Distinct specificities of the HEMK2 protein methyltransferase in methylation of glutamine and lysine residues.

The HEMK2 protein methyltransferase has been described as glutamine methyltransferase catalyzing ERF1-Q185me1 and lysine methyltransferase catalyzing H4K12me1. Methylation of two distinct target residues is unique for this class of enzymes. To understand the specific catalytic adaptations of HEMK2 allowing it to master this chemically challenging task, we conducted a detailed investigation of the substrate sequence specificities of HEMK2 for Q- and K-methylation. Our data show that HEMK2 prefers methylation of Q over K at peptide and protein level. Moreover, the ERF1 sequence is strongly preferred as substrate over the H4K12 sequence. With peptide SPOT array methylation experiments, we show that Q-methylation preferentially occurs in a G-Q-X3 -R context, while K-methylation prefers S/T at the first position of the motif. Based on this, we identified novel HEMK2 K-methylation peptide substrates with sequences taken from human proteins which are methylated with high activity. Since H4K12 methylation by HEMK2 was very low, other protein lysine methyltransferases were examined for their ability to methylate the H4K12 site. We show that SETD6 has a high H4K12me1 methylation activity (about 1000-times stronger than HEMK2) and this enzyme is mainly responsible for H4K12me1 in DU145 prostate cancer cells.

Defining external factors that determine neuronal survival, apoptosis and necrosis during excitotoxic injury using a high content screening imaging platform.

Cell death induced by excessive glutamate receptor overactivation, excitotoxicity, has been implicated in several acute and chronic neurological disorders. While numerous studies have demonstrated the contribution of biochemically and genetically activated cell death pathways in excitotoxic injury, the factors mediating passive, excitotoxic necrosis are less thoroughly investigated. To address this question, we developed a high content screening (HCS) based assay to collect high volumes of quantitative cellular imaging data and elucidated the effects of intrinsic and external factors on excitotoxic necrosis and apoptosis. The analysis workflow consisted of robust nuclei segmentation, tracking and a classification algorithm, which enabled automated analysis of large amounts of data to identify and quantify viable, apoptotic and necrotic neuronal populations. We show that mouse cerebellar granule neurons plated at low or high density underwent significantly increased necrosis compared to neurons seeded at medium density. Increased extracellular Ca2+ sensitized neurons to glutamate-induced excitotoxicity, but surprisingly potentiated cell death mainly through apoptosis. We also demonstrate that inhibition of various cell death signaling pathways (including inhibition of calpain, PARP and AMPK activation) primarily reduced excitotoxic apoptosis. Excitotoxic necrosis instead increased with low extracellular glucose availability. Our study is the first of its kind to establish and implement a HCS based assay to investigate the contribution of external and intrinsic factors to excitotoxic apoptosis and necrosis.

Influence of Cardiovascular Risk Factors on the Prevalence of Coronary Atherosclerosis in Patients with Angiographically Normal Coronary Arteries.

RATIONALE AND OBJECTIVES: Cardiovascular (CV) disease is predominately influenced by CV risk factors and coronary computed tomography angiography (CTA) is capable of detecting early-stage coronary artery disease. We sought to determine the influence of CV risk factors on the prevalence of nonobstructive atherosclerosis in patients with normal-appearing coronary arteries in invasive coronary angiography (ICA). MATERIALS AND METHODS: In this retrospective analysis, we included 60 consecutive symptomatic patients, having undergone ICA and coronary CTA. Coronary dual source CTA was performed using electrocardiogram-triggered retrospective gated image acquisition at 40%-70% of RR interval (tube voltage 100-120 kV, tube current time product 320-440 mAs, 60 mL contrast, and flow rate 6 mL/s). RESULTS: Out of 60 patients (32 men, mean age 61 ± 11 years) with a normal coronary artery appearance in ICA, 45 (75%) patients showed atherosclerotic plaque in CTA. Plaque was present in 14 of 60 (23%) left main, 41 of 60 (68%) left anterior descending, 21 of 60 (35%) circumflex coronary arteries, and 24 of 60 (40%) right coronary arteries. More than 15% of all coronary artery segments showed detectable plaques. Interobserver agreement ranged from good to very good on a per-patient, per-vessel, and per-segment level. Patients with presence of plaque were significantly older (P = 0.005) and showed higher incidence of arterial hypertension (P = 0.019) as compared to individuals without coronary plaque in dual source computed tomography. CONCLUSIONS: The prevalence of coronary atherosclerosis by CTA is substantial in symptomatic patients with normal invasive coronary angiogram. Hypertension and older age significantly influence the prevalence of atherosclerotic plaque and highlight the importance of risk-modifying therapy.

