Few data are available about intakes and food sources of trans-fatty acids (TFAs) or their associations with cardiometabolic outcomes in Asian people who consume a prudent diet but are experiencing rapid nutritional transitions. We aimed to investigate the relationships between TFA biomarkers and type 2 diabetes and cardiovascular risk factors in Chinese individuals.
Erythrocyte fatty acids were measured by gas chromatography among 3,107 men and women (50–70 years) recruited from urban and rural areas in Beijing and Shanghai, China.
Total trans-18:1 and two trans-18:2 isomers were detected and accounted for 0.37% of the total fatty acids in the erythrocytes. Concentrations of TFAs were higher in women than men, and in urban than rural residents. Of the TFAs, trans-18:1, but not trans-18:2, showed a modest association with dairy consumption (β=0.27), but not with other foods. After adjustment for BMI, social-demographic, lifestyle and dietary factors and other TFAs, erythrocyte trans-18:1 was shown to be associated with a lower risk of type 2 diabetes (OR comparing extreme quartiles=0.68, 95% CI=0.48, 0.97, ptrend=0.02), as well as 20–50% lower odds of central obesity, dyslipidaemia, hyperglycemia, insulin resistance and chronic inflammation. In contrast, trans-18:2 fatty acids were positively associated with high triacylglycerol (ptrend<0.001) and LDL-cholesterol (ptrend=0.03) levels, but not with diabetes and other cardiometabolic risk factors.
Among middle-aged and older Chinese individuals with overall low erythrocyte TFAs levels, trans-18:1 might serve as a marker of dairy intake. Higher trans-18:1 levels were associated with a lower risk of type 2 diabetes, whereas higher trans-18:2 levels were associated with dyslipidaemia.
Biomarkers; Diet; Dyslipidaemia; trans-Fatty acids; Type 2 diabetes
The aim of this article was to prospectively evaluate the accuracy and radiation dose of 320-detector row dynamic volume CT (DVCT) for the detection of coronary artery disease (CAD) in a high-risk population.
60 patients with a high risk of CAD underwent DVCT without preceding heart rate control and also underwent invasive coronary angiography (ICA), which served as the standard reference.
On a per segment analysis, overall sensitivity was 95.3%, specificity was 97.6%, positive predictive value was 90.6%, negative predictive value was 98.8% and Youden index was 0.93. In both heart rate subgroups, diagnostic accuracy for the assessment of coronary artery stenosis was similar. The accuracy of the subgroup with an Agatston score ≥100 was lower than that for patients with an Agatston score <100. However, the difference between DVCT and ICA results was not significant (p=0.08). The mean estimated effective dose of CT was 12.5±9.4 mSv. In those patients with heart rates less than 70 beats per minute (bpm), the mean radiation exposure of DVCT was 5.2±0.9 mSv. The effective radiation dose was significantly lower than that of ICA (14.1±5.9 mSv) (p<0.001). When the heart rate was >70 bpm, a significantly higher dose was delivered to patients with DVCT (22.6±5.2 mSv, p<0.001) than with ICA (15.0±5.3 mSv, p<0.001).
DVCT reliably provides high diagnostic accuracy without heart rate/rhythm control. However, from a dosimetric point of view, it is recommended that heart rate should be controlled to <70 bpm to decrease radiation dose.
Periodic blood exchange transfusion is a treatment modality commonly used to manage pediatric sickle cell anemia (SCA) at the University of California Davis Medical Center. The goal of exchange transfusion therapy is to ameliorate vasoocclusion and improve tissue perfusion by removing sickled red blood cells (RBCs) and introducing normal RBCs. Using computer-assisted intravital microscopy, pre- and post-transfusion microvascular characteristics were analyzed. In this study, the bulbar conjunctiva exhibited a “blanched” avascular appearance in all six pediatric SCA patients prior to transfusion, indicative of tissue hypoperfusion and ischemia. Immediately following transfusion, substantial improvement in vascularization and tissue perfusion resulted, reflected by the enhanced appearance of capillaries and arterioles. In addition, a decrease in red cell velocity was observed. These observations provide evidence that exchange transfusion therapy is beneficial in ameliorating vasoocclusion and improving tissue perfusion. However, with the paradoxical post-transfusion decrease in red cell velocity presumably due to induced hyperviscosity from the large transfusion volume, blood flow is still impaired. This decreased velocity may thwart efforts to improve oxygen delivery via transfusion and may, to some extent, promote vasoocclusion instead. This paradoxical result warrants further investigation on the effects of transfusion volume and viscosity in the exchange transfusion process.
