Gordana Derado - Academia.edu (original) (raw)
Papers by Gordana Derado
Statistical Methods in Medical Research, 2013
Increasing the clinical applicability of functional neuroimaging technology is an emerging object... more Increasing the clinical applicability of functional neuroimaging technology is an emerging objective, e.g. for diagnostic and treatment purposes. We propose a novel Bayesian spatial hierarchical framework for predicting follow-up neural activity based on an individual's baseline functional neuroimaging data. Our approach attempts to overcome some shortcomings of the modeling methods used in other neuroimaging settings, by borrowing strength from the spatial correlations present in the data. Our proposed methodology is applicable to data from various imaging modalities including functional magnetic resonance imaging and positron emission tomography, and we provide an illustration here using positron emission tomography data from a study of Alzheimer's disease to predict disease progression.
Open Forum Infectious Diseases, 2016
We examined trends in histoplasmosis-associated hospitalizations in the United States using the 2... more We examined trends in histoplasmosis-associated hospitalizations in the United States using the 2001-2012 National (Nationwide) Inpatient Sample. An estimated 50 778 hospitalizations occurred, with significant increases in hospitalizations overall and in the proportion of hospitalizations associated with transplant, diabetes, and autoimmune conditions often treated with biologic therapies; therefore, histoplasmosis remains an important opportunistic infection.
Open Forum Infectious Diseases, 2015
Background. Echinocandins are first-line treatment for Candida glabrata candidemia. Echinocandin... more Background. Echinocandins are first-line treatment for Candida glabrata candidemia. Echinocandin resistance is concerning due to limited remaining treatment options. We used data from a multisite, population-based surveillance program to describe the epidemiology and risk factors for echinocandin nonsusceptible (NS) C glabrata candidemia. Methods. The Centers for Disease Control and Prevention's Emerging Infections Program conducts population-based laboratory surveillance for candidemia in 4 metropolitan areas (7.9 million persons; 80 hospitals). We identified C glabrata cases occurring during 2008-2014; medical records of cases were reviewed, and C glabrata isolates underwent broth microdilution antifungal susceptibility testing. We defined echinocandin-NS C glabrata (intermediate or resistant) based on 2012 Clinical and Laboratory Standards Institute minimum inhibitory concentration breakpoints. Independent risk factors for NS C glabrata were determined by stepwise logistic regression. Results. Of 1385 C glabrata cases, 83 (6.0%) had NS isolates (19 intermediate and 64 resistant); the proportion of NS isolates rose from 4.2% in 2008 to 7.8% in 2014 (P < .001). The proportion of NS isolates at each hospital ranged from 0% to 25.8%; 3 large, academic hospitals accounted for almost half of all NS isolates. In multivariate analysis, prior echinocandin exposure (adjusted odds ratio [aOR], 5.3; 95% CI, 2.6-1.2), previous candidemia episode (aOR, 2.5; 95% CI, 1.2-5.1), hospitalization in the last 90 days (aOR, 1.9; 95% CI, 1.0-3.5, and fluconazole resistance [aOR, 3.6; 95% CI, 2.0-6.4]) were significantly associated with NS C glabrata. Fifty-nine percent of NS C glabrata cases had no known prior echinocandin exposure. Conclusion. The proportion of NS C glabrata isolates rose significantly during 2008-2014, and NS C glabrata frequency differed across hospitals. In addition to acquired resistance resulting from prior drug exposure, occurrence of NS C glabrata without prior echinocandin exposure suggests possible transmission of resistant organisms.
Emerging infectious diseases, 2015
Background: During 2012-2013, CDC and health departments responded to a large outbreak of fungal ... more Background: During 2012-2013, CDC and health departments responded to a large outbreak of fungal meningitis among persons injected with contaminated methylprednisolone acetate (MPA). Several public health actions were taken to limit the effects of contaminated MPA: prompt recall of MPA, notification of exposed persons, and clinician outreach to promote early diagnosis and treatment. We estimated the impact of these actions. Methods: Clinical data were collected with a standardized form. Analysis was restricted to outbreak-associated patients with meningitis or stroke due to presumed meningitis. Exposures averted through MPA recall were estimated by dividing recalled MPA volume (from pharmacy records) by estimated 1ml per-injection volume (dose used in 80% of exposures). Meningitis cases averted through recall were estimated by multiplying MPA attack rates (AR) by recalled MPA volume; sensitivity analysis was done using high and low AR estimates. Differences in survival pre- and post...