Structural Insights into Water-Based Spider Silk Protein-Nanoclay Composites with Excellent Gas and Water Vapor Barrier Properties.

Nature reveals a great variety of inorganic-organic composite materials exhibiting good mechanical properties, high thermal and chemical stability, and good barrier properties. One class of natural bio-nanocomposites, e.g. found in mussel shells, comprises protein matrices with layered inorganic fillers. Inspired by such natural bio-nanocomposites, the cationic recombinant spider silk protein eADF4(κ16) was processed together with the synthetic layered silicate sodium hectorite in an all-aqueous setup. Drop-casting of this bio-nanocomposite resulted in a thermally and chemically stable film reflecting a one-dimensional crystal. Surprisingly, this bio-nanocomposite coating was, though produced in an all-aqueous process, completely water insoluble. Analyzing the structural details showed a low inner free volume due to the well-oriented self-assembly/alignment of the spider silk proteins on the nanoclay surface, yielding high oxygen and water vapor barrier properties. The here demonstrated properties in combination with good biocompatibility qualify this new bio-nanocomposite to be used in packaging applications.

Influence of the coronary calcium score on the ability to rule out coronary artery stenoses by coronary CT angiography in patients with suspected coronary artery disease.

BACKGROUND: Recent guidelines for the workup of patients with chest pain and suspected coronary artery disease include coronary computed tomography angiography (CTA). However, its diagnostic value may be limited in patients with severe coronary calcification. OBJECTIVE: We investigated the relationship between the extent of coronary calcium and the ability of coronary CTA to rule out significant stenoses in a series of consecutive patients with suspected coronary artery disease. METHODS: 2614 consecutive patients with suspected coronary artery disease in whom coronary calcium scoring and coronary CTA had been performed by Dual Source CT were analyzed. The ability of coronary CTA to rule out coronary artery stenoses (fully evaluable coronary arteries and absence of any luminal stenosis >75%) was analyzed relative to the coronary calcium score. RESULTS: The median coronary calcium score was 12, with calcium present in 60.5% of all patients. Coronary CTA ruled out stenoses in 82% of patients, while in 18% of patients at least one stenosis was found or could not be excluded. The threshold above which coronary CTA permitted to rule out stenoses in less than 50% of patients was an "Agatston Score" of 287. This threshold was significantly lower for male patients (213 vs. 330), for patients with a heart rate >65 beats/min (157 vs. 317) and for patients with a body mass index ≥25 kg/m(2) (208 vs. 392). The evaluability of coronary arteries decreased with increasing amounts of calcium and differed significantly between heart rates ≤65 beats/min and >65 beats/min (p < 0.0001). CONCLUSION: In the largest patient series evaluated so far, we identified an "Agatston Score" of 287 to represent a threshold above which coronary CTA permits to rule out coronary artery stenoses in less than 50% of cases.

MicroRNA-224 is Readily Detectable in Urine of Individuals with Diabetes Mellitus and is a Potential Indicator of Beta-Cell Demise.

