Uniqueness in multispectral constant-wave epi-illumination imaging

Multispectral tissue imaging based on optical cameras and continuous-wave tissue illumination is commonly used in medicine and biology. Surprisingly, there is a characteristic absence of a critical look at the quantities that can be uniquely characterized from optically diffuse matter by multispectral imaging. Here, we investigate the fundamental question of uniqueness in epi-illumination measurements from turbid media obtained at multiple wavelengths. By utilizing an analytical model, tissue-mimicking phantoms, and an in vivo imaging experiment we show that independent of the bands employed, spectral measurements cannot uniquely retrieve absorption and scattering coefficients. We also establish that it is, nevertheless, possible to uniquely quantify oxygen saturation and the Mie scattering power-a previously undocumented uniqueness condition.

Knowledge of pelvic organ prolapse in patients and their information-seeking preferences: comparing Vienna and Moscow

Introduction and hypothesis

We hypothesized that knowledge of pelvic organ prolapse (POP) and patient information-seeking preferences are the same in the two capital cities.

Methods

First-visit patients were recruited at tertiary referral urogynaecological units in Vienna (137) and in Moscow (112). A 16-item scale was used to assess the patient knowledge of POP. The 16 items comprised 12 specific items taken from the Prolapse and Incontinence Knowledge Questionnaire (PIKQ) and four added items. The preliminary psychometric assessment of the knowledge scales in German and Russian was performed in the Vienna and in Moscow centres.

Results

The mean total knowledge scores in patients in Vienna and in Moscow were not significantly different: 9.7 ± 3.5 vs. 9.8 ± 2.9 (p = 0.92). Patients in Vienna were more likely to answer questions about the pathogenesis of POP correctly. Patients in Moscow achieved higher scores for items assessing knowledge about the diagnosis of POP. Women in the two study groups equally preferred to obtain information about POP from medical specialists (72 % and 82 %; p = 0.61), followed by friends and family for patients in Vienna (25 %), and the internet for patients in Moscow (23 %). Patients in Vienna were more likely to use printed sources (18 % and 7 %; p = 0.001) than patients in Moscow.

Conclusions

The mean level of knowledge of POP did not differ between patients in Vienna and patients in Moscow. The differences between the specific knowledge domains might be explained by different cultural preferences for seeking health information and by the range of the information sources available.

In vitro human skin penetration model for organophosphorus compounds with different physicochemical properties

A flow-through diffusion cell was validated for in vitro human epidermal penetration studies of organophosphorus compounds (OPCs) applied by infinite dosing. By testing OPCs with similar molecular weight but different physicochemical properties, it was shown that hydrophilic and lipophilic properties are major determinants for the penetration rate. Lipophilic OPCs displayed maximum cumulative penetration in the 20-75% agent concentration range whereas the hydrophilic OPCs displayed maximum cumulative penetration at 10 or 20% agent concentration. Low penetration was observed for all agents at 1% agent concentration or when applied as neat agents. The impact of the receptor solution composition was evaluated by comparing the penetration using receptor solutions of different ratios of ethanol and water. For diluted OPCs, a high concentration of ethanol in the receptor solution significantly increased the penetration compared to lower concentrations. When OPCs were applied as neat agents, the composition of the receptor solution only affected the penetration for one of four tested compounds. In conclusion, the flow-through diffusion cell was useful for examining the penetration of OPCs through the epidermal membrane. It was also demonstrated that the penetration rates of OPCs are strongly influenced by dilution in water and the receptor fluid composition.

Terahertz meets sculptural and architectural art: Evaluation and conservation of stone objects with T-ray technology

Conservation of cultural heritage is an area where novel scientific techniques are having enormous impact. Given the value and uniqueness of art pieces, non-invasive diagnostic methods are highly appreciated by conservators. Terahertz radiation has shown enormous potential as non-contact probe that can be used for the three-dimensional reconstruction of internal structure of stone-made objects. In this article we report the evaluation of the internal damage state of two art pieces, a medallion from the Castle of Celle and a window sill from the St. Peter of Trier Cathedral. We also used terahertz radiation to follow and assess the restoration process of the window sill. We found that terahertz spectroscopy is an excellent non-destructive evaluation method for stone artwork that shows enormous potential as a tool for conservation.

Bimodal Exciplex Formation in Bimolecular Photoinduced Electron Transfer Revealed by Ultrafast Time-Resolved Infrared Absorption

The dynamics of a moderately exergonic photoinduced charge separation has been investigated by ultrafast time-resolved infrared absorption with the dimethylanthracene/phthalonitrile donor/acceptor pair in solvents covering a broad range of polarity. A distinct spectral signature of an exciplex could be identified in the -C≡N stretching region. On the basis of quantum chemistry calculations, the 4-5 times larger width of this band compared to those of the ions and of the locally excited donor bands is explained by a dynamic distribution of exciplex geometry with different mutual orientations and distances of the constituents and, thus, with varying charge-transfer character. Although spectrally similar, two types of exciplexes could be distinguished by their dynamics: short-lived, "tight", exciplexes generated upon static quenching and longer-lived, "loose", exciplexes formed upon dynamic quenching in parallel with ion pairs. Tight exciplexes were observed in all solvents, except in the least polar diethyl ether where quenching is slower than diffusion. The product distribution of the dynamic quenching depends strongly on the solvent polarity: whereas no significant loose exciplex population could be detected in acetonitrile, both exciplex and ion pair are generated in less polar solvents, with the relative population of exciplex increasing with decreasing solvent polarity. These results are compared with those reported previously with donor/acceptor pairs in different driving force regimes to obtain a comprehensive picture of the role of the exciplexes in bimolecular photoinduced charge separation.

