Antigenic variation and cross-reactivity in Bacteroides forsythus clinical isolates detected by western blot

Bacteroides forsythus is one of the etiologic agents of destructive periodontal diseases. Determining which antigenic components of the bacterium are recognized in the immune response of periodontitis patients is an important step in assessing strategies for vaccine development. The aim of this study was to identify the major strain-variable and cross-reactive antigens of B. forsythus clinical isolates recognized by serum IgG from patients with early-onset rapidly progressive periodontitis. Ten patient sera with measurable IgG against antigenic components of the species were identified by Western blot. Positive sera were tested by checkerboard ELISA to identify those most responsive to strain-variable antigens in nine clinical isolates and ATCC strain 43037. Correlation analysis of the ELISA data suggested that different subsets of isolates were preferentially recognized by different sera. Western blots revealed that certain sera also recognized major shared components across all the isolates, but preferential recognition of different isolate subsets by different patients was clearly confirmed. To determine if the variable antigens recognized were nonprotein, proteinase K-digested isolates were compared to undigested controls by Western blot. The main strain-variable antigens were proteinase resistant, while proteins at 200 and 210 kDa were identified as the major shared components. Two-dimensional SDS-PAGE revealed that these proteins are the quantitatively dominant heat-modifiable components of the cell envelope. Even though variable antigens are prominent in the immune response of patients, a cross-protective vaccine based on the shared envelope proteins of B. forsythus seems feasible in light of these observations.     

Diffuse ocular metastases as an initial sign of metastatic lung cancer

A 68-year-old man with lung carcinoma and no systemic metastasis presented with a blind, painful right eye. Examination showed no perception of light in the affected eye, elevated intraocular pressure, marked epibulbar hyperemia, and a white placoid mass in the conjunctiva nasally. Although a cataract precluded a clear view of the fundus, ultrasonography disclosed a total retinal detachment and a diffuse thickening of the choroid. Metastatic carcinoma was suspected clinically and the eye was enucleated because of severe, intractable pain. Pathologic examination demonstrated extensively necrotic metastatic adenocarcinoma involving the conjunctiva, peripheral cornea, sclera, iris, ciliary body, choroid, optic nerve, subarachnoid space, and orbit. Metastatic disease usually affects a singular ocular tissue, and it is highly unusual for such widespread ocular involvement to be the first sign of systemic metastasis from a primary neoplasm.     

Advanced components and sub-system solutions for 40 Gb/s transmission

With the commissioning of the latest 10-Gb/s systems, vendors are now in the process of developing architectures for their next-generation products. 40-Gb/s components and subsystems are currently in development to address the necessities of these next-generation systems. The top three challenges associated with 40-Gb/s transmission are optical signal-to-noise ratio, dispersion, and high-speed components. In order to realize 40-Gb/s transmission, new component and subsystem developments are crucial. This paper reviews the latest transmission technologies and dispersion compensation techniques developed to fulfill 40-Gb/s transmission system requirements.     

Digital geological mapping with tablet PC and PDA: A comparison

Both the hardware and software available for digital geological mapping (DGM) have advanced considerably in recent years. Mobile computers have become cheaper, lighter, faster and more power efficient. Global Positioning Systems (GPS) have become cheaper, smaller and more accurate, and software specifically designed for geological mapping has become available. These advances have now reached a stage where it is effective to replace traditional paper-based mapping techniques with those employing DGM methodologies. This paper attempts to assess and evaluate two currently available DGM systems for geological outcrop mapping: one based on a Personal Digital Assistant (PDA) running ESRI “ArcPad”, and the second based on a Tablet PC running “Map IT” software. Evaluation was based on field assessment during mapping of a well-exposed coastal section of deformed Carboniferous and Permian rocks at N. Tynemouth in NE England. Prior to the field assessment, several key criteria were identified as essential attributes of an effective DGM system. These criteria were used as the basis for the assessment and evaluation process. Our findings suggest that the main concerns presented by sceptics opposed to DGM have largely been resolved.In general, DGM systems using a Tablet PC were found to be most suitable for a wide range of geological data collection tasks, including detailed outcrop mapping. In contrast, systems based on a PDA, due to small screen and limited processing power, were best suited for more basic mapping and simple data collection tasks. In addition, PDA-based systems can be particularly advantageous for mapping projects in remote regions, in situations where there is a limited power supply or where total weight of equipment is an important consideration.     

Double heterozygosity for mutations in the BRCA1 and BRCA2 genes in a breast cancer patient

BACKGROUND: Germline mutations in the tumor suppressor genes BRCA1 and BRCA2 confer substantial increased lifetime risk for breast cancer, and in the case of BRCA1, for ovarian carcinoma as well. These two genes alone account for the vast majority of hereditary breast cancer families. Numerous mutations have been described in each gene, the majority of which are small insertions or deletions resulting in expression of a truncated protein. MATERIALS AND METHODS: Several common mutations can be detected using a polymerase chain reaction-mediated, site-directed mutagenesis assay, which transforms the amplicon derived from either the wild-type or mutant allele by adding or removing a restriction endonuclease site. We screened 49 putative sporadic breast tumors using this methodology, targeting four BRCA1 mutations (185delAG, 5382insC, R1443X, and E1250X) and a single BRCA2 mutation (6174delT). RESULTS: Using the polymerase chain reaction-mediated, site-directed mutagenesis assay, we identified two mutations, namely, a 185delAG mutation (BRCA1) and a 6174delT mutation (BRCA2). Interestingly, these two mutations were found in the same sample. None of the remaining 48 breast tumors showed evidence of these mutations. Allele-specific oligonucleotide probes were then employed in conjunction with the Universal GeneComb Test Kit, which confirmed the presence of mutations. CONCLUSIONS: Our data suggest that the common germline BRCA1 and BRCA2 mutations are infrequently encountered in sporadic breast cancers. The one case with dual BRCA1 and BRCA2 mutations suggests that this tumor may be hereditary in origin, despite the lack of a positive family history. Double heterozygosity for mutations in BRCA1 and BRCA2 may have increasingly significant implications with regard to predisposition to breast cancer.