Emerging infectious diseases, 2015
During 2012-2013, the US Centers for Disease Control and Prevention and partners responded to a m... more During 2012-2013, the US Centers for Disease Control and Prevention and partners responded to a multistate outbreak of fungal infections linked to methylprednisolone acetate (MPA) injections produced by a compounding pharmacy. We evaluated the effects of public health actions on the scope of this outbreak. A comparison of 60-day case-fatality rates and clinical characteristics of patients given a diagnosis on or before October 4, the date the outbreak was widely publicized, with those of patients given a diagnosis after October 4 showed that an estimated 3,150 MPA injections, 153 cases of meningitis or stroke, and 124 deaths were averted. Compared with diagnosis after October 4, diagnosis on or before October 4 was significantly associated with a higher 60-day case-fatality rate (28% vs. 5%; p<0.0001). Aggressive public health action resulted in a substantially reduced estimated number of persons affected by this outbreak and improved survival of affected patients.
The 2004 47th Midwest Symposium on Circuits and Systems, 2004. MWSCAS '04., 2004
The 47th IEEE International Midwest Symposium on Circuits and Systems ... The effectiveness of mu... more The 47th IEEE International Midwest Symposium on Circuits and Systems ... The effectiveness of multi resolution image segmentation for measuring spatial heterogeneity in mixed population biofilms Saeid Belkasim', Gordana Derado, Eric Gilbert and Heather O'Connell Georgia ...
2003 46th Midwest Symposium on Circuits and Systems, 2003
ABSTRACT A new pre-processing approach for the removal of the blocking effect, associated with th... more ABSTRACT A new pre-processing approach for the removal of the blocking effect, associated with the standard 2D-DCT, is introduced in this paper. In this method, the processing of the image is started from the top corners by zigzagging rows and columns of an image into horizontal, vertical or diagonal streams of pixels. These pixel streams are transformed into one-dimensional line arrays. The one-dimensional DCT transform is applied to each array. The experimental results reveal the effectiveness of this method in reducing the blocking effect associated with the standard DCT. The zigzag line method produces very good subjective as well as PSNR results
Computerized Medical Imaging and Graphics, 2008
Multi-resolution image clustering and segmentation interactive system has been developed to analy... more Multi-resolution image clustering and segmentation interactive system has been developed to analyze the interaction between clusters of heterogeneous microbial populations residing in biofilms. Biofilms are biological microorganisms attached to surfaces, which develop a complex heterogeneous three-dimensional structure. The hierarchical structural analysis concept underlying multi-resolution image segmentation is that the clusters will be more complex and noisy for higher-resolution while less complex and smoother for lower-resolution image. This hierarchical structure analysis can be used to simplify the image storage and retrieval in well-mixed populations. We are proposing an algorithm that combines Fuzzy C-Means, SOM and LVQ neural networks to segment and identify clusters. The outcome of the image segmentation is quantified by the number of cluster objects of each kind of microorganism within sections of the biofilm, and the centroid distances between the identified cluster objects. Experimental evaluations of the algorithm showed its effectiveness in enumerating cluster objects of bacteria in dual-species biofilms at the substratum and measuring the associated intercellular distances.
Clinical Infectious Diseases, 2012
Candidemia is common and associated with high morbidity and mortality; changes in population-base... more Candidemia is common and associated with high morbidity and mortality; changes in population-based incidence rates have not been reported. We conducted active, population-based surveillance in metropolitan Atlanta, Georgia, and Baltimore City/County, Maryland (combined population 5.2 million), during 2008-2011. We calculated candidemia incidence and antifungal drug resistance compared with prior surveillance (Atlanta, 1992-1993; Baltimore, 1998-2000). We identified 2675 cases of candidemia with 2329 isolates during 3 years of surveillance. Mean annual crude incidence per 100 000 person-years was 13.3 in Atlanta and 26.2 in Baltimore. Rates were highest among adults aged ≥65 years (Atlanta, 59.1; Baltimore, 72.4) and infants (aged &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;1 year; Atlanta, 34.3; Baltimore, 46.2). In both locations compared with prior surveillance, adjusted incidence significantly declined for infants of both black and white race (Atlanta: black risk ratio [RR], 0.26 [95% confidence interval {CI}, .17-.38]; white RR: 0.19 [95% CI, .12-.29]; Baltimore: black RR, 0.38 [95% CI, .22-.64]; white RR: 0.51 [95% CI: .29-.90]). Prevalence of fluconazole resistance (7%) was unchanged compared with prior surveillance; 32 (1%) isolates were echinocandin-resistant, and 9 (8 Candida glabrata) were multidrug resistant to both fluconazole and an echinocandin. We describe marked shifts in candidemia epidemiology over the past 2 decades. Adults aged ≥65 years replaced infants as the highest incidence group; adjusted incidence has declined significantly in infants. Use of antifungal prophylaxis, improvements in infection control, or changes in catheter insertion practices may be contributing to these declines. Further surveillance for antifungal resistance and efforts to determine effective prevention strategies are needed.
