Seismic background level (SBL) growth can reveal slowly developing long-term eruption precursors.

The accelerating growth of seismic unrest before eruptions has been observed at many volcanoes and utilized for eruption forecasts. However, there are still many eruptions for which no precursory unrest has been identified, even at well-monitored volcanoes. The recent eruptions of Shinmoe-dake, Japan, have been another negative example of this kind. Here we present seismological evidence that the eruption preparation had been ongoing at the shallow depths beneath Shinmoe-dake for several months to a year. We investigated the seismic background level (SBL) of eleven-year data recorded around the volcano, including two stations about 1 km from the eruptive crater. We searched for persistent weak signals, focusing on low-amplitude time windows recorded during quiet nighttime. Then the spectra of daily background noise were classified by clustering analysis. The SBL analysis successfully revealed very weak precursory tremors from more than several months before the eruption, and residual tremors to the end of the eruptive period. The precursory signals grew acceleratory in a similar way as is assumed in the material failure forecast method applied to eruption forecasts. However, their growth was significantly slower and longer compared to other cases reported in the literature. Such slow and quiet eruption preparations would not be captured by conventional seismological methods. We expect that long-term SBL analyses on proximal seismic data will help detect early precursors, even at seismically quiet volcanoes, and will also help towards judging the end of an eruptive period.

Association of Pathology Markers with Somatostatin Analogue Responsiveness in Acromegaly.

Background: Somatotroph adenomas (SAs) exhibit a variable responsiveness to somatostatin analogue (SS-a) treatment, a process that is not well understood. We investigated established and novel histological markers as predictors of SS-a responsiveness. Methods: We retrospectively investigated pathology samples from 36 acromegalic patients that underwent transsphenoidal surgery. Clinical, hormonal, and imaging data were available in 24/36 patients, before and after SS-a treatment. Specimens were semiquantitatively analyzed with immunocytochemistry for Ki-67, KER, SSTR-2, SSTR-5, ZAC-1, E-cadherin, and AIP. Results: Collectively, 18 (50%) adenomas were each classified as densely/sparsely granulated somatotroph adenomas (DGSAs/SGSAs), respectively. Patients that received preoperative SS-a had lower expression of SSTR-2 compared to those that did not (2.0 (1.0, 3.0) vs. 3.0 (3.0, 3.0), p = 0.042). Compared with DGSAs, SGSAs had higher Ki-67 labeling index (LI) (1.0 (0.5, 1.0) vs. 2.0 (1.0, 3.5), p = 0.013), and a higher proportion of high MR T2 signal (1 (6%) vs. 6 (33%), p = 0.035), and tended to express less ZAC-1 (p = 0.061) and E-cadherin (p = 0.067). In linear regression corrected for baseline growth hormone (GH), ZAC-1 immunostaining was significantly associated with a decrease in GH levels after SS-a treatment (beta (95% confidence interval): -1.53 (-2.80, -0.26), p = 0.021). No markers were associated with changes in circulating insulin-like growth factor-I (IGF-I) after treatment with SS-a. Conclusion: The novel marker ZAC-1 was associated with GH response to medical treatment with SS-a. The SGSA cases were characterized by higher Ki-67 values and MR T2 signals indicative of an inferior response to SS-a. These findings improve our understanding of the mechanisms underlying SA response to medical treatment.

Segmentation and volume quantification of MR Images for the detection and monitoring multiple sclerosis progression.

Multiple Sclerosis (MS) lesions detection and disease's progression monitoring at the same time, play an important role. The purpose of this research is to demonstrate a method for detecting MS plaques and volume estimation from MR Images for monitoring the progression of the disease and the brain atrophy caused. In the proposed research, a clustering-based method is utilized in order to delineate MS plaques in brain, based on anatomical information, brain geometry and lesion features. In addition to volumetric information concerning lesions and whole brain volume, volume quantification is employed to estimate MS atrophy by measuring Brain Parenchymal Fraction (BPF). In the present study, Fluid Attenuated Inversion Recovery (FLAIR) images were utilized for the detection of MS lesions and BPF evaluation, while Tl-weighted MR Images utilized in volume estimation. 30 MS patients were included in a dataset consisted of 3D FLAIR and T1-weighted MR images in order to evaluate the proposed technique. MRI scans performed in two different clinical visits, a baseline and a visit after 6 months. The results extracted in segmentation of MS lesions in terms of sensitivity is 73.80 %. The BPF at baseline estimated to 0.82 ± 0.01, and at 1stfollow up, 0.83 ± 0.01. Finally, the brain volume loss between baseline and after 6 months is 0.4%.

