Kahn CA,Schultz CH,Miller KT,Anderson CL
Department of Emergency Medicine, University of California, Irvine, Orange, CA 92868, USA. ckahn@uci.edu
|
Does START triage work? An outcomes assessment after a disaster.
Ann Emerg Med. 2009 Sep;54(3):424-30, 430.e1
STUDY OBJECTIVE: The mass casualty triage system known as simple triage and rapid treatment (START) has been widely used in the United States since the 1980s. However, no outcomes assessment has been conducted after a disaster to determine whether assigned triage levels match patients' actual clinical status. Researchers hypothesize that START achieves at least 90% sensitivity and specificity for each triage level and ensures that the most critical patients are transported first to area hospitals. METHODS: The performance of START was evaluated at a train crash disaster in 2003. Patient field triage categories and scene times were obtained from county reports. Patient medical records were then reviewed at all receiving hospitals. Victim arrival times were obtained and correct triage categories determined a priori using a combination of the modified Baxt criteria and hospital admission. Field and outcomes-based triage categories were compared, defining the appropriateness of each triage assignment. RESULTS: Investigators reviewed 148 records at 14 receiving hospitals. Field triage designations comprised 22 red (immediate), 68 yellow (delayed), and 58 green (minor) patients. Outcomes-based designations found 2 red, 26 yellow, and 120 green patients. Seventy-nine patients were overtriaged, 3 were undertriaged, and 66 patients' outcomes matched their triage level. No triage level met both the 90% sensitivity and 90% specificity requirement set forth in the hypothesis, although red was 100% sensitive (95% confidence interval [CI] 16% to 100%) and green was 89.3% specific (95% CI 72% to 98%). The Obuchowski statistic was 0.81, meaning that victims from a higher-acuity outcome group had an 81% chance of assignment to a higher-acuity triage category. The median arrival time for red patients was more than 1 hour earlier than the other patients. CONCLUSION: This analysis demonstrates poor agreement between triage levels assigned by START at a train crash and a priori outcomes criteria for each level. START ensured acceptable levels of undertriage (100% red sensitivity and 89% green specificity) but incorporated a substantial amount of overtriage. START proved useful in prioritizing transport of the most critical patients to area hospitals first.
PMID: 19195739
|
Odgers CL,Moffitt TE,Tach LM,Sampson A,Taylor RJ,Matthews CL,Caspi A
Department of Psychology and Social Behavior, University of California, Irvine, CA, 92697-7085, USA. codgers@uci.edu
|
The protective effects of neighborhood collective efficacy on British children growing up in deprivation: a developmental analysis.
Dev Psychol. 2009 Jul;45(4):942-57
This article reports on the influence of neighborhood-level deprivation and collective efficacy on children's antisocial behavior between the ages of 5 and 10 years. Latent growth curve modeling was applied to characterize the developmental course of antisocial behavior among children in the E-Risk Longitudinal Twin Study, an epidemiological cohort of 2,232 children. Children in deprived versus affluent neighborhoods had higher levels of antisocial behavior at school entry (24.1 vs. 20.5, p < .001) and a slower rate of decline from involvement in antisocial behavior between the ages of 5 and 10 (-0.54 vs. -0.78, p < .01). Neighborhood collective efficacy was negatively associated with levels of antisocial behavior at school entry (r = -.10, p < .01) but only in deprived neighborhoods; this relationship held after controlling for neighborhood problems and family-level factors. Collective efficacy did not predict the rate of change in antisocial behavior between the ages of 5 and 10. Findings suggest that neighborhood collective efficacy may have a protective effect on children living in deprived contexts.
PMID: 19586172
|
Baliraine FN,Afrane YA,Amenya DA,Bonizzoni M,Menge DM,Zhou G,Zhong D,Vardo-Zalik AM,Githeko AK,Yan G
Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California 92697, USA. fbalirai@uci.edu
|
High prevalence of asymptomatic plasmodium falciparum infections in a highland area of western Kenya: a cohort study.