MicroRNA (miRNA) are a class of non-coding, 19-25 nucleotide RNA critical for network-level regulation of gene expression. miRNA serve as paracrine signaling molecules. Using an unbiased array approach, we previously identified elevated levels of miR-224 and miR-103 to be associated with a monogenic form of diabetes; HNF1A-MODY. miR-224 is a novel miRNA in the field of diabetes. We sought to explore the role of miR-224 as a potential biomarker in diabetes, and whether such diabetes-associated-miRNA can also be detected in the urine of patients. Absolute levels of miR-224 and miR-103 were determined in the urine of n = 144 individuals including carriers of a HNF1A mutation, participants with type 1 diabetes mellitus (T1DM), type 2 diabetes mellitus (T2DM) and normal controls. Expression levels were correlated with clinical and biochemical parameters. miR-224 was significantly elevated in the urine of carriers of a HNF1A mutation and participants with T1DM. miR-103 was highly expressed in urine across all diabetes cohorts when compared to controls. For both miR-224 and-103, we found a significant correlation between serum and urine levels (p < 0.01). We demonstrate that miRNA can be readily detected in the urine independent of clinical indices of renal dysfunction. We surmise that the differential expression levels of miR-224 in both HNF1A-MODY mutation carriers and T1DM may be an attempt to compensate for beta-cell demise.

Aortic annulus eccentricity before and after transcatheter aortic valve implantation: Comparison of balloon-expandable and self-expanding prostheses.

INTRODUCTION: The geometry of the aortic annulus and implanted transcatheter aortic valve prosthesis might influence valve function. We investigated the influence of valve type and aortic valve calcification on post-implant geometry of catheter-based aortic valve prostheses. METHODS: Eighty consecutive patients with severe aortic valve stenosis (mean age 82 ± 6 years) underwent computed tomography before and after TAVI. Aortic annulus diameters were determined. Influence of prosthesis type and degree of aortic valve calcification on post-implant eccentricity were analysed. RESULTS: Aortic annulus eccentricity was reduced in patients after TAVI (0.21 ± 0.06 vs. 0.08 ± 0.06, p<0.0001). Post-TAVI eccentricity was significantly lower in 65 patients following implantation of a balloon-expandable prosthesis as compared to 15 patients who received a self-expanding prosthesis (0.06 ± 0.05 vs. 0.15 ± 0.07, p<0.0001), even though the extent of aortic valve calcification was not different. After TAVI, patients with a higher calcium amount retained a significantly higher eccentricity compared to patients with lower amounts of calcium. CONCLUSIONS: Patients undergoing TAVI with a balloon-expandable prosthesis show a more circular shape of the implanted prosthesis as compared to patients with a self-expanding prosthesis. Eccentricity of the deployed prosthesis is affected by the extent of aortic valve calcification.

The clinical management of hyperglycemia in pregnancy complicated by maturity-onset diabetes of the young.

OBJECTIVE: Women with maturity-onset diabetes of the young (MODY) are often first identified and diagnosed with diabetes during pregnancy. Genetics and hyperglycemia play an important role in determining fetal size in MODY pregnancies. The principal objective of the current study is to determine the outcomes and clinical management of hyperglycemia in pregnancies complicated by glucokinase gene (GCK) and hepatocyte nuclear factor (HNF)-1α MODY mutations. STUDY DESIGN: A retrospective chart review of 37 women with a GCK/HNF-1α mutation was conducted. Data on variables such as birthweight, mode of delivery, and the treatment of hyperglycemia were available on 89 pregnancies. RESULTS: The birthweight in unaffected GCK offspring was significantly higher than in the affected GCK offspring (4.8 [4.1-5.2] kg vs 3.2 [3.1-3.7] kg; P = .01). Seven-point home blood glucose monitoring over a 7-day period in each trimester demonstrated higher fasting and postprandial glycemic excursions in the first trimester of GCK pregnancies when compared to HNF-1α pregnancies (fasting 104 [90-115] mg/dL vs 84 [77-88] mg/dL; P = .01 and postprandial 154 [135-196] mg/dL vs 111 [100-131] mg/dL; P = .04) despite insulin treatment. There was a higher percentage of miscarriages in the GCK group when compared to the HNF-1α MODY group (33.3% vs 14%; P = .07), which was similar to the background population. Insulin initiated at an early gestation appeared to lower the incidence of macrosomia in GCK unaffected offspring. CONCLUSION: Hyperglycemia in HNF-1α pregnancies is easily managed with current insulin protocols; in contrast, glycemic excursions are difficult to manage in GCK pregnancies. There was an increased percentage of miscarriages in GCK pregnancies highlighting the importance of a diagnosis of GCK-MODY in women prior to conception and the necessity for preconception care.

