2012/2013 Recipients

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This collection contains research papers that were sponsored by the JHU Libraries Open Access Fund in the 2012/2013 academic year. For more information about the fund, please visit webpage

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Use of case reports and the Adverse Event Reporting System in systematic reviews: overcoming barriers to assess the link between Crohn's disease medications and hepatosplenic T-cell lymphoma
(BioMed Central, 2013-07-05) Selvaraj, Saranya A.; Chairez, Elizabeth; Wilson, Lisa M.; Lazarev, Mark; Bass, Eric B.; Hutfless, Susan
BACKGROUND: To identify demographic and clinical characteristics associated with cases of hepatosplenic T-cell lymphoma (HSTCL) in patients with Crohn's disease, and to assess strength of evidence for a causal relationship between medications and HSTCL in Crohn's disease. METHODS: We identified cases of HSTCL in Crohn's disease in studies included in a comparative effectiveness review of Crohn's disease medications, through a separate search of PubMed and Embase for published case reports, and from the Food and Drug Administration (FDA) Adverse Event Reporting System (AERS). We used three causality assessment tools to evaluate the relationship between medication exposure and HSTCL. RESULTS: We found 37 unique cases of HSTCL in patients with Crohn's disease. Six cases were unique to the published literature and nine were unique to AERS. Cases were typically young (<40 years of age) and male (86%). The most commonly reported medications were anti-metabolites (97%) and anti-tumor necrosis factor alpha (anti-TNFa) medications (76%). Dose and duration of therapy were not consistently reported. Use of aminosalicylates and corticosteroids were rarely reported, despite the high prevalence of these medications in routine treatment. Using the causality assessment tools, it could only be determined that anti-metabolite and anti-TNFa therapies were possible causes of HSTCL in Crohn's disease based on the data contained in the case reports. CONCLUSION: Systematic reviews that incorporate case reports of rare lethal events should search both published literature and AERS, but consideration should be given to the limitations of case reports. In this study, establishing a causative effect other than 'possible' between anti-metabolite or anti-TNFa therapies and HSTCL was not feasible because case reports lacked data required by the causality assessments, and because of the limited applicability of causality assessment tools for rare irreversible events. We recommend minimum reporting requirements for case reports to improve causality assessment and routine reporting of rare life-threatening events, including their absence, in clinical trials to help clinicians determine whether rare adverse events are causally related to a medication.
Patient-reported assessment of functional gait outcomes following superior gluteal artery perforator reconstruction
(American Society of Plastic Surgeons, 2013-08-14) Hur, Kevin; Ohkuma, Rika; Bellamy, Justin L.; Yamazaki, Michiyo; Manahan, Michele A.; Rad, Ariel N.; Cooney, Damon S.; Rosson, Gedge D.
BACKGROUND: Harvesting the superior gluteal artery perforator (SGAP) flap involves dissection of vessels through the gluteal muscle, potentially compromising gait and ambulation. We compared patient-reported gait and ambulation problems between SGAP flap and deep inferior epigastric perforator (DIEP) flap reconstructions. METHODS: Forty-three patients who underwent bilateral free flap breast reconstruction (17 SGAP, 26 DIEP) participated in the study. The Lower Extremity Functional Score (LEFS) was administered with a supplementary section evaluating gait, balance, fatigue, and pain. Patients evaluated how they felt 2 months postoperatively and at time of survey administration. Multivariate regressions were fit to assess association between type of reconstruction and self-reported lower extremity function controlling for potential confounding factors. RESULTS: Although there was no significant difference in overall LEFS between the cohorts on the date of survey, the SGAP patients reported greater difficulty performing the following activities after surgery (P < 0.05): work, usual hobbies, squatting, walking a mile, walking up stairs, sitting for an hour, running, turning, and hopping. The SGAP patients also reported easier fatigue (P < 0.01) both during the early postoperative period and on the date of survey. CONCLUSIONS: SGAP flap surgery causes no statistically significant differences in overall LEFS. However, SGAP patients did report donor-site morbidity with decreased ability to perform certain activities and increased fatigue and pain in the longer follow-up period. We feel that patients should be educated regarding gait issues and undergo physical therapy during the early postoperative period.
Positive effect of neurolysis on diabetic patients with compressed nerves of the lower extremities: a systematic review and meta-analysis
(American Society of Plastic Surgeons, 2013-07-02) Baltodano, Pablo A.; Basdag, Basak; Bailey, Christopher R.; Baez, Marcelo J. Lacayo; Tong, Anne; Seal, Stella M.; Meléndez, Mark M.; Xie, Li; Manahan, Michele A.; Rosson, Gedge D.