Sickle cell anemia; microcirculation; exchange transfusion; vasoocclusion; tissue perfusion; intravital microscopy
The abundances, compositions, and activities of microbial communities were investigated at bog and fen sites in the Glacial Lake Agassiz Peatland of northwestern Minnesota. These sites contrast in the reactivity of dissolved organic matter (DOM) and the presence or absence of groundwater inputs. Microbial community composition was characterized using pyrosequencing and clone library construction of phylogenetic marker genes. Microbial distribution patterns were linked to pH, concentrations of dissolved organic carbon and nitrogen, C/N ratios, optical properties of DOM, and activities of laccase and peroxidase enzymes. Both bacterial and archaeal richness and rRNA gene abundance were >2 times higher on average in the fen than in the bog, in agreement with a higher pH, labile DOM content, and enhanced enzyme activities in the fen. Fungi were equivalent to an average of 1.4% of total prokaryotes in gene abundance assayed by quantitative PCR. Results revealed statistically distinct spatial patterns between bacterial and fungal communities. Fungal distribution did not covary with pH and DOM optical properties and was vertically stratified, with a prevalence of Ascomycota and Basidiomycota near the surface and much higher representation of Zygomycota in the subsurface. In contrast, bacterial community composition largely varied between environments, with the bog dominated by Acidobacteria (61% of total sequences), while the Firmicutes (52%) dominated in the fen. Acetoclastic Methanosarcinales showed a much higher relative abundance in the bog, in contrast to the dominance of diverse hydrogenotrophic methanogens in the fen. This is the first quantitative and compositional analysis of three microbial domains in peatlands and demonstrates that the microbial abundance, diversity, and activity parallel with the pronounced differences in environmental variables between bog and fen sites.
The objective of this study was to examine the effect of the off axis retinoscopy on objective central refractive measurement in adult clinical practice.
In all, 40 subjects underwent undilated retinoscopy in a randomly selected eye both on and off the visual axis by a single masked examiner. Off axis retinoscopy was defined as retinoscopy performed with the testing eye of the examiner aligned with the contralateral (non-test) eye of the subject resulting in an off axis deviation in the nasal horizontal visual field. Retinoscopy was performed in negative cylinder only and spherocylindrical measurements were converted to power vectors for analysis. Paired t-test was used to assess differences in M, J0 and J45 power vectors including differences between mean aided and unaided LogMar acuities.
In all, 14 subjects were myopic (SE≤−0.5 D), 13 subjects were emmetropic (SE between −0.49 and 1.0 D) and 13 subjects were hyperopic (SE >1.0 D). Mean angle of deviation was 5.58° in the nasal horizontal visual field. J0 showed a significant negative shift in those with myopia (P<0.001) and emmetropia (P=0.049) following off axis retinoscopy. No significant differences in M, J0 and J45 were found in the hyperopes. Mean aided LogMar acuities after on and off axis retinoscopy were both significantly better than mean unaided LogMar VA (P<0.001 in both cases).
Small degrees of off axis retinoscopy encountered in everyday clinical practice can induce errors in objective central refractive measurement.
off axis; retinoscopy; refractive; error; power; vectors
Ischaemic heart failure remains a significant health and economic problem worldwide. This paper presents a user-friendly software system that will form a part of the virtual pathological heart of the Virtual Physiological Human (VPH2) project, currently being developed under the European Commission Virtual Physiological Human (VPH) programme. VPH2 is an integrated medicine project, which will create a suite of modelling, simulation and visualization tools for patient-specific prediction and planning in cases of post-ischaemic left ventricular dysfunction. The work presented here describes a three-dimensional interactive visualization for simulating left ventricle restoration surgery, comprising the operations of cutting, stitching and patching, and for simulating the elastic deformation of the ventricle to its post-operative shape. This will supply the quantitative measurements required for the post-operative prediction tools being developed in parallel in the same project.
heart; heart failure; surgical planning; virtual surgery; visualization; computer graphics
To determine the supporting role of a novel foldable capsular vitreous body (FCVB) with magnetic resonance imaging (MRI) in the treatment of severe retinal detachment in human eyes.