J Infect Dis. 2009 Jul 1;200(1):66-74
BACKGROUND: Transmission of malaria in an area of hypoendemicity in the highlands of western Kenya is not expected to lead to rapid acquisition of immunity to malaria. However, the subpopulation of individuals with asymptomatic Plasmodium falciparum infection may play a significant role as an infection reservoir and should be considered in malaria-control programs. Determination of the spatiotemporal dynamics of asymptomatic subpopulations provides an opportunity to estimate the epidemiological importance of this group to malaria transmission. METHODS: Monthly parasitological surveys were undertaken for a cohort of 246 schoolchildren over 12 months. The prevalence of P. falciparum infection among 2,611 blood samples was analyzed by both microscopy and polymerase chain reaction, and infection durations were determined. RESULTS: Infection prevalence and duration (range, 1-12 months) decreased with age and altitude. The prevalence was high among pooled blood samples recovered from children aged 5-9 years (34.4%) and from those aged 10-14 years (34.1%) but was significantly lower among blood samples obtained from older children (9.1%). The prevalence decreased from 52.4% among pooled blood samples from children living at an altitude of approximately 1,430 m to 23.3% among pooled samples from children living at an altitude of 1,580 m. CONCLUSIONS: The prevalence of asymptomatic P. falciparum infection was high, with polymerase chain reaction analysis detecting a significantly greater number of infections, compared with microscopy. Our results are consistent with gradual acquisition of immunity with increasing age upon repeated infection, and they also show that the risk of malaria transmission is highly heterogeneous in the highland area. The results provide strong support for targeted malaria-control interventions.
PMID: 19476434
|
Berger WE
Department of pediatrics, division of allergy and immunology, College of Medicine, University of California, Irvine, USA. wberger@uci.edu
|
Acute bronchospasm from the patient's perspective.
Postgrad Med. 2005 Dec;118(6 Suppl Acute):44-7; discussion 48
Vast differences exist between the actions physicians report that they take and the patient's perception of those actions. Several patient satisfaction survey results are presented in this article. Many show that although patients are not often satisfied with their treatments or with the side effects they experience from medications, they are, in general, very satisfied with their physicians. These research studies point out that a very real "communications gap" exists between physicians and patients when examined from the patient's perspective.
PMID: 19667716
|
Berger WE
Department of pediatrics, division of allergy and immunology, College of Medicine, University of California, Irvine, USA. weberger@uci.edu
|
Treatment of acute bronchospasm in elderly patients.
Postgrad Med. 2005 Dec;118(6 Suppl Acute):34-7; discussion 38
Both asthma and chronic obstructive pulmonary disease (COPD) are often underdiagnosed and undertreated among the elderly. Patient compliance with treatments plans and medication schedules are often less than ideal. This paper presents results from clinical studies examining levalbuterol and racemic albuterol use among elderly patients who have asthma or COPD.
PMID: 19667714
|
Berger WE
Department of pediatrics, division of allergy and immunology, College of Medicine, University of California, Irvine, USA. wberger@uci.edu
|
Current options in the treatment of acute bronchospasm.
Postgrad Med. 2005 Dec;118(6 Suppl Acute):18-26
Asthma therapy has evolved significantly in the last 40 years from that used for primarily symptomatic relief to that which incorporates short-term relief agents, long-term preventive medications, and exacerbation relief products. Agents can now be prescribed for routine as well as emergency care. Continued development of medications are likely to offer patients better agents for control of their illness and mitigate occurrence of acute exacerbations. Better control allows for better patient health, reduced number of physician and emergency department visits, and reduced health care costs.
PMID: 19667712
|
Berger WE,Cline DC
Department of pediatrics, division of allergy and immunology, College of Medicine, University of California, Irvine, USA. wberger@uci.edu
|
Asthma and COPD: definitions, epidemiology, and treatment guidelines.
Postgrad Med. 2005 Dec;118(6 Suppl Acute):2-8
Asthma and chronic obstructive pulmonary disease (COPD) are disorders that affect millions of people in the United States and other countries in the world. Asthma is a chronic inflammatory disease of the airways that has cellular and molecular pathways. Affected patients have recurrent episodes of wheezing, dyspnea, chest tightness, and cough that can be treated to minimize impact. COPD is a disease that is characterized by airflow limitation that is not fully reversible. Prevalence of asthma may be leveling off. Prevalence of COPD is increasing, especially in women. Although several therapies are available, many patients do not seek treatment until COPD is moderately advanced.
PMID: 19667710
|
Tanaka H,Yi TM
Department of Developmental and Cell Biology, University of California Irvine, Irvine, California, USA.
|
Synthetic morphology using alternative inputs.
