66 research outputs found

    Surveillance for the Management of Small Renal Masses

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    Surveillance is a new management option for small renal masses (SRMs) in aged and infirm patients with short-life expectancy. The current literature on surveillance of SRM contains mostly small, retrospective studies with limited data. Imaging alone is inadequate for suggesting the aggressive potential of SRM for both diagnosis and followup. Current data suggest that a computed tomography (CT) or magnetic resonance imaging (MRI) every 3 months in the 1st year, every 6 months in the next 2 years, and every year thereafter, is appropriate for observation. The authors rather believe in active surveillance with mandatory initial and followup renal tumor biopsies than classical observation. Since not all SRMs are harmless, selection criteria for active surveillance need to be improved. In addition, there is need for larger studies in order to better outline oncological outcome and followup protocols

    Effects of ivabradine therapy on heart failure biomarkers

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    Background: Heart rate (HR) reduction is associated with improved outcomes in patients with heart failure (HF) and biomarkers can be a valuable diagnostic tool in HF management. The primary aim of our study was to evaluate the short-term (6 months) effect of ivabradine on N-terminal pro B-type natriuretic peptide (NT-proBNP), CA-125, and cystatin-C values in systolic HF outpatients, and secondary aim was to determine the relationship between baseline HR and the NT-proBNP, CA-125, cystatin-C, and clinical status variation with ivabradine therapy. Methods: Ninety-eight patients (mean age: 65.81 ± 10.20 years; 33 men), left ventricular ejection fraction < 35% with Simpson method, New York Heart Association (NYHA) class II–III, sinus rhythm and resting HR > 70/min, optimally treated before the study were included. Among them, two matched groups were formed: the ivabradine group and the control group. Patients received ivabradine with an average (range of 10–15) mg/day during 6 months of follow-up. Blood samples for NT-proBNP, CA-125, and cystatin-C were taken at baseline and at the end of a 6-month follow-up in both groups. Results: There was a significant decrease in NYHA class in the ivabradine group (2.67 ± ± 0.47 vs. 1.85 ± 0.61, p < 0.001). When ivabradine and control groups were compared, a significant difference was also found in NHYA class 6 months later (p = 0.013). A significant decrease was found in HR in the ivabradine and control groups (84.10 ± 8.76 vs. 68.36 ± ± 8.32 bpm, p = 0.001; 84.51 ± 10 vs. 80.40 ± 8.3 bpm, p = 0.001). When both groups were compared, a significant difference was also found in HR after 6 months (p = 0.001). A significant decrease was found in cystatin-C (2.10 ± 0.73 vs. 1.50 ± 0.44 mg/L, p < 0.001), CA-125 (30.09 ± 21.08 vs. 13.22 ± 8.51 U/mL, p < 0.001), and NT-proBNP (1,353.02 ± 1,453.77 vs. 717.81 ± 834.76 pg/mL, p < 0.001) in the ivabradine group. When ivabradine and control groups were compared after 6 months, a significant decrease was found in all HF parameters (respectively; cystatin-C: p = 0.001, CA-125: p = 0.001, NT-proBNP: p = 0.001). Creatinine level was significantly decreased and glomerular filtration rate (GFR) was significantly increased in the ivabradine group (1.02 ± 0.26 vs. 0.86 ± 0.17, creatinine: p = 0.001; 79.26 ± 18.58 vs. 92.48 ± 19.88, GFR: p = 0.001). There was no significant correlation between NYHA classes (before and after ivabradine therapy) and biochemical markers, or HR. Conclusions: In the outpatients with systolic HF, persistent resting HF > 70/min with optimal medical therapy, the NT-proBNP, CA-125, and cystatin-C reductions were obtained with ivabradine treatment. Measurement of NT-proBNP, CA-125, and cystatin-C may prove to be useful in biomarker panels evaluating ivabradine therapy response in HF patients.