The study examined nine eyes of nine patients. Among the nine eyes, five had suffered penetrating injuries while four had suffered contusions of the eyeball involving large defects of the retina or choroids. A standard three-port pars plana vitrectomy was performed, FCVB was triple-folded and sent into the vitreous cavity; balanced salt solution (BSS) was injected into the capsule to support the retina. Three cardinal axes of nine eyes were examined using MRI at baseline and at the 3-month follow up.
MRI revealed that the signal intensity of the FCVB was similar to the normal vitreous body, with low-signal intensity on T1-weighted image and high-signal intensity on T2-weighted image. In three pre-operative silicone oil- or heavy silicone oil-filled eyes, FCVBs were not fully inflated, and eyeball deformation was observed in one eye. Shifts of three cardinal axes of three eyes (horizontal, anteroposterior, and vertical) according to MRI, were −4.33, −4.67, and −2.67 mm. In the remaining six eyes, FCVBs were well distributed in the vitreous cavity and evenly supported the retina; the cardinal axes of the eyes were similar to pre-operation. Shifts of three cardinal axes of six eyes were −0.34, −0.34, and −0.34 mm. In a total of nine eyes, shifts of three cardinal axes were −1.67, −1.77, and −1.11 mm. Statistically significant difference showed only between the horizontal axis of nine eyes pre-operatively and post-operatively (P1=0.041, P2=0.058, P3=0.123).
This study demonstrated the effectiveness of MRI to monitor the supporting role of an FCVB in the treatment of severe retinal detachment in human eyes.
FCVB; human eyes; magnetic resonance imaging
The Wnt signaling pathway is capable of self-regulation through positive and negative feedback mechanisms. For example, the oncoprotein c-Myc, which is upregulated by Wnt signaling activity, participates in a positive feedback loop of canonical Wnt signaling through repression of Wnt antagonists DKK1 and SFRP1. In this study, we investigated the mechanism of Wnt inhibitory factor-1 (WIF-1) silencing. Mapping of CpG island methylation of the WIF-1 promoter reveals regional methylation (–295 to –95 bp from the transcription start site) that correlates with transcriptional silencing. We identified Miz-1 as a direct activator of WIF-1 transcriptional activity, which is found at WIF-1 promoter. In addition, we show that c-Myc contributes to WIF-1 transcriptional repression in a Miz-1-dependent manner. Although the transient repression mediated by Miz-1/c-Myc is independent of de novo methylation, the stable repression by this complex is associated with CpG island methylation of the critical –295 to –95-bp region of the WIF-1 promoter. Importantly, Miz-1 and c-Myc are found at WIF-1 promoter in WIF-1 non-expressing cell lines DLD-1 and 209myc. Transient knockdown or somatic knockout of c-Myc in DLD-1 failed to restore WIF-1 expression suggesting that c-Myc is involved in initiating rather than maintaining WIF-1 epigenetic silencing. In a genome-wide screen, DNAJA4, TGFβ-induced and TRIM59 were repressed by c-Myc overexpression and DNA promoter hypermethylation. Our data reveal novel insights into c-Myc-mediated DNA methylation-dependent transcriptional silencing, a mechanism that might contribute to the dysregulation of Wnt signaling in cancer.
WIF-1; Wnt signaling; c-Myc; Miz-1; DNA methylation
Polycythemia vera (PV), essential thrombocythemia and primary myelofibrosis, are myeloproliferative neoplasms (MPNs) with distinct clinical features and are associated with the JAK2V617F mutation. To identify genomic anomalies involved in the pathogenesis of these disorders, we profiled 87 MPN patients using Affymetrix 250K single-nucleotide polymorphism (SNP) arrays. Aberrations affecting chr9 were the most frequently observed and included 9pLOH (n=16), trisomy 9 (n=6) and amplifications of 9p13.3–23.3 (n=1), 9q33.1–34.13 (n=1) and 9q34.13 (n=6). Patients with trisomy 9 were associated with elevated JAK2V617F mutant allele burden, suggesting that gain of chr9 represents an alternative mechanism for increasing JAK2V617F dosage. Gene expression profiling of patients with and without chr9 abnormalities (+9, 9pLOH), identified genes potentially involved in disease pathogenesis including JAK2, STAT5B and MAPK14. We also observed recurrent gains of 1p36.31–36.33 (n=6), 17q21.2–q21.31 (n=5) and 17q25.1–25.3 (n=5) and deletions affecting 18p11.31–11.32 (n=8). Combined SNP and gene expression analysis identified aberrations affecting components of a non-canonical PRC2 complex (EZH1, SUZ12 and JARID2) and genes comprising a ‘HSC signature' (MLLT3, SMARCA2 and PBX1). We show that NFIB, which is amplified in 7/87 MPN patients and upregulated in PV CD34+ cells, protects cells from apoptosis induced by cytokine withdrawal.