Target localization accuracy in frame-based stereotactic radiosurgery: Comparison between MR-only and MR/CT co-registration approaches.

PURPOSE: In frame-based Gamma Knife (GK) stereotactic radiosurgery two treatment planning workflows are commonly employed; one based solely on magnetic resonance (MR) images and the other based on magnetic resonance/computed tomography (MR/CT) co-registered images. In both workflows, target localization accuracy (TLA) can be deteriorated due to MR-related geometric distortions and/or MR/CT co-registration uncertainties. In this study, the overall TLA following both clinical workflows is evaluated for cases of multiple brain metastases. METHODS: A polymer gel-filled head phantom, having the Leksell stereotactic headframe attached, was CT-imaged and irradiated by a GK Perfexion unit. A total of 26 4-mm shots were delivered at 26 locations directly defined in the Leksell stereotactic space (LSS), inducing adequate contrast in corresponding T2-weighted (T2w) MR images. Prescribed shot coordinates served as reference locations. An additional MR scan was acquired to implement the "mean image" distortion correction technique. The TLA for each workflow was assessed by comparing the radiation-induced target locations, identified in MR images, with corresponding reference locations. Using T1w MR and CT images of 15 patients (totaling 81 lesions), TLA in clinical cases was similarly assessed, considering MR-corrected data as reference. For the MR/CT workflow, both global and region of interest (ROI)-based MR/CT registration approaches were studied. RESULTS: In phantom measurements, the MR-corrected workflow demonstrated unsurpassed TLA (median offset of 0.2 mm) which deteriorated for MR-only and MR/CT workflows (median offsets of 0.8 and 0.6 mm, respectively). In real-patient cases, the MR-only workflow resulted in offsets that exhibit a significant positive correlation with the distance from the MR isocenter, reaching 1.1 mm (median 0.6 mm). Comparable results were obtained for the MR/CT-global workflow, although a maximum offset of 1.4 mm was detected. TLA was improved with the MR/CT-ROI workflow resulting in median/maximum offsets of 0.4 mm/1.1 mm. CONCLUSIONS: Subpixel TLA is achievable in all workflows. For the MR/CT workflow, a ROI-based MR/CT co-registration approach could considerably increase TLA and should be preferred instead of a global registration.

Evaluation of patient-specific MR distortion correction schemes for improved target localization accuracy in SRS.

PURPOSE: This work aims at promoting target localization accuracy in cranial stereotactic radiosurgery (SRS) applications by focusing on the correction of sequence-dependent (also patient induced) magnetic resonance (MR) distortions at the lesion locations. A phantom-based quality assurance (QA) methodology was developed and implemented for the evaluation of three distortion correction techniques. The same approach was also adapted to cranial MR images used for SRS treatment planning purposes in single or multiple brain metastases cases. METHODS: A three-dimensional (3D)-printed head phantom was filled with a 3D polymer gel dosimeter. Following treatment planning and dose delivery, volumes of radiation-induced polymerization served as hypothetical lesions, offering adequate MR contrast with respect to the surrounding unirradiated areas. T1-weighted (T1w) MR imaging was performed at 1.5 T using the clinical scanning protocol for SRS. Additional images were acquired to implement three distortion correction methods; the field mapping (FM), mean image (MI) and signal integration (SI) techniques. Reference lesion locations were calculated as the averaged centroid positions of each target identified in the forward and reverse read gradient polarity MRI scans. The same techniques and workflows were implemented for the correction of contrast-enhanced T1w MR images of 10 patients with a total of 27 brain metastases. RESULTS: All methods employed in the phantom study diminished spatial distortion. Median and maximum distortion magnitude decreased from 0.7 mm (2.10 ppm) and 0.8 mm (2.36 ppm), respectively, to <0.2 mm (0.61 ppm) at all target locations, using any of the three techniques. Image quality of the corrected images was acceptable, while contrast-to-noise ratio slightly increased. Results of the patient study were in accordance with the findings of the phantom study. Residual distortion in corrected patient images was found to be <0.3 mm in the vast majority of targets. Overall, the MI approach appears to be the most efficient correction method from the three investigated. CONCLUSIONS: In cranial SRS applications, patient-specific distortion correction at the target location(s) is feasible and effective, despite the expense of longer imaging time since additional MRI scan(s) need to be performed. A phantom-based QA methodology was developed and presented to reassure efficient implementation of correction techniques for sequence-dependent spatial distortion.