American Journal of Tropical Medicine and Hygiene, 2014
Haitian children were monitored longitudinally in a filariasis study. Included were stool samples... more Haitian children were monitored longitudinally in a filariasis study. Included were stool samples examined for Giardia intestinalis and Entamoeba histolytica cysts, and serum specimens analyzed for immunoglobulin G (IgG) responses to eight recombinant antigens from G. intestinalis (variant-specific surface protein [VSP1-VSP5]), E. histolytica (lectin adhesion molecule [LecA]), and Cryptosporidium parvum (17- and 27-kDa) using a multiplex bead assay. The IgG responses to VSP antigens peaked at 2 years of age and then diminished and were significantly lower (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.002) in children &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 4.5 years than in children &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 4.5 years. The IgG responses to Cryptosporidium tended to increase with age. The IgG responses to LecA and VSP antigens and the prevalence of stools positive for cysts were significantly higher (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.037 and P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.035, respectively) in the rainy season than in the dry season. The multiplex bead assay provides a powerful tool for analyzing serologic responses to multiple pathogens.
The American journal of tropical medicine and hygiene, Jan 29, 2016
In the developing world, fetching water for drinking and other household uses is a substantial bu... more In the developing world, fetching water for drinking and other household uses is a substantial burden that affects water quantity and quality in the household. We used logistic regression to examine whether reported household water fetching times were a risk factor for moderate-to-severe diarrhea (MSD) using case-control data of 3,359 households from the Global Enterics Multi-Center Study in Kenya in 2009-2011. We collected additional global positioning system (GPS) data for a subset of 254 randomly selected households and compared GPS-based straight line and actual travel path distances to fetching times reported by respondents. GPS-based data were highly correlated with respondent-provided times (Spearman correlation coefficient = 0.81, P < 0.0001). The median estimated one-way distance to water source was 200 m for cases and 171 for controls (Wilcoxon rank sums/Mann-Whitney P = 0.21). A round-trip fetching time of > 30 minutes was reported by 25% of cases versus 15% of cont...
Water, 2015
In this study, hollow-fiber ultrafiltration (UF) was assessed for recovery of Escherichia coli, C... more In this study, hollow-fiber ultrafiltration (UF) was assessed for recovery of Escherichia coli, Clostridium perfringens spores, Cryptosporidium parvum oocysts, echovirus 1, and bacteriophages MS2 and ΦX174 from ground and surface waters. Microbes were seeded into twenty-two 50-L water samples that were collected from the Southeastern United States and concentrated to ∼500 mL by UF. Secondary concentration was performed for C. parvum by centrifugation followed by immunomagnetic separation. Secondary concentration for viruses was performed using centrifugal ultrafilters or polyethylene glycol precipitation. Nine water quality parameters were measured in each water sample to determine whether water quality data correlated with UF and secondary concentration recovery efficiencies. Average UF recovery efficiencies were 66%-95% for the six enteric microbes. Average recovery efficiencies for the secondary concentration methods were 35%-95% for C. parvum and the viruses. Overall, measured water quality parameters were not significantly associated with UF recovery efficiencies. However, recovery of ΦX174 was negatively correlated with turbidity. The recovery data demonstrate that UF can be an effective method for concentrating diverse microbes from ground and surface waters. This study highlights the utility of tangential-flow hollow fiber ultrafiltration for recovery of bacteria, viruses, and parasites from large volume environmental water samples.
IEEE Workshop on Statistical Signal Processing, 2003, 2003
ABSTRACT In this paper we describe a technique of fusing larger scenes from multiple views, using... more ABSTRACT In this paper we describe a technique of fusing larger scenes from multiple views, using a landmark approach. For images of remote scenes, the fused image is reconstructed using sample mean shapes on affine shape manifolds. This manifold of configurations of points in general position is a real Grassmann manifold which can be equivariantly embedded in a space of matrices, and we consider the extrinsic means w.r.t. this embedding. On the other hand, for photographs taken from a close distance by a noncalibrated camera, the fused image is reconstructed using sample mean shapes on projective shape manifolds. This manifold of configurations of points under a given projective frame is a product of real projective planes and we consider extrinsic means w.r.t. to a standard embedding in a space of blocks of symmetric matrices. We illustrate these methods on two sets of images.