myeloproliferative neoplasms; JAK2V617F; NFIB; SNP
Photovoltaic functions in organic materials are intimately connected to interfacial morphologies of molecular packing in films on the nanometer scale and molecular levels. This review will focus on current studies on correlations of nanoscale morphologies in organic photovoltaic (OPV) materials with fundamental processes relevant to photovoltaic functions, such as light harvesting, exciton splitting, exciton diffusion, and charge separation (CS) and diffusion. Small molecule photovoltaic materials will be discussed here. The donor and acceptor materials in small molecule OPV devices can be fabricated in vacuum-deposited, multilayer, crystalline thin films, or spin-coated together to form blended bulk heterojunction (BHJ) films. These two methods result in very different morphologies of the solar cell active layers. There is still a formidable debate regarding which morphology is favored for OPV optimization. The morphology of the conducting films has been systematically altered; using variations of the techniques above, the whole spectrum of film qualities can be fabricated. It is possible to form a highly crystalline material, one which is completely amorphous, or an intermediate morphology. In this review, we will summarize the past key findings that have driven organic solar cell research and the current state-of-the-art of small molecule and conducting oligomer materials. We will also discuss the merits and drawbacks of these devices. Finally, we will highlight some works that directly compare the spectra and morphology of systematically elongated oligothiophene derivatives and compare these oligomers to their polymer counterparts. We hope this review will shed some new light on the morphology differences of these two systems.
organic photovoltaics; perylene; thiophene; charge transport; transient absorption; grazing incidence x-ray scattering
We investigated receptor activator of nuclear factor-κB ligand (RANKL) expression by B lymphocytes during early and late aspects of the immune response to Aggregatibacter actinomycetemcomitans, a gram-negative, anaerobic bacterium associated with aggressive periodontal disease.
Expression of messenger RNA transcripts (tumor necrosis factor-α, Toll-like receptors 4 and 9, interleukins 4 and 10, and RANKL) involved in early (1-day) and late (10-day) responses in cultured rat splenocytes was examined by reverse transcription–polymerase chain reaction (RT-PCR). The immune cell distribution (T, B, and natural killer cells and macrophages) in cultured rat splenocytes and RANKL expression in B cells were determined by flow cytometric analyses. B-cell capacity for induction of osteoclast differentiation was evaluated by coculture with RAW 264.7 cells followed by a tartrate-resistant acid phosphatase (TRAP) activity assay.
The expression levels of interleukins 4 and 10 in cultured cells were not changed in the presence of A. actinomycetemcomitans until cultured for 3 days, and peaked after 7 days. After culture for 10 days, the percentages of B and T cells, the overall RANKL messenger RNA transcripts, and the percentage of RANKL-expressing immunoglobulin G-positive cells were significantly increased in the presence of A. actinomycetemcomitans. These increases were considerably greater in cells isolated from A. actinomycetemcomitans-immunized animals than from non-immunized animals. RAW 264.7 cells demonstrated significantly increased TRAP activity when cocultured with B cells from A. actinomycetemcomitans-immunized animals. The addition of human osteoprotegerin-Fc to the culture significantly diminished such increases.
This study suggests that B-lymphocyte involvement in the immune response to A. actinomycetemcomitans through upregulation of RANKL expression potentially contribute to bone resorption in periodontal disease.
Aggregatibacter actinomycetemcomitans; B lymphocytes; immune response; periodontal disease; receptor activator of nuclear factor-κB ligand
The s allele variant of the serotonin transporter gene (5-HTT) has recently been observed to moderate the relationship of stress to depression and anxiety. To date no study has considered interactive effects of 5-HTT genotype, stress and HPA function on cognition in healthy, older adults, which may reflect developmental, functional, or neurodegenerative effects of the serotonin transporter polymorphism.