Earthquake and typhoon trigger unprecedented transient shifts in shallow hydrothermal vents biogeochemistry.

Shallow hydrothermal vents are of pivotal relevance for ocean biogeochemical cycles, including seawater dissolved heavy metals and trace elements as well as the carbonate system balance. The Kueishan Tao (KST) stratovolcano off Taiwan is associated with numerous hydrothermal vents emitting warm sulfur-rich fluids at so-called White Vents (WV) and Yellow Vent (YV) that impact the surrounding seawater masses and habitats. The morphological and biogeochemical consequences caused by a M5.8 earthquake and a C5 typhoon ("Nepartak") hitting KST (12th May, and 2nd-10th July, 2016) were studied within a 10-year time series (2009-2018) combining aerial drone imagery, technical diving, and hydrographic surveys. The catastrophic disturbances triggered landslides that reshaped the shoreline, burying the seabed and, as a consequence, native sulfur accretions that were abundant on the seafloor disappeared. A significant reduction in venting activity and fluid flow was observed at the high-temperature YV. Dissolved Inorganic Carbon (DIC) maxima in surrounding seawater reached 3000-5000 µmol kg-1, and Total Alkalinity (TA) drawdowns were below 1500-1000 µmol kg-1 lasting for one year. A strong decrease and, in some cases, depletion of dissolved elements (Cd, Ba, Tl, Pb, Fe, Cu, As) including Mg and Cl in seawater from shallow depths to the open ocean followed the disturbance, with a recovery of Mg and Cl to pre-disturbance concentrations in 2018. The WV and YV benthic megafauna exhibited mixed responses in their skeleton Mg:Ca and Sr:Ca ratios, not always following directions of seawater chemical changes. Over 70% of the organisms increased skeleton Mg:Ca ratio during rising DIC (higher CO2) despite decreasing seawater Mg:Ca ratios showing a high level of resilience. KST benthic organisms have historically co-existed with such events providing them ecological advantages under extreme conditions. The sudden and catastrophic changes observed at the KST site profoundly reshaped biogeochemical processes in shallow and offshore waters for one year, but they remained transient in nature, with a possible recovery of the system within two years.

Assessment of sequence dependent geometric distortion in contrast-enhanced MR images employed in stereotactic radiosurgery treatment planning.

This work focuses on MR-related sequence dependent geometric distortions, which are associated with B 0 inhomogeneity and patient-induced distortion (susceptibility differences and chemical shift effects), in MR images used in stereotactic radiosurgery (SRS) applications. Emphasis is put on characterizing distortion at target brain areas identified by gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) paramagnetic contrast agent uptake. A custom-made phantom for distortion detection was modified to accommodate two small cylindrical inserts, simulating small brain targets. The inserts were filled with Gd-DTPA solutions of various concentrations (0-20 mM). The phantom was scanned at 1.5 T unit using both the reversed read gradient polarity (to determine the overall distortion as reflected by the inserts centroid offset) and the field mapping (to determine B 0 inhomogeneity related distortion in the vicinity of the inserts) techniques. Post-Gd patient images involving a total of 10 brain metastases/targets were also studied using a similar methodology. For the specific imaging conditions, contrast agent presence was found to evidently affect phantom insert position, with centroid offset extending up to 0.068 mm mM-1 (0.208 ppm mM-1). The Gd-DTPA induced distortion in patient images was of the order of 0.5 mm for the MRI protocol used, in agreement with the phantom results. Total localization uncertainty of metastases-targets in patient images ranged from 0.35 mm to 0.87 mm, depending on target location, with an average value of 0.54 mm (2.24 ppm). This relative wide range of target localization uncertainty results from the fact that the B 0 inhomogeneity distortion vector in a specific location may add to or partly counterbalance Gd-DTPA induced distortion, thus increasing or decreasing, respectively, the total sequence dependent distortion. Although relatively small, the sequence dependent distortion in Gd-DTPA enhanced brain images can be easily taken into account for SRS treatment planning and target definition purposes by carefully inspecting both the forward and reversed polarity series.