Non-invasive prediction of hemodynamically significant coronary artery stenoses by contrast density difference in coronary CT angiography.

OBJECTIVES: Coronary computed tomography angiography (CTA) allows the detection of obstructive coronary artery disease. However, its ability to predict the hemodynamic significance of stenoses is limited. We assessed differences in plaque characteristics and contrast density difference between hemodynamically significant and non-significant stenoses, as defined by invasive fractional flow reserve (FFR). METHODS: Lesion characteristics of 59 consecutive patients (72 lesions) in whom invasive FFR was performed in at least one coronary artery with moderate to high-grade stenoses in coronary CTA were evaluated by two experienced readers. Coronary CTA data sets were acquired on a second-generation dual-source CT scanner using retrospectively ECG-gated spiral acquisition or prospectively ECG-triggered axial acquisition mode. Plaque volume and composition (non-calcified, calcified), remodeling index as well as contrast density difference (defined as the percentage decline in luminal CT attenuation/cross-sectional area over the lesion) were assessed using a semi-automatic software tool (Autoplaq). Additionally, the transluminal attenuation gradient (defined as the linear regression coefficient between intraluminal CT attenuation and length from the ostium) was determined. Differences in lesion characteristics between hemodynamically significant (invasively measured FFR ≤0.80) and non-significant lesions (FFR >0.80) were determined. RESULTS: Mean patient age was 64±11 years with 44 males (75%). 21 out of 72 coronary artery lesions (29%) were hemodynamically significant according to invasive FFR. Mean invasive FFR was 0.66±0.12 vs. 0.91±0.05 for hemodynamically significant versus non-significant lesions. Hemodynamically significant lesions showed a significantly greater percentage of non-calcified plaque compared to non-hemodynamically relevant lesions (51.3±15.3% vs. 43.6±16.5%, p=0.021). Contrast density difference was significantly increased in hemodynamically relevant lesions (26.0±20.2% vs. 16.6±10.9% for non-significant lesions; p=0.013). At a threshold of ≥24%, the contrast density difference predicted hemodynamically significant lesions with a specificity of 75%, sensitivity of 33%, PPV of 35% and NPV of 73%. The transluminal attenuation gradient showed no significant difference between hemodynamically significant and non-significant lesions (-1.4±1.4HU/mm vs. -1.1±1.3HU/mm, p=n.s.). CONCLUSIONS: Quantitative contrast density difference across coronary lesions in coronary CTA data sets may be applied as a non-invasive tool to identify hemodynamically significant stenoses.

Quasi-epitaxial growth of [Ru(bpy)3 ](2+) by confinement in clay nanoplatelets yields polarized emission.

A nano confinement strategy is presented to control the spatial orientation and emission polarization of phosphorescent metal complexes. Through nano-confinement of the phosphorescent metal complex [Ru(bpy)3 ](2+) by attaching it to anionic clay nanoplatelets, it is possible to simultaneously lock the spatial orientation of the complex and fix its emission polarization. This quasi-epitaxial approach may provide a future work strategy directed at light emitting diodes and lasers.

Accuracy of prospectively ECG-triggered very low-dose coronary dual-source CT angiography using iterative reconstruction for the detection of coronary artery stenosis: comparison with invasive catheterization.