Statistics and Its Interface, 2010
Data-driven statistical approaches, such as cluster analysis or independent component analysis, a... more Data-driven statistical approaches, such as cluster analysis or independent component analysis, applied to in vivo functional neuroimaging data help to identify neural processing networks that exhibit similar task-related or restingstate patterns of activity. Ideally, the measured brain activity for voxels within such networks should exhibit high autocorrelation. An important limitation is that the algorithms do not typically quantify or statistically test the strength or nature of the within-network relatedness between voxels. To extend the results given by such data-driven analyses, we propose the use of Moran's I statistic to measure the degree of functional autocorrelation within identified neural processing networks and to evaluate the statistical significance of the observed associations. We adapt the conventional definition of Moran's I, for applicability to neuroimaging analyses, by defining the global autocorrelation index using network-based neighborhoods. Also, we compute network-specific contributions to the overall autocorrelation. We present results from a bootstrap analysis that provide empirical support for the use of our hypothesis testing framework. We illustrate our methodology using positron emission tomography (PET) data from a study that examines the neural representation of working memory among individuals with schizophrenia and functional magnetic resonance imaging (fMRI) data from a study of depression.
The New England journal of medicine, Jan 6, 2012
Mucormycosis is a fungal infection caused by environmentally acquired molds. We investigated a cl... more Mucormycosis is a fungal infection caused by environmentally acquired molds. We investigated a cluster of cases of cutaneous mucormycosis among persons injured during the May 22, 2011, tornado in Joplin, Missouri. We defined a case as a soft-tissue infection in a person injured during the tornado, with evidence of a mucormycete on culture or immunohistochemical testing plus DNA sequencing. We conducted a case-control study by reviewing medical records and conducting interviews with case patients and hospitalized controls. DNA sequencing and whole-genome sequencing were performed on clinical specimens to identify species and assess strain-level differences, respectively. A total of 13 case patients were identified, 5 of whom (38%) died. The patients had a median of 5 wounds (range, 1 to 7); 11 patients (85%) had at least one fracture, 9 (69%) had blunt trauma, and 5 (38%) had penetrating trauma. All case patients had been located in the zone that sustained the most severe damage duri...
Lecture Notes in Computer Science, 2008
Breast cancer is the second leading cause of death in women in the United States. Breast Magnetic... more Breast cancer is the second leading cause of death in women in the United States. Breast Magnetic Resonance Imaging (BMRI) is an emerging tool in breast cancer diagnostics and research, and it is becoming routine in clinical practice. Recently, the American Cancer Society (ACS) recommended that women at very high risk of developing breast cancer have annual BMRI exams, in addition to annual mammograms, to increase the likelihood of early detection. (Saslow et al. [20]). Many medical images demonstrate a certain degree of self-similarity over a range of scales. The multifractal spectrum (MFS) summarizes possibly variable degrees of scaling in one dimensional signals and has been widely used in fractal analysis. In this work, we develop a generalization of MFS to three dimensions and use dynamics of the scaling as discriminatory descriptors for the classification of BMRI images to benign and malignant. Methodology we propose was tested using breast MRI images for four anonymous subjects (two cancer, and two cancer-free cases). The dataset consists of BMRI scans obtained on a 1.5T GE Signa MR (with VIBRANT) scanner at Emory University. We demonstrate that meaningful descriptors show potential for classifying inference.
Lecture Notes in Computer Science, 2007
Cancer detection using mammography focuses on characteristics of tiny microcalcifications, includ... more Cancer detection using mammography focuses on characteristics of tiny microcalcifications, including the number, size, and spatial arrangement of microcalcification clusters as well as morphological features of individual microcalcifications. We developed state-of-theart wavelet-based methods to enhance the resolution of microcalcifications visible in digital mammograms, thereby improving the specificity of breast cancer diagnoses. In our research, we develop, refine, and evaluate a Wavelet Image Interpolation (WII) procedure and create accompanying software to implement it. WII involves the application of an inverse wavelet transformation to a coarse or degraded image and constructed detail coefficients to produce an enhanced higher resolution image. The construction of detail coefficients is supervised by the observed image and innate regular scaling assessed by a statistical model. Methodology we propose was tested by an experienced radiologist in a blind study using 40 images from the University of South Florida Digital Database for Screening Mammography (DDSM) (Heat et. al. [10]).
Parasitology Research, 2014
Balamuthia mandrillaris, a free-living ameba, has a case fatality rate exceeding 90 % among recog... more Balamuthia mandrillaris, a free-living ameba, has a case fatality rate exceeding 90 % among recognized cases in the USA. In August 2010, a GAE cluster occurred following transplantation of infected organs from a previously healthy landscaper in Tucson, AZ, USA, who died from a suspected stroke. As B. mandrillaris is thought to be transmitted through soil, a serologic survey of landscapers and a comparison group of blood donors in southern Arizona was performed. Three (3.6 %) of 83 serum samples from landscapers and 11 (2.5 %) of 441 serum samples from blood donors were seropositive (p=0.47). On multivariable analysis, county of residence was associated with seropositivity, whereas age, sex, and ethnicity were not. Exposure to B. mandrillaris, previously unexamined in North America, appears to be far more common than GAE in Southern Arizona. Risk factors for disease progression and the ameba's geographic range should be examined.