Factors influencing the outcome of microsurgical transsphenoidal surgery for pituitary adenomas: a study on 184 patients.

OBJECTIVE: Evaluation of factors influencing the outcome of microsurgical transsphenoidal surgery in patients harbouring pituitary adenomas as well as of the efficacy and safety of this procedure. DESIGN: A total of 184 consecutive patients with pituitary adenomas, undergoing microsurgical transsphenoidal resection of their lesions from March 2004 to June 2011, were prospectively studied. Extent of tumour resection and disease remission were defined according to recently established radiological and hormonal consensus criteria. RESULTS: The study included 97 nonfunctioning and 87 functioning adenomas. A gross-total removal, as documented on postoperative imaging, was achieved in 67.4% of all patients. Residual tumour after surgery was detected in 37.1% of patients with nonfunctioning adenomas. The remission rates for patients with functioning adenomas, as documented by the last endocrinological evaluation, were 54.9% for growth hormone-secreting, 69.5% for adrenocorticotropin hormone-secreting, 72.7% for prolactin-secreting and 100% for thyroid-stimulating hormone-secreting, with two recurrences in patients with Cushing's disease. Multivariate analysis showed that factors influencing surgical outcome were cavernous sinus invasion, large tumour diameter (≥25 mm) and reoperation for the nonfunctioning adenomas, and cavernous sinus invasion as well as large tumour diameter (≥25 mm) for the functioning adenomas. In the latter cohort, predictors for endocrinological remission were maximum tumour diameter (≤20 mm) and reoperation. Postoperative complications were present in 3.3% of the cases. One patient developed epistaxis, two hemorrhage at the surgical field, one postoperative rhinorrhea, one postoperative permanent diabetes insipidus and one postoperative panhypopituitarism. CONCLUSIONS: Microsurgical transsphenoidal surgery is an effective and safe treatment in all patients with pituitary adenomas, except for prolactinomas responsive to medical therapy.

Dogma disputed: postdialysis increase of aminotransferase values cannot be attributed to an inhibitor removal by hemodialysis.

The objective of this study was to assess changes of aspartate aminotransferase (AST [serum glutamic oxalacetic transaminase]) and alanine aminotransferase (ALT [serum glutamic pyruvic transaminase]) values after a hemodialysis (HD) session. Aspartate aminotransferase and ALT serum values were measured before and after a 4 h HD session in 37 stable patients (group A), before and after a 3.5 h isovolemic HD (IVHD, with a zero ultrafiltration rate) session in eight patients (group B), as well as before and after a session of "isolated ultrafiltration" (IUF) in eight more patients (group C). In group A, mean predialysis AST and ALT serum values that were 16.4 ± 4.3 and 16.0 ± 5.5 IU/L, increased to 20.1 ± 5.4 and 17.7 ± 6.2 IU/L, respectively (p < 0.0001, comparing pre- to postdialysis values, for both). When the postdialysis values were corrected for hemoconcentration induced by ultrafiltration, no differences were found in ALT values. However, postdialysis-corrected AST values (mean 17.7 ± 4.4 IU/l) remained higher compared with predialysis values (p < 0.001). The AST/ALT ratio was 1.13 ± 0.4 for predialysis values and 1.26 ± 0.5 for postdialysis values (p < 0.0001). Predialysis mean serum AST and ALT values did not show any difference after the 3.5 h IVHD sessions (group B), but increased significantly (p < 0.02) after the removal of 1.7 ± 0.2 L of fluid by IUF (group C). In chronic HD patients, postdialysis serum AST and ALT values increased significantly compared with predialysis values. This increment is mainly due to hemoconcentration induced by ultrafiltration and cannot be attributed to the removal of an aminotransferase inhibitor by HD.

Subtherapeutic serum vancomycin concentrations during on-line hemodiafiltration.