BACKGROUND: Despite proven benefits of upper extremity nerve decompression in diabetics, neurolysis for diabetic patients with lower extremity (LE) nerve compression remains controversial. METHODS: A search of ClinicalTrials.gov and Cochrane clinical trials registries, CENTRAL (The Cochrane Library), MEDLINE, EMBASE, LILACS, CINAHL, SCOPUS, and Google Scholar from 1962 to 2012, yielded 1956 citations. Any potential randomized or quasi-randomized controlled trials and observational cohort studies of diabetics with neurolysis of the common peroneal nerve, deep peroneal nerve, or tibial nerve were assessed. We included articles in any language that 1) provided information about diabetic patients who had neurolysis for symptomatic nerve compression diagnosed by (+) Tinel sign or electrodiagnostic study, and 2) quantified outcomes for pain, sensibility, or ulcerations/amputations. Case reports, review articles, animal or cadaver studies, and studies with <10 patients were excluded. We assessed pain relief, recovery of sensibility, and postoperative incidence of ulcerations/amputations at follow-up >3 months. A meta-analysis of descriptive statistics was performed. RESULTS: Ten clinical series with a mean clinical relevance score of 70% and a mean methodologic quality score of 50% met inclusion criteria. We included 875 diabetic patients and 1053 LEs. Pain relief >3 points on visual analog scale occurred in 91% of patients; sensibility improved in 69%. Postoperative ulceration/amputation incidence was significantly reduced compared to preoperative incidence (odds ratio = 0.066, 95% confidence interval = 0.026-0.164, P < 0.0001). CONCLUSIONS: Observational data suggest that neurolysis significantly improves outcomes for diabetic patients with compressed nerves of the LE. No randomized controlled trials have been published.
Increased flap weight and decreased perforator number predict fat necrosis in DIEP breast reconstruction
(American Society of Plastic Surgeons, 2013-05-28) Mulvey, Carolyn L.; Cooney, Carisa M.; Daily, Francis F.; Colantuoni, Elizabeth; Ogbuago, Onyebuchi U.; Cooney, Damon S.; Rad, Ariel N.; Manahan, Michele A.; Rosson, Gedge D.; Sacks, Justin M.
BACKGROUND: Compromised perfusion in autologous breast reconstruction results in fat necrosis and flap loss. Increased flap weight with fewer perforator vessels may exacerbate imbalances in flap perfusion. We studied deep inferior epigastric perforator (DIEP) and muscle-sparing transverse rectus abdominis myocutaneous (MS-TRAM) flaps to assess this concept. METHODS: Data from patients who underwent reconstruction with DIEP and/or MS-TRAM flaps between January 1, 2010 and December 31, 2011 (n = 123) were retrospectively reviewed. Patient demographics, comorbidities, intraoperative parameters, and postoperative outcomes were collected, including flap fat necrosis and donor/recipient site complications. Logistic regression analysis was used to examine effects of flap weight and perforator number on breast flap fat necrosis. RESULTS: One hundred twenty-three patients who underwent 179 total flap reconstructions (166 DIEP, 13 MS-TRAM) were included. Mean flap weight was 658 ± 289 g; 132 (73.7%) were single perforator flaps. Thirteen flaps (7.5%) developed fat necrosis. African American patients had increased odds of fat necrosis (odds ratio, 11.58; P < 0.001). Odds of developing fat necrosis significantly increased with flap weight (odds ratio, 1.5 per 100 g increase; P < 0.001). In single perforator flaps weighing more than 1000 g, six (42.9%) developed fat necrosis, compared to 14.3% of large multiple perforator flaps. CONCLUSIONS: Flaps with increasing weight have increased risk of fat necrosis. These data suggest that inclusion of more than 1 perforator may decrease odds of fat necrosis in large flaps. Perforator flap breast reconstruction can be performed safely; however, considerations concerning race, body mass index, staging with tissue expanders, perforator number, and flap weight may optimize outcomes.
Preoperative anemia and postoperative outcomes in immediate breast reconstructive surgery : a critical analysis of 10,958 patients from the ACS-NSQIP database
(Plastic and reconstructive surgery. Global open., 2013-08-06) Sarhane, Karim A.; Flores, José M.; Cooney, Carisa M.; Abreu, Francis M.; Lacayo, Marcelo; Baltodano, Pablo A.; Ibrahim, Zuhaib; Alrakan, Mohammed; Brandacher, Gerald; Rosson, Gedge D.