    Development and mechanical modeling of Si1-XGex/Si MQW based uncooled microbolometers in a 130 nm BiCMOS

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    This paper presents the development of process integration and mechanical modeling of a Si1-xGex/Si MQW based uncooled micro-bolometer. The recent progress on layer transfer based integration scheme of Si1-xGex/Si based micro-bolometer into a 130 nm BiCMOS process is presented. The two important parts of the process integration, namely the layer-transfer and stress compensation of the arms are studied. The initial successful results on layer transfer and the FEM modeling for the stress compensation of the thin and narrow arms of the bolometer is presented. Finally, the developed FEM model is compared with the fabricated cantilevers. The results show that the developed FEM model has a very good matching with the experimental results; thus very convenient to use for the FEM modeling of the full bolometer structure

    Demographic and microbial characteristics of extrapulmonary tuberculosis cases diagnosed in Malatya, Turkey, 2001-2007

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    <p>Abstract</p> <p>Background</p> <p>Extrapulmonary tuberculosis (EPTB) has an increasing rate in Turkey. The reason remains largely unknown. A better understanding of the demographic and microbial characteristics of EPTB in the Turkish population would extend the knowledgebase of EPTB and allow us to develop better strategies to control tuberculosis (TB).</p> <p><b>Methods</b></p> <p>We retrospectively evaluated clinical and laboratory data of 397 bacteriologically-confirmed TB cases diagnosed during an eight year-period using by chi-square analysis and multivariate logistic regression model.</p> <p>Results</p> <p>Of the 397 study patients, 103 (25.9%) had EPTB and 294 (74.1%) had pulmonary tuberculosis (PTB). The most commonly seen two types of EPTB were genitourinary TB (27.2%) and meningeal TB (19.4%). TB in bone/joints, pleural cavity, lymph nodes, skin, and peritoneal cavity occurred at a frequency ranging from 9.7% to 10.7%. The age distribution was significantly different (P < 0.01) between PTB and EPTB, with patients older than 45 years tending to have an increased risk of EPTB. Furthermore, the distribution of different types of EPTB differed significantly among age groups (P = 0.03). Meningeal and bone and/or joint TB were more commonly observed among the male patients, while lymphatic, genitourinary, and peritoneal TB cases were more frequently seen among females. Unique strain infection was statistically significantly associated with EPTB (OR: 2.82, 95% CI [1.59, 5.00])</p> <p>Conclusions</p> <p>EPTB accounted for a significant proportion of TB cases in Malatya, Turkey between 2001 and 2007. The current study has provided an insight into the dynamics of EPTB in Malatya, Turkey. However, the risk factors for having EPTB in Malatya, Turkey remain to be assessed in future studies using population-based or randomly selected sample.</p