The aim of the study is to study vancomycin serum concentration changes during on-line hemodiafiltration (OL-HDF) and determine whether administration of vancomycin during the last hour of OL-HDF provides therapeutic serum concentrations. Vancomycin was administered intravenously at a dose of 15 mg/kg to 17 chronic hemodialysis patients who were enrolled into two study groups (A and B). In group A patients (n = 11), vancomycin was administered immediately postdialysis. Forty-three hours later, a 4-hour OL-HDF session was performed. Blood samples (S) for vancomycin measurement were drawn before, during, and after the session. In group B patients (n = 6), vancomycin was administered during the last hour of a 4-hour OL-HDF session on Monday. Vancomycin serum concentrations were measured postdialysis, as well as before and after the next two dialysis sessions of the week. In group A patients, mean vancomycin concentrations were reduced by 50% (S(pre): 10.2 ± 1.4 µg/ml, S(post): 5.0 ± 0.9 µg/ml). Vancomycin dialysance was 74.6 ± 29.3 ml/min, while the volume of distribution was 0.42 L/kg. In group B patients, mean vancomycin concentrations before the beginning of Wednesday and Friday dialysis sessions were 3.1 ± 0.7 and 1.4 ± 0.4 µg/ml, respectively. Postdialysis administration of vancomycin followed by OL-HDF resulted in a 50% reduction of vancomycin serum concentrations. Administration during the last treatment hour of OL-HDF results in subtherapeutic vancomycin serum concentrations over the course of the subsequent inter- and intradialytic intervals.

Endothelial nitric oxide synthase gene polymorphisms -786T > C and 894G > T in coronary artery bypass graft surgery patients.

Polymorphisms in the endothelial nitric oxide synthase ( eNOS ) gene (- 786T > C and 894G > T ) enhance endothelial dysfunction and have been studied in relation to coronary artery disease (CAD). In the present study, we examined the association of the above polymorphisms with CAD, as well as with myocardial infarction (MI), hypertension, diabetes and smoking in CAD patients. Study subjects consisted of 154 consecutive coronary artery bypass graft (CABG) patients and 155 non-CAD controls. eNOS - 786T > C and 894G > T polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism. The estimated frequencies of the - 786C and 894T alleles did not differ between the two groups ( p = 0.46 and p = 0.84, respectively). The prevalence of eNOS polymorphisms was not associated with MI, hypertension or diabetes in CABG patients; however, we found that the 894TT genotype and 894T allele were significantly more frequent in current/past smoker CABG patients (16.7 per cent and 39.6 per cent, respectively) compared with never smoker CABG patients (6.1 per cent and 24.4 per cent, respectively) ( p = 0.01 and p < 0.01, respectively). We found no association of eNOS - 786C and 894T variant alleles with CAD; however, within CABG patients, a gene-environment interaction was found between the eNOS 894T allele and smoking.

Renin-angiotensin-aldosterone system gene polymorphisms in coronary artery bypass graft surgery patients.

INTRODUCTION: Candidates for coronary artery bypass grafting (CABG) represent a group of patients with well documented, severe coronary artery disease (CAD). Genetic polymorphisms of renin-angiotensin-aldosterone system (RAAS) components have been associated with CAD. We examined the association of polymorphisms of angiotensin-converting enzyme (ACE), angiotensinogen (AGT), and angiotensin II type 1 receptor (AT(1) receptor) with severe CAD in CABG patients. MATERIALS AND METHODS: One hundred and fifty-four CABG patients and 155 non-CAD controls were included in the study. Established PCR methods were used for genotyping of AGT M235T, AGT T174M, AT(1) receptor A1166C, and ACE I/D polymorphisms. Cumulative effect of analysed polymorphisms was assessed by calculation of each individual's RAAS gene score (addition of 0.5 points for each variant allele and then calculating the sum for all four polymorphisms). RESULTS: No association between AGT M235T, AGT T174M, ACE I/D and AT(1) receptor A1166C polymorphisms and CAD was observed. Within CABG patients, the frequency of homozygous AGT 235TT genotype was higher in hypertensive compared to normotensive CABG patients (21.7% vs. 6.3%, p=0.03). RAAS gene score did not differ between CABG patients and non-CAD controls. CONCLUSIONS: There is no association of the analysed RAAS polymorphisms with severe CAD in CABG patients. However, within these patients, an association was found between AGT 235TT genotype and hypertension.