OBJECTIVE: To evaluate the image quality and diagnostic accuracy of very low-dose computed tomography (CT) angiography (CTA) for the evaluation of coronary artery stenosis. BACKGROUND: Iterative reconstruction (IR) has shown to substantially reduce image noise and hence permit the use of very low-dose data acquisition protocols in coronary CTA. METHODS: Fifty symptomatic patients with an intermediate likelihood for coronary artery disease underwent coronary CTA (heart rate: 59 ± 5 bpm, prospectively ECG-triggered axial acquisition, 100 kV, 160 mAs, 2 × 128 × 0.6 mm collimation, 60 mL contrast, 6 mL/s) prior to invasive coronary angiography. CTA images were reconstructed using both standard filtered back projection (FBP) and a raw data-based IR algorithm [Sinogram Affirmed Iterative Reconstruction (SAFIRE), Siemens Healthcare]. Subjective image quality (four-point Likert scale from 0 = non-diagnostic to 3 = excellent image quality), image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), as well as the presence of coronary stenosis >50% were independently determined by two observers. RESULTS: The mean dose-length product was 46.8 ± 3.5 mGy cm (estimated effective dose 0.66 ± 0.05 mSv). IR led to significantly improved objective image quality compared with FBP (image noise: 41 ± 12 vs. 49 ± 11 HU, P < 0.0001; CNR: 16 ± 8 vs. 12 ± 4, P < 0.0001; SNR: 13 ± 7 vs. 10 ± 3, P < 0.0001). Four coronary segments were not evaluable on FBP data, whereas all segments showed diagnostic image quality with IR. To detect significant coronary stenosis, sensitivity, specificity, positive predictive value, and negative predictive value were 69% (11/16), 97% (175/180), 69% (11/16), and 97% (175/180) per vessel with FBP data sets, respectively. With IR data sets, the corresponding values were 81% (13/16), 97% (178/184), 68% (13/19), and 98% (178/181). These differences were not statistically significant (P = 0.617). CONCLUSIONS: Raw data-based IR significantly improves image quality in very low-dose prospectively ECG-triggered coronary dual-source CTA when compared with standard reconstruction using FBP.

Reproducibility of aortic annulus measurements by computed tomography.

OBJECTIVES: To evaluate a systematic approach for measurement of aortic annulus dimensions by cardiac computed tomography. METHODS: CT data sets of 64 patients were evaluated. An oblique cross-section aligned with the aortic root was created by systematically identifying the caudal insertion points of the three aortic cusps and sequentially aligning them in a double oblique plane. Aortic annulus dimensions, distances of coronary ostia and a suitable fluoroscopic projection angle were independently determined by two observers. RESULTS: Interobserver intraclass correlation coefficients (ICC) for aortic annulus diameters were excellent (ICC 0.89-0.93). Agreement for prosthesis size selection was excellent (ĸ = 0.86 for mean, ĸ = 0.84 for area-derived and ĸ = 0.91 for circumference-derived diameter). Mean distances of the left/right coronary ostium were 13.4 ± 2.4/14.4 ± 2.8 mm for observer 1 and 13.2 ± 2.7/13.5 ± 3.2 mm for observer 2 (p = 0.30 and p = 0.0001, respectively; ICC 0.76/0.77 for left/right coronary artery). A difference of less than 10° for fluoroscopic projection angle was achieved in 84.3% of patients. CONCLUSIONS: A systematic approach to generate a double oblique imaging plane exactly aligned with the aortic annulus demonstrates high interobserver and intraobserver agreements for derived measurements which are not influenced by aortic root calcification. KEY POINTS: • Systematic approach to generate a double oblique imaging plane for TAVI evaluation. • This method is straightforward and software independent. • An approach with high reproducibility, not influenced by aortic root calcification.

The frequencies and clinical implications of mutations in 33 kinase-related genes in locally advanced rectal cancer: a pilot study.