PLoS One. 2009;4(9):e6946
Designing the shape and size of a cell is an interesting challenge for synthetic biology. Prolonged exposure to the mating pheromone alpha-factor induces an unusual morphology in yeast cells: multiple mating projections. The goal of this work was to reproduce the multiple projections phenotype in the absence of alpha-factor using a gain-of-function approach termed "Alternative Inputs (AIs)". An alternative input is defined as any genetic manipulation that can activate the signaling pathway instead of the natural input. Interestingly, none of the alternative inputs were sufficient to produce multiple projections although some produced a single projection. Then, we extended our search by creating all combinations of alternative inputs and deletions that were summarized in an AIs-Deletions matrix. We found a genetic manipulation (AI-Ste5p ste2Delta) that enhanced the formation of multiple projections. Following up this lead, we demonstrated that AI-Ste4p and AI-Ste5p were sufficient to produce multiple projections when combined. Further, we showed that overexpression of a membrane-targeted form of Ste5p alone could also induce multiple projections. Thus, we successfully re-engineered the multiple projections mating morphology using alternative inputs without alpha-factor.
PMID: 19746161
|
Fisk Z
Department of Physics and Astronomy, University of California, Irvine, Irvine, CA 92697-4575, USA. zfisk@uci.edu
|
Physics. The thermodynamics of quantum critical points.
Science. 2009 Sep 11;325(5946):1348-9
PMID: 19745139
|
Yakob L,Yan G
Program in Public Health, University of California Irvine, Irvine, California, United States of America. lyakob@uci.edu
|
Modeling the effects of integrating larval habitat source reduction and insecticide treated nets for malaria control.
PLoS One. 2009;4(9):e6921
Integrated vector management for malaria control has received a lot of recent interest. Attacking multiple points in the transmission cycle is hoped to act synergistically and improve upon current single-tool interventions based on the use of insecticide-treated bed nets (ITNs). In the present study, we theoretically examined the application of larval habitat source reduction with ITNs in reducing malaria transmission. We selected this type of environmental management to complement ITNs because of a potential secondary mode of action that both control strategies share. In addition to increasing vector mortality, ITNs reduce the rate at which female mosquitoes locate human hosts for blood feeding, thereby extending their gonotrophic cycle. Similarly, while reducing adult vector emergence and abundance, source reduction of larval habitats may prolong the cycle duration by extending delays in locating oviposition sites. We found, however, that source reduction of larval habitats only operates through this secondary mode of action when habitat density is below a critical threshold. Hence, we illustrate how this strategy becomes increasingly effective when larval habitats are limited. We also demonstrate that habitat source reduction is better suited to human populations of higher density and in the presence of insecticide resistance or when the insecticidal properties of ITNs are depleted.
PMID: 19742312
|
Malinoski DJ,Hadjizacharia P,Salim A,Kim H,Dolich MO,Cinat M,Barrios C,Lekawa ME,Hoyt DB
Division of Trauma & Critical Care Surgery, UCI Medical Center, 333 City Boulevard West, Suite 705, Orange, CA 92868, USA. malinosd@uci.edu
|
Elevated serum pancreatic enzyme levels after hemorrhagic shock predict organ failure and death.
J Trauma. 2009 Sep;67(3):445-9
BACKGROUND: Intraluminal pancreatic enzymes have been shown in animal models to be associated with multiple organ failure after hemorrhagic shock, independent of pancreatitis. The translocation of these enzymes into the circulation may serve as a marker of hemorrhagic shock-induced gut ischemia in critically injured trauma patients. We hypothesized that serum amylase and lipase would be significantly elevated in patients presenting in hemorrhagic shock and in those who develop organ failure. METHODS:: Review of a prospective database at a level-1 trauma center from 2000 to 2005. Two thousand seven hundred eleven critically injured trauma patients without pancreatic injuries were evaluated for shock (systolic pressure <90 mm Hg in the emergency department), massive transfusion (10 units of packed red blood cells within the first 24 hours), and organ failure (standard criteria for acute pulmonary, cardiovascular, renal, and hepatic system failure were used). Serum levels >2 times the upper limit of normal for amylase (30-130 U/L) and lipase (7-60 U/L) were defined as elevated. Univariate analyses were performed with the Pearson's chi, and binary logistic regression was used to determine significant risk factors for organ failure. Results with a p value <0.05 were considered significant and are reported. RESULTS:: Patients with elevated amylase (n = 481, 18%) were more likely to present in shock (16% vs. 8%), require massive transfusion (19% vs. 9%), develop organ failure (34% vs. 16%), and die (23% vs. 13%). Patients with elevated lipase (n = 288, 11%) were more likely to require massive transfusion (18% vs. 10%) and develop organ failure (43% vs. 16%). Independent predictors of organ failure were age (odds ratio [OR] = 1.016), Injury Severity Score (OR = 1.02), massive transfusion (OR = 3.1), elevated amylase (OR = 1.9), and elevated lipase (OR = 3.2). Elevated amylase was also an independent predictor of mortality (OR = 1.3). CONCLUSIONS:: Serum levels of pancreatic enzymes are elevated in patients who present in shock or require a massive transfusion and are independent predictors of organ failure. Whether these elevations are caused by ischemic pancreatitis or the translocation of intraluminal enteric pancreatic enzymes is uncertain and future studies are needed. Trauma patients with elevated pancreatic enzymes in the absence of a pancreatic injury have an increased risk of morbidity and mortality.