Background: Preoperative anemia is independently associated with adverse outcomes after general and cardiac surgery. Outcomes after breast reconstruction are not established. We assessed the effect of preoperative anemia on 30-day postoperative morbidity and length of hospital stay (LOS) in patients undergoing immediate breast reconstruction. Methods: We identified patients undergoing immediate breast reconstruction from 2008 to 2010 from the American College of Surgeons’ National Surgical Quality Improvement Program database (a prospective outcomesbased registry from hospitals worldwide). De-identified data were obtained for demographics, preoperative risk factors, 30-day morbidity, and LOS. Morbidity variables included flap/graft/prosthesis, cardiac, respiratory, neurological, urinary, wound, and venous thromboembolism outcomes. Logistic regression assessed the crude and adjusted effect of anemia (hematocrit <36%) on postoperative 30-day morbidity. Measures of central tendency of LOS were compared across increasing severities of anemia in patients developing adverse events versus controls. Results: The study population included 10,958 patients; 1556 (16.74%) had preoperative anemia. Crude odds ratio for 30-day morbidity was significantly higher in anemic patients, unadjusted odds ratio = 1.33 (P < 0.008). This prevailed after extensive adjustment for confounding, yielding an adjusted odds ratio = 1.38 (P < 0.03). Patients who experienced adverse effects had protracted LOS, and the presence of anemia significantly amplified this effect. Conclusions: These data provide new insight into the effect of anemia in immediate breast reconstruction, demonstrating an independent association between preoperative anemia and 30-day morbidity. These findings suggest treating anemia when possible; however, prospective studies should explore the efficacy, safety, and cost-effectiveness of such treatments.
A multi-level system quality improvement intervention to reduce racial disparities in hypertension care and control: study protocol.
(BioMed Central, 2013-06-04) Cooper, Lisa A; Marsteller, Jill A.; Noronha, Gary J.; Flynn, Sarah J.; Carson, Kathryn A.; Boonyasai, Romsai T.; Anderson, Cheryl A.; Aboumatar, Hanan J.; Roter, Debra L.; Dietz, Katherine B.; Miller, Edgar R III; Prokopowicz, Gregory P.; Dalcin, Arlene T.; Charleston, Jeanne B.; Simmons, Michelle; Huizinga, Mary Margaret
Abstract BACKGROUND: Racial disparities in blood pressure control have been well documented in the United States. Research suggests that many factors contribute to this disparity, including barriers to care at patient, clinician, healthcare system, and community levels. To date, few interventions aimed at reducing hypertension disparities have addressed factors at all of these levels. This paper describes the design of Project ReD CHiP (Reducing Disparities and Controlling Hypertension in Primary Care), a multi-level system quality improvement project. By intervening on multiple levels, this project aims to reduce disparities in blood pressure control and improve guideline concordant hypertension care. METHODS: Using a pragmatic trial design, we are implementing three complementary multi-level interventions designed to improve blood pressure measurement, provide patient care management services and offer expanded provider education resources in six primary care clinics in Baltimore, Maryland. We are staggering the introduction of the interventions and will use Statistical Process Control (SPC) charting to determine if there are changes in outcomes at each clinic after implementation of each intervention. The main hypothesis is that each intervention will have an additive effect on improvements in guideline concordant care and reductions in hypertension disparities, but the combination of all three interventions will result in the greatest impact, followed by blood pressure measurement with care management support, blood pressure measurement with provider education, and blood pressure measurement only. This study also examines how organizational functioning and cultural competence affect the success of the interventions. DISCUSSION: As a quality improvement project, Project ReD CHiP employs a novel study design that specifically targets multi-level factors known to contribute to hypertension disparities. To facilitate its implementation and improve its sustainability, we have incorporated stakeholder input and tailored components of the interventions to meet the specific needs of the involved clinics and communities. Results from this study will provide knowledge about how integrated multi-level interventions can improve hypertension care and reduce disparities. TRIAL REGISTRATION: ClinicalTrials.gov NCT01566864.
Individual and contextual factors of influence on adherence to antiretrovirals among people attending public clinics in Rio de Janeiro, Brazil.
