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2.  Gadoxetic acid-enhanced MRI for T-staging of gallbladder carcinoma: emphasis on liver invasion 
The British Journal of Radiology  2013;87(1033):20130608.
To evaluate the diagnostic performance of gadoxetic acid-enhanced MRI with an emphasis on the usefulness of the hepatobiliary phase (HBP) in T-staging of gallbladder carcinoma.
66 patients with surgically confirmed gallbladder carcinoma underwent MRI. Two radiologists independently reviewed two sets of gadoxetic acid-enhanced MRI without and with the HBP. Local tumour spread was evaluated according to T-staging, and the results were compared with pathological findings. The diagnostic performance of two image sets to differentiate each T-stage was compared.
The sensitivities of MRI with the HBP to differentiate T1 vs ≥T2 lesions, ≤T2 vs ≥T3 lesions and ≤T3 vs T4 lesions were 96.3%, 85.7% and 100% for Observer 1 and 92.6%, 95.2% and 100% for Observer 2, respectively (p < 0.0001). By adding the HBP, the sensitivities to differentiate ≤T2 vs ≥T3 lesions were increased from 66.7% to 85.7% for Observer 1 and from 81.0% to 95.2% for Observer 2, although there was no significant difference (p > 0.05). The overall accuracies for T-staging were increased from 80.3% to 86.4% for Observer 1, a statistically significant degree (p = 0.046), and from 83.8% to 87.9% for Observer 2 (p > 0.05). The k-value for the two observers indicated excellent agreement.
Gadoxetic acid-enhanced MRI provided acceptable diagnostic performance for T-staging of gallbladder carcinoma. Addition of the HBP aids in the detection of liver invasion.
Advances in knowledge:
In the T-staging of gallbladder carcinoma, gadoxetic acid-enhanced MRI with the HBP may enhance detection of liver invasion.
PMCID: PMC3898979  PMID: 24288397
3.  A semi-automated vascular access system (VAS) for preclinical models 
Physics in medicine and biology  2013;58(16):5351-5362.
Murine models are used extensively in biological and translational research. For many of these studies it is necessary to access the vasculature for the injection of biologically active agents. Among the possible methods for accessing the mouse vasculature, tail vein injections are a routine but critical step for many experimental protocols. To perform successful tail vein injections, a high skill set and experience is required, leaving most scientists ill-suited to perform this task. This can lead to a high variability between injections, which can impact experimental results. To allow more scientists to perform their own tail vein injections and to decrease the variability between injections a vascular access system (VAS) that semi-automatically inserts a needle into the tail vein of a mouse was developed. The VAS uses near infrared (NIR) light, image processing techniques, computer controlled motors, and a pressure feedback system to insert the needle and to validate its proper placement within the vein. The VAS was tested by injecting a commonly used radiolabeled probe (FDG) into the tail veins of five mice. These mice were then imaged using micro-positron emission tomography (PET) to measure the percentage of the injected probe remaining in the tail. These studies showed that, on average, the VAS leaves 3.4% of the injected probe in the tail. With these preliminary results, the VAS system demonstrates the potential for improving the accuracy of tail vein injections in mice.
PMCID: PMC4271828  PMID: 23877111
4.  Relative effects of segregation and recombination on the evolution of sex in finite diploid populations 
Jiang, X | Hu, S | Xu, Q | Chang, Y | Tao, S
Heredity  2013;111(6):505-512.
The mechanism of reproducing more viable offspring in response to selection is a major factor influencing the advantages of sex. In diploids, sexual reproduction combines genotype by recombination and segregation. Theoretical studies of sexual reproduction have investigated the advantage of recombination in haploids. However, the potential advantage of segregation in diploids is less studied. This study aimed to quantify the relative contribution of recombination and segregation to the evolution of sex in finite diploids by using multilocus simulations. The mean fitness of a sexually or asexually reproduced population was calculated to describe the long-term effects of sex. The evolutionary fate of a sex or recombination modifier was also monitored to investigate the short-term effects of sex. Two different scenarios of mutations were considered: (1) only deleterious mutations were present and (2) a combination of deleterious and beneficial mutations. Results showed that the combined effects of segregation and recombination strongly contributed to the evolution of sex in diploids. If deleterious mutations were only present, segregation efficiently slowed down the speed of Muller's ratchet. As the recombination level was increased, the accumulation of deleterious mutations was totally inhibited and recombination substantially contributed to the evolution of sex. The presence of beneficial mutations evidently increased the fixation rate of a recombination modifier. We also observed that the twofold cost of sex was easily to overcome in diploids if a sex modifier caused a moderate frequency of sex.
