1,160 research outputs found

    Internal evaluation of a physically-based distributed model using data from a Mediterranean mountain catchment

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    An evaluation of the performance of a physically-based distributed model of a small Mediterennean mountain catchment is presented. This was carried out using hydrological response data, including measurements of runoff, soil moisture, phreactic surface level and actual evapotranspiration. A-priori model parameterisation was based as far as possible on property data measured in the catchment. Limited model calibration was required to identify an appropriate value for terms controlling water loss to a deeper regional aquifer. The model provided good results for an initial calibration period, when judge in terms of catchment discharge. However, model performance for runoff declined substantially when evaluated againts a consecutive, rather drier, period of data. Evaluation against other catchment responses allowed identification of the problems responsible for the observed lack of model robustness in flow simulation. In particular, it was shown that an incorrect parameterisation of the soil water was preventing adequate representation of drainage from soils during hydrogeraph recessions. This excess moisture was then being removed via an overestimation of evapotranspiration. It also appeared that the model underestimated canopy interception. The results presented here suggest that model evaluation against catchment scale variables summarising its water balance can be of great use in identifying problems with model parameterisation, even for distributed models. Evaluation using spatially distributed data yielded less useful information on model performance, owing to the relative sparseness of data points, and problems of mismatch of scale between the measurement and the model grid.This work was carried out as part of project VAHMPIRE (Validating Hydrological Models using Process Studies and Internal Data from Research Basins: tools for assessing the hydrological impacts of environmental change), which was funded by the European Commission Framework IV Environment and Climate Program (Contract No. ENV4- CT95-0134). Simulations were carried out on a UNIX workstation funded jointly by UK Nirex Ltd. and NERC grant GR3/ E0009.Peer Reviewe

    Neuropsychological profiles of patients with obsessive-compulsive disorder: early onset versus late onset

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    In this study, we assess the neuropsychological profiles of both early and late symptom-onset obsessive-compulsive disorder (OCD) patients. The early and late-onset OCD patients are compared to the control group with a series of neuropsychological measurements. The late-onset OCD patients exhibited impaired performance on the immediate and the delayed recall conditions of the Rey-Osterrieth Complex Figure Test (RCFT) and the letter and category fluency of the Controlled Oral Word Association Test (COWA), compared to the normal controls and the early-onset OCD patients. The controls and early-onset OCD patients did not differ on any of the neuropsychological measurements taken in this study. These results suggest that different neurophysiological mechanisms are in play in early and late-onset OCD patients, and age of onset can serve as a potential marker for the subtyping of OCD

    Clinicopathologic Features of Polypoid Lesions of the Gallbladder and Risk Factors of Gallbladder Cancer

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    It is difficult to differentiate benign and malignancy in polypoid lesions of the gallbladder (PLG) by solely depending on imaging studies. Therefore clinicopathologic features of benign and malignant polyps are compared in an attempt to identify the risk factors of malignant polypoid lesions. The medical records of 291 patients who were confirmed to have PLG through cholecystectomy were reviewed and analyzed for age, sex, symptom, associated gallstone, morphology of PLG, size of PLG, number of PLG, and preoperative tumor markers. Benign PLG was found in 256 patients (88.0%) and malignant PLG in 35 patients (12.0%). Compared with benign group, the malignant group were older (61.1 yr vs. 47.1 yr, P<0.001), more often accompanied with symptoms (62.9% vs. 28.9%, P<0.001). Malignant PLG tended to be sessile (60.0% vs. 10.5%, P<0.001), larger (28.0 mm vs. 8.6 mm, P<0.001) and single lesion (65.7% vs. 44.1%, P<0.016). Age over 60 yr (P=0.021, odds ratio [OR], 8.16), sessile morphology (P<0.001, OR, 7.70), and size over 10 mm (P=0.009, OR, 8.87) were identified as risk factors for malignant PLG. Careful decision making on therapeutic plans should be made with consideration of malignancy for patients over 60 yr, with sessile morphology of PLG, and with PLG size of over 10 mm

    GnRH peripherally modulates nociceptor functions, exacerbating mechanical pain

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    The function of peripheral nociceptors, the neurons that relay pain signals to the brain, are frequently tuned by local and systemic modulator substances. In this context, neurohormonal effects are emerging as an important modulatory mechanism, but many aspects remain to be elucidated. Here we report that gonadotropin-releasing hormone (GnRH), a brain-specific neurohormone, can aggravate pain by acting on nociceptors in mice. GnRH and GnRHR, the receptor for GnRH, are expressed in a nociceptor subpopulation. Administration of GnRH and its analogue, localized for selectively affecting the peripheral neurons, deteriorated mechanical pain, which was reproducible in neuropathic conditions. Nociceptor function was promoted by GnRH treatment in vitro, which appears to involve specific sensory transient receptor potential ion channels. These data suggest that peripheral GnRH can positively modulate nociceptor activities in its receptor-specific manner, contributing to pain exacerbation. Our study indicates that GnRH plays an important role in neurohormonal pain modulation via a peripheral mechanism