We investigated whether 5-HTT genotype interacts with cumulative life stress and HPA-axis measures of waking and diurnal cortisol slope to impact cognition in 154 non-depressed, older adults. Structural images of hippocampal volume were acquired on a subsample of 56 participants.
The 5-HTT s allele was associated with both significantly lower delayed recall and higher waking cortisol levels. Presence of the s allele interacted with higher waking cortisol to negatively impact memory. We also observed a significant interaction of higher waking cortisol and the s allele on lower hippocampal volume. Smaller hippocampi and higher cortisol were associated with lower delayed recall only in s allele carriers. No impact or interactions of cumulative life stress with 5-HTT or cortisol were observed.
This is the first investigation to identify an association of the 5-HTT s allele with poorer memory function in older adults. The interactive effects of the s allele and waking cortisol levels on reduced hippocampal volume and lower memory suggest that the negative effect of the serotonin polymorphism on memory is mediated by the HPA axis. Further, given the significant association of the s allele with higher waking cortisol in our investigation, future studies may want to evaluate the impact of the serotonin transporter polymorphism on any neuropsychiatric or behavioral outcome which is influenced by HPA axis function in older adults.
Serotonin transporter; 5-HTT; Stress; HPA; Memory; Hippocampus; Aging
Epstein-Barr virus nuclear antigen EBNA1, the one viral protein uniformly expressed in nasopharyngeal carcinoma (NPC), represents a prime target for T-cell-based immunotherapy. However, little is known about the EBNA1 epitopes, particularly CD4 epitopes, presented by HLA alleles in Chinese people, the group at highest risk for NPC. We analyzed the CD4+ T-cell responses to EBNA1 in 78 healthy Chinese donors and found marked focusing on a small number of epitopes in the EBNA1 C-terminal region, including a DP5-restricted epitope that was recognized by almost half of the donors tested and elicited responses able to recognize EBNA1-expressing, DP5-positive target cells.
Aim: To investigate T-bet mRNA and protein expression on peripheral blood mononuclear cells (PBMC) in patients with Behçet’s disease with active uveitis.
Methods: Blood samples were taken from 24 patients with Behçet’s disease who had active uveitis and 16 healthy individuals. PBMC were subjected to analysis of T-bet mRNA and protein expression using semiquatitative reverse transcriptase-polymerase chain reaction (RT-PCR) and western blot, respectively. The products from PCR were sequenced. In order to determine the influence of activation on T-bet expression, the phytohaemagglutinin (PHA) stimulated PBMC from each sample were also evaluated for expression of T-bet mRNA and protein.
Results: A significantly increased T-bet mRNA accumulation was detected in the samples from patients with active Behçet’s disease compared with that in controls. A 62 kDa band was detectable in patients with active Behçet’s disease, but not in controls. No difference was found between patients with Behçet’s disease who had active uveitis and normal controls concerning the expression of either T-bet mRNA or its protein after stimulation with PHA for 72 hours.
Conclusion: Behçet’s disease is associated with an upregulation of T-bet expression, which supports a role for the Th1 subset of T cells in the pathogenesis of this disease.
Behçet’s disease; T-bet; Th1 cells; human
Background: Pathology in the cervical spinal cord is considered an important cause of disability in multiple sclerosis. However, the majority of serial studies have failed to find a correlation between spinal cord atrophy and disability.
Objectives: To use a highly reproducible and accurate method to quantify spinal cord area change on three dimensional magnetic resonance imaging and relate this to disability change in patients with multiple sclerosis.
Methods: 38 patients with multiple sclerosis (20 with the relapsing–remitting (RRMS) form and 18 with the secondary progressive (SPMS) form) were imaged at baseline and at months 6, 12, 18, and 48 during two treatment trials of the high dose subcutaneous thrice weekly interferon ß-1a (IFNß, Rebif). Thirty one healthy subjects were also imaged at baseline. Upper cervical cord area (UCCA) was measured using Sobel edge detection.