Statistical Methods in Medical Research, 2013
Increasing the clinical applicability of functional neuroimaging technology is an emerging object... more Increasing the clinical applicability of functional neuroimaging technology is an emerging objective, e.g. for diagnostic and treatment purposes. We propose a novel Bayesian spatial hierarchical framework for predicting follow-up neural activity based on an individual&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s baseline functional neuroimaging data. Our approach attempts to overcome some shortcomings of the modeling methods used in other neuroimaging settings, by borrowing strength from the spatial correlations present in the data. Our proposed methodology is applicable to data from various imaging modalities including functional magnetic resonance imaging and positron emission tomography, and we provide an illustration here using positron emission tomography data from a study of Alzheimer&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s disease to predict disease progression.
Open Forum Infectious Diseases, 2016
We examined trends in histoplasmosis-associated hospitalizations in the United States using the 2... more We examined trends in histoplasmosis-associated hospitalizations in the United States using the 2001-2012 National (Nationwide) Inpatient Sample. An estimated 50 778 hospitalizations occurred, with significant increases in hospitalizations overall and in the proportion of hospitalizations associated with transplant, diabetes, and autoimmune conditions often treated with biologic therapies; therefore, histoplasmosis remains an important opportunistic infection.
Open Forum Infectious Diseases, 2015
Background. Echinocandins are first-line treatment for Candida glabrata candidemia. Echinocandin... more Background. Echinocandins are first-line treatment for Candida glabrata candidemia. Echinocandin resistance is concerning due to limited remaining treatment options. We used data from a multisite, population-based surveillance program to describe the epidemiology and risk factors for echinocandin nonsusceptible (NS) C glabrata candidemia. Methods. The Centers for Disease Control and Prevention&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s Emerging Infections Program conducts population-based laboratory surveillance for candidemia in 4 metropolitan areas (7.9 million persons; 80 hospitals). We identified C glabrata cases occurring during 2008-2014; medical records of cases were reviewed, and C glabrata isolates underwent broth microdilution antifungal susceptibility testing. We defined echinocandin-NS C glabrata (intermediate or resistant) based on 2012 Clinical and Laboratory Standards Institute minimum inhibitory concentration breakpoints. Independent risk factors for NS C glabrata were determined by stepwise logistic regression. Results. Of 1385 C glabrata cases, 83 (6.0%) had NS isolates (19 intermediate and 64 resistant); the proportion of NS isolates rose from 4.2% in 2008 to 7.8% in 2014 (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001). The proportion of NS isolates at each hospital ranged from 0% to 25.8%; 3 large, academic hospitals accounted for almost half of all NS isolates. In multivariate analysis, prior echinocandin exposure (adjusted odds ratio [aOR], 5.3; 95% CI, 2.6-1.2), previous candidemia episode (aOR, 2.5; 95% CI, 1.2-5.1), hospitalization in the last 90 days (aOR, 1.9; 95% CI, 1.0-3.5, and fluconazole resistance [aOR, 3.6; 95% CI, 2.0-6.4]) were significantly associated with NS C glabrata. Fifty-nine percent of NS C glabrata cases had no known prior echinocandin exposure. Conclusion. The proportion of NS C glabrata isolates rose significantly during 2008-2014, and NS C glabrata frequency differed across hospitals. In addition to acquired resistance resulting from prior drug exposure, occurrence of NS C glabrata without prior echinocandin exposure suggests possible transmission of resistant organisms.
Emerging infectious diseases, 2015
Background: During 2012-2013, CDC and health departments responded to a large outbreak of fungal ... more Background: During 2012-2013, CDC and health departments responded to a large outbreak of fungal meningitis among persons injected with contaminated methylprednisolone acetate (MPA). Several public health actions were taken to limit the effects of contaminated MPA: prompt recall of MPA, notification of exposed persons, and clinician outreach to promote early diagnosis and treatment. We estimated the impact of these actions. Methods: Clinical data were collected with a standardized form. Analysis was restricted to outbreak-associated patients with meningitis or stroke due to presumed meningitis. Exposures averted through MPA recall were estimated by dividing recalled MPA volume (from pharmacy records) by estimated 1ml per-injection volume (dose used in 80% of exposures). Meningitis cases averted through recall were estimated by multiplying MPA attack rates (AR) by recalled MPA volume; sensitivity analysis was done using high and low AR estimates. Differences in survival pre- and post...
