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Selected AbstractsMagnetic resonance microscopy at 17.6-Tesla on chicken embryos in vitroJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 1 2001Bianca Hogers PhD Abstract The non-destructive nature and the rapid acquisition of a three-dimensional image makes magnetic resonance microscopy (MRM) very attractive and suitable for functional imaging investigations. We explored the use of an ultra high magnetic field for MRM to increase image quality per image acquisition time. Improved image quality was characterized by a better signal-to-noise ratio (SNR), better image contrast, and higher resolution compared to images obtained at lower magnetic field strengths. Fixed chicken embryos at several stages of development were imaged at 7.0-T (300 MHz) and at 17.6-T (750 MHz). Maximum intensity projection resulted in three-dimensional vascular images with ample detail of the embryonic vasculature. We showed that at 750 MHz frequency, an image with approximately three times better SNR can be obtained by T1 -weighting using a standard gadolinium contrast agent, compared to the same measurement at 300 MHz. The image contrast improved by around 20 percent and the contrast-to-noise ratio improved by almost a factor of 3.5. Smaller blood vessels of the vascular system were identified at the high field, which indicates a better image resolution. Thus, ultra high field is beneficial for MRM and opens new areas for functional imaging research, in particular when SNR, resolution, and contrast are limited by acquisition time. J. Magn. Reson. Imaging 2001;14:83,86. © 2001 Wiley-Liss, Inc. [source] Serum IgG to heat shock proteins and Porphyromonas gingivalis antigens in diabetic patients with periodontitisJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 6 2002Tom J. Sims Abstract Background: Past studies have reported a correlation between the presence and severity of periodontitis and serum antibody titers to species-specific antigens of Porphyromonas gingivalis or to cross-reactive antigens, such as lipopolysaccharide (LPS) and heat shock proteins (HSP), shared between P. gingivalis and other bacteria. Our recent study of periodontal treatment outcome in insulin-dependent (type 1) diabetes mellitus patients with severe periodontitis (IDDMI/periodontitis) resulted in two key findings: 1. serum glutamic acid decarboxylase autoantibody (GAD65 Ab) levels were significantly associated with periodontal pocket depth change (PDC) and 2. serum IgG titers to P. gingivalis cells were positively associated with GAD65 Ab level in seropositive (GAD65 Ab +) patients. We have therefore hypothesized that profiles of serum autoantibody levels and IgG titers, to P. gingivalis -specific antigens may be useful in assessing risk for refractory periodontitis in such patients. Aim: To determine whether PDC resulting from non-surgical periodontal treatment can be predicted using profiles of baseline IgG titers to P. gingivalisspecific antigens, human HSP, and GAD65. Methods: PDC was assessed two months after non-surgical periodontal treatment of 7 GAD65 Ab + and 11 GAD65 AbIDDM/periodontitis patients. Pretreatment titers to GAD65, recombinant human heat shock proteins (HSP90, HSP70, and HSP60), and various P. gingivalis antigens were measured using radioligand precipitation or enzyme-linked immunosorbent (ELISA) assays and compared to the same measurements for 154 recent-onset IDDM patients and 46 non-diabetic controls. Results: Median titers (ELISA units) to HSP90 and HSP70 were significantly higher than non-diabetic controls for GAD65 Ab + (p°= 0.002) and GAD65 Ab- (p =,0.034) IDDM/periodontitis patients, respectively. Multivariate regression analysis indicated significant partial correlation of PDC with log-transformed titers to HSP90 (r =,, 0.62, p = 0.008), HSP70 (r =,+ 0.62, p = 0.009), GAD65 (r =,, 0.60, p = 0.01) and P. gingivalis LPS (r = , 0.5 1, p = 0.04). Furthermore, hierarchical clustering of baseline profiles of log-transformed HSP90, HSP70, and GAD65 Ab titers sorted patients into two distinct clusters with significantly different median PDC (1.45 min, n = 10 vs. 0.65 min, n = 8; p = 0.016, Mann,Whitney). Conclusion: Pretreatment profiles of serum antibody titers to HSP90, HSP70, GAD65, and P. gingivalis LPS may be useful for predicting which patients with IDDM/periodontitis will have a poor response to non-surgical periodontal therapy. [source] Reliability and Validity of the Alcohol Use Disorders Identification Test (AUDIT) Imbedded Within a General Health Risk Screening Questionnaire: Results of a Survey in 332 Primary Care PatientsALCOHOLISM, Issue 5 2000Jean-Bernard Daeppen Background: Self-administered, general health risk screening questionnaires that are administered while patients wait in the doctor's office may be a reasonable and timesaving approach to address the requirements of preventive medicine in a typical 10-min medical visit. The psychometric characteristics of the Alcohol Use Disorders Identification Test (AUDIT) incorporated within a health questionnaire (H-AUDIT) have not been examined. Methods: The reliability and validity of the self-administered AUDIT were compared between the H-AUDIT and the AUDIT used as a single scale (S-AUDIT) in 332 primary care patients. Results: No