PMCID: PMC3833686  PMID: 23900397
linkage disequilibrium; segregation; recombination; beneficial mutations; modifier model
5.  Role of hepcidin in murine brain iron metabolism 
Brain iron homeostasis is maintained by a balance of both iron uptake and release, and accumulating evidence has revealed that brain iron concentrations increase with aging. Hepcidin, an iron regulatory hormone produced by hepatocytes in response to inflammatory stimuli, iron, and hypoxia, has been shown to be the long-sought hormone responsible for the regulation of body iron balance and recycling in mammals. In this study, we report that hepcidin is widely expressed in the murine brain. In cerebral cortex, hippocampus and striatum, hepcidin mRNA levels increased with aging. Injection of hepcidin into the lateral cerebral ventricle resulted in decreased Fpn1 protein levels in cerebral cortex, hippocampus, and striatum. Additionally, treatment of primary cultured neurons with hepcidin caused decreased neuronal iron release and Fpn1 protein levels. Together, our data provide further evidence that hepcidin may be involved in the regulation of brain iron metabolism.
PMCID: PMC4225129  PMID: 19898775
Hepcidin; Ferroportin1; Brain iron metabolism; Aging; Murine
6.  Patient-Reported Outcomes in the Practice-based Opportunities for Weight Reduction (POWER) Trial 
To evaluate effects of two behavioral weight loss interventions (in-person, remote) on health-related quality of life (HRQOL) compared to a control intervention.
415 obese US adults with at least one cardiovascular risk factor completed five measures of HRQOL and depression: MOS SF-12 physical component summary [PCS] and mental component summary [MCS]; EuroQoL 5-Dimensions [EQ-5D] single index and visual analog scale; PHQ-8 depression symptoms, and PSQI sleep quality scores at baseline and 6 and 24 months after randomization. Change in each outcome was analyzed using outcome-specific mixed effects models controlling for participant demographic characteristics.
PCS-12 scores over 24 months improved more among participants in the in-person active intervention arm than among control arm participants (P<0.05, ES = 0.21); there were no other statistically significant treatment arm differences in HRQOL change. Greater weight loss was associated with improvements in most outcomes (P<0.05 to <0.0001).
Participants in the in-person active intervention improved more in physical function HRQOL than participants in the control arm did. Greater weight loss during the study was associated with greater improvement in all PRO except for sleep quality, suggesting that weight loss is a key factor in improving HRQOL.
PMCID: PMC4137865  PMID: 23515902
weight reduction trial; comparative effectiveness trial; patient-reported outcomes; quality of life; depression
7.  CBAP promotes thymocyte negative selection by facilitating T-cell receptor proximal signaling 
Cell Death & Disease  2014;5(11):e1518-.
T-cell receptor (TCR)-transduced signaling is critical to thymocyte development at the CD4/CD8 double-positive stage, but the molecules involved in this process are not yet fully characterized. We previously demonstrated that GM-CSF/IL-3/IL-5 receptor common β-chain-associated protein (CBAP) modulates ZAP70-mediated T-cell migration and adhesion. On the basis of the high expression of CBAP during thymocyte development, we investigated the function of CBAP in thymocyte development using a CBAP knockout mouse. CBAP-deficient mice showed normal early thymocyte development and positive selection. In contrast, several negative selection models (including TCR transgene, superantigen staphylococcal enterotoxin B, and anti-CD3 antibody treatment) revealed an attenuation of TCR-induced thymocyte deletion in CBAP knockout mice. This phenotype correlated with a reduced accumulation of BIM upon TCR crosslinking in CBAP-deficient thymocytes. Loss of CBAP led to reduced TCR-induced phosphorylation of proteins involved in both proximal and distal signaling events, including ZAP70, LAT, PLCγ1, and JNK1/2. Moreover, TCR-induced association of LAT signalosome components was reduced in CBAP-deficient thymocytes. Our data demonstrate that CBAP is a novel component in the TCR signaling pathway and modulates thymocyte apoptosis during negative selection.