Emerging infectious diseases, 2015
During 2012-2013, the US Centers for Disease Control and Prevention and partners responded to a m... more During 2012-2013, the US Centers for Disease Control and Prevention and partners responded to a multistate outbreak of fungal infections linked to methylprednisolone acetate (MPA) injections produced by a compounding pharmacy. We evaluated the effects of public health actions on the scope of this outbreak. A comparison of 60-day case-fatality rates and clinical characteristics of patients given a diagnosis on or before October 4, the date the outbreak was widely publicized, with those of patients given a diagnosis after October 4 showed that an estimated 3,150 MPA injections, 153 cases of meningitis or stroke, and 124 deaths were averted. Compared with diagnosis after October 4, diagnosis on or before October 4 was significantly associated with a higher 60-day case-fatality rate (28% vs. 5%; p<0.0001). Aggressive public health action resulted in a substantially reduced estimated number of persons affected by this outbreak and improved survival of affected patients.
The 2004 47th Midwest Symposium on Circuits and Systems, 2004. MWSCAS '04., 2004
The 47th IEEE International Midwest Symposium on Circuits and Systems ... The effectiveness of mu... more The 47th IEEE International Midwest Symposium on Circuits and Systems ... The effectiveness of multi resolution image segmentation for measuring spatial heterogeneity in mixed population biofilms Saeid Belkasim', Gordana Derado, Eric Gilbert and Heather O'Connell Georgia ...
2003 46th Midwest Symposium on Circuits and Systems, 2003
ABSTRACT A new pre-processing approach for the removal of the blocking effect, associated with th... more ABSTRACT A new pre-processing approach for the removal of the blocking effect, associated with the standard 2D-DCT, is introduced in this paper. In this method, the processing of the image is started from the top corners by zigzagging rows and columns of an image into horizontal, vertical or diagonal streams of pixels. These pixel streams are transformed into one-dimensional line arrays. The one-dimensional DCT transform is applied to each array. The experimental results reveal the effectiveness of this method in reducing the blocking effect associated with the standard DCT. The zigzag line method produces very good subjective as well as PSNR results
Computerized Medical Imaging and Graphics, 2008
Multi-resolution image clustering and segmentation interactive system has been developed to analy... more Multi-resolution image clustering and segmentation interactive system has been developed to analyze the interaction between clusters of heterogeneous microbial populations residing in biofilms. Biofilms are biological microorganisms attached to surfaces, which develop a complex heterogeneous three-dimensional structure. The hierarchical structural analysis concept underlying multi-resolution image segmentation is that the clusters will be more complex and noisy for higher-resolution while less complex and smoother for lower-resolution image. This hierarchical structure analysis can be used to simplify the image storage and retrieval in well-mixed populations. We are proposing an algorithm that combines Fuzzy C-Means, SOM and LVQ neural networks to segment and identify clusters. The outcome of the image segmentation is quantified by the number of cluster objects of each kind of microorganism within sections of the biofilm, and the centroid distances between the identified cluster objects. Experimental evaluations of the algorithm showed its effectiveness in enumerating cluster objects of bacteria in dual-species biofilms at the substratum and measuring the associated intercellular distances.
Clinical Infectious Diseases, 2012
Candidemia is common and associated with high morbidity and mortality; changes in population-base... more Candidemia is common and associated with high morbidity and mortality; changes in population-based incidence rates have not been reported. We conducted active, population-based surveillance in metropolitan Atlanta, Georgia, and Baltimore City/County, Maryland (combined population 5.2 million), during 2008-2011. We calculated candidemia incidence and antifungal drug resistance compared with prior surveillance (Atlanta, 1992-1993; Baltimore, 1998-2000). We identified 2675 cases of candidemia with 2329 isolates during 3 years of surveillance. Mean annual crude incidence per 100 000 person-years was 13.3 in Atlanta and 26.2 in Baltimore. Rates were highest among adults aged ≥65 years (Atlanta, 59.1; Baltimore, 72.4) and infants (aged &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;1 year; Atlanta, 34.3; Baltimore, 46.2). In both locations compared with prior surveillance, adjusted incidence significantly declined for infants of both black and white race (Atlanta: black risk ratio [RR], 0.26 [95% confidence interval {CI}, .17-.38]; white RR: 0.19 [95% CI, .12-.29]; Baltimore: black RR, 0.38 [95% CI, .22-.64]; white RR: 0.51 [95% CI: .29-.90]). Prevalence of fluconazole resistance (7%) was unchanged compared with prior surveillance; 32 (1%) isolates were echinocandin-resistant, and 9 (8 Candida glabrata) were multidrug resistant to both fluconazole and an echinocandin. We describe marked shifts in candidemia epidemiology over the past 2 decades. Adults aged ≥65 years replaced infants as the highest incidence group; adjusted incidence has declined significantly in infants. Use of antifungal prophylaxis, improvements in infection control, or changes in catheter insertion practices may be contributing to these declines. Further surveillance for antifungal resistance and efforts to determine effective prevention strategies are needed.
