Biomedical subjects

Daniel M Stein

Publications and source records attributed to Daniel M Stein.

5 recordsLinked to original sources

PubMed2006

Effect of corneal drying on optical coherence tomography.

PURPOSE: To determine the effect of corneal drying on the outcome of optical coherence tomography (OCT). DESIGN: Cohort study. PARTICIPANTS: Seventeen normal participants (mean age, 39+/-12 years). METHODS: Subjects underwent a series of peripapillary circular StratusOCT scans (version 3.0; Carl Zeiss Meditec, Inc., Dublin, CA) in a randomly selected eye. Baseline scan sets were acquired, and thereafter, blinking was prevented by taping the eyelid. Eyelid taping was immediately followed by 6 to 8 serial scan sets, each separated by 20 seconds. After removing the eyelid tape, 3 additional scans were acquired at 1, 2, and 4 minutes of blinking freely. MAIN OUTCOME MEASURES: The analyzed outcome measures were scan quality as defined by signal-to-noise ratio (SNR) and signal strength (SS) provided by the built-in OCT software and mean nerve fiber layer (NFL) thickness. RESULTS: Significant reductions in SNR, SS, and NFL were noted at each scanning point in the drying phase (for each, P<0.015, paired t test) except for NFL thickness measurements acquired at 140 and 160 seconds. The reduction in NFL thickness exceeded the 95% confidence limit of the reported reproducibility error of StratusOCT after 15 seconds of corneal drying. After 1 and 2 minutes of blinking freely, there was still a significant reduction in NFL thickness compared with the baseline value, which was no longer evident at the 4-minute scan. CONCLUSIONS: Corneal dryness affects OCT scan quality and measured NFL thickness after a short exposure time. It is recommended to instruct those who are scanned to blink frequently or to instill artificial tears.

Adult↗

PubMed2005

Are antibodies to the capsular polysaccharide of Neisseria meningitidis group B and Escherichia coli K1 associated with immunopathology?

As polysialic acid (PSA), the capsule of Group B meningococcus (GBM) and Escherichia coli K1, is a component of mammalian glycopeptides, there is concern that vaccines against PSA could induce immunopathology. Purified PSA is not immunogenic; however, as a component of bacteria or bound to proteins, it induces protective antibodies. In this review, we did not unearth data indicating an association of IgG anti-PSA with immunopathology in experimental animals or humans. We found no increased incidence of autoimmunity from GBM infections in our review of the natural history/sequellae of Neisseria meningitis infections. Accordingly, we propose that clinical trials of PSA conjugate vaccines, be considered.

Animals↗

PubMed2005

Macular segmentation with optical coherence tomography.

PURPOSE: To develop a software algorithm to perform automated segmentation of retinal layer structures on linear macular optical coherence tomography (StratusOCT; Carl Zeiss Meditec, Inc., Dublin, CA) scan images and to test its performance in discriminating normal from glaucomatous eyes in comparison with conventional circumpapillary nerve fiber layer (cpNFL) thickness measurement. METHODS: Four layer structures within the retina were defined: the macular nerve fiber layer (mNFL), the inner retinal complex (IRC; retinal ganglion cell [RGC] layer + inner plexiform and nuclear layers), outer plexiform layer (OPL), and outer retinal complex (ORC; outer nuclear layer + photoreceptor layer). Normal and glaucomatous eyes underwent fast macular map and fast NFL OCT scans. Linear macular images were analyzed using the developed algorithm, and the results were compared with the cpNFL thickness measurement. RESULTS: Forty-seven subjects (23 normal and 24 with glaucoma) were analyzed. mNFL, cpNFL, IRC, and the total retinal thicknesses were significantly greater in normal than in glaucomatous eyes (P < or = 0.0002; Wilcoxon), whereas OPL thickness did not show a significant difference (P = 0.46). ORC thickness was significantly greater in glaucomatous than normal eyes (P = 0.035). Areas under the receiver operator characteristic curve (AROCs) for discriminating normal from glaucomatous eyes were highest with mNFL + IRC (0.97) and lowest with OPL (0.56). AROCs for OPL and ORC were significantly smaller than those for mNFL, IRC, mNFL+IRC, and cpNFL (P < or = 0.01). AROCs for IRC, mNFL + IRC, and cpNFL were significantly larger than for retinal thickness (P < or = 0.049). Among the best-performing parameters (mNFL, IRC, mNFL + IRC, and cpNFL) there was no significant difference in AROCs (P > or = 0.15). CONCLUSIONS: The newly developed macular segmentation algorithm described herein demonstrated its ability to quantify objectively the glaucomatous damage to RGCs and NFL and to discriminate between glaucomatous and normal eyes. Further algorithm refinement and improvements in resolution and image quality may yield a more powerful methodology for clinical glaucoma evaluation.

Algorithms↗

PubMed2004

Imaging in glaucoma.

Structural assessment using the imaging technologies discussed herein provides reproducible quantitative measurements of posterior segment ocular structures. These measurements have been found to provide useful data for glaucoma detection in various regions of the posterior segment. Further studies are needed to evaluate the utility of these technologies for pre-perimetric glaucoma detection and for monitoring glaucoma progression over an extended period.

Diagnostic Imaging↗

PubMed2004

Early infant multivitamin supplementation is associated with increased risk for food allergy and asthma.

OBJECTIVE: Dietary vitamins have potent immunomodulating effects in vitro. Individual vitamins have been shown to skew T cells toward either T-helper 1 or T-helper 2 phenotypic classes, suggesting that they may participate in inflammatory or allergic disease. With the exception of antioxidant protection, there has been little study on the effect of early vitamin supplementation on the subsequent risk for asthma and allergic disease. The objective of this study was to determine whether early vitamin supplementation during infancy affects the risk for asthma and allergic disease during early childhood. METHODS: Cohort data were analyzed from the National Center for Health Statistics 1988 National Maternal-Infant Health Survey, which followed pregnant women and their newborns, and the 1991 Longitudinal Follow-up of the same patients, which measured health and disease outcomes. Patients were stratified by race and breastfeeding status. Factors that are known to be associated with alteration of risk for asthma or food allergies were identified using univariate logistic regression. Those factors were then analyzed in multivariate logistic regression models. Early vitamin supplementation was defined as vitamin use within the first 6 months. RESULTS: There were >8000 total patients in the study. The overall incidence of asthma was 10.5% and of food allergy was 4.9%. In univariate analysis, male gender, smoker in the household, child care, prematurity (<37 weeks), being black, no history of breastfeeding, lower income, and lower education were associated with higher risk for asthma. Child care, higher levels of education, income, and history of breastfeeding were associated with a higher risk for food allergies. In multivariate logistic analyses, a history of vitamin use within the first 6 months of life was associated with a higher risk for asthma in black infants (odds ratio [OR]: 1.27; 95% confidence interval [CI]: 1.04-1.56). Early vitamin use was also associated with a higher risk for food allergies in the exclusively formula-fed population (OR: 1.63; 95% CI: 1.21-2.20). Vitamin use at 3 years of age was associated with increased risk for food allergies but not asthma in both breastfed (OR: 1.62; 95% CI: 1.19-2.21) and exclusively formula-fed infants (OR: 1.39; 95% CI: 1.03-1.88). CONCLUSIONS: Early vitamin supplementation is associated with increased risk for asthma in black children and food allergies in exclusively formula-fed children. Additional study is warranted to examine which components most strongly contribute to this risk.

Analysis of Variance↗