Results: The intraobserver coefficient of variation of the method was 0.42%. A significant reduction in UCCA was detected at month 6 in the placebo group (p = 0.04) and at month 12 for INFß (p = 0.03). The mean reduction of UCCA at month 48 was 5.7% for patients initially on placebo who received treatment at 24 months (RRMS) or at 36 months (SPMS), and 4.5% for those on IFNß throughout the study (p = 0.35). The change in UCCA was significantly correlated with change in the expanded disability status scale at month 12 (r = 0.4, p = 0.016), month 18 (r = 0.32, p = 0.05), and month 48 (r = 0.4, p = 0.016) in the total cohort.
Conclusions: Despite the small number of patients studied and the possible confounding effects of interferon treatment, this study showed that edge detection is reproducible and sensitive to changes in spinal cord area, and that this change is related to changes in clinical disability. This suggests a role for measurement of spinal cord atrophy in monitoring disease progression and possible treatment effects in clinical trails.
investigate the relations between quantitative diffusion coefficient
MRI histograms, clinical variables, and cerebral atrophy.
two patients with clinically definite multiple sclerosis and 11 healthy
volunteers were studied. Histograms of apparent diffusion coefficient
(ADC) from a volume of interest that included multiple slices
encompassing the lateral ventricles were processed from diffusion
weighted MRI. In addition, total lesion load was measured on T2
weighted dual echo images, and cerebral volume from 3D magnetisation
prepared rapid acquisition gradient echo scans. All patients underwent
neurological assessment, including disability on the expanded
disability status scale (EDSS).
from the patient group showed a reduced peak height and a "right
shift" compared with healthy controls. Peak height of the diffusion
histogram correlated with both EDSS
(r=−0.54, p=0.0101) and disease duration
(r=−0.52, p=0.0140), but not with age.
Brain volume correlated with peak height of the ADC histogram (r=0.55, p=0.0129), but not with disability.
Total lesion load also correlated moderately with EDSS
study shows for the first time that quantitative MRI measures of
diffusion correlate with clinical variables (disability, disease
duration) and cerebral atrophy in multiple sclerosis. Cerebral atrophy
and fixed neurological deficit may be attributed to axonal loss, which
would be expected to have a significant effect on ADC. Extension of
this method to more patients and longitudinal studies will further
elucidate its sensitivity, reproducibility, and potential role in
clinical practice and treatment trials.
STUDY OBJECTIVE—To determine whether long term weight gain and weight loss are associated with subsequent risk of type 2 diabetes in overweight, non-diabetic adults.
DESIGN—Prospective cohort. Baseline overweight was defined as BMI⩾27.3 for women and BMI⩾27.8 for men. Annual weight change (kg/year) over 10 years was calculated using measured weight at subjects' baseline and first follow up examinations. In the 10 years after measurement of weight change, incident cases of diabetes were ascertained by self report, hospital discharge records, and death certificates.
PARTICIPANTS—1929 overweight, non-diabetic adults.
MAIN RESULTS—Incident diabetes was ascertained in 251 subjects. Age adjusted cumulative incidence increased from 9.6% for BMI<29 to 26.2% for BMI⩾37. Annual weight change over 10 years was higher in subjects who become diabetic compared with those who did not for all BMI<35. Relative to overweight people with stable weight, each kg of weight gained annually over 10 years was associated with a 49% increase in risk of developing diabetes in the subsequent 10 years. Each kg of weight lost annually over 10 years was associated with a 33% lower risk of diabetes in the subsequent 10 years.
CONCLUSIONS—Weight gain was associated with substantially increased risk of diabetes among overweight adults, and even modest weight loss was associated with significantly reduced diabetes risk. Minor weight reductions may have major beneficial effects on subsequent diabetes risk in overweight adults at high risk of developing diabetes.