(BioMed Central, 2013-06-13) Hanif, Homaira; Bastos, Francisco Inácio; Malta, Monica; Bertoni, Neilane; Surkan, Pamela J.; Winch, Peter J.; Kerrigan, Deanna
BACKGROUND: There are inconsistencies in the determinants of adherence to antiretrovirals (ARVs) across settings as well as a lack of studies that take into consideration factors beyond the individual level. This makes it necessary to examine factors holistically in multiple settings and populations while taking into consideration the particularities of each context, in order to understand the patterns of ARV adherence. This research explored ARV adherence and individual, relational and environmental-structural factors. METHODS: A cross-sectional survey was conducted from August 2008 through July 2009 among participants currently on ARVs recruited from 6 public health clinics, selected to maximize diversity in terms of caseload and location, representing the range of clinics within Rio de Janeiro city, Brazil. Multivariate logistic regression analysis was used to assess the association between our multilevel factors with ARV adherence among participants with complete cases (n = 632). RESULTS: Eighty-four percent of respondents reported adherence to all of their ARV doses in the last 4 days. Of the socio-demographic variables, those who had one child were positively associated with adherence (AOR 2.29 CI [1.33-3.94]). On the relational level, those with high social support (AOR 2.85 CI [1.50-5.41]) were positively associated with adherence to ARVs. On the environmental-structural level, we found gender was significant with women negatively associated with adherence to ARVs (AOR 0.58 CI [0.38-0.88]) while those with a high asset index (AOR 2.47 CI [1.79-3.40]) were positively associated with adherence to ARVs. CONCLUSIONS: This research highlights the importance of examining the multiple levels of influence on ARV adherence. Intervention research in lower and middle-income settings should address and evaluate the impact of attending to both gender and economic inequalities to improve ARV adherence, as well as relational areas such as the provision of social support.
Development of a screening tool to identify female survivors of gender-based violence in a humanitarian setting:qualitative evidence from research among refugees in Ethiopia.
(BioMed Central, 2013-06-12) Wirtz, Andrea L; Glass, Nancy; Pham, Kiemanh; Aberra, Amsale; Rubenstein, Leonard S.; Singh, Sonal; Vu, Alexander
BACKGROUND: High levels of gender-based violence (GBV) persist among conflict-affected populations and within humanitarian settings and are paralleled by under-reporting and low service utilization. Novel and evidence-based approaches are necessary to change the current state of GBV amongst these populations. We present the findings of qualitative research, which were used to inform the development of a screening tool as one potential strategy to identify and respond to GBV for females in humanitarian settings. METHODS: Qualitative research methods were conducted from January-February 2011 to explore the range of experiences of GBV and barriers to reporting GBV among female refugees. Individual interview participants (n=37) included female refugees (≥15 years), who were survivors of GBV, living in urban or one of three camps settings in Ethiopia, and originating from six conflict countries. Focus group discussion participants (11 groups; 77 participants) included health, protection and community service staff working in the urban or camp settings. Interviews and discussions were conducted in the language of preference, with assistance by interpreters when needed, and transcribed for analysis by grounded-theory technique. RESULTS: Single and multiple counts of GBV were reported and ranged from psychological and social violence; rape, gang rape, sexual coercion, and other sexual violence; abduction; and physical violence. Domestic violence was predominantly reported to occur when participants were living in the host country. Opportunistic violence, often manifested by rape, occurred during transit when women depended on others to reach their destination. Abduction within the host country, and often across borders, highlighted the constant state of vulnerability of refugees. Barriers to reporting included perceived and experienced stigma in health settings and in the wider community, lack of awareness of services, and inability to protect children while mothers sought services. CONCLUSIONS: Findings demonstrate that GBV persists across the span of the refugee experience, though there is a transition in the range of perpetrators and types of GBV that are experienced. Further, survivors experience significant individual and system barriers to disclosure and service utilization. The findings suggest that routine GBV screening by skilled service providers offers a strategy to confidentially identify and refer survivors to needed services within refugee settings, potentially enabling survivors to overcome existing barriers.
ClinicalTrials.gov registration can supplement information in abstracts for systematic reviews: a comparisonstudy.
