was 5 to 10 copies of target DNA per sample. The assay was specific for members of the genus Orthopoxvirus ; the DNAs of herpes simplex virus and varicella-zoster virus were not detected by the smallpox virus LightCycler PCR.

The apolipoprotein E ( APOE ) gene is the only genetic risk factor that has so far been linked to risk for late-onset Alzheimer's disease (LOAD). However, 50 percent of Alzheimer's disease cases do not carry an APOE4 allele, suggesting that other risk factors must exist. We performed a two-stage genome-wide screen in sibling pairs with LOAD to detect other susceptibility loci. Here we report evidence for an Alzheimer's disease locus on chromosome 10. Our stage one multipoint lod score (logarithm of the odds ratio for linkage/no linkage) of 2.48 (266 sibling pairs) increased to 3.83 in stage 2 (429 sibling pairs) close to D10S1225 (79 centimorgans). This locus modifies risk for Alzheimer's disease independent of APOE genotype.

Ectomesenchymomas (EM) are rare malignant neoplasms usually consisting of rhabdomyosarcoma (RMS) with a neural component. Only 21 cases have been previously reported. Here we extend the clinicopathologic spectrum of EM by describing our findings in 15 cases. Only 5 patients were infants; 10 were ≤3 years old and 5 were ≥6 years old. No male predilection was observed; 7 were female. The originating institutional diagnoses were; RMS (12), undifferentiated sarcoma (1), or EM (2), suggesting underdiagnosis of this entity. The primary tumor sites included external genital (5), pelvis/abdomen (6), head and neck (3), and extremity (1). The size of the primary neoplasm was usually ≥5 cm at diagnosis but dissemination only occurred in a minority. Local infiltration was not uncommon. These neoplasms were typically multilobate, thinly encapsulated, hemorrhagic, and necrotic. Light microscopic features were highly variable, but embryonal RMS with scattered or clustered ganglion cells, often in lacunae, was characteristic. In some cases, primitive neuroblastic or neuroectodermal areas were found and/or a component of alveolar RMS was seen. Focal anaplasia was occasionally observed. Mitotic activity appears higher than previously appreciated and some necrosis was invariably present. Electron microscopy was performed in 11 cases, which confirmed skeletal muscle ± neural differentiation. Cytogenetic studies performed in five cases revealed no specific abnormality. Monoclonal neuron-specific enolase was the best marker of ganglion cells and primitive neural elements. MIC-2 (CD99) membrane expression was not definitively present in any of the six cases examined. A number of the above parameters appear to be of some prognostic significance, but overall, these neoplasms appear to have a similar outcome as would be predicted for their RMS element alone (exclusive of any neural component), with respect to the RMS subtype, age of the patient, and anatomic location of the neoplasm.