American Journal of Tropical Medicine and Hygiene, 2014
Haitian children were monitored longitudinally in a filariasis study. Included were stool samples... more Haitian children were monitored longitudinally in a filariasis study. Included were stool samples examined for Giardia intestinalis and Entamoeba histolytica cysts, and serum specimens analyzed for immunoglobulin G (IgG) responses to eight recombinant antigens from G. intestinalis (variant-specific surface protein [VSP1-VSP5]), E. histolytica (lectin adhesion molecule [LecA]), and Cryptosporidium parvum (17- and 27-kDa) using a multiplex bead assay. The IgG responses to VSP antigens peaked at 2 years of age and then diminished and were significantly lower (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.002) in children &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 4.5 years than in children &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 4.5 years. The IgG responses to Cryptosporidium tended to increase with age. The IgG responses to LecA and VSP antigens and the prevalence of stools positive for cysts were significantly higher (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.037 and P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.035, respectively) in the rainy season than in the dry season. The multiplex bead assay provides a powerful tool for analyzing serologic responses to multiple pathogens.
The American journal of tropical medicine and hygiene, Jan 29, 2016
In the developing world, fetching water for drinking and other household uses is a substantial bu... more In the developing world, fetching water for drinking and other household uses is a substantial burden that affects water quantity and quality in the household. We used logistic regression to examine whether reported household water fetching times were a risk factor for moderate-to-severe diarrhea (MSD) using case-control data of 3,359 households from the Global Enterics Multi-Center Study in Kenya in 2009-2011. We collected additional global positioning system (GPS) data for a subset of 254 randomly selected households and compared GPS-based straight line and actual travel path distances to fetching times reported by respondents. GPS-based data were highly correlated with respondent-provided times (Spearman correlation coefficient = 0.81, P < 0.0001). The median estimated one-way distance to water source was 200 m for cases and 171 for controls (Wilcoxon rank sums/Mann-Whitney P = 0.21). A round-trip fetching time of > 30 minutes was reported by 25% of cases versus 15% of cont...
Water, 2015
In this study, hollow-fiber ultrafiltration (UF) was assessed for recovery of Escherichia coli, C... more In this study, hollow-fiber ultrafiltration (UF) was assessed for recovery of Escherichia coli, Clostridium perfringens spores, Cryptosporidium parvum oocysts, echovirus 1, and bacteriophages MS2 and ΦX174 from ground and surface waters. Microbes were seeded into twenty-two 50-L water samples that were collected from the Southeastern United States and concentrated to ∼500 mL by UF. Secondary concentration was performed for C. parvum by centrifugation followed by immunomagnetic separation. Secondary concentration for viruses was performed using centrifugal ultrafilters or polyethylene glycol precipitation. Nine water quality parameters were measured in each water sample to determine whether water quality data correlated with UF and secondary concentration recovery efficiencies. Average UF recovery efficiencies were 66%-95% for the six enteric microbes. Average recovery efficiencies for the secondary concentration methods were 35%-95% for C. parvum and the viruses. Overall, measured water quality parameters were not significantly associated with UF recovery efficiencies. However, recovery of ΦX174 was negatively correlated with turbidity. The recovery data demonstrate that UF can be an effective method for concentrating diverse microbes from ground and surface waters. This study highlights the utility of tangential-flow hollow fiber ultrafiltration for recovery of bacteria, viruses, and parasites from large volume environmental water samples.
IEEE Workshop on Statistical Signal Processing, 2003, 2003
ABSTRACT In this paper we describe a technique of fusing larger scenes from multiple views, using... more ABSTRACT In this paper we describe a technique of fusing larger scenes from multiple views, using a landmark approach. For images of remote scenes, the fused image is reconstructed using sample mean shapes on affine shape manifolds. This manifold of configurations of points in general position is a real Grassmann manifold which can be equivariantly embedded in a space of matrices, and we consider the extrinsic means w.r.t. this embedding. On the other hand, for photographs taken from a close distance by a noncalibrated camera, the fused image is reconstructed using sample mean shapes on projective shape manifolds. This manifold of configurations of points under a given projective frame is a product of real projective planes and we consider extrinsic means w.r.t. to a standard embedding in a space of blocks of symmetric matrices. We illustrate these methods on two sets of images.