Distribution of deoxynivalenol, zearalenone, and their respective modified analogues in milling fractions of naturally contaminated wheat grains

Mycotoxins are among the most abundant contaminants in food and feed worldwide. Therefore, in the EU maximum levels are established, e.g. for the frequently occurring Fusarium toxins deoxynivalenol (DON) and zearalenone (ZEA). Additional to DON and ZEA, modified mycotoxins are present in naturally contaminated grain products contributing significantly to the exposure of humans and animals with mycotoxins. Up to now data on the spatial distribution of many (masked) mycotoxins in the kernels of wheat are missing. The aim of the present study was to investigate the amounts of DON and ZEA as well as their most abundant derivatives DON-3-glucoside (DON-3G), 3- and 15-acetyl-DON, ZEA-14- and 16-glucoside and ZEA-14-sulphate (ZEA-14S) in mill fractions of naturally contaminated wheat batches using HPLC-MS/MS. The investigated distribution pattern in ten milling fractions is comparable among the three investigated different wheat batches. Interestingly, DON and DON-3G were found to be present to similar amounts in all fractions. In bran, the levels were only slightly higher than in the endosperm. By contrast, for ZEA and ZEA-14S a significantly higher amount of toxin is located in the fibre-rich fractions. The relative mass proportion of DON-3G comprises for only between 2.9 and 11.2% of the free DON, while the relative mass proportion of ZEA-14S is estimated to even exceed the amount of free ZEA in certain fractions. Acetylated DON derivatives and ZEA-glucosides were only detected in low amounts. The experimental results show that a significant reduction of the ZEA and ZEA-14S level in wheat flour is feasible by applying milling technology strategies. However, the almost evenly distribution of DON and DON-3G in all fractions does not allow for the technological removal of relevant toxin amounts. Furthermore, the relative share of masked forms was higher for ZEA derivatives than for the DON conjugates in the investigated wheat lots.

Body weight gain and risk of colorectal cancer: a systematic review and meta-analysis of observational studies

While the relationship between body mass index as an indicator of excess body weight and the risk of colorectal cancer (CRC) is well established, the association between body weight gain in adulthood and risk of CRC remains unresolved. We quantified this association in a meta-analysis of 12 observational studies published until November 2014 with a total of 16,151 incident CRC cases. Random effect models were used to obtain summary relative risks (RR) and 95% confidence intervals (95% CIs). Between-study heterogeneity was assessed using I(2) statistics. Overall, the summary RR (95% CI) was 1.22 (1.14-1.30) for high body weight gain (midpoint: 15.2 kg) compared with stable weight (P for heterogeneity = 0.182; I(2) = 21.2%). In a dose-response analysis, each 5 kg weight gain was associated with a 4% (95% CI: 2%-5%) higher risk of CRC. The association persisted after adjustment for body weight at younger age and was present for both men and women, as well as for colon and rectal cancer. Differences by sex were detected for colon cancer (P for interaction = 0.003, with higher risk for men than women), but not for rectal cancer (P for interaction = 0.613). In conclusion, these data underscore the importance of body weight management from early adulthood onwards for the prevention of CRC development.

Effect of education intervention on the quality and long-term outcomes of root canal treatment in general practice

AIM

To compare the technical quality and long-term outcomes of root canal treatment by general practitioners of a Swedish Public Dental Service, before and after an endodontic education including Ni-Ti rotary technique (NiTiR).

METHODOLOGY

A random sample was compiled, comprising one root filled tooth from each of 830 patients, treated by 69 general practitioners participating in the education: 414 teeth root filled in 2002, pre-education, using primarily stainless steel instrumentation and filling by lateral compaction, and 416 teeth root filled post-education (2005), using mainly NiTiR and single-cone obturation. Follow-up radiographs taken in 2009 were evaluated alongside immediate post-filling radiographs from 2002 to 2005. The density and length of the root fillings were registered. Periapical status was assessed by the Periapical Index (PAI), using two definitions of disease: apical periodontitis (AP) (PAI 3 + 4 + 5) and definite AP (PAI 4 + 5). Tooth survival was registered. Root fillings pre- and post-education were compared using chi-square and Fisher's exact tests. Crude extraction rates per 100 years were calculated for comparison of tooth survival. Explanatory variables (type of tooth, root filling quality, periapical status, marginal bone loss, type and quality of coronal restoration) in relation to the dependent variable (AP at follow-up) were analysed by multivariable logistic regression.