The serotonin transporter promoter polymorphism (5-HTTLPR) is associated with type 2 diabetes.

BACKGROUND: The serotonergic system contributes substantially to the regulation of glucose homeostasis and feeding. 5-HTTLPR is a serotonin transporter (5-HTT) gene-linked polymorphic region that regulates the transcriptional activity of 5-HTT. Our aim was to investigate the possible association of 5-HTTLPR polymorphism with type 2 diabetes mellitus and obesity. METHODS: Study population consisted of 252 subjects diagnosed with Type 2 DM and 211 non-diabetic subjects, all Caucasians of Greek ethnic origin. Genomic DNA was extracted from peripheral blood and analyzed for 5-HTTLPR polymorphism with a novel PCR protocol. RESULTS: The frequency of SS and SL genotypes of HTTLPR was significantly higher in the diabetic group (77.0%) than in the non-diabetic group (61.6%) (P<0.001). The genetic risk of Type 2 DM for subjects carrying at least one S allele was increased compared to non-diabetic subjects (OR=2.08, 95% CI=1.39-3.12). When subjects were divided according to BMI status, the frequency of S allele carriers was similar in obese and non-obese subjects. CONCLUSIONS: The S allele of 5-HTTLPR is strongly associated with the presence of Type 2 DM. This association appears to be direct and not dependent on obesity status. Therefore, 5-HTTLPR LL genotype might be protective for development of Type 2 DM.

Sensory innervation of the subregions of the scapholunate interosseous ligament in relation to their structural composition.

PURPOSE: To investigate the different types of innervation and the presence of mechanoreceptors in relation to the structural composition of the scapholunate interosseous ligament and to correlate the findings with the known mechanical properties of the ligament subregions. METHODS: Six fresh cadaveric scapholunate interosseous ligaments were divided into their 3 subregions: dorsal, palmar, and proximal. The microscopic features were investigated with use of a standard hematoxylin-eosin stain and immunostains for S-100, neurofilaments, neuron-specific enolase, protein gene product 9.5, CD31, and smooth muscle actin. The connective tissue structural composition and the presence of blood vessels and neural structures (myelinated and unmyelinated nerve fibers and mechanoreceptors) were investigated. The macroscopic anatomic details were also noted. RESULTS: The palmar subregion consists of structured, densely collagenized tissue at the core, surrounded by looser connective tissue. Myelinated nerve fibers forming fascicles accompany the interspersed blood vessels inside the ligament substance. Their concentration is greater in the proximal part of the palmar subregion, reaching a distance of approximately 150 mum from the ligament free surface. The dorsal subregion has similar structure to the palmar one, but the fibrous tissue ratio and density are higher. The proximal subregion consists of chondroid matrix and of loose connective tissue at its core. The radio-scapholunate ligament insertion is noted at the palmar aspect of the proximal subregion. Pacinian and other sensory corpuscles were found mostly at the palmar and proximal subregions. CONCLUSIONS: The scapholunate interosseous ligament is a richly innervated ligament that contributes to carpal proprioception, a fundamental element of dynamic wrist stability. The palmar subregion, apart from its major mechanical role, contains the greatest amount of the neural structures and mechanoreceptors. The dorsal subregion, with densely packed collagen fibers and limited innervation, functions mainly to constrain the scaphoid-lunate relative motion.

The anticoagulant activity of enoxaparin sodium during on-line hemodiafiltration and conventional hemodialysis.