Statistics and Its Interface, 2010
Data-driven statistical approaches, such as cluster analysis or independent component analysis, a... more Data-driven statistical approaches, such as cluster analysis or independent component analysis, applied to in vivo functional neuroimaging data help to identify neural processing networks that exhibit similar task-related or restingstate patterns of activity. Ideally, the measured brain activity for voxels within such networks should exhibit high autocorrelation. An important limitation is that the algorithms do not typically quantify or statistically test the strength or nature of the within-network relatedness between voxels. To extend the results given by such data-driven analyses, we propose the use of Moran's I statistic to measure the degree of functional autocorrelation within identified neural processing networks and to evaluate the statistical significance of the observed associations. We adapt the conventional definition of Moran's I, for applicability to neuroimaging analyses, by defining the global autocorrelation index using network-based neighborhoods. Also, we compute network-specific contributions to the overall autocorrelation. We present results from a bootstrap analysis that provide empirical support for the use of our hypothesis testing framework. We illustrate our methodology using positron emission tomography (PET) data from a study that examines the neural representation of working memory among individuals with schizophrenia and functional magnetic resonance imaging (fMRI) data from a study of depression.
The New England journal of medicine, Jan 6, 2012
Mucormycosis is a fungal infection caused by environmentally acquired molds. We investigated a cl... more Mucormycosis is a fungal infection caused by environmentally acquired molds. We investigated a cluster of cases of cutaneous mucormycosis among persons injured during the May 22, 2011, tornado in Joplin, Missouri. We defined a case as a soft-tissue infection in a person injured during the tornado, with evidence of a mucormycete on culture or immunohistochemical testing plus DNA sequencing. We conducted a case-control study by reviewing medical records and conducting interviews with case patients and hospitalized controls. DNA sequencing and whole-genome sequencing were performed on clinical specimens to identify species and assess strain-level differences, respectively. A total of 13 case patients were identified, 5 of whom (38%) died. The patients had a median of 5 wounds (range, 1 to 7); 11 patients (85%) had at least one fracture, 9 (69%) had blunt trauma, and 5 (38%) had penetrating trauma. All case patients had been located in the zone that sustained the most severe damage duri...
Lecture Notes in Computer Science, 2008
Breast cancer is the second leading cause of death in women in the United States. Breast Magnetic... more Breast cancer is the second leading cause of death in women in the United States. Breast Magnetic Resonance Imaging (BMRI) is an emerging tool in breast cancer diagnostics and research, and it is becoming routine in clinical practice. Recently, the American Cancer Society (ACS) recommended that women at very high risk of developing breast cancer have annual BMRI exams, in addition to annual mammograms, to increase the likelihood of early detection. (Saslow et al. [20]). Many medical images demonstrate a certain degree of self-similarity over a range of scales. The multifractal spectrum (MFS) summarizes possibly variable degrees of scaling in one dimensional signals and has been widely used in fractal analysis. In this work, we develop a generalization of MFS to three dimensions and use dynamics of the scaling as discriminatory descriptors for the classification of BMRI images to benign and malignant. Methodology we propose was tested using breast MRI images for four anonymous subjects (two cancer, and two cancer-free cases). The dataset consists of BMRI scans obtained on a 1.5T GE Signa MR (with VIBRANT) scanner at Emory University. We demonstrate that meaningful descriptors show potential for classifying inference.
Lecture Notes in Computer Science, 2007
Cancer detection using mammography focuses on characteristics of tiny microcalcifications, includ... more Cancer detection using mammography focuses on characteristics of tiny microcalcifications, including the number, size, and spatial arrangement of microcalcification clusters as well as morphological features of individual microcalcifications. We developed state-of-theart wavelet-based methods to enhance the resolution of microcalcifications visible in digital mammograms, thereby improving the specificity of breast cancer diagnoses. In our research, we develop, refine, and evaluate a Wavelet Image Interpolation (WII) procedure and create accompanying software to implement it. WII involves the application of an inverse wavelet transformation to a coarse or degraded image and constructed detail coefficients to produce an enhanced higher resolution image. The construction of detail coefficients is supervised by the observed image and innate regular scaling assessed by a statistical model. Methodology we propose was tested by an experienced radiologist in a blind study using 40 images from the University of South Florida Digital Database for Screening Mammography (DDSM) (Heat et. al. [10]).
Parasitology Research, 2014
Balamuthia mandrillaris, a free-living ameba, has a case fatality rate exceeding 90 % among recog... more Balamuthia mandrillaris, a free-living ameba, has a case fatality rate exceeding 90 % among recognized cases in the USA. In August 2010, a GAE cluster occurred following transplantation of infected organs from a previously healthy landscaper in Tucson, AZ, USA, who died from a suspected stroke. As B. mandrillaris is thought to be transmitted through soil, a serologic survey of landscapers and a comparison group of blood donors in southern Arizona was performed. Three (3.6 %) of 83 serum samples from landscapers and 11 (2.5 %) of 441 serum samples from blood donors were seropositive (p=0.47). On multivariable analysis, county of residence was associated with seropositivity, whereas age, sex, and ethnicity were not. Exposure to B. mandrillaris, previously unexamined in North America, appears to be far more common than GAE in Southern Arizona. Risk factors for disease progression and the ameba's geographic range should be examined.