PMCID: PMC4260732  PMID: 25393474
8.  Liquid antibiotics in bone cement 
Bone & Joint Research  2014;3(8):246-251.
The objective of this study was to compare the elution characteristics, antimicrobial activity and mechanical properties of antibiotic-loaded bone cement (ALBC) loaded with powdered antibiotic, powdered antibiotic with inert filler (xylitol), or liquid antibiotic, particularly focusing on vancomycin and amphotericin B.
Cement specimens loaded with 2 g of vancomycin or amphotericin B powder (powder group), 2 g of antibiotic powder and 2 g of xylitol (xylitol group) or 12 ml of antibiotic solution containing 2 g of antibiotic (liquid group) were tested.
Vancomycin elution was enhanced by 234% in the liquid group and by 12% in the xylitol group compared with the powder group. Amphotericin B elution was enhanced by 265% in the liquid group and by 65% in the xylitol group compared with the powder group. Based on the disk-diffusion assay, the eluate samples of vancomycin-loaded ALBC of the liquid group exhibited a significantly larger inhibitory zone than samples of the powder or the xylitol group. Regarding the ALBCs loaded with amphotericin B, only the eluate samples of the liquid group exhibited a clear inhibitory zone, which was not observed in either the xylitol or the powder groups. The ultimate compressive strength was significantly reduced in specimens containing liquid antibiotics.
Adding vancomycin or amphotericin B antibiotic powder in distilled water before mixing with bone cement can significantly improve the efficiency of antibiotic release than can loading ALBC with the same dose of antibiotic powder. This simple and effective method for preparation of ALBCs can significantly improve the efficiency of antibiotic release in ALBCs.
Cite this article: Bone Joint Res 2014;3:246–51.
PMCID: PMC4127657  PMID: 25104836
Osteomyelitis; Antibiotic loaded bone cement; Vancomycin; Amphotericin B; Skeletal infection
9.  An attenuating role of a WASP-related protein, WASP-B, in the regulation of F-actin polymerization and pseudopod formation via the regulation of RacC during Dictyostelium chemotaxis 
The WASP family of proteins has emerged as important regulators that connect multiple signaling pathways to regulate the actin cytoskeleton. Dictyostelium cells express WASP, as well as a WASP related protein, WASP-B, endoded by wasB gene. WASP-B contains many of the domains present in WASP. Analysis of wild type, wasB null cells revealed that WASP-B is required for proper control of F-actin polymerization in response to a cAMP gradient. Due to the lack of tight control on actin polymerization, wasB null cells exhibited higher level of F-actin polymerization. wasB− cells extend more de novo pseudopods laterally and their average life span is longer than those of wild type cells, causing more turns and inefficient chemotaxis. YFP-WASP-B appears to be uniformly distributed in the cytosol and shows no translocation to cortical membrane upon cAMP stimulation. Active RacC pull-down assay reveals that the level of active RacC in wasB− cells is significantly higher than wild type cells. Moreover, the distribution of active RacC is not localized in wasB− cells. We conclude that chemotaxis defects of wasB− cells are likely to result from the aberrant regulation of RacC activation and localization.
PMCID: PMC3799868  PMID: 23791739
10.  Merkel cell polyomavirus and non-small cell lung cancer 
British Journal of Cancer  2013;108(12):2623.
PMCID: PMC3694227  PMID: 23736034
11.  New Approaches to Human Mobility: Using Mobile Phones for Demographic Research 
Demography  2013;50(3):10.1007/s13524-012-0175-z.