PMID: 19741384
|
Chen X,Aledia AS,Ghajar CM,Griffith CK,Putnam AJ,Hughes CC,George SC
Department of Biomedical Engineering, University of California Irvine, Irvine, California 92697-2715, USA.
|
Prevascularization of a fibrin-based tissue construct accelerates the formation of functional anastomosis with host vasculature.
Tissue Eng Part A. 2009 Jun;15(6):1363-71
One critical obstacle facing tissue engineering is the formation of functional vascular networks that can support tissue survival in vivo. We hypothesized that prevascularizing a tissue construct with networks of well-formed capillaries would accelerate functional anastomosis with the host upon implantation. Fibrin-based tissues were prevascularized with capillary networks by coculturing human umbilical vein endothelial cells (HUVECs) and fibroblasts in fibrin gels for 1 week. The prevascularized tissue and nonprevascularized controls were implanted subcutaneously onto the dorsal surface of immune-deficient mice and retrieved at days 3, 5, 7 and 14. HUVEC-lined vessels containing red blood cells were evident in the prevascularized tissue by day 5, significantly earlier than nonprevascularized tissues (14 days). Analysis of the HUVEC-lined vessels demonstrated that the number and area of perfused lumens in the prevascularized tissue were significantly larger compared to controls. In addition, collagen deposition and a larger number of proliferating cells were evident in the prevascularized tissue at day 14. Our results demonstrate that prevascularizing a fibrin-based tissue with well-formed capillaries accelerates anastomosis with the host vasculature, and promotes cellular activity consistent with tissue remodeling. Our prevascularization strategy may be useful to design large three-dimensional engineered tissues.
PMID: 18976155
|
Chen X,Aledia AS,Popson SA,Him LK,Hughes CC,George S
University of California, Irvine, Biomedical Engineering, Irvine, California, United States; xchen1@uci.edu.
|
Rapid anastomosis of endothelial precursor cell-derived vessels with host vasculature is promoted by a high density of co-transplanted fibroblasts.
Tissue Eng Part A. 2009 Sep 8;:
To ensure survival of engineered implantable tissues thicker than 2-3 mm, convection of nutrients and waste products to enhance the rate of transport will be required. Creating a network of vessels in vitro, prior to implantation (prevascularization), is one potential strategy to achieve this aim. In this study we developed 3-dimensional engineered vessel networks in vitro by co-culture of endothelial cells (EC) and fibroblasts in a fibrin gel for 7 days. Vessels formed by cord blood endothelial precursor cell-derived EC (EPC-EC) in the presence of a high density of fibroblasts created an interconnected tubular network within 4 days, compared to 5-7 days in the presence of a low density of fibroblasts. Vessels derived from human umbilical vein EC (HUVEC) in vitro showed similar kinetics. Implantation of the prevascularized tissues into immune compromised mice, however, revealed a dramatic difference in the ability of EPC-EC and HUVEC to form anastomoses with the host vasculature. Vascular beds derived from EPC-EC were perfused within one day of implantation whereas no HUVEC vessels were perfused at day 1. Furthermore, while almost 90% of EPC-EC derived vascular beds were perfused at day 3, only one third of HUVEC derived vascular beds were perfused. In both cases a high density of fibroblasts accelerated anastomosis by 2-3 days. We conclude that both EPC-EC and a high density of fibroblasts significantly accelerate the rate of functional anastomosis, and that prevascularizing an engineered tissue may be an effective strategy to enhance convective transport of nutrients in vivo.