    A Newly Identified Insertion Mutation in the Thyroid Hormone Receptor-β Gene in a Korean Family with Generalized Thyroid Hormone Resistance

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    Thyroid hormone resistance syndrome (RTH) is a rare disorder and is characterized by elevated levels of circulating free thyroid hormones, inappropriate secretion of thyroid stimulating hormone (TSH), and reduced peripheral tissue response to thyroid hormone. 90% of RTH subjects, when studied at the level of the gene, have been found to harbor mutations in the thyroid hormone receptor-β (THRB) gene. These affected individuals have been shown to possess a variety of missense mutations, resulting from changes in a single nucleotide in the THRB gene that corresponds to amino acid alternation. However, insertion or deletion mutations in the THRB gene sequence are quite rare, and have been observed in only a very few cases. In this study, we describe two such cases, in which two members of the same family were determined to harbor an insertion mutation in exon 10, and had also been diagnosed with generalized RTH. This insertion mutation, specifically the insertion of a cytosine at nucleotide 1358 of the THRB gene, is, to the best of our knowledge, the first such mutation reported among RTH patients in Korea

    Interferon-Stimulated Genes Response in Endothelial Cells Following Hantaan Virus Infection

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    The regulation mechanism of interferon (IFN) and IFN-stimulated genes is a very complex procedure and is dependent on cell types and virus species. We observed molecular changes related to anti-viral responses in endothelial cells during Hantaan virus (HTNV) infection. We found that there are two patterns of gene expression, the first pattern of gene expression being characterized by early induction and short action, as in that of type I IFNs,' and the other being characterized by delayed induction and long duration, as those of IRF-7, MxA, and TAP-1/2. Even though there are significant differences in their induction folds, we found that all of IFN-α/β, IRF-3/7, MxA, and TAP-1/2 mRNA expressions reached the peak when the viral replication was most active, which took place 3 days of post infection (d.p.i.). In addition, an interesting phenomenon was observed; only one gene was highly expressed in paired genes such as IFN-α/β (3/277-folds), IRF-3/7 (2.2/29.4-folds), and TAP-1/2 (26.2/6.1-folds). Therefore, IFN-β, IRF-7, and TAP-1 seem to be more important for the anti-viral response in HTNV infection. MxA was increased to 296-folds at 3 d.p.i. and kept continuing 207-folds until 7 d.p.i.. The above results indicate that IFN-β works for an early anti-viral response, while IRF7, MxA, and TAP-1 work for prolonged anti-viral response in HTNV infection

    Clinical Efficacy of Organ-Preserving Pancreatectomy for Benign or Low-Grade Malignant Potential Lesion

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    The clinical usefulness of organ-preserving pancreatectomy is not well established due to technical difficulty and ambiguity of functional merit. The purpose of this study is to evaluate the clinical efficacy of organ-preserving pancreatectomy such as duodenum-preserving resection of the head of the pancreas (DPRHP), pancreatic head resection with segmental duodenectomy (PHRSD), central pancreatectomy (CP) and spleen-preserving distal pancreatectomy (SPDP). Between 1995 and 2007, the DPRHP were performed in 14 patients, the PHRSD in 16 patients, the CP in 13 patients, and the SPDP in 45 patients for preoperatively diagnosed benign lesions or tumors with low-grade malignant potential. The clinical outcomes including surgical details, postoperative complications and long-term functional outcomes were compared between organ-preserving pancreatectomy and conventional pancreatectomy group. Major postoperative complications constituted the following: bile duct stricture (7.1% [1/14]) in DPRHP, delayed gastric emptying (31.2% [5/16]) in PHRSD, pancreatic fistula (21.4% [3/14]) in CP. There were no significant differences in postoperative complications and long-term functional outcomes between two groups. Organ-preserving pancreatectomy is associated with tolerable postoperative complications, and good long-term outcome comparing to conventional pancreatectomy. Organ-preserving pancreatectomy could be alternative treatment for benign or low-grade malignant potential lesion of the pancreas or ampullary/parapapillary duodenum
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