(BioMed Central, 2013-06-18) Scherer, Roberta W.; Huynh, Lynn; Ervin, Ann Margret; Taylor, Jakeisha; Dickersin, Kay
BACKGROUND: The inclusion of randomized controlled trials (RCTs) reported in conference abstracts in systematic reviews is controversial, partly because study design information and risk of bias is often not fully reported in the abstract. The Association for Research in Vision and Ophthalmology (ARVO) requires trial registration of abstracts submitted for their annual conference as of 2007. Our goal was to assess the feasibility of obtaining study design information critical to systematic reviews, but not typically included in conference abstracts, from the trial registration record. METHODS: We reviewed all conference abstracts presented at the ARVO meetings from 2007 through 2009, and identified 496 RCTs; 154 had a single matching registration record in ClinicalTrials.gov. Two individuals independently extracted information from the abstract and the ClinicalTrials.gov record, including study design, sample size, inclusion criteria, masking, interventions, outcomes, funder, and investigator name and contact information. Discrepancies were resolved by consensus. We assessed the frequencies of reporting variables appearing in the abstract and the trial register and assessed agreement of information reported in both sources. RESULTS: We found a substantial amount of study design information in the ClinicalTrials.gov record that was unavailable in the corresponding conference abstract, including eligibility criteria associated with gender (83%; 128/154); masking or blinding of study participants (53%, 82/154), persons administering treatment (30%, 46/154), and persons measuring the outcomes (40%, 61/154)); and number of study centers (58%; 90/154). Only 34% (52/154) of abstracts explicitly described a primary outcome, but a primary outcome was included in the "Primary Outcome" field in the ClinicalTrials.gov record for 82% (126/154) of studies. One or more study interventions were reported in each abstract, but agreed exactly with those reported in ClinicalTrials.gov only slightly more than half the time (88/154, 56%). We found no contact information for study investigators in the abstract, but this information was available in less than one quarter of ClinicalTrial.gov records (17%; 26/154). CONCLUSION: RCT design information not reported in conference abstracts is often available in the corresponding ClinicalTrials.gov registration record. Sometimes there is conflicting information reported in the two sources and further contact with the trial investigators may still be required.
Mechanisms of Siglec-F-induced eosinophil apoptosis: a role for caspases but not for SHP-1, Src kinases, NADPH oxidase or reactive oxygen.
(PLoS Organization, 2013-06-28) Mao, Hui; Kano, Gen; Hudson, Sherry A.; Brummet, Mary; Zimmermann, Nives; Zhu, Zhou; Bochner, Bruce S.
Abstract BACKGROUND: Siglec-F and Siglec-8 are functional paralog proapoptotic cell surface receptors expressed on mouse and human eosinophils, respectively. Whereas Siglec-8 mediated death involves caspases and/or reactive oxygen species (ROS) generation and mitochondrial injury, very little is known about Siglec-F-mediated signaling and apoptosis. Therefore the objective of the current experiments was to better define apoptosis pathways mediated by Siglec-F and Siglec-8. Given that Siglec-F-induced apoptosis is much less robust than Siglec-8-induced apoptosis, we hypothesized that mechanisms involved in cell death via these receptors would differ. METHODS: Consequences of engagement of Siglec-F on mouse eosinophils were studied by measuring ROS production, and by performing apoptosis assays using eosinophils from normal, hypereosinophilic, NADPH oxidase-deficient, src homology domain-containing protein tyrosine phosphatase (SHP)-1-deficient, and Lyn kinase-deficient mice. Inhibitors of caspase and Src family kinase activity were also used. RESULTS: Engagement of Siglec-F induced mouse eosinophil apoptosis that was modest in magnitude and dependent on caspase activity. There was no detectable ROS generation, or any role for ROS, NADPH oxidase, SHP-1, or Src family kinases in this apoptotic process. CONCLUSIONS: These data suggest that Siglec-F-mediated apoptosis is different in both magnitude and mechanisms when compared to published data on Siglec-8-mediated human eosinophil apoptosis. One likely implication of this work is that models targeting Siglec-F in vivo in mice may not provide identical mechanistic predictions for consequences of Siglec-8 targeting in vivo in humans.
A Particle Model for Prediction of Cement Infiltration of Cancellous Bone in Osteoporotic Bone Augmentation.
(PLoS Organization, 2013-06-26) Basafa, Ehsan; Murphy, Ryan J.; Kutzer, Michael D.; Otake, Yoshito; Armand, Mehran
Femoroplasty is a potential preventive treatment for osteoporotic hip fractures. It involves augmenting mechanical properties of the femur by injecting Polymethylmethacrylate (PMMA) bone cement. To reduce the risks involved and maximize the outcome, however, the procedure needs to be carefully planned and executed. An important part of the planning system is predicting infiltration of cement into the porous medium of cancellous bone. We used the method of Smoothed Particle Hydrodynamics (SPH) to model the flow of PMMA inside porous media. We modified the standard formulation of SPH to incorporate the extreme viscosities associated with bone cement. Darcy creeping flow of fluids through isotropic porous media was simulated and the results were compared with those reported in the literature. Further validation involved injecting PMMA cement inside porous foam blocks - osteoporotic cancellous bone surrogates - and simulating the injections using our proposed SPH model. Millimeter accuracy was obtained in comparing the simulated and actual cement shapes. Also, strong correlations were found between the simulated and the experimental data of spreading distance (R2 = 0.86) and normalized pressure (R2 = 0.90). Results suggest that the proposed model is suitable for use in an osteoporotic femoral augmentation planning framework.