BACKGROUND: Locally advanced rectal cancer (LARC: T3/4 and/or node-positive) is treated with preoperative/neoadjuvant chemoradiotherapy (CRT), but responses are not uniform. The phosphatidylinositol 3-kinase (PI3K), MAP kinase (MAPK), and related pathways are implicated in rectal cancer tumorigenesis. Here, we investigated the association between genetic mutations in these pathways and LARC clinical outcomes. METHODS: We genotyped 234 potentially clinically relevant nonsynonymous mutations in 33 PI3K and MAPK pathway-related genes, including PIK3CA, PIK3R1, AKT, STK11, KRAS, BRAF, MEK, CTNNB1, EGFR, MET, and NRAS, using the Sequenom platform. DNA samples were extracted from pretreatment LARC biopsy samples taken from 201 patients who were then treated with long-course neoadjuvant CRT followed by surgical resection. RESULTS: Sixty-two mutations were detected in 15 genes, with the highest frequencies occurring in KRAS (47 %), PIK3CA (14 %), STK11 (6.5 %), and CTNNB1 (6 %). Mutations were detected in BRAF, NRAS, AKT1, PIK3R1, EGFR, GNAS, MEK1, PDGFRA, ALK, and TNK2, but at frequencies of <5 %. As expected, a pathologic complete response (pCR) was associated with improved 5-year recurrence-free survival (RFS; hazard ratio, 0.074; 95 % CI 0.01-0.54; p = 0.001). Mutations in PI3K pathway-related genes (odds ratio, 5.146; 95 % CI 1.17-22.58; p = 0.030), but not MAPK pathway-related genes (p = 0.911), were associated with absence of pCR after neoadjuvant CRT. In contrast, in patients who did not achieve pCR, mutations in PI3K pathway-related genes were not associated with recurrence-free survival (p = 0.987). However, in these patients, codon 12 (G12D/G12 V/G12S) and 13 mutations in KRAS were associated with poor recurrence-free survival (hazard ratio, 1.579; 95 % confidence ratio, 1.00-2.48; p = 0.048). CONCLUSIONS: Mutations in kinase signaling pathways modulate treatment responsiveness and clinical outcomes in LARC and may constitute rational targets for novel therapies.

The Wide and Complex Field of NAFLD Biomarker Research: Trends.

Background. Nonalcoholic fatty liver disease is now acknowledged as a complex public health issue linked to sedentary lifestyle, obesity, and related disorders like type 2 diabetes and metabolic syndrome. Aims. We aimed to retrieve its trends out of the huge amount of published data. Therefore, we conducted an extensive literature search to identify possible biomarker and/or biomarker combinations by retrospectively assessing and evaluating common and novel biomarkers to predict progression and prognosis of obesity related liver diseases. Methodology. We analyzed finally 62 articles accounting for 157 cohorts and 45,288 subjects. Results. Despite the various approaches, most cohorts were considerably small and rarely comparable. Also, we found that the same standard parameters were measured rather than novel biomarkers. Diagnostics approaches appeared incomparable. Conclusions. Further collaborative investigations on harmonizing ways of data acquisition and identifying such biomarkers for clinical use are necessary to yield sufficient significant results of potential biomarkers.

Automated attenuation-based selection of tube voltage and tube current for coronary CT angiography: reduction of radiation exposure versus a BMI-based strategy with an expert investigator.

BACKGROUND: Recently developed automated algorithms use the topogram and the corresponding attenuation information before coronary CT angiography (CTA) to allow for an individualized anatomic-based selection of tube current (mAs) and voltage (kV). OBJECTIVES: The value of these algorithms in reducing the associated radiation exposure was evaluated. METHODS: One hundred patients underwent coronary CTA with dual-source CT with prospectively electrocardiogram-triggered axial data acquisition. In all patients, tube parameters (current and voltage) were suggested by both an experienced investigator according to the patient's body mass index (BMI; calculated as weight divided by height squared; kg/m(2)) and by an automated software according to attenuation values of the initial topogram. The first 50 consecutive patients (group 1) underwent coronary CTA with dual-source CT with tube parameters suggested by the experienced investigator (BMI-based tube parameters), whereas in another 50 consecutive patients (group 2) CT data acquisition was performed with tube settings of the automated software. Subsequently, subjective image quality (4-point rating score from 0 = nondiagnostic to 3 = excellent image quality), image noise (SD of CT number within the aortic root), as well as signal- and contrast-to-noise ratios and mean effective radiation doses, were compared between both groups. RESULTS: Both groups showed comparable image quality parameters (group 1 vs 2: noise, 28.1 ± 6.0 HU vs 29.9 ± 5.4 HU, P = .12; signal-to-noise ratio, 16.4 ± 3.9 vs 16.8 ± 4.1, P = .54; contrast-to-noise ratio, 18.6 ± 4.1 vs 19.2 ± 4.3, P = .49; 4-point rating score, 2.8 ± 0.3 vs 2.9 ± 0.3, P = .81). Tube voltage, current, and mean effective radiation dose for groups 1 and 2 were 111 ± 12 kV and 108 ± 12 kV (P = .18), 361 ± 32 mAs and 320 ± 48 mAs (P < .001), and 2.3 mSv (25th; 75th percentile, 1.5; 2.8 mSv) and 1.4 mSv (25th; 75th percentile, 1.1; 1.9 mSv) (P < .001), respectively. CONCLUSIONS: Automated attenuation-based selections of individualized tube parameters are superior to BMI-based selections with expert oversight and show a potential for reduction of radiation exposure in coronary CTA, and image quality is maintained.