To study and compare the anticoagulant activity of enoxaparin sodium during on-line hemodiafiltration (OL-HDF) and conventional hemodialysis (C-HD). Enoxaparin was administered as an anticoagulant to 21 hemodialysis patients at the beginning of a single 4-hour OL-HDF session as an intravenous bolus dose of 80 IU/kg [DOSAGE ERROR CORRECTED] On-line hemodiafiltration was performed using a high-flux polyester polymer alloy dialyzer and a total of 18 L replacement fluid (session A). One week later, the study was repeated in the same patients during a single 4-hour session of C-HD using a low-flux polysulfone dialyzer (session B). Blood samples for the measurement of Hb, blood urea and nitrogen (BUN), activated partial thromboplastin time (APTT), and anti-Xa levels were taken before each study session and 5-minute postdialysis. In 13 more patients, the same study was performed during OL-HDF using a high-flux polysulfone dialyzer (session C). No differences were found between sessions A, B, and C when predialysis values for Hb, BUN, APTT, and anti-Xa were compared. The mean postdialysis APTT and anti-Xa values were 32.5+/-3.8 seconds and 0.19+/-0.11 IU/mL, respectively, in session A, 39.0+/-5.0 seconds and 0.71+/-0.17 IU/mL in session B, and 33.8+/-3.1 seconds and 0.35+/-17 IU/mL in session C (A vs. B, P<0.0001, for both parameters, A vs. C, P<0.003 for anti-XA, and B vs. C, P<0.005, for both parameters). The anticoagulant activity of enoxaparin sodium is decreased significantly during a 4-hour OL-HDF session compared with to a similar session of C-HD. The degree of the reduction seems to depend on the dialyzer's membrane.

Need for reassessment of reported CYP2C19 allele frequencies in various populations in view of CYP2C19*17 discovery: the case of Greece.

INTRODUCTION: CYP2C19*17 is a novel variant allele causing ultrarapid metabolism of CYP2C19 substrates. In the present study we investigated the CYP2C19*17 allelic frequency and recalculated previously reported frequencies of the CYP2C19*1/*1 genotype and of all genotype-derived phenotypes for CYP2C19 in the Greek population. MATERIALS & METHODS: A total of 283 nonrelated healthy Greek ethnic subjects that had already been genotyped for CYP2C19*2 and *3 alleles as well as for CYP2D6 and CYP2C9 variant alleles participated in the study. The CYP2C19*17 allele was genotyped by the PCR-RFLP method. RESULTS: The CYP2C19*17 allele frequency was 19.61%. The prevalence of CYP2C19*17 carriers in the Greek population was estimated at 31.80%, while the frequency of CYP2C19*1/*1 genotype was recalculated to 44.17% from 75.97% in our previous study. Several subjects possessing both CYP2C19*17 and variant alleles of CYP2D6 and CYP2C9 were also identified. DISCUSSION & CONCLUSION: The CYP2C19*17 allele is present in Greeks at a high frequency similar to that found in other European populations of Caucasian origin. Our study highlights the need of reassessing and updating CYP2C19 allelic frequencies in various populations in view of the major role that CYP2C19*17 may have in predicting the clinical outcome of drugs metabolized by CYP2C19.

Estimating airborne pollutant concentrations in vegetated urban sites using statistical models with microclimate and urban geometry parameters as predictor variables: a case study in the city of Athens Greece.

The present study demonstrates the efficiency of applying statistical models to estimate airborne pollutant concentrations in urban vegetation by using as predictor variables readily available or easily accessible data. Results revealed that airborne cadmium concentrations in vegetation showed a predictable response to wind conditions and to various urban landscape features such as the distance between the vegetation and the adjacent street, the mean height of the adjacent buildings, the mean density of vegetation between vegetation and the adjacent street and the mean height of vegetation. An artificial neural network (ANN) model was found to have superiority in terms of accuracy with an R(2) value on the order of 0.9. The lowest R(2) value (on the order of 0.7) was associated with the linear model (SMLR model). The linear model with interactions (SMLRI model) and the tree regression (RTM) model gave similar results in terms of accuracy with R(2) values on the order of 0.8. The improvement of the results with the use of the non-linear models (RTM and ANN) and the inclusion of interaction terms in the SMLRI model implied the nonlinear relationships of pollutant concentrations to the selected predictors and showed the importance of the interactions between the various predictor variables. Despite the limitations of the models, some of them appear to be promising alternatives to multimedia-based simulation modeling approaches in urban areas with vegetation, where the application of typical deposition models is sometimes limited.

An application of artificial neural network models to estimate air temperature data in areas with sparse network of meteorological stations.