PMID: 19737050
|
Wilder-Smith P,Lee K,Guo S,Zhang J,Osann K,Chen Z,Messadi D
Beckman Laser Institute, University of California, Irvine, California 92612, USA. pwsmith@uci.edu
|
In vivo diagnosis of oral dysplasia and malignancy using optical coherence tomography: preliminary studies in 50 patients.
Lasers Surg Med. 2009 Jul;41(5):353-7
BACKGROUND: In vivo, non-invasive optical coherence tomography (OCT) permits high-resolution imaging of tissue surfaces and subsurfaces, with the potential capability for detection and mapping of epithelial pathologies. PURPOSE: To evaluate the clinical capability of non-invasive in vivo OCT for diagnosing oral dysplasia and malignancy. EXPERIMENTAL DESIGN: In 50 patients with oral lesions, conventional clinical examination was followed by OCT imaging, then standard biopsy and histopathology. Two blinded, pre-standardized investigators separately diagnosed each lesion based on (1) OCT and (2) histopathology. RESULTS: Intra- and inter-observer agreement between diagnoses based on histopathology and imaging data was excellent, with lambda values between 0.844 and 0.896. Sensitivity and specificity were also very good. CONCLUSIONS: These data demonstrate the excellent capability of in vivo OCT for detecting and diagnosing oral premalignancy and malignancy in human subjects.
PMID: 19533765
|
Wang A,Raniga PP,Lane S,Lu Y,Liu H
Department of Biological Chemistry, University of California, Irvine, CA 92697-1700, USA. h4liu@uci.edu
|
Hyphal chain formation in Candida albicans: Cdc28-Hgc1 phosphorylation of Efg1 represses cell separation genes.
Mol Cell Biol. 2009 Aug;29(16):4406-16
Cell chain formation is a characteristic of filamentous growth in fungi. How it is regulated developmentally in multimorphic fungi is not known. In Candida albicans, degradation of septa during yeast growth is accomplished by enzymes encoded by Ace2 activated genes expressed in G(1). We found that phosphorylation of a conserved developmental regulator, Efg1, by the cyclin-dependent kinase Cdc28-Hgc1 (hypha-specific G(1) cyclin) downregulates Ace2 target genes during hyphal growth in G(1). A strain containing a threonine-to-alanine mutation at a conserved Cdc28 phosphorylation site of Efg1 displays a loss of hypha-specific repression of these genes and impaired cell chain formation, mimicking the hgc1 deletion, whereas a strain containing the threonine to aspartic acid mutation leads to a downregulation of these genes and cell chain formation during yeast growth. Furthermore, the phosphomimic mutation can suppress cell separation defects of hgc1. Efg1 also displays preferential association with Ace2 target gene promoters during hyphal growth. We show that convergent regulation of Ace2 and Efg1 defines the transcriptional program of cell chain formation.
PMID: 19528234
|
Peralta ER,Edinger AL
Department of Developmental and Cell Biology, University of California-Irvine, Irvine, CA 92697-2300, USA.
|
Ceramide-induced starvation triggers homeostatic autophagy.
Autophagy. 2009 Apr;5(3):407-9
Autophagy is triggered by ceramide, a sphingolipid that regulates diverse cellular processes including survival, differentiation and senescence. Both ceramide and autophagy play important, but incompletely understood, roles in type 2 diabetes and cancer. We reasoned that defining the connection between ceramide and autophagy might provide an important insight into these highly prevalent diseases. Our recently published work demonstrates that ceramide-induced autophagy is a homeostatic response to starvation caused by nutrient transporter downregulation. Preventing nutrient transporter loss or supplementation with transporter-independent nutrients protects cells from ceramide-induced death and delays the onset of autophagy. Thus, we propose a model where ceramide kills cells by inducing acute and severe intracellular nutrient limitation. Consistent with this idea, AMPK-deficient cells that are less able to deal with bioenergetic stress are also more sensitive to ceramide than wild-type cells. Our observation that gradually adapting cells to tolerate low levels of extracellular nutrients confers striking resistance to ceramide toxicity further supports this model. These results highlight the value of measuring nutrient transporter expression in cells undergoing protective autophagy. In addition, this novel mechanism for ceramide-induced cell death suggests new approaches to studying and treating multiple human diseases.