Outbreak of H3N2 influenza at a US military base in Djibouti during the H1N1 pandemic of 2009.
(PLoS Organization, 2013-12-05) Cosby, Michael T.; Pimentel, Guillermo; Nevin, Remington L.; Ahmed, Salwa Fouad; Klena, John D.; Amir, Ehab; Younan, Mary; Browning, Robert; Sebeny, Peter J.
BACKGROUND: Influenza pandemics have significant operational impact on deployed military personnel working in areas throughout the world. The US Department of Defense global influenza-like illness (ILI) surveillance network serves an important role in establishing baseline trends and can be leveraged to respond to outbreaks of respiratory illness. OBJECTIVE: We identified and characterized an operationally unique outbreak of H3N2 influenza at Camp Lemonnier, Djibouti occurring simultaneously with the H1N1 pandemic of 2009 [A(H1N1)pdm09]. METHODS: Enhanced surveillance for ILI was conducted at Camp Lemonnier in response to local reports of a possible outbreak during the A(H1N1)pdm09 pandemic. Samples were collected from consenting patients presenting with ILI (utilizing a modified case definition) and who completed a case report form. Samples were cultured and analyzed using standard real-time reverse transcriptase PCR (rt-RT-PCR) methodology and sequenced genetic material was phylogenetically compared to other published strains. RESULTS: rt-RT-PCR and DNA sequencing revealed that 25 (78%) of the 32 clinical samples collected were seasonal H3N2 and only 2 (6%) were A(H1N1)pdm09 influenza. The highest incidence of H3N2 occurred during the month of May and 80% of these were active duty military personnel. Phylogenetic analysis revealed that sequenced H3N2 strains were genetically similar to 2009 strains from the United States of America, Australia, and South east Asia. CONCLUSIONS: This outbreak highlights challenges in the investigation of influenza among deployed military populations and corroborates the public health importance of maintaining surveillance systems for ILI that can be enhanced locally when needed.
Pulmonary Tuberculosis Incidence and Risk Factors in Rural Areas of China: A Cohort Study
(PLoS Organization, 2013-03-12) Chen, Wei; Shu, Wen; Wang, Min; Hou, Yongchun; Xia, Yinyin; Xu, Weiguo; Bai, Liqiong; Nie, Shaofa; Cheng, Shiming; Xu, Yihua
The incidence of tuberculosis (TB) and its risk factors in China remains unclear. This study examined TB incidence and relative risk factors in rural areas of China. Participants (n = 177,529) were recruited in Xiangtan County (in the central area of China) and in Danyang County (in the eastern area of China) in 2009 and a followed-up study was conducted for one year. The incidence density of pulmonary TB and smear-positive TB were 91.6 (95% CI: 78.7, 106.0) per 100,000 person-year and 36.7 (95% CI: 33.1, 52.4) per 100,000 person-year respectively in Xiangtan, and 47.3 (95% CI: 38.2, 57.5) per 100,000 person-year and 22.7 (95% CI: 16.5, 30.8) per 100,000 person-year in Danyang. The medical history of TB was associated with TB, with the relative risk (RR) of 7.00 (95% CI: 2.76, 17.18) in Xiangtan and that of 31.08 (95% CI: 13.22, 73.10) in Danyang. The association between TB and per capita living space over median was found in Xiangtan, with the RR of 1.86 (95% CI: 1.15, 3.01). No association was found between TB and the insurance status, the contact history with TB, the history of diabetes, smoking, or per capita annual income. The host genetic susceptibility, and social factors such as education and income could be considered in future studies.
