191 research outputs found

    Morphological Evidence of Apoptosis During Early Structural Luteolysis in the Golden Hamster

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    Structural luteolysis (SL) in the golden hamster (Mesocricetus auratus) is a remarkable event. The corpus luteum (CL) virtually disappears during a time span of 42 hours. SL begins around 0600 hours on day three of the cycle and is essentially complete by 2400 hours on day four of the cycle. The purpose of this study was to determine when SL in the golden hamster actually begins and secondly to determine the way in which the three cell types involved in SL are depleted. The three cell types in question include luteal cells, endothelial cells, and neutrophils. This study employed two separate In Situ techniques. The first technique incorporates biotinylated nucleotides onto the ends of fragmented genomic DNA. Since the fragmentation of DNA is the biochemical hallmark of apoptosis, labeling the fragmented DNA greatly enhances the detection of apoptotic cells in paraffin embedded tissue sections. Apoptag which utilizes digoxigenin conjugated dUTP is also used in this study. This system proves to be highly valuable in the detection of apoptotic cells due to low background staining and extremely consistent results. In both of these systems nuclei which contain fragmented DNA stain brown. Ovaries were collected at nine different time frames throughout the four day estrus cycle. Ovaries from a minimum of three animals were harvested for each time frame. Serial sections of three to four microns were then subjected to the two separate techniques. The results of this study indicate that SL begins at 0600 hours on day three of the cycle, and is marked by a large infiltration of neutrophils. Following this neutrophilic infiltration there is a marked increase in apoptotic activity throughout the CL. Interestingly, in this model of study all three cell types involved, die by the process of apoptosis. The fact that apoptosis is the mode of cell death is important, since it does not elicit an intense inflammatory respons

    Positive FP-CIT SPECT (DaTSCAN) in Clinical Alzheimer's Disease – An Unexpected Finding?

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    Clinically, Alzheimer's disease (AD) is by far the most common cause of dementia. Criteria for the diagnosis of dementia with Lewy bodies (DLB) are highly specific but not at all sensitive, which is reflected by the higher number of DLB cases detected histopathologically at autopsy. Imaging of dopamine transporter with FP-CIT SPECT is one possibility to increase sensitivity. Pathological confirmation was also included in the revised consensus criteria for the diagnosis of DLB. However, in the absence of parkinsonism, one of the core features, a clinical diagnosis of AD is more likely. The role of FP-CIT SPECT in DLB diagnosis remains to be clarified. Based on our 3 case reports and a review of the literature, the utility of this imaging method in the differential diagnosis of AD and DLB is highlighted

    Numerical convergence of the block-maxima approach to the Generalized Extreme Value distribution

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    In this paper we perform an analytical and numerical study of Extreme Value distributions in discrete dynamical systems. In this setting, recent works have shown how to get a statistics of extremes in agreement with the classical Extreme Value Theory. We pursue these investigations by giving analytical expressions of Extreme Value distribution parameters for maps that have an absolutely continuous invariant measure. We compare these analytical results with numerical experiments in which we study the convergence to limiting distributions using the so called block-maxima approach, pointing out in which cases we obtain robust estimation of parameters. In regular maps for which mixing properties do not hold, we show that the fitting procedure to the classical Extreme Value Distribution fails, as expected. However, we obtain an empirical distribution that can be explained starting from a different observable function for which Nicolis et al. [2006] have found analytical results.Comment: 34 pages, 7 figures; Journal of Statistical Physics 201

    Fixation of osteochondral fragments in the human knee using Meniscus Arrows®

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    The aim of this study is to compare the hold in bone of Meniscus Arrows® and Smart Nails®, followed by the report of the results of the clinical application of Meniscus Arrows® as fixation devices. First, pull-out tests were performed to analyse the holdfast of both nails in bone. Statistical analysis showed no significant difference; therefore, the thinner Meniscus Arrow® was chosen as fixation device in the patient series of two patients with a symptomatic Osteochondritis dissecans fragment and three patients with an osteochondral fracture of a femur condyle. The cartilage margins were glued with Tissuecoll®. All fragments consolidated. Second look arthroscopy in three patients showed fixed fragments with stable, congruent cartilage edges. At an average follow-up period of 5 years no pain, effusion, locking, restricted range of motion or signs of osteoarthritis were reported. Based on the results of the pull-out tests and available clinical studies, Meniscus Arrows® and Smart Nails® are both likely to perform adequately as fixation devices in the treatment of Osteochondritis dissecans and osteochondral fractures in the knee. They both provide the advantage of one stage surgery. However, based on their smaller diameter, the Meniscus Arrows® should be preferred for this indication

    CD24 Expression is an Independent Prognostic Marker in Cholangiocarcinoma

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    CD24 has been described as an adverse prognostic marker in several malignancies. This study evaluates CD24 expression in cholangiocarcinoma and correlates the findings with clinicopathologic data and patient survival. Between 1996 and 2002, 22 consecutive patients with cholangiocarcinoma were treated at our institution. Demographic data, SEER stage, pathologic data, treatment, expression of CD24, mitogen-activated protein kinase (MAPK), phosphorylated MAPK, and survival were analyzed. The majority of the tumors demonstrated CD24 (81.8%) and p-MAPK (87%) expression. A negative association was noted between the expression of CD24 and p-MAPK. Median survival for patients with low expression of CD24 was 36 months and high expression was 8 months. Median survival for patients who received chemotherapy with low CD24 expression was 163 months, and for seven patients with high CD24 expression, it was 17 months (p = 0.04). With the addition of radiation therapy, median survival for patients with low expression of CD24 was 52 months and high expression was 17 months (p = 0.08). On multivariate analysis, the use of chemotherapy (p = 0.0014, hazard ratio 0.069) and the CD24 overexpression (p = 0.02, hazard ratio 7.528) were predictive of survival. CD24 is commonly expressed in cholangiocarcinoma, and overexpression is predictive of poor survival and possibly of lack of response to chemotherapy and radiation therapy. These findings may improve selection of patients for the appropriate treatment modality and the development of CD24-targeted therapy
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