Circulating CD36 is reduced in HNF1A-MODY carriers.

INTRODUCTION: Premature atherosclerosis is a significant cause of morbidity and mortality in type 2 diabetes mellitus. Maturity onset diabetes of the young (MODY) accounts for approximately 2% of all diabetes, with mutations in the transcription factor; hepatocyte nuclear factor 1 alpha (HNF1A) accounting for the majority of MODY cases. There is somewhat limited data available on the prevalence of macrovascular disease in HNF1A-MODY carriers with diabetes. Marked insulin resistance and the associated dyslipidaemia are not clinical features of HNF1A-MODY carriers. The scavenger protein CD36 has been shown to play a substantial role in the pathogenesis of atherosclerosis, largely through its interaction with oxidised LDL. Higher levels of monocyte CD36 and plasma CD36(sCD36) are seen to cluster with insulin resistance and diabetes. The aim of this study was to determine levels of sCD36 in participants with HNF1A-MODY diabetes and to compare them with unaffected normoglycaemic family members and participants with type 2 diabetes mellitus. METHODS: We recruited 37 participants with HNF1A-MODY diabetes and compared levels of sCD36 with BMI-matched participants with type 2 diabetes mellitus and normoglycaemic HNF1A-MODY negative family controls. Levels of sCD36 were correlated with phenotypic and biochemical parameters. RESULTS: HNF1A-MODY participants were lean, normotensive, with higher HDL and lower triglyceride levels when compared to controls and participants with type 2 diabetes mellitus. sCD36 was also significantly lower in HNF1A-MODY participants when compared to both the normoglycaemic family controls and to lean participants with type 2 diabetes mellitus. CONCLUSION: In conclusion, sCD36 is significantly lower in lean participants with HNF1A-MODY diabetes when compared to weight-matched normoglycaemic familial HNF1A-MODY negative controls and to lean participants with type 2 diabetes mellitus. Lower levels of this pro-atherogenic marker may result from the higher HDL component in the lipid profile of HNF1A-MODY participants.

Phototunable surface interactions.

Photoresponsive polymer brushes constitute an attractive platform for tuning surface properties and functionality. Since the degree of photoconversion can be controlled by the light dose, functional states with intermediate properties between those of the nonexposed and fully exposed brushes are accessible. Here we investigate the light-modulated interfacial, adhesion, and frictional properties of photosensitive polymer brushes with a methacrylate backbone and ionizable -COOH side groups modified with the photoremovable group 6-nitroveratryloxycarbonyl (NVOC). The original brush (PNVOCMA) gradually changes into a charged poly(methacrylic acid) (PMAA) brush upon exposure to ultraviolet light due to the photoremoval of the chromophore and generation of free COOH groups. We show how the physical properties of the brush can be gradually tuned with the exposure dose using condensation microscopy, atomic force microscopy (AFM), force mapping, and friction force spectroscopy.

Effects of hepatocyte nuclear factor-1A and -4A on pancreatic stone protein/regenerating protein and C-reactive protein gene expression: implications for maturity-onset diabetes of the young.