RESULTS

Follow-up data were available for 229 (55%) of teeth treated pre- and 288 (69%) treated post-education: both tooth survival (P < 0.001) and root filling quality were significantly higher (P < 0.001) in the latter. However, there was no corresponding improvement in periapical status. Both pre- and post-education, root fillings with definite AP on completion of treatment had significantly higher odds of AP or definite AP at follow-up. For teeth treated post-education, inadequate root filling quality was significantly associated with AP at follow-up.

CONCLUSIONS

Despite a higher tooth survival rate and a significant improvement in technical quality of root fillings after the education, there was no corresponding improvement in periapical status.

Locally controlling mesenchymal stem cell morphogenesis by 3D PDGF-BB gradients towards the establishment of an in vitro perivascular niche

We report on the creation of a three dimensional biomimetic tissue model that recapitulates the stable PDGF-BB gradient controlling mesenchymal stem cell morphogenetic behavior in the perivascular niche.

Mycotoxins as antagonistic or supporting agents in the interaction between phytopathogenic Fusarium and Alternaria fungi

The role of mycotoxins in the microbial competition in an ecosystem or on the same host plant is still unclear. Therefore, a laboratory study was conducted to evaluate the influence of mycotoxins on growth and mycotoxin production of Fusarium and Alternaria fungi. Fusarium culmorum Fc13, Fusarium graminearum Fg23 and two Alternaria tenuissima isolates (At18 and At220) were incubated on wheat kernels supplemented with alternariol (AOH), tetramic acid derivates (TeA), deoxynivalenol (DON) and zearalenone (ZEA) in an in vitro test system. Fungal biomass was quantified by determining ergosterol content. Three Fusarium toxins (DON, nivalenol and ZEA) and three Alternaria toxins (AOH, alternariol methyl ether (AME) and altenuene) were analysed by HPLC-MS/MS. If Alternaria strains grew in wheat kernels spiked with Fusarium mycotoxins, their growth rates were moderately increased, their AOH and AME production was enhanced and they were simultaneously capable of degrading the Fusarium mycotoxins DON and ZEA. In contrast, both Fusarium strains behaved quite differently. The growth rate of Fc13 was not distinctly influenced, while Fg23 increased its growth in wheat kernels spiked with AOH. TeA depressed the ergosterol content in Fc13 as well as in Fg23. The DON production of Fc13 was slightly depressed, whereas the ZEA production was significantly increased. In contrast, Fg23 restricted its ZEA production. Both Fusarium strains were not capable of degrading the Alternaria mycotoxin AOH. Mycotoxins might play an important role in the interfungal competitive processes. They influence growth rates and mycotoxin production of the antagonistic combatants. The observed effects between phytopathogenic Alternaria and Fusarium strains and their mycotoxins aid the understanding of the complexity of microbial competitive behaviour in natural environments.

Enhanced uptake and siRNA-mediated knockdown of a biologically relevant gene using cyclodextrin polyrotaxane

Cellular investigations confirm the ability of cyclodextrin polyrotaxane nanoplexes to deliver siRNA for down-regulating genes relevant to the pathogenesis of tuberculosis.

[Lichtenstein's hernia repair]

AIM

Lichtenstein's hernia repair (LHR) is presented as a technically feasible procedure for inguinal hernia.

INDICATION

LHR is a standard procedure for open mesh techniques with very good postoperative results.

METHOD

We demonstrate an LHR step by step with preservation of the iliohypogastricus and ilioinguinalis nerves.

CONCLUSION

LHR is a technically feasible and safe procedure which should have a firm place in a general surgical education.

Long term course of ulcerative colitis in the prebiologic era. A retrospective study in a tertiary referral center

AIM

Several population-based studies have shown that long term prognosis of ulcerative colitis (UC) may be better than previously reported. The aim of this study was to evaluate the course of UC in a referral center cohort in the pre-biologic era and to identify possible prognostic factors.

METHODS

All patients with established diagnosis of UC have been extracted from our GI Unit IBD Database. Clinical and demographic characteristics of all patients were recorded at the time of diagnosis. The disease course was retrospectively evaluated considering four primary end points: change in disease extension, need of corticosteroids, need of immunomodulators, and need of colectomy. The Kaplan-Meier survival method was used to estimate the cumulative probability of a course free of the outcome of interest.

RESULTS

Eight hundred and seven UC patients diagnosed between 1984 and 2008 have been included: 21.8% had proctitis, 47.6% had distal colitis and 30.6% had extensive colitis. The median follow up after diagnosis was 91 months (range 12-596). The probability of extension of proctitis within 10 years was 39.7%. In the whole cohort, the 10 years probability of receiving corticosteroids and immunomodulators was 46.7% and 12.4%, respectively. The 10-year probability of colectomy was 6.5%. Extensive colitis was associated with a higher probability of receiving corticosteroids, immunomodulators and surgery.

CONCLUSION

Long-term prognosis of UC is favourable for the majority of patients. Extensive colitis is the most relevant negative prognostic factor. Results from our referral center study are similar to that reported in population-based studies. Further studies are required to assess the possible impact of biologics and new treatment strategies on long term outcomes.