Multiple Consequences of a Single Amino Acid Pathogenic RTK Mutation: The A391E Mutation in FGFR3
(PLoS Organization, 2013-02-20) Chen, Fenghao; Sarabipour, Sarvenaz; Hristova, Kalina
The A391E mutation in fibroblast growth factor receptor 3 (FGFR3) is the genetic cause for Crouzon syndrome with Acanthosis Nigricans. Here we investigate the effect of this mutation on FGFR3 activation in HEK 293 T cells over a wide range of fibroblast growth factor 1 concentrations using a physical-chemical approach that deconvolutes the effects of the mutation on dimerization, ligand binding, and efficiency of phosphorylation. It is believed that the mutation increases FGFR3 dimerization, and our results verify this. However, our results also demonstrate that the increase in dimerization is not the sole effect of the mutation, as the mutation also facilitates the phosphorylation of critical tyrosines in the activation loop of FGFR3. The activation of mutant FGFR3 is substantially increased due to a combination of these two effects. The low expression of the mutant, however, attenuates its signaling and may explain the mild phenotype in Crouzon syndrome with Acanthosis Nigricans. The results presented here provide new knowledge about the physical basis behind growth disorders and highlight the fact that a single RTK mutation may affect multiple steps in RTK activation.
APOBEC3G-Augmented Stem Cell Therapy to Modulate HIV Replication: A Computational Study
(PLoS Organization, 2013-05-22) Mac Gabhann, Feilim; Hosseini, Iraj
The interplay between the innate immune system restriction factor APOBEC3G and the HIV protein Vif is a key host-retrovirus interaction. APOBEC3G can counteract HIV infection in at least two ways: by inducing lethal mutations on the viral cDNA; and by blocking steps in reverse transcription and viral integration into the host genome. HIV-Vif blocks these antiviral functions of APOBEC3G by impeding its encapsulation. Nonetheless, it has been shown that overexpression of APOBEC3G, or interfering with APOBEC3G-Vif binding, can efficiently block in vitro HIV replication. Some clinical studies have also suggested that high levels of APOBEC3G expression in HIV patients are correlated with increased CD4+ T cell count and low levels of viral load; however, other studies have reported contradictory results and challenged this observation. Stem cell therapy to replace a patient's immune cells with cells that are more HIV-resistant is a promising approach. Pre-implantation gene transfection of these stem cells can augment the HIV-resistance of progeny CD4+ T cells. As a protein, APOBEC3G has the advantage that it can be genetically encoded, while small molecules cannot. We have developed a mathematical model to quantitatively study the effects on in vivo HIV replication of therapeutic delivery of CD34+ stem cells transfected to overexpress APOBEC3G. Our model suggests that stem cell therapy resulting in a high fraction of APOBEC3G-overexpressing CD4+ T cells can effectively inhibit in vivo HIV replication. We extended our model to simulate the combination of APOBEC3G therapy with other biological activities, to estimate the likelihood of improved outcomes.
Consequences of replacing EGFR juxtamembrane domain with an unstructured sequence.
(Nature Publishing Group, 2012-11-14) He, Lijuan; Hristova, Kalina
EGFR is the best studied receptor tyrosine kinase. Yet, a comprehensive mechanistic understanding of EGFR signaling is lacking, despite very active research in the field. In this paper, we investigate the role of the juxtamembrane (JM) domain in EGFR signaling by replacing it with a (GGS)(10) unstructured sequence. We probe the effect of this replacement on (i) EGFR phosphorylation, (ii) EGFR dimerization and (iii) ligand (EGF) binding. We show that the replacement of EGFR JM domain with a (GGS)(10) unstructured linker completely abolishes the phosphorylation of all tyrosine residues, without measurable effects on receptor dimerization or ligand binding. Our results suggest that the JM domain does not stabilize the inactive EGFR dimer in the absence of ligand, and is likely critical only for the last step of EGFR activation, the ligand-induced transition from the inactive to active dimer.
Role of exhaled nitric oxide as a predictor of atopy.
(BioMed Central, 2013-05-02) Romero, Karina M.; Robinson, Colin L.; Baumann, Lauren M.; Gilman, Robert H.; Hamilton, Robert G.; Hansel, Nadia N; Checkley, William; PURA Study Investigators
BACKGROUND: The fractional exhaled nitric oxide (FeNO) is a quantitative, noninvasive and safe measure of airways inflammation that may complement the assessment of asthma. Elevations of FeNO have recently been found to correlate with allergic sensitization. Therefore, FeNO may be a useful predictor of atopy in the general population. We sought to determine the diagnostic accuracy of FeNO in predicting atopy in a population-based study. METHODS: We conducted a cross-sectional study in an age- and sex- stratified random sample of 13 to 15 year-olds in two communities in Peru. We asked participants about asthma symptoms, environmental exposures and sociodemographics, and underwent spirometry, assessment of FeNO and an allergy skin test. We used multivariable logistic regression to model the odds of atopy as a function of FeNO, and calculated area-under-the-curves (AUC) to determine the diagnostic accuracy of FeNO as a predictor of atopy. RESULTS: Of 1441 recruited participants, 1119 (83%) completed all evaluations. Mean FeNO was 17.6 ppb (SD=0.6) in atopics and 11.6 ppb (SD=0.8) in non-atopics (p<0.001). In multivariable analyses, a FeNO>20 ppb was associated with an increase in the odds of atopy in non-asthmatics (OR=5.3, 95% CI 3.3 to 8.5) and asthmatics (OR=16.2, 95% CI 3.4 to 77.5). A FeNO>20 ppb was the best predictor for atopy with an AUC of 68% (95% CI 64% to 69%). Stratified by asthma, the AUC was 65% (95% CI 61% to 69%) in non-asthmatics and 82% (95% CI 71% to 91%) in asthmatics. CONCLUSIONS: FeNO had limited accuracy to identify atopy among the general population; however, it may be a useful indicator of atopic phenotype among asthmatics.