Keywords: obesity; diabetes
We report that all- trans retinoic acid (ATRA) enhanced the toxicity of docetaxel against DU145 and LNCaP prostate cancer cells, and that the nature of the interaction between ATRA and docetaxel was highly synergistic. Docetaxel-induced apoptotic cell death was associated with phosphorylation and hence inactivation of Bcl-2. ATRA enhanced docetaxel-induced apoptosis and combined treatment with ATRA and docetaxel resulted in down-regulation of Bcl-2. Docetaxel caused phosphorylation and hence inactivation of cdc2 kinase result ing in G2/M arrest. ATRA inhibited docetaxel-induced phosphorylation of cdc2 resulting in activation of cdc2 kinase and partial reversal of the G2/M arrest. ATRA also inhibited docetaxel-induced activation of MAPK indicating that the effects of docetaxel and ATRA on cdc2 phosphorylation are dependent on MAPK. We conclude that ATRA synergistically enhances docetaxel toxicity by down-regulating Bcl-2 expression and partially reverses the docetaxel-induced G2/M arrest by inhibiting docetaxel-induced cdc2 phosphorylation in a pathway that is dependent on MAPK. © 2001 Cancer Research Campaign http://www.bjcancer.com
docetaxel; all- trans retinoic acid; prostate cancer; apoptosis; cell cycle
DNA damage has been shown to activate c-Abl tyrosine kinase. We now report that, in addition to DNA damage, microtubule damage induced by paclitaxel results in activation of c-Abl kinase. In 3T3 cells, the presence of c-Abl kinase increased paclitaxel-induced cell death. In Abl-proficient cells, paclitaxel produced a marked and prolonged G2/M arrest which peaked at 24 h and a rapid and marked induction of p21WAF1which also peaked at 24 h. In Abl-deficient cells, the G2/M arrest induced by paclitaxel was less prominent and shorter in duration and the effect of paclitaxel on p21WAF1expression was reduced and delayed. Paclitaxel had no effect on p53 expression and MAPK phosphorylation. These findings indicate that, in 3T3 cells, c-Abl kinase facilitates cell death and regulates G2/M arrest in response to paclitaxel-induced microtubule damage in a pathway that is dependent on p21WAF1and independent of MAPK activity. © 2000 Cancer Research Campaign
c-Abl tyrosine kinase; paclitaxel; p21WAF1; p53; cell cycle
Following intracerebral infection with Theiler’s murine encephalomyelitis virus (TMEV), susceptible strains of mice (SJL and PLJ) develop virus persistence and demyelination similar to that found in human multiple sclerosis. Resistant strains of mice (C57BL/6) clear virus and do not develop demyelination. To resolve the controversy about the role of CD4+ and CD8+ T cells in the development of demyelination and neurologic deficits in diseases of the central nervous system, we analyzed TMEV infection in CD4- and CD8-deficient B6, PLJ, and SJL mice. Genetic deletion of either CD4 or CD8 from resistant B6 mice resulted in viral persistence and demyelination during the chronic stage of disease. Viral persistence and demyelination were detected in all strains of susceptible background. Although genetic deletion of CD8 had no effect on the extent of demyelination in susceptible strains, deletion of CD4 dramatically increased the degree of demyelination observed. Whereas strains with deletions of CD4 showed severe neurologic deficits, mice with deletions of CD8 showed minimal or no deficits despite demyelination. In all strains, deletion of CD4 but not CD8 resulted in a decreased delayed-type hypersensitivity response to viral antigen. We conclude that each T-cell subset makes a discrete and nonredundant contribution to protection from viral persistence and demyelination in resistant strains. In contrast, in susceptible strains, CD8+ T cells do not provide protection against chronic demyelinating disease. Furthermore, in persistent TMEV infection of the central nervous system, neurologic deficits appear to result either from the absence of a protective class II-restricted immune response or from the presence of a pathogenic class I-restricted response.
Theiler's murine encephalomyelitis viruses (TMEVs) belong to the Picornaviridae family and are divided into two groups, typified by strain GDVII virus and members of the TO (Theiler's original) group. The highly virulent GDVII group causes acute encephalitis in mice, while the TO group is less virulent and causes a chronic demyelinating disease which is associated with viral persistence in mice. This persistent central nervous system infection with demyelination resembles multiple sclerosis (MS) in humans and has thus become an important model for studying MS. It has been shown that some of the determinants associated with viral persistence are located on the capsid proteins of the TO group. Structural comparisons of two persistent strains (BeAn and DA) and a highly virulent strain (GDVII) showed that the most significant structural variations between these two groups of viruses are located on the sites that may influence virus binding to cellular receptors. Most animal viruses attach to specific cellular receptors that, in part, determine host range and tissue tropism. In this study, atomic models of TMEV chimeras were built with the known structures of GDVII, BeAn, and DA viruses. Comparisons among the known GDVII, BeAn, and DA structures as well as the predicted models for the TMEV chimeras suggested that a gap on the capsid surface next to the putative receptor binding site, composed of residues from VP1 and VP2, may be important in determining viral persistence by influencing virus attachment to cellular receptors, such as sialyloligosaccharides. Our results showed that sialyllactose, the first three sugar molecules of common oligosaccharides on the surface of mammalian cells, inhibits virus binding to the host cell and infection with the persistent BeAn virus but not the nonpersistent GDVII and chimera 39 viruses.