    Asymmetric Correlations in Financial Markets

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    <p>This dissertation consists of three essays on asymmetric correlations in financial markets. In the first essay, I have two main contributions. First, I show that dividend growth rates have symmetric correlations. Second, I show that asymmetric correlations are different than correlations being counter-cyclical. The correlation asymmetry I study in this dissertation should not be confused with correlations being counter-cyclical, i.e. being higher during recessions than during booms. I show that while counter-cyclical correlations can simply be explained by counter-cyclical aggregate market volatility, the correlation asymmetry with respect to joint upside and downside movements of returns are not just due to the heightened market volatility during those times. </p><p>In the second essay I present a model in order to explain the correlation asymmetry observed in the data. This is the first paper to offer an explanation for observed correlation asymmetry. I formalize the explanation using an equilibrium model. The model is useful to understand both the cross-section and time-series of correlation asymmetry. By the means of my model, we can answer questions about why some stocks have higher correlation asymmetry, and why the correlation asymmetry was higher during 1990s? In the model asset prices respond the realization of dividends and news about the future. However, price responses to news are asymmetric and this asymmetry is endogenous. Price responses are endogenously stronger conditional on bad news than conditional on good news. This asymmetry also generates the observed correlation asymmetry. The price responses are asymmetric due to the ambiguity about the news quality. Information about the quality of the signal is incomplete in the sense that the exact precision of the signal is unknown; it is only known to be in an interval, which makes the representative agent treat news as ambiguous. To model ambiguity aversion, I use Gilboa and Schmeidler (1989)'s max-min expected utility representation. The agent has a set of beliefs about the quality of signals, and the ambiguity-averse agent behaves as if she maximizes expected utility under a worst-case scenario. This incomplete information about the news quality, together with ambiguity-averse agents, generates an asymmetric response to news. Endogenous worst-case scenarios differ depending on the realization of news. When observing ``bad" news, the worst-case scenario is that the news is reliable and the prices of trees decrease strongly. On the other hand, when ``good news" is observed, under the worst-case scenario the news is evaluated as less reliable, and thus the price increases are mild. Therefore, price responses are stronger conditional on a negative signal and this asymmetry creates a higher correlation conditional on a negative signal than conditional on a positive signal. I also show that the results are robust to the smooth ambiguity aversion representation.</p><p>Motivated by the model, I uncover a new empirical regularity that is unknown in the literature. I show that correlation asymmetry is related to idiosyncratic volatility: the higher the idiosyncratic volatility, the higher the correlation asymmetry. This novel empirical finding is also useful to understand the time-series and cross-sectional variation in correlation asymmetry. Stocks with smaller market capitalizations have greater correlation asymmetry compared to stocks with higher market capitalization. However, an explanation for this finding has been lacking. According to the explanation offered in this paper, smaller size stocks have greater correlation asymmetry compared to bigger size stocks because small size stocks tend to have higher idiosyncratic volatilities compared to bigger size stocks. In the time-series, correlation asymmetry shows quite significant variation as well. The average correlation asymmetry is especially high for the 1990s and decreases significantly at the beginning of the 2000s. This pattern in times-series can also be explained in terms of the time-series behavior of idiosyncratic volatilities. Several papers including Brandt et al. (2010), document higher idiosyncratic volatilities during 1990s while the aggregate volatility stays fairly stable. Basically, the high idiosyncratic volatilities during the 1990s also caused greater correlation asymmetry. </p><p>In the third essay, I study the correlation of returns in government bond markets. Similar to the findings in equity markets, I show that there is some evidence for asymmetric correlations in government bond markets. First, I show that the maturity structure matters for correlation asymmetry in bonds markets: Unlike long-maturity bonds, shorter-maturity bonds tend to have asymmetric correlations. Second, I show that the correlation asymmetry observed in European bond markets disappears with the formation of a common currency area. Lastly, I study the correlation between equity and bond returns in different countries. For long-maturity bonds, correlations with the domestic equity returns are asymmetric for half of the countries in the sample, including the U.S. These findings show that results on asymmetric correlations from equity markets can generalize, at least to some extent, to other financial markets.</p>Dissertatio

    Case Report Primary Malignant Melanoma of the Gallbladder: A Case Report and Review of the Literature

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    Malignant melanoma is characterized by the ability of diffuse metastases. Since the first report of an isolated malignant melanoma case of the gallbladder, it is already controversial whether isolated cases are metastatic or primary tumors. A 49-year-old woman appealed to the emergency unit because of abdominal pain. Ultrasonography revealed increased thickness of the gallbladder wall and a lesion with surrounding fluid sized 12 mm without acoustic shadow, which arose from the gallbladder wall and was consistent with a polyp. Histopathologic evaluation of the surgical specimen after laparoscopic cholecystectomy revealed malign epithelial tumor consisting of atypical cells with large eosinophilic cytoplasm and dense melanin pigment within the cytoplasm of the tumor cells. As no other focus was identified as a result of the evaluation, the patient was diagnosed with primary malignant melanoma of the gallbladder. In this paper, we aimed to define our treatment modality for a case with isolated malignant melanoma of the gallbladder