This article explores new methods for gathering and analyzing spatially rich demographic data using mobile phones. It describes a pilot study (the Human Mobility Project) in which volunteers around the world were successfully recruited to share GPS and cellular tower information on their trajectories and respond to dynamic, location-based surveys using an open-source Android application. The pilot study illustrates the great potential of mobile phone methodology for moving spatial measures beyond residential census units and investigating a range of important social phenomena, including the heterogeneity of activity spaces, the dynamic nature of spatial segregation, and the contextual dependence of subjective well-being.
PMCID: PMC3633623  PMID: 23192393
Spatial demography; Activity space; Segregation; Subjective well-being; Ecological momentary assessment
12.  Mechanism of Origin DNA Recognition and Assembly of an Initiator-Helicase Complex by SV40 Large Tumor Antigen 
Cell reports  2013;3(4):1117-1127.
The DNA tumor virus Simian virus 40 (SV40) is a model system for studying eukaryotic replication. SV40 large tumor antigen (LTag) is the initiator/helicase that is essential for genome replication. LTag recognizes and assembles at the viral replication origin. We determined the structure of two multidomain LTag subunits bound to origin DNA. The structure reveals that the origin binding domains (OBDs) and Zn and AAA+ domains are involved in origin recognition and assembly. Notably, the OBDs recognize the origin in an unexpected manner. The histidine residues of the AAA+ domains insert into a narrow minor groove region with enhanced negative electrostatic potential. Computational analysis indicates that this region is intrinsically narrow, demonstrating the role of DNA shape readout in origin recognition. Our results provide important insights into the assembly of the LTag initiator/ helicase at the replication origin and suggest that histidine contacts with the minor groove serve as a mechanism of DNA shape readout.
PMCID: PMC3748285  PMID: 23545501
13.  β-Arrestin 2-dependent activation of ERK1/2 is required for ADP-induced paxillin phosphorylation at Ser83 and microglia chemotaxis 
Glia  2012;60(9):1366-1377.
Microglia play crucial roles in increased inflammation in the CNS upon brain injuries and diseases. Extracellular ADP has been reported to induce microglia chemotaxis and membrane ruffle formation through P2Y12 receptor. In this study, we examined the role of ERK1/2 activation in ADP-induced microglia chemotaxis. ADP stimulation increases the phosphorylation of ERK1/2 and paxillin phosphorylation at Tyr31 and Ser83. Inhibition of ERK1/2 significantly inhibited paxillin phosphorylation at Ser83 and the retraction of membrane ruffles, causing inefficient chemotaxis. Close examination of dynamics of focal adhesion formation with GFP-paxillin revealed that the disassembly of focal adhesions in U0126-treated cells was significantly impaired. Depletion of β-Arr2 with shRNA markedly reduced the phosphorylation of ERK1/2 and Pax/Ser83, indicating that β-Arr2 is required for ERK1/2 activation upon ADP stimulation. A large fraction of phosphorylated ERK1/2 and β-Arr2 were translocated and co-localized at focal contacts in the newly forming lamellipodia. Examination of kinetics and rate constant of paxillin formation and disassembly revealed that the phosphorylation of paxillin at Tyr31 by c-Src appears to be involved in adhesion formation upon ADP stimulation while Ser83 required for adhesion disassembly.
PMCID: PMC3984973  PMID: 22638989
ERK1/2; paxillin phosphorylation; focal adhesion; chemotaxis; microglia
14.  Basophile: Accurate Fragment Charge State Prediction Improves Peptide Identification Rates 
In shotgun proteomics, database search algorithms rely on fragmentation models to predict fragment ions that should be observed for a given peptide sequence. The most widely used strategy (Naive model) is oversimplified, cleaving all peptide bonds with equal probability to produce fragments of all charges below that of the precursor ion. More accurate models, based on fragmentation simulation, are too computationally intensive for on-the-fly use in database search algorithms. We have created an ordinal-regression-based model called Basophile that takes fragment size and basic residue distribution into account when determining the charge retention during CID/higher-energy collision induced dissociation (HCD) of charged peptides. This model improves the accuracy of predictions by reducing the number of unnecessary fragments that are routinely predicted for highly-charged precursors. Basophile increased the identification rates by 26% (on average) over the Naive model, when analyzing triply-charged precursors from ion trap data. Basophile achieves simplicity and speed by solving the prediction problem with an ordinal regression equation, which can be incorporated into any database search software for shotgun proteomic identification.