In this work artificial neural network (ANN) models are developed to estimate meteorological data values in areas with sparse meteorological stations. A more traditional interpolation model (multiple regression model, MLR) is also used to compare model results and performance. The application site is a canyon in a National Forest located in southern Greece. Four meteorological stations were established in the canyon; the models were then applied to estimate air temperature values as a function of the corresponding values of one or more reference stations. The evaluation of the ANN model results showed that fair to very good air temperature estimations may be achieved depending on the number of the meteorological stations used as reference stations. In addition, the ANN model was found to have better performance than the MLR model: mean absolute error values were found to be in the range 0.82-1.72 degrees C and 0.90-1.81 degrees C, for the ANN and the MLR models, respectively. These results indicate that ANN models may provide advantages over more traditional models or methods for temperature and other data estimations in areas where meteorological stations are sparse; they may be adopted, therefore, as an important component in various environmental modeling and management studies.

Tc2 response at the onset of COPD exacerbations.

BACKGROUND: T lymphocytes and especially the subpopulations of CD8+ cells are believed to have a key role in COPD pathophysiology, but there are only few data regarding the role of these cells in COPD exacerbation. AIM: We aimed to study prospectively changes of CD8+ T-lymphocyte subpopulations in the sputum of COPD patients at the onset of mild exacerbations and at a stable condition in order to provide further insight in the pathophysiology of the disease. METHODS: Induced-sputum samples were collected from 24 COPD patients with median age of 52 years (interquartile range [IQR], 44 to 58 years) and FEV(1) percentage of predicted of 78.05% (IQR, 75.8 to 80.1%) at the onset of mild exacerbations not requiring hospitalization and when stable. Inflammatory cells and T-lymphocyte subpopulations (CD4+, CD8+, and cells producing interferon [IFN]-gamma or interleukin [IL]-4) were measured using flow cytometry and immunocytochemical methods. RESULTS: A significant increase in sputum CD8+ T lymphocytes (p < 0.0001) and significant decreases in CD4+ T lymphocytes as well as in CD4+/CD8+ (p = 0.0001) and CD8+IFN-gamma+/CD8+IL-4+ (p = 0.001), CD4+IFN-gamma+/CD4+IL-4+ (p = 0.0003) sputum cells ratios were found decreased at the onset of exacerbations compared to stable condition. The changes in T-lymphocyte subpopulations were not associated with smoking history, demographic characteristics, or disease severity. CONCLUSION: The findings of the present study suggest that CD8+ lymphocytes are increased and potentially polarized toward a Tc2 profile in the airways of COPD patients at the onset of COPD exacerbations with respect to stable condition. The clinical impact of the observed phenomenon requires further investigation.

The -759C/T polymorphism of the 5-HT2C receptor is associated with type 2 diabetes in male and female Caucasians.

OBJECTIVES: Type 2 diabetes mellitus and obesity constitute serious health problems. Studies reveal that the 5-HT2C receptor contributes substantially to the regulation of a wide variety of behavioral and physiological processes including feeding and glucose homeostasis. Our aim was to determine the possible association of the -759C/T polymorphism of the 5-HT2C receptor gene with type 2 diabetes and obesity in male and female individuals Caucasian origin. METHODS: The study population consisted of 151 patients diagnosed with type 2 diabetes and 164 nondiabetic patients, all of Greek origin. Genomic DNA was extracted from peripheral blood and analyzed for the -759C/T polymorphism of the 5-HT2C receptor gene using polymerase chain reaction-restriction fragment length polymorphism method. RESULTS: The frequency of T allele of the -759C/T polymorphism of the 5-HT2C receptor was significantly lower in the diabetic group (12.6%) than in the nondiabetic group (23.3%) (P=0.003). The genetic risk of type 2 diabetes for patients not carrying the T allele was increased compared with nondiabetic patients (odds ratio (OR)=2.34, 95% confidence interval (CI)=1.36-4.02). The reduced frequency of T allele was present both in male [10% in patients with diabetes and 21.6% in patients without diabetes (P=0.041)] and female patients [14.1% in patients with diabetes and 24.3% in patients without diabetes (P=0.030)]. In contrast, the frequency of T allele was similar in obese (16.4%) and nonobese (17.1%) patients. CONCLUSIONS: Lower frequency of -759T allele of the 5- HT2C receptor gene was associated with type 2 diabetes but not with obesity in male and female Caucasians. Thus, this polymorphism might constitute a prognostic marker for diabetic risk.