    The effects of early or late treatment of osteochondral defects on joint homoeostasis: an experimental study in rabbits

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    WOS: 000266482200003PubMed ID: 19083207A 3.5 x 4 mm tubular osteochondral defect was created on the right medial femoral condyles of 51 adult rabbits. In the control group (CG), defects were left untreated. In the early-(ETG) and late-(LTG) treatment groups, defects were treated by an osteoperiosteal graft 1 and 12 weeks, respectively, after the index procedure. Synovial fluid (SF) samples were collected regularly and proteoglycan fragments (PF), total collagen (TC) and collagenase (MMP-1) levels were measured. Rabbits were killed at 4 (early period), 12 (intermediate period), or 24 (late period) weeks postoperatively. Histological examination indicated a more successful healing in both grafting groups than in the CG, but without any difference at any time period between the grafting groups. In the CG, PF, and TC levels in SF increased continuously until the late period, indicating an ongoing degenerative activity in the joints. In contrast, SF marker levels in both grafting groups indicated that normalization in joint metabolism could be achieved-at least partially-after treatment. However, PF levels in the SF showed that the treatment of defects in earlier stages might result in better outcomes since the negative effects were more prominent in chronic stages, presumably due to the more prolonged period of disturbed homeostasis. Thus, histological values and SF marker levels indicated that treatment of osteochondral defects at any time of the disease had a positive effect on healing when compared to no treatment. Early treatment might better assist the recovery of joint homeostasis than late treatment.Ege University Research FundEge University [98/TIP/006]; Ege University Science and Technology CenterEge UniversityWe thank Dr. Emin Taskiran and Dr. Veli Lok for their helpful suggestions in planning this research. All authors declare that these experiments comply with the current laws of our country. We also want to acknowledge financial support from Ege University Research Fund (Research Project No: 98/TIP/006) and Ege University Science and Technology Center, Co-funding of Research Projects Programme

    Heteroropic Pregnancy which corse with tubal Ectopic and Intrauterine Triplet

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    Heterotopic pregnancies, simultaneous precence of intrauterine and extrauterine pregnancies is rare condition. Heterotopic pregnancies incidance is increasing with the use of asisted reproductive technology and ovulation induction methods. The early diagnosis of the heterotopic pregnancies is very important for maternal-fetal mortality and morbidity. An 8 week multipl pregnant women with clomiphene citrate ovulation induction, admitted to our hospital with complaints of acute abdomen and vaginal bleeding. Transvaginal USG revealed intraabdominal wide free fluid, intrauterine triplet pregnancy, and fetal cardiac activity positive, living fetus in left fallopian tube. Explaratory laparotomy was made for the cause of acute abdomen. Laparatomy revealed 2000 cc blood, and unruptured left tubal ectopic pregnancy. Left salpengectomy was done. After discharge patient was controlled with follow up visits. As a result if first trimester pregnancies of asisted reproductive technologies and ovulation induction, with complaint of abdominal pain and vaginal bleeding, heterotropic pregnancies also be discarded

    Surveillance for the Management of Small Renal Masses

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    Surveillance is a new management option for small renal masses (SRMs) in aged and infirm patients with short-life expectancy. The current literature on surveillance of SRM contains mostly small, retrospective studies with limited data. Imaging alone is inadequate for suggesting the aggressive potential of SRM for both diagnosis and followup. Current data suggest that a computed tomography (CT) or magnetic resonance imaging (MRI) every 3 months in the 1st year, every 6 months in the next 2 years, and every year thereafter, is appropriate for observation. The authors rather believe in active surveillance with mandatory initial and followup renal tumor biopsies than classical observation. Since not all SRMs are harmless, selection criteria for active surveillance need to be improved. In addition, there is need for larger studies in order to better outline oncological outcome and followup protocols
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