PMCID: PMC3737598  PMID: 23499924
Fragmentation; Basicity; Fragment size; Ordinal regression
15.  Viscoelastic properties of the ferret brain measured in vivo at multiple frequencies by magnetic resonance elastography 
Journal of biomechanics  2013;46(5):863-870.
Characterization of the dynamic mechanical behavior of brain tissue is essential for understanding and simulating the mechanisms of traumatic brain injury (TBI). Changes in mechanical properties may also reflect changes in the brain due to aging or disease. In this study, we used magnetic resonance elastography (MRE) to measure the viscoelastic properties of ferret brain tissue in vivo. Three-dimensional (3D) displacement fields were acquired during wave propagation in the brain induced by harmonic excitation of the skull at 400 Hz, 600 Hz and 800 Hz. Shear waves with wavelengths on the order of millimeters were clearly visible in the displacement field, in strain fields, and in the curl of displacement field (which contains no contributions from longitudinal waves). Viscoelastic parameters (storage and loss moduli) governing dynamic shear deformation were estimated in gray and white matter for these excitation frequencies. To characterize the reproducibility of measurements, two ferrets were studied on three different dates each. Estimated viscoelastic properties of white matter in the ferret brain were generally similar to those of gray matter and consistent between animals and scan dates. In both tissue types G′ increased from approximately 3 kPa at 400 Hz to 7 kPa at 800 Hz and G″ increased from approximately 1 kPa at 400 Hz to 2 kPa at 800 Hz. These measurements of shear wave propagation in the ferret brain can be used to both parameterize and validate finite element models of brain biomechanics.
PMCID: PMC3616770  PMID: 23352648
16.  The shape of things to come? Obesity prevalence among foreign-born vs. US-born Mexican youth in California 
Obesity among the Mexican-origin adult population in the US has been associated with longer stays in the US and with being US- vs. Mexican-born, two proxies for acculturation. This pattern is less clear for Mexican-origin children and young adults: recent evidence suggests that it may be reversed, with foreign-born Mexican youth in the US at higher risk of obesity than their US-born Mexican–American counterparts. The objective of this study is to evaluate the hypothesis that the immigrant advantage in obesity prevalence for Mexican-origin populations in the US does not hold for children and young adults. We use data from the Los Angeles Family and Neighborhood Survey (N = 1143) and the California Health Interview Survey (N = 25,487) for respondents ages 4–24 to calculate the odds of overweight/obesity by ethnicity and nativity. We find support for the hypothesis that overweight/obesity prevalence is not significantly lower for first-generation compared to second- and third-generation Mexican-origin youth. Significantly higher obesity prevalence among the first generation was observed for young adult males (ages 18–24) and adolescent females (ages 12–17). The previously-observed protective effect against obesity risk among recent adult immigrants does not hold for Mexican-origin youth.
PMCID: PMC3888820  PMID: 23273875
U.S.A; Adolescent; Children; Obesity; Hispanic and Latino; Immigrant populations
17.  Manganese exposure and cognitive deficits: A growing concern for manganese neurotoxicity⋆ 
Neurotoxicology  2012;33(4):10.1016/j.neuro.2012.03.009.
This symposium comprised five oral presentations dealing with recent findings on Mn-related cognitive and motor changes from epidemiological studies across the life span. The first contribution highlighted the usefulness of functional neuroimaging of the central nervous system (CNS) to evaluate cognitive as well as motor deficits in Mn-exposed welders. The second dealt with results of two prospective studies in Mn-exposed workers or welders showing that after decrease of Mn exposure the outcome of reversibility in adverse CNS effects may differ for motor and cognitive function and, in addition the issue of plasma Mn as a reliable biomarker for Mn exposure in welders has been addressed. The third presentation showed a brief overview of the results of an ongoing study assessing the relationship between environmental airborne Mn exposure and neurological or neuropsychological effects in adult Ohio residents living near a Mn point source. The fourth paper focused on the association between blood Mn and neurodevelopment in early childhood which seems to be sensitive to both low and high Mn concentrations. The fifth contribution gave an overview of six studies indicating a negative impact of excess environmental Mn exposure from air and drinking water on children’s cognitive performance, with special attention to hair Mn as a potential biomarker of exposure. These studies highlight a series of questions about Mn neurotoxicity with respect to cognitive processes, forms and routes of exposure, adequate biomarkers of exposure, gender differences, susceptibility and exposure limits with regard to age.
