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Lung cancer is the leading cause of cancer deaths in the U.S. with survival dramatically depending on stage at diagnosis. We had earlier reported that nanocytology of buccal cells can accurately risk-stratify smokers for the presence of early and late-stage lung cancer. To translate the technique into clinical practice, standardization of operating procedures is necessary to consistently yield precise and repeatable results. Here, we develop and validate simple, robust, and easily implementable procedures for specimen collection, processing, etc. in addition to a commercially-viable instrument prototype. Results of this work enable translation of the technology from academic lab to physicians’ office.

Background & Aims: Identification of preneoplastic changes in histologically normal epithelium (the ''field effect'') could provide a powerful screening tool for colorectal cancer. However, to date, reliable detection has not been possible. We have recently developed a new generation of optical technology, 4-dimensional elastic light-scattering fingerprinting (4D-ELF), which enables us to probe the nanoscale/microscale architecture of living cells. We therefore investigated whether 4D-ELF would be able to identify preneoplastic changes in the colonocytes of the azoxymethane (AOM)-treated rat model of colon carcinogenesis. Methods: Forty-eight Fisher 344 rats were randomized to either 2 weekly injections of AOM or saline. Animals were killed 2-20 weeks after the second injection of AOM. Colons were removed and subjected to 4D-ELF analysis, with a subset undergoing assessment of aberrant crypt foci (ACF). All AOM-treated animals were compared with age-matched saline-treated controls. Results: AOM-induced ACF became apparent at approximately 4-6 weeks and continued to increase over time. ACF were predominantly located in the distal colon. At 2 weeks (before development of ACF), there were marked changes in a number of 4D-ELF signatures. The relevance to carcinogenesis of these 4D-ELF-detected microarchitectural abnormalities is supported by their spatial and temporal correlation with subsequent development of ACF. All changes reported were highly statistically significant. Conclusions: We show that probing the nanoscale cellular architecture with 4D-ELF provided an unprecedented tool for detecting the earliest stages of colon carcinogenesis. Future studies are necessary to explore the clinical applicability of this technology and elucidate the biological determinants of these microarchitectural changes.

In a genetic screen designed to generate Escherichia coli strains completely devoid of the heme precursor 5-aminolevulinic acid (ALA), we isolated a class of mutants which were defective for exogenous ALA uptake. The mutations, designated alu (ALA uptake), mapped to the 80-min region of the E. coli chromosome. They were complemented by a recombinant plasmid containing the dpp operon, which encodes a dipeptide permease transport system. Alu mutants displayed a severe reduction in ALA import, as did a strain with a chromosomal insertion in the first gene of the dpp operon. A recognized substrate of Dpp transport, prolyl-glycine, effectively competed with ALA for uptake. E. coli strains defective in ALA biosynthesis (hemA or hemL) require exogenous ALA to achieve wild-type growth but show limited aerobic and anaerobic growth in the absence of ALA. The presence of an alu or dpp mutation in hemA or hemL strains abolishes growth in the absence of ALA and requires increased levels of ALA for normal growth. We conclude that the alu mutations are within the dpp operon and that the dipeptide transport system mediates uptake of the important metabolite ALA.

Background: Since the urea breath test (UBT) indirectly detects gastric Helicobacter pylori infection by measuring urease activity, the possibility of false-positive results due to other urease-producing bacteria cannot be excluded. Previous studies have shown that increased 14CO2 activity in early breath samples could be attributed to urea hydrolysis in the oropharynx. For that reason, reliable assessment of H. pylori status is hampered for at least 20 min after administration of a 14C-urea drink. Methods: To overcome this problem, we have developed a modified breath test in which 111kBq 14C-urea is supplied in a gelatin capsule, which prevents release of 14C before reaching the stomach. Our modified 14C UBT was evaluated in 100 healthy volunteers, and results were compared with those from enzyme-linked immunosorbent assay serology. Results: The study showed a 99% concordance between the two non-invasive tests. When a biometric method for determination of cut-off values between positive and negative UBT results with the smallest possible arbitrariness was used, the calculated statistical probability of a false diagnosis was lowest in the 10-min breath sample (0.20%), and 100% sensitivity and specificity was achieved. Our capsule method was also compared with the urea drink method and was found more reliable because no overlapping in 14CO2 activity occurred between H. pylori-positive and -negative subjects, whereas conventional breath testing showed overlapping during the whole 30-min test period. Our study also showed that a fatty test meal lowers the 14CO2 excretion the first 20 min and may adversely affect the accuracy of a rapid UBT. Conclusions: Supplying the 14C-urea in a capsule obviates the problem of false-positive results in early breath samples and makes it possible to diagnose H. pylori infection with 99.8% reliability from a single 10-min breath sample, without the use of a test meal or adjustments for assumed individual CO2 production.

Polarization analysis of vacuum ultraviolet (VUV) radiation, especially the analysis of elliptical polarization is of considerable scientific interest in many areas of physics including solar physics. Polarization measurements in the VUV region are much less developed than those in visible and infrared spectral regions. It is due to lack of efficient phase shifting elements and small reflection coefficients of polarizers for VUV radiation. We propose two techniques, to determine the arbitrary polarization of VUV radiation with photon energies in the range 10 – 100 eV, which seem to be more efficient and precise than the known techniques, especially to study the polarization of atomic or molecular spectral lines.

Various staining techniques are commonly used in biomedical research to investigate cellular morphology. By inducing absorption of light, staining dyes change the intracellular refractive index due to the Kramers–Kronig relationship. We present a method for creating 2D maps of real and imaginary refractive indices of stained biological cells using their thickness and absorptance. We validate our technique on dyed polystyrene microspheres and quantify the alteration in refractive index of stained biological cells. We reveal that specific staining of individual organelles can increase their scattering cross-section by orders of magnitudes, implying a major impact in the field of biophotonics.