PMID: 19202357
|
McDougall EM,Kolla SB,Santos RT,Gan JM,Box GN,Louie MK,Gamboa AJ,Kaplan AG,Moskowitz RM,Andrade LA,Skarecky DW,Osann KE,Clayman RV
Department of Urology, University of California, Irvine, Orange, California, USA. elspethm@uci.edu
|
Preliminary study of virtual reality and model simulation for learning laparoscopic suturing skills.
J Urol. 2009 Sep;182(3):1018-25
PURPOSE: Repetitive practice of laparoscopic suturing and knot tying can facilitate surgeon proficiency in performing this reconstructive technique. We compared a silicone model and pelvic trainer to a virtual reality simulator in the learning of laparoscopic suturing and knot tying by laparoscopically naïve medical students, and evaluated the subsequent performance of porcine laparoscopic cystorrhaphy. MATERIALS AND METHODS: A total of 20 medical students underwent a 1-hour didactic session with video demonstration of laparoscopic suturing and knot tying by an expert laparoscopic surgeon. The students were randomized to a pelvic trainer (10) or virtual reality simulator (10) for a minimum of 2 hours of laparoscopic suturing and knot tying training. Within 1 week of the training session the medical students performed laparoscopic closure of a 2 cm cystotomy in a porcine model. Objective structured assessment of technical skills for laparoscopic cystorrhaphy was performed at the procedure by laparoscopic surgeons blinded to the medical student training format. A video of the procedure was evaluated with an objective structured assessment of technical skills by an expert laparoscopic surgeon blinded to medical student identity and training format. The medical students completed an evaluation questionnaire regarding the training format after the laparoscopic cystorrhaphy. RESULTS: All students were able to complete the laparoscopic cystorrhaphy. There was no difference between the pelvic trainer and virtual reality groups in mean +/- SD time to perform the porcine cystorrhaphy at 40 +/- 15 vs 41 +/- 10 minutes (p = 0.87) or the objective structured assessment of technical skills score of 8.8 +/- 2.3 vs 8.2 +/- 2.2 (p = 0.24), respectively. Bladder leak occurred in 3 (30%) of the pelvic trainer trained and 6 (60%) of the virtual reality trained medical student laparoscopic cystorrhaphy procedures (Fisher exact test p = 0.37). The only significant difference between the 2 groups was that 4 virtual reality trained medical students considered the training session too short compared to none of those trained on the pelvic trainer (p = 0.04). CONCLUSIONS: There is no significant difference between the pelvic trainer and virtual reality trained medical students in proficiency to perform laparoscopic cystorrhaphy in a pig model, although both groups require considerably more training before performing this procedure clinically. The pelvic trainer training may be more user-friendly for the novice surgeon to begin learning these challenging laparoscopic skills.
PMID: 19616797
|
Nien CJ,Paugh JR,Massei S,Wahlert AJ,Kao WW,Jester JV
The Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA.
|
Age-related changes in the meibomian gland.
Exp Eye Res. 2009 Sep 3;:
The purpose of this study was to characterize the age-related changes of the mouse meibomian gland. Eyelids from adult C57Bl/6 mice at 2, 6, 12 and 24 months of age were stained with specific antibodies against peroxisome proliferator activated receptor gamma (PPARgamma) to identify differentiating meibocytes, Oil Red O(ORO) to identify lipid, Ki67 nuclear antigen to identify cycling cells, B-lymphocyte-induced maturation protein-1 (Blimp1) to identify potential stem cells and CD45 to identify immune cells. Meibomian glands from younger mice (2 and 6 months) showed cytoplasmic and perinuclear staining with anti-PPARgamma antibodies with abundant ORO staining of small, intracellular lipid droplets. Meibomian glands from older mice (12 and 24 months) showed only nuclear PPARgamma localization with less ORO staining and significantly reduced acinar tissue (p<0.04). Acini of older mice also showed significantly reduced (p<0.004) numbers of Ki67 stained nuclei. While Blimp1 appeared to diffusely stain the superficial ductal epithelium, isolated cells were occasionally stained within the meibomian gland duct and acini of older mice that also stained with CD45 antibodies, suggesting the presence of infiltrating plasmacytoid cells.These findings suggest that there is altered PPARgamma receptor signaling in older mice that may underlie changes in cell cycle entry/proliferation, lipid synthesis and gland atrophy during aging. These results are consistent with the hypothesis that mouse meibomian glands undergo age-related changes similar to those identified in humans and may be used as a model for age-related meibomian gland dysfunction.