BACKGROUND: There is a significant clinical overlap between patients with hepatocyte nuclear factor (HNF)-1A and HNF4A maturity-onset diabetes of the young (MODY), two forms of monogenic diabetes. HNF1A and HNF4A are transcription factors that control common and partly overlapping sets of target genes. We have previously shown that elevated serum pancreatic stone protein / regenerating protein A (PSP/reg1A) levels can be detected in subjects with HNF1A-MODY. In this study, we investigated whether PSP/reg is differentially regulated by HNF1A and HNF4A. METHODS: Quantitative real-time PCR (qPCR) and Western blotting were used to validate gene and protein expression in cellular models of HNF1A- and HNF4A-MODY. Serum PSP/reg1A levels and high-sensitivity C-reactive protein (hsCRP) were measured by ELISA in 31 HNF1A- and 9 HNF4A-MODY subjects. The two groups were matched for age, body mass index, diabetes duration, blood pressure, lipid profile and aspirin and statin use. RESULTS: Inducible repression of HNF1A and HNF4A function in INS-1 cells suggested that PSP/reg induction required HNF4A, but not HNF1A. In contrast, crp gene expression was significantly reduced by repression of HNF1A, but not HNF4A function. PSP/reg levels were significantly lower in HNF4A subjects when compared to HNF1A subjects [9.25 (7.85-12.85) ng/ml vs. 12.5 (10.61-17.87) ng/ml, U-test P = 0.025]. hsCRP levels were significantly lower in HNF1A-MODY [0.22 (0.17-0.35) mg/L] compared to HNF4A-MODY group [0.81 (0.38-1.41) mg/L, U-test P = 0.002], Parallel measurements of serum PSP/reg1A and hsCRP levels were able to discriminate HNF1A- and HNF4A-MODY subjects. CONCLUSION: Our study demonstrates that two distinct target genes, PSP/reg and crp, are differentially regulated by HNF1A and HNF4A, and provides clinical proof-of-concept that serum PSP/reg1A and hsCRP levels may distinguish HNF1A-MODY from HNF4A-MODY subjects.

Clay-based nanocomposite coating for flexible optoelectronics applying commercial polymers.

Transparency, flexibility, and especially ultralow oxygen (OTR) and water vapor (WVTR) transmission rates are the key issues to be addressed for packaging of flexible organic photovoltaics and organic light-emitting diodes. Concomitant optimization of all essential features is still a big challenge. Here we present a thin (1.5 µm), highly transparent, and at the same time flexible nanocomposite coating with an exceptionally low OTR and WVTR (1.0 × 10(-2) cm(3) m(-2) day(-1) bar(-1) and <0.05 g m(-2) day(-1) at 50% RH, respectively). A commercially available polyurethane (Desmodur N 3600 and Desmophen 670 BA, Bayer MaterialScience AG) was filled with a delaminated synthetic layered silicate exhibiting huge aspect ratios of about 25,000. Functional films were prepared by simple doctor-blading a suspension of the matrix and the organophilized clay. This preparation procedure is technically benign, is easy to scale up, and may readily be applied for encapsulation of sensitive flexible electronics.

Systems analysis of cancer cell heterogeneity in caspase-dependent apoptosis subsequent to mitochondrial outer membrane permeabilization.

Deregulation of apoptosis is a hallmark of carcinogenesis. We here combine live cell imaging and systems modeling to investigate caspase-dependent apoptosis execution subsequent to mitochondrial outer membrane permeabilization (MOMP) in several cancer cell lines. We demonstrate that, although most cell lines that underwent MOMP also showed robust and fast activation of executioner caspases and apoptosis, the colorectal cancer cell lines LoVo and HCT-116 Smac(-/-), similar to X-linked inhibitor of apoptosis protein (XIAP)-overexpressing HeLa (HeLa XIAP(Adv)) cells, only showed delayed and often no caspase activation, suggesting apoptosis impairment subsequent to MOMP. Employing APOPTO-CELL, a recently established model of apoptosis subsequent to MOMP, this impairment could be understood by studying the systemic interaction of five proteins that are present in the apoptosis pathway subsequent to MOMP. Using APOPTO-CELL as a tool to study detailed molecular mechanisms during apoptosis execution in individual cell lines, we demonstrate that caspase-9 was the most important regulator in DLD-1, HCT-116, and HeLa cells and identified additional cell line-specific co-regulators. Developing and applying a computational workflow for parameter screening, systems modeling identified that apoptosis execution kinetics are more robust against changes in reaction kinetics in HCT-116 and HeLa than in DLD-1 cells. Our systems modeling study is the first to draw attention to the variability in cell specific protein levels and reaction rates and to the emergent effects of such variability on the efficiency of apoptosis execution and on apoptosis impairment subsequent to MOMP.