Expression of VEGF and semaphorin genes define subgroups of triple negative breast cancer.
(PLoS Organizaton, 2013-05-08) Bender, R. Joseph; Mac Gabhann, Feilim
Triple negative breast cancers (TNBC) are difficult to treat due to a lack of targets and heterogeneity. Inhibition of angiogenesis is a promising therapeutic strategy, but has had limited effectiveness so far in breast cancer. To quantify heterogeneity in angiogenesis-related gene expression in breast cancer, we focused on two families--VEGFs and semaphorins--that compete for neuropilin co-receptors on endothelial cells. We compiled microarray data for over 2,600 patient tumor samples and analyzed the expression of VEGF- and semaphorin-related ligands and receptors. We used principal component analysis to identify patterns of gene expression, and clustering to group samples according to these patterns. We used available survival data to determine whether these clusters had prognostic as well as therapeutic relevance. TNBC was highly associated with dysregulation of VEGF- and semaphorin-related genes; in particular, it appeared that expression of both VEGF and semaphorin genes were altered in a pro-angiogenesis direction. A pattern of high VEGFA expression with low expression of secreted semaphorins was associated with 60% of triple-negative breast tumors. While all TNBC groups demonstrated poor prognosis, this signature also correlated with lower 5-year survival rates in non-TNBC samples. A second TNBC pattern, including high VEGFC expression, was also identified. These pro-angiogenesis signatures may identify cancers that are more susceptible to VEGF inhibition.
Characterizing optical properties of nano contrast agents by using cross-referencing OCT imaging.
(Optical Society of America, 2013-05-09) Xi, Jiefeng; Chen, Yongping; Li, Xingde
We report a cross-referencing method to quickly and accurately characterize the optical properties of nanoparticles including the extinction, scattering, absorption and backscattering cross sections by using an OCT system alone. Among other applications, such a method is particularly useful for developing nanoparticle-based OCT imaging contrast agents. The method involves comparing two depth-dependent OCT intensity signals collected from two samples (with one having and the other not having the nanoparticles), to extract the extinction and backscattering coefficient, from which the absorption coefficient can be further deduced (with the help of the established scattering theories for predicting the ratio of the backscattering to total scattering cross section). The method has been experimentally validated using test nanoparticles and was then applied to characterizing gold nanocages. With the aid of this method, we were able to successfully synthesize scattering dominant gold nanocages for the first time and demonstrated the highest contrast enhancement ever achieved by the gold nanocages (and by any nanoparticles of a similar size and concentration) in an in vivo mouse tumor model. This method also enables quantitative analysis of contrast enhancement and provides a general guideline on choosing the optimal concentration and optical properties for the nanoparticle-based OCT contrast agents.
Epidermal stem cells in orthopaedic regenerative medicine.
(Multidisciplinary Digital Publishing Institute, 2013-05-31) Li, Jin; Zhen, Gehua; Tsai, Shin-Yi; Jia, Xiaofeng
In the last decade, great advances have been made in epidermal stem cell studies at the cellular and molecular level. These studies reported various subpopulations and differentiations existing in the epidermal stem cell. Although controversies and unknown issues remain, epidermal stem cells possess an immune-privileged property in transplantation together with easy accessibility, which is favorable for future clinical application. In this review, we will summarize the biological characteristics of epidermal stem cells, and their potential in orthopedic regenerative medicine. Epidermal stem cells play a critical role via cell replacement, and demonstrate significant translational potential in the treatment of orthopedic injuries and diseases, including treatment for wound healing, peripheral nerve and spinal cord injury, and even muscle and bone remodeling.

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