PMCID: PMC3839941  PMID: 22498092
Manganese; Biomarkers; Neurotoxicity; Cognitive performance; Functional neuroimaging; Neuropsychological testing; Reversibility; Adults; Children; Postnatal neurodevelopment
18.  Nucleolar protein GLTSCR2 stabilizes p53 in response to ribosomal stresses 
Cell Death and Differentiation  2012;19(10):1613-1622.
p53 is a key regulator of cell growth and death by controlling cell cycle progression and apoptosis under conditions of stress such as DNA damage or oncogenic stimulation. As these processes are critical for cell function and inhibition of tumor development, p53 regulatory pathways are strictly monitored in cells. Recently, it was recognized that nucleolar proteins, including nucleophosmin/B23, ribosomal protein L11, and alternate reading frame (ARF), form the nucleolus-ARF-murine double minute 2 (MDM2) axis in p53 regulatory pathways, which increases p53 stability by suppressing the activity of MDM2. In this work, we show that nucleolar protein glioma tumor-suppressor candidate region gene 2 (GLTSCR2) translocates to the nucleoplasm under ribosomal stress, where it interacts with and stabilizes p53 and inhibits cell cycle progression without the involvement of the major upstream p53 regulator, ARF. Furthermore, ectopic expression of GLTSCR2 significantly suppressed growth of cancer cells in a xenograft animal model via p53-dependent pathway. Our data identify GLTSCR2 as a new member of the nucleolus–nucleoplasmic axis for p53 regulation. ARF-independent direct regulation of p53 by GLTSCR2 may be a key mechanism and therapeutic target for cell death or growth inhibition when nucleolus-ARF-p53 pathways are inactivated by genetic or epigenetic modifications of ARF, which are the second most common types of genetic change observed in human cancers.
PMCID: PMC3438492  PMID: 22522597
GLTSCR2; p53; tumor suppressor; nucleolus
19.  Gentamicin in bone cement 
Bone & Joint Research  2013;2(10):220-226.
The objective of this study is to determine an optimal antibiotic-loaded bone cement (ALBC) for infection prophylaxis in total joint arthroplasty (TJA).
We evaluated the antibacterial effects of polymethylmethacrylate (PMMA) bone cements loaded with vancomycin, teicoplanin, ceftazidime, imipenem, piperacillin, gentamicin, and tobramycin against methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant Staph. aureus (MRSA), coagulase-negative staphylococci (CoNS), Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Standardised cement specimens made from 40 g PMMA loaded with 1 g antibiotics were tested for elution characteristics, antibacterial activities, and compressive strength in vitro.
The ALBC containing gentamicin provided a much longer duration of antibiotic release than those containing other antibiotic. Imipenem-loading on the cement had a significant adverse effect on the compressive strength of the ALBC, which made it insufficient for use in prosthesis fixation. All of the tested antibiotics maintained their antibacterial properties after being mixed with PMMA. The gentamicin-loaded ALBC provided a broad antibacterial spectrum against all the test organisms and had the greatest duration of antibacterial activity against MSSA, CoNS, P. aeruginosa and E. coli.
When considering the use of ALBC as infection prophylaxis in TJA, gentamicin-loaded ALBC may be a very effective choice.
Cite this article: Bone Joint Res 2013;2:220–6.
PMCID: PMC3809714  PMID: 24128666
Bone cement; Arthroplasty; Peri-prosthetic joint infection; Gentamicin; Infection
20.  Correlation of the apparent diffusion coefficiency values on diffusion-weighted imaging with prognostic factors for breast cancer 
The British Journal of Radiology  2012;85(1016):e474-e479.