PMID: 19733559
|
Jian Z,Yu Z,Yu L,Rao B,Chen Z,Tromberg BJ
Beckman Laser Institute, University of California, Irvine, California 92612, USA. zjian@uci.edu
|
Speckle attenuation in optical coherence tomography by curvelet shrinkage.
Opt Lett. 2009 May 15;34(10):1516-8
We describe an algorithm based on shrinkage in the curvelet domain to attenuate speckles in optical coherence tomography (OCT) images. The algorithm exploits the curvelet transform's sparse representation of edge discontinuities that are common in OCT images and its ability to map signals and noise into different areas in the curvelet domain. The speckle attenuation is controlled by a single parameter that determines the threshold in the curvelet domain. Applying the algorithm to OCT images shows significant improvement of image quality.
PMID: 19448806
|
Bateman AP,Nizkorodov SA,Laskin J,Laskin A
Department of Chemistry, University of California, Irvine, Irvine, California 92697, USA. nizkorod@uci.edu.
|
Time-resolved molecular characterization of limonene/ozone aerosol using high-resolution electrospray ionization mass spectrometry.
Phys Chem Chem Phys. 2009 Sep 28;11(36):7931-42
Molecular composition of limonene/O(3) secondary organic aerosol (SOA) was investigated using high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) as a function of reaction time. SOA was generated by ozonation of d-limonene in a reaction chamber and sampled at different time intervals using a cascade impactor. The SOA samples were extracted into acetonitrile and analyzed using a HR-ESI-MS instrument with a resolving power of 100 000 (m/Deltam). The resulting mass spectra provided detailed information about the extent of oxidation inferred from the O : C ratios, double bond equivalency (DBE) factors, and aromaticity index (AI) values in hundreds of identified individual SOA species. The chemical composition of SOA was approximately the same for all size-fractionated samples studied in this experiment (0.05 to 0.5 mum range). The SOA constituents quickly reached an average O : C ratio of 0.43, which grew to 0.46 after one hour of additional oxidation of particles by the excess ozone. The dominant mechanism of oligomerization, inferred from high resolution ESI-MS data, was reaction between Criegee intermediates and stable first-generation products of limonene ozonolysis. Although the SOA composition was dominated by various oxidized aliphatic compounds, a small fraction of products appeared to contain aromatic rings. SOA generation was also studied in the presence of UV radiation and at elevated relative humidity (RH). The presence of UV radiation had a negligible effect on the SOA composition. The presence of water vapor resulted in a slight redistribution of peak intensities in the mass spectrum likely arising from hydration of certain SOA constituents. The data are consistent with fast production of the first-generation SOA constituents, including oligomers, followed by very slow aging processes that have a relatively small effect on the average molecular composition on the timescale of our experiments.
PMID: 19727500
|
Finlayson-Pitts BJ
Department of Chemistry, University of California, Irvine, Irvine, CA 92697-2025, USA. bjfinlay@uci.edu
|
Reactions at surfaces in the atmosphere: integration of experiments and theory as necessary (but not necessarily sufficient) for predicting the physical chemistry of aerosols.
Phys Chem Chem Phys. 2009 Sep 28;11(36):7760-79
While particles have significant deleterious impacts on human health, visibility and climate, quantitative understanding of their formation, composition and fates remains problematic. Indeed, in many cases, even qualitative understanding is lacking. One area of particular uncertainty is the nature of particle surfaces and how this determines interactions with gases in the atmosphere, including water, which is important for cloud formation and properties. The focus in this Perspective article is on some chemistry relevant to airborne particles and especially to reactions occurring on their surfaces. The intent is not to provide a comprehensive review, but rather to highlight a few selected examples of interface chemistry involving inorganic and organic species that may be important in the lower atmosphere. This includes sea salt chemistry, nitrate and nitrite ion photochemistry, organics on surfaces and heterogeneous reactions of oxides of nitrogen on proxies for airborne mineral dust and boundary layer surfaces. Emphasis is on the molecular level understanding that can only be gained by fully integrating experiment and theory to elucidate these complex systems.
PMID: 19727483
|
Ngo-Metzger Q
University of California, Irvine, CA, USA. Qhngo@uci.edu
|
Breaking bad news over the phone.
