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Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is utilized to examine the mass spectra and fragmentation patterns of seven isomeric monosaccharides. Multivariate statistical analysis techniques, including principal component analysis (PCA), allow discrimination of the extremely similar mass spectra of stereoisomers. Furthermore, PCA identifies those fragment peaks that vary significantly between spectra. Heavy isotope studies confirm that these peaks are indeed sugar fragments, allow identification of the fragments, and provide clues to the fragmentation pathways. Excellent reproducibility is shown by multiple experiments performed over time and on separate samples. This study demonstrates the combined selectivity and discrimination power of TOF-SIMS and PCA and suggests new applications of the technique including differentiation of subtle chemical changes in biological samples that may provide insights into cellular processes, disease progress, and disease diagnosis.

We use time-of-flight secondary ion mass spectrometry (TOF-SIMS) to image and classify individual cells on the basis of their characteristic mass spectra. Using statistical data reduction on the large data sets generated during TOF-SIMS analysis, similar biological materials can be differentiated on the basis of a combination of small changes in protein expression, metabolic activity and cell structure. We apply this powerful technique to image and differentiate three carcinoma-derived human breast cancer cell lines (MCF-7, T47D, and MDA-MB-231). In homogenized cells, we show the ability to differentiate the cell types as well as cellular compartments (cytosol, nuclear, and membrane). These studies illustrate the capacity of TOF-SIMS to characterize individual cells by chemical composition, which could ultimately be applied to detect and identify single aberrant cells within a normal cell population. Ultimately, we anticipate characterizing rare chemical changes that may provide clues to single cell progression within carcinogenic and metastatic pathways.

(Arch Pathol Lab Med. 2008;132:675-683) Nasopharyngeal carcinoma (NPC) is endemic in southern China, Southeast Asia, and North Africa, but it is rare in most parts of the world. (1) The [...], Context.--Nasopharyngeal carcinoma (NPC), common in southern China and North Africa, has a complex etiology involving interplay between viral, environmental, and hereditary factors and is almost constantly associated with the Epstein-Barr virus. Since the prognosis of locally advanced and metastatic diseases is poor, increased understanding of the pathogenesis of NPC would be important for discovering novel markers for patients' management. Objectives.--To compare the proteomic expression profile between an Epstein-Barr virus-associated NPC cell line (C666-1) and a normal NP cell line (NP69). The proteins with differential expression were analyzed in 40 undifferentiated NPC paraffin-embedded specimens. Design.--Differentially expressed proteins discovered between the two cell lines were identified by mass spectrometry. After confirmation by immunocytochemical staining, their expression in patient samples was measured using 40 pairs of undifferentiated NPCs together with their adjacent normal epithelia. Results.--Proteomic findings indicated that adenosine triphosphate synthase [alpha] chain was up-regulated, whereas annexin II, annexin V, [[beta].sub.2]-tubulin, and profilin 1 were down-regulated. After confirming the results in agar-processed cell lines, annexin II and [[beta].sub.2]-tubulin expression were found to be lower in tumor cells than in adjacent normal epithelial cells in 100% and 90% of the patients' specimens, respectively. Finally, annexin II down-regulation was positively associated with lymph node metastasis, suggesting that it may be a prognostic factor in NPC. Conclusions.--The results suggest that annexin II and [[beta].sub.2]-tubulin down-regulation is important in NPC formation and may represent potential targets for further investigations.

Immunohistochemistry (IHC) has revolutionized the practice of surgical pathology by providing accurate information for patient diagnosis, prognosis, and even therapy. (1) The success of IHC can be attributed to improvements [...], * Context.--In immunohistochemistry, nonstandardized antigen retrieval protocols and fluids, poor-quality antibodies, and the presence of endogenous biotin frequently lead to incorrect results. Recently, advanced reagents including bifunctional SkipDewax pretreatment solution (BSPS), rabbit monoclonal (RM) antibodies, and biotin-free polymer detection systems (PDSs) have been developed, which, it is claimed, resolve these problems. Objectives.--To determine whether BSPS, RM antibodies, and biotin-free PDSs improve the accuracy of immunohistochemistry; to optimize a new protocol consisting of a combination of BSPS, RM antibodies, and PDSs; and to compare it with a conventional protocol. Design.--The efficacies of BSPS, RM antibodies, and PDSs were compared with those of their respective conventional reagents using multitissue spring-roll sections. The new protocol was compared with a conventional protocol using Ki-67 immunostaining of 49 colorectal carcinoma specimens. Results.--For antigen retrieval, BSPS resulted in similar or better tissue staining than an EDTA solution, but the efficacy of BSPS decreased when it was reused. Most RM antibodies resulted in a greater proportion of positive cells than the corresponding non-RM antibodies, which did not produce satisfactory results in the absence of antigen retrieval. The PDSs Bond, ChemMate, and SuperPicture resulted in a high percentage of positive cells, good staining intensities, and low backgrounds. Other PDSs, except that from Ventana, resulted in high backgrounds and false positivity. The new combined protocol resulted in better Ki-67 staining than the conventional assay. Conclusions.--Bifunctional SkipDewax pretreatment solution, RM antibodies, and PDSs improve staining quality and diagnostic accuracy of immunohistochemistry assays and provide a foundation for standardization.

The meso and rac isomers of Ru(dipa)(sub 2)(super +2) (dipa=di-2-pyridylmethanamine) are prepared. The electronic spectra of the isomers show pyridyl pi-> pi* transitions in the UV region and MLCT bands in the visible region. The electrochemical properties of two isomers are identical.

In this study the effect of host changes and multiple passages on Pepino mosaic virus ( PepMV) evolution was analysed. A population of a mild isolate of PepMV was used to generate five independent evolution lineages on three tomato cultivars, which differ in rate of appearance of symptoms and their severity during viral infection (Beta Lux, Moneymaker and Malinowy Ożarowski) and on Datura inoxia. Twenty serial passages were performed over a period of 217-220 days. Symptom severity was monitored along the entire experiment. After the last series of passages total RNAs from each lineage and host were isolated and the triple gene block 3 ( TGB3) and coat protein ( CP) were amplified, cloned and 10 clones for each gene sequenced. Among the 400 clones for both genes, 143 individual mutations (61 synonymous and 82 nonsynonymous) were identified, with the largest number of nonsynonymous mutations being observed for the tomato cultivars Malinowy Ożarowski and Beta Lux. In two of the lineages evolving in the most susceptible variety of tomato (Beta Lux) necrotic changes in leaf blades appeared after 17 passages, leading to death of the plants. In these two lineages the mutation responsible for necrotic symptoms was K67E in TGB3. The appearance of this convergent mutation in independently evolving lineages may suggest that selection in this experimental set up favours more aggressive PepMV variants. We found a positive association between the severity of symptoms and the amount of genetic variability contained on viral populations. Indeed, the severity of symptoms turned out to be a good predictor for several indices of molecular variability. In addition, mapping all observed mutations in CP and TGB3 protein structures revealed that most were located on the surface, indicating a possible implication in viral-viral or viral-host interactions. [ABSTRACT FROM AUTHOR]

Investigates the effects of multiple infection dynamics on the fitness of RNA viruses. Generation of complex mixtures of genomes after infection; Selection of generic variants within an infected host through the differences in growth and competition rates; Method employing the Lotka-Volterra competition equations.

Reports on the second-order reduction of methylene blue to leucomethylene blue (MBH) by ascorbic acid in acetonitrile. Use of cavity ring-down spectroscopy (CRDS) to carry out the measurements; Monitoring of absorbing species in a variety of organic solvents; Use of highly reflective mirrors to form an optical cavity in CRDS.