The aim of this study was to correlate the apparent diffusion coefficient (ADC) value of breast cancer with prognostic factors.
335 patients with invasive ductal carcinoma not otherwise specified (IDC NOS) and ductal carcinoma in situ (DCIS) who underwent breast MRI with diffusion-weighted imaging were included in this study. ADC of breast cancer was calculated using two b factors (0 and 1000 s mm–2). Mean ADCs of IDC NOS and DCIS were compared and evaluated. Among cases of IDC NOS, mean ADCs were compared with lymph node status, size and immunochemical prognostic factors using Student's t-test. ADC was also correlated with histological grade using the Kruskal–Wallis test.
Mean ADC of IDC NOS was significantly lower than that of DCIS (p<0.001). However, the mean ADC of histological grade of IDC NOS was not significantly different (p=0.564). Mean ADC of oestrogen receptor (ER)-positive or progesterone receptor (PR)-positive cancer was significantly lower than that of ER-negative or PR-negative cancer (p=0.003 vs p=0.032). Mean ADC of Ki-67 index-positive cancer was significantly lower than that of Ki-67 index-negative cancer (p=0.028). Mean ADC values of cancers with increased microvascular density (MVD) were significantly lower than those of cancer with no MVD increase (p=0.009). No correlations were observed between mean ADC value and human growth factor receptor 2 expression, tumour size and lymph node metastasis.
Low ADC value was correlated with positive expression of ER, PR, increased Ki-67 index, and increased MVD of breast cancer.
PMCID: PMC3587081  PMID: 22128125
21.  Durational and generational differences in Mexican immigrant obesity: Is acculturation the explanation? 
Social science & medicine (1982)  2012;75(2):300-310.
Using the Los Angeles Family and Neighborhood Survey (L.A.FANS-2; n = 1610), we explore the link between Mexican immigrant acculturation, diet, exercise and obesity. We distinguish Mexican immigrants and 2nd generation Mexicans from 3rd+ generation whites, blacks and Mexicans. First, we examine variation in social and linguistic measures by race/ethnicity, duration of residence and immigrant generation. Second, we consider the association between acculturation, diet and exercise. Third, we evaluate the degree to which acculturation, diet, exercise, and socioeconomic status explain the association between race/ethnicity, immigrant exposure to the US (duration since immigration/generation), and adult obesity. Among immigrants, we find a clear relationship between acculturation measures, exposure to the US, and obesity-related behaviors (diet and exercise). However, the acculturation measures do not clearly account for the link between adult obesity, immigrant duration and generation, and race/ethnicity.
PMCID: PMC3595158  PMID: 22575698
Immigration; Health; Acculturation; Obesity; USA; Mexican; Diet; Exercise
22.  Late diagnosis of HIV infection at two academic medical centers: 1994–2004 
AIDS care  2008;20(8):977-983.
Over the last decade, there has been increased attention to the role of earlier HIV testing in the United States. Our objective was to determine if this has translated into changes in the proportion of inpatients with advanced disease at the time of initial HIV diagnosis. We identified inpatients discharged with a new diagnosis of HIV infection or AIDS between 1994 and 2004 at two academic medical centers. We examined trends in initial CD4 count at diagnosis over three time periods: 1994–1996, 1997–2000 and 2001–2004. Between 1994 and 2004, 235 inpatients were newly diagnosed with HIV infection or AIDS in the two centers. For the 217 patients with available CD4 count data, the median initial CD4 count was 41/μl (interquartile range 19–138/μl). Of the 217 patients, 184(85%) had CD4 ≤200/μl and 119/217 (55%) had CD4 ≤50/μl. There were no significant differences in median CD4 count by time period. A large majority of inpatients with newly diagnosed HIV infection at two academic medical centers between 1994 and 2004 had signs of advanced immunodeficiency. Over this recent 11-year period there was no evidence that inpatients with a new HIV diagnosis were identified at earlier stages of disease.