Am Fam Physician. 2009 Sep 1;80(5):520
PMID: 19725492
|
Garcia JO,Grossman ED
Department of Cognitive Sciences, University of California Irvine, Irvine, CA 92697-5100, USA. jogarcia@uci.edu
|
Motion opponency and transparency in the human middle temporal area.
Eur J Neurosci. 2009 Sep;30(6):1172-82
Motion transparency is the perception of multiple, moving surfaces within the same retinal location (for example, a ripple on the surface of a drifting stream), and is an interesting challenge to motion models because multiple velocities must be represented within the same region of space. When these motion vectors are in opposite directions, brief in duration and spatially constrained within a very local region, the result is little or no perceived motion (motion opponency). Both motion transparency and motion opponency inhibit the firing rate of single middle temporal area (MT) neurons as compared with the preferred direction alone, but neither generally influences the firing rate of primary visual cortex neurons. Surprisingly, neuroimaging studies of human middle temporal area (hMT+) have found less activation due only to motion opponency and an increase in neural responses for motion transparency. Here we parametrically manipulate the local balance between competing motion vectors and find an interaction between motion opponency and transparency in the population blood oxygen level-dependent (BOLD) response. We find reduced BOLD amplitude for motion opponency throughout visual cortex, but weakened responses due to perceptual transparency that is most apparent only within the hMT+. We interpret our results as evidence for two distinct mechanisms mediating opponency and transparency.
PMID: 19723288
|
Anderson KD
Reeve-Irvine Research Center, Department of Neurological Surgery, University of California, 92697-1385, USA. kanderso@uci.edu
|
Consideration of user priorities when developing neural prosthetics.
J Neural Eng. 2009 Oct;6(5):55003
For too long there has been separation of basic science, biomedical engineering, clinical science and the people these disciplines are serving. A key ingredient to understanding the real-life consequences of many neurologic disorders that produce physical disabilities, such as spinal cord injury, is to obtain valuable information from the individuals that are actually living with the disorders everyday. This information can be obtained in an objective and usable format, which can then be used to direct biomedical research in a manner that is meaningful to the intended beneficiaries. In particular, the field of neural prosthetics for spinal cord injury can make great strides if user input is obtained throughout the stages of development. Presented here is the perspective of a scientist who also has 20 years of experience living with a cervical spinal cord injury.
PMID: 19721182
|
Shahrestani P,Leung HT,Le PK,Pak WL,Tse S,Ocorr K,Huang T
Ecology and Evolution, University of California Irvine, Irvine, California, United States of America.
|
Heterozygous mutation of Drosophila Opa1 causes the development of multiple organ abnormalities in an age-dependent and organ-specific manner.
PLoS One. 2009;4(8):e6867
Optic Atrophy 1 (OPA1) is a ubiquitously expressed dynamin-like GTPase in the inner mitochondrial membrane. It plays important roles in mitochondrial fusion, apoptosis, reactive oxygen species (ROS) and ATP production. Mutations of OPA1 result in autosomal dominant optic atrophy (DOA). The molecular mechanisms by which link OPA1 mutations and DOA are not fully understood. Recently, we created a Drosophila model to study the pathogenesis of optic atrophy. Heterozygous mutation of Drosophila OPA1 (dOpa1) by P-element insertion results in no obvious morphological abnormalities, whereas homozygous mutation is embryonic lethal. In eye-specific somatic clones, homozygous mutation of dOpa1 causes rough (mispatterning) and glossy (decreased lens deposition) eye phenotypes in adult Drosophila. In humans, heterozygous mutations in OPA1 have been associated with mitochondrial dysfunction, which is predicted to affect multiple organs. In this study, we demonstrated that heterozygous dOpa1 mutation perturbs the visual function and an ERG profile of the Drosophila compound eye. We independently showed that antioxidants delayed the onset of mutant phenotypes in ERG and improved larval vision function in phototaxis assay. Furthermore, heterozygous dOpa1 mutation also caused decreased heart rate, increased heart arrhythmia, and poor tolerance to stress induced by electrical pacing. However, antioxidants had no effects on the dysfunctional heart of heterozygous dOpa1 mutants. Under stress, heterozygous dOpa1 mutations caused reduced escape response, suggesting abnormal function of the skeletal muscles. Our results suggest that heterozygous mutation of dOpa1 shows organ-specific pathogenesis and is associated with multiple organ abnormalities in an age-dependent and organ-specific manner.
PMID: 19718456
|
|
first | prev 10 | prev | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | next | next 10 | last |
|
back