major demographic or alcohol use characteristics were found between the 166 subjects who completed the H-AUDIT and the 166 individuals who completed the S-AUDIT. The test-retest reliability of the 166 subjects who completed the H-AUDIT [estimated by Spearman correlation coefficient at a 6-week interval (0.88), internal consistency (total correlation coefficients for all items ranged from 0.38 to 0.69; Cronbach , index 0.85), and the sensitivity and specificity of the H-AUDIT were used to identify at-risk drinkers' areas under receiver operating characteristic (0.77) and alcohol-dependent subjects' areas under receiver operating characteristic (0.89)] was similar to the same measurements obtained with the 166 individuals who completed the S-AUDIT. Conclusions: The AUDIT incorporated in a health risk screening questionnaire is a reliable and valid self-administered instrument to identify at-risk drinkers and alcohol-dependent individuals in primary care settings. [source] Comparative study between laser performance and carrier lifetime of 400 nm emitting GaInN/GaN laser diodesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2003C. Netzel Abstract GaInN/GaN laser diodes with different laser performance but nearly identical structural design, all emitting at around 400 nm, were investigated with time-resolved and temperature-dependent photoluminescence under pulsed excitation and with temperature- and power-dependent photoluminescence under cw excitation. To compare the laser diodes with LEDs, the same measurements were performed for an LED structure emitting in the same spectral region. The time-resolved photoluminescence as well as the measurements under continuous excitation point at a more efficient nonradiative recombination for laser structures. This enhancement of nonradiative recombination for the laser diodes was observed to be most pronounced for the best laser diodes. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A reciprocal backcross monosomic analysis of the scab resistant spring wheat (Triticum aestivum L.) cultivar, ,Frontana'PLANT BREEDING, Issue 3 2007W. A. Berzonsky Abstract Fusarium head blight (FHB) reduces grain yield of spring wheat and results in deoxynivalenol (DON) production. The resistant spring wheat ,Frontana' could be used to diversify and pyramid resistance. A backcross reciprocal monosomic analysis was conducted to identify ,Frontana' chromosomes with resistance. Disomic lines, one set containing critical chromosomes from ,Frontana' and the other containing chromosomes from susceptible ,Chris', were spray-inoculated and evaluated in separate greenhouse studies (GH-1 and GH-2). Measurements were disease severity at 7 and 14 days, visually diseased kernels, kernels/g and DON content. In GH-2, reciprocal chromosome lines 5B for visually diseased kernels, lines 7B for kernels/g, and lines 4B and 6A for DON content were significantly different. Lines with ,Frontana' chromosomes 3A, 6A and 4D reduced visually diseased kernels, kernels/g and DON content in both studies, while ,Frontana' chromosomes 2A, 2B, 4B and 7B increased susceptibility, as indicated by an increase in these same measurements in both studies. Genes carried on ,Frontana' chromosomes 3A, 6A and 4D could be useful for diversifying and pyramiding sources of FHB resistance. [source] Risk of silicosis in cohorts of Chinese tin and tungsten miners and pottery workers (II): Workplace-specific silica particle surface composition,,AMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 1 2005J. Harrison Abstract Background It is hypothesized that surface occlusion by alumino-silicate affects the toxic activity of silica particles in respirable dust. In conjunction with an epidemiological investigation of silicosis disease risk in Chinese tin and tungsten mine and pottery workplaces, we analyzed respirable silica dusts using a multiple-voltage scanning electron microscopy,energy dispersive X-ray spectroscopy (MVSEM-EDS). Methods Forty-seven samples of respirable sized dust were collected on filters from 13 worksites and were analyzed by MVSEM-EDS using high (20 keV) and low (5 keV) electron beam accelerating voltages. Changes in the silicon-to-aluminum X-ray line intensity ratio between the two voltages are compared particle-by-particle with the 90th percentile value of the same measurements for a ground glass homogeneous control sample. This provides an index that distinguishes a silica particle that is homogeneously aluminum-contaminated from a clay-coated silica particle. Results The average sample percentages of respirable-sized silica particles alumino-silicate occlusion were: 45% for potteries, 18% for tin mines, and 13% for tungsten mines. The difference between the pottery and the metal mine worksites accounted for one third of an overall chi-square statistic for differences in change in measured silicon fraction between the samples. Conclusion The companion epidemiological study found lower silicosis risk per unit cumulative respirable silica dust exposure for pottery workers compared to metal miners. Using these surface analysis results resolves differences in risk when exposure is normalized to cumulative respirable surface-available silica dust. Am. J. Ind. Med. 48:10,15, 2005. Published 2005 Wiley-Liss, Inc. [source] | ||||||||||