Mice expressing the H2b haplotype are resistant to infection with Theiler's murine encephalomyelitis virus (TMEV), which causes chronic demyelination in susceptible mice. The prominent cytolytic T-lymphocyte (CTL) response to the VP2 antigen encoded by TMEV led us to the identification of a class I-binding peptide derived from the VP2 antigen. Escherichia coli transformants overexpressing a series of 11 overlapping VP2 protein fragments were subjected to lysis and alkali digestion, and the resultant peptide pools were tested for their abilities to sensitize RMA-S targets for lysis by CTLs. The source of effector CD8+ T cells for the assays was either freshly harvested central nervous system-infiltrating lymphocytes (CNS-IL) or CNS-IL-derived VP2-specific CTL clones and lines. A 10-residue peptide at VP2 positions 121 to 130 (VP2(121-130)) (FHAGSLLVFM) was identified that sensitized targets for lysis and formed stable complexes with H2Db class I molecules. The VP2(121-130) peptide sensitized target cells for lysis by freshly harvested CNS-IL CTLs at femtomolar concentrations. Despite its relative high level of biological activity, the VP2(121-130) peptide is distinguished from other Db-binding peptides by its lack of an asparagine residue at position five, which had been previously proposed to be a requirement for Db-peptide complexing.
We have determined previously that IGF-I is dependent on the presence of IGF binding protein-1 (IGFBP-1) to act as a wound healing agent. We sought to determine the mechanism whereby IGFBP-1 is able to enhance IGF-I bioactivity. As IGFBP-1 binds both the alpha5beta1 integrin as well as IGF-I in vitro, we asked which of the following interactions were important: (a) the ability of IGFBP-1 to interact with an integrin receptor, and/or (b) the binding of IGF-I by IGFBP-1. We used an IGF-1 analogue (des(1-3)IGF-I) with a > 100-fold reduction in affinity for IGFBP-1 as well as an IGFBP-1 mutant (WGD-IGFBP-1) which does not associate with the alpha5beta1 integrin to selectively abrogate each of these interactions. We also tested the ability of IGFBP-2, a related binding protein which has an arginine-glycine-aspartate sequence but does not associate with integrin family members, to enhance IGF-I bioactivity. Full-thickness dermal wounds were created on rabbit ears; various combinations of native IGF-I, native IGFBP-1, native IGFBP-2, and their respective analogues/mutants were applied to each wound. Wounds were harvested 7 d later for analysis. Only native IGF-I in combination with native IGFBP-1 was effective as a wound healing agent, enhancing reepithelialization and granulation tissue deposition by 64+/-5 and 83+/-12% over controls (P = 0.008 and 0.016, respectively). The same doses of IGF-I/WGD-IGFBP-1, des(1-3)IGF-I/IGFBP-1, and IGF-I/IGFBP-2 were ineffective. We propose that IGF-I physically interacts with IGFBP-1 and that IGFBP-1 also binds to an integrin receptor, most likely the alpha5beta1 integrin. This interaction is unique to IGFBP-1 as the closely related IGFBP-2 had no effect, a finding consistent with its inability to bind to integrin receptors. Our results suggest that activation of both the IGF-I receptor and the alpha5beta1 integrin is required for IGF-I to stimulate wound healing.
A large cohort of 74,828 benzene-exposed and 35,805 nonexposed workers employed between 1972 and 1987 in 12 cities in China was followed to determine mortality from all causes. Benzene-exposed study subjects were employed in a variety of occupations including coating applications, and rubber, chemical, and shoe production. Mortality was slightly increased among workers with greater cumulative exposure to benzene (ptrend < 0.05), but this excess was largely due to cancer deaths (ptrend < 0.01). Deaths due to lymphatic and hematopoietic malignancies (ptrend = 0.01) and lung cancer (ptrend = 0.01) increased with increasing cumulative exposure to benzene. Investigations continue to relate benzene exposure to specific lymphatic and hematopoietic malignancies and other causes of death.