PMCID: PMC3651850  PMID: 18608072
HIV infections/testing; HIV infections/epidemiology; HIV infections/diagnosis
23.  Hepatitis C among methadone maintenance treatment patients in Shanghai and Kunming, China 
This study aims to: (1) document the prevalence of hepatitis C virus (HCV) among methadone maintenance treatment (MMT) patients in Kunming and Shanghai; (2) examine risk factors for HCV by comparing those who tested positive with those who were negative and (3) examine if HCV serostatus is related to attitudes toward MMT.
Using data collected from 306 patients admitted to MMT in 2009–2010 in Shanghai and Kunming, we compared HCV-positive and HCV-negative patients (based on clinical records) on their HCV knowledge and risk behaviors and attitudes toward MMT.
The HCV seropositive rate was 53.3% (51.3% in Shanghai and 55.5% in Kunming) and a majority of patients did not know their serostatus. Patients scored on average fewer than 6 correct out of the 20 items in the HCV knowledge questionnaire. Recent injection use and length of opiate use were strong predictors of HCV status, while no differences were found between HCV-positive and HCV-negative individuals in sexual risks or HCV knowledge. Both groups expressed similar views toward MMT.
The high HCV prevalence and the general lack of knowledge about HCV infection, transmission and treatment suggest the need to provide HCV education and health promotion programs among patients in MMT.
PMCID: PMC3285118  PMID: 22138488
communicable diseases; health services; public health
24.  Expression, purification and biochemical characterization of Schizosaccharomyces pombe Mcm4, 6 and 7 
BMC Biochemistry  2013;14:5.
The hetero-hexamer of the eukaryotic minichromosome maintenance (MCM) proteins plays an essential role in replication of genomic DNA. The ring-shaped Mcm2-7 hexamers comprising one of each subunit show helicase activity in vitro, and form double-hexamers on DNA. The Mcm4/6/7 also forms a hexameric complex with helicase activity in vitro.
We used an Escherichiai coli expression system to express various domains of Schizosaccharomyces pombe Mcm4, 6 and 7 in order to characterize their domain structure, oligomeric states, and possible inter-/intra-subunit interactions. We also successfully employed a co-expression system to express Mcm4/6/7 at the same time in Escherichiai coli, and have purified functional Mcm4/6/7 complex in a hexameric state in high yield and purity, providing a means for generating large quantity of proteins for future structural and biochemical studies.
Based on our results and those of others, models were proposed for the subunit arrangement and architecture of both the Mcm4/6/7 hexamer and the Mcm2-7 double-hexamer.
PMCID: PMC3605359  PMID: 23444842
Cell cycle proteins; DNA-binding proteins; Recombinant proteins; Protein binding; Protein oligomerization; Schizosaccharomyces pombe; Escherichiai coli
25.  BPR1J-097, a novel FLT3 kinase inhibitor, exerts potent inhibitory activity against AML 
British Journal of Cancer  2011;106(3):475-481.
Activating mutations of Fms-like tyrosine kinase 3 (FLT3) constitute a major driver in the pathogenesis of acute myeloid leukaemia (AML). Hence, pharmacological inhibitors of FLT3 are of therapeutic interest for AML.
The effects of inhibition of FLT3 activity by a novel potent FLT3 inhibitor, BPR1J-097, were investigated using in vitro and in vivo assays.
The 50% inhibitory concentration (IC50) of BPR1J-097 required to inhibit FLT3 kinase activity ranged from 1 to 10 n, and the 50% growth inhibition concentrations (GC50s) were 21±7 and 46±14 n for MOLM-13 and MV4-11 cells, respectively. BPR1J-097 inhibited FLT3/signal transducer and activator of transcription 5 phosphorylation and triggered apoptosis in FLT3-driven AML cells. BPR1J-097 also showed favourable pharmacokinetic property and pronounced dose-dependent tumour growth inhibition and regression in FLT3-driven AML murine xenograft models.
These results indicate that BPR1J-097 is a novel small molecule FLT-3 inhibitor with promising in vivo anti-tumour activities and suggest that BPR1J-097 may be further developed in preclinical and clinical studies as therapeutics in AML treatments.
PMCID: PMC3273346  PMID: 22187040
acute myeloid leukaemia; FLT3; FLT3-ITD; MOLM-13; MV4-11; kinase inhibitor

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