2,940 research outputs found

    Isolated foetal ascites.

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    The prenatal diagnosis and perinatal outcome of two patients with isolated foetal ascites compatible with chyloperitoneum is described. The foetal ascites resolved spontaneously after delivery with good perinatal outcome in both cases. A good prognosis can be anticipated in such cases. Antepartum and intrapartum interventions are seldom necessary.published_or_final_versio

    Design consideration of a multi-function otoacoustic emission measurement system

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    A new approach for recording otoacoustic emissions (OAEs) is described in the paper. The system is based on a personal computer equipped with INTEL Pentium CPU. A single chip microcomputer INTEL 8096 is developed to be a stimulus generator. Some critical problems and circuit parameters in the design of this system are presented in the paper. The main advantages of the system are (1) it can record three kinds of OAEs which have many clinical applications; (2) it can save raw data for further analysis, as most researchers need; (3) plenty of analysis functions can be developed in this system. With the use of the newly developed system, SOAEs, TEOAEs, and DPOAEs have been successfully measured.published_or_final_versio

    Fast tracking of evoked potential variations using correlated scale function designed by multiresolution analysis

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    Fast tracking of evoked potential variations is of great importance in clinical operation. The paper describes a method whereby an ensemble averaged signal is used as the prototype of the scale function and designs a correlated scale function based on multiresolution analysis. Hence, an effective low pass digital filter having powerful tracking capability is obtained. Results show that the filter designed filters out the noise more effectively than that using general wavelet filtering, and the tracking of the peak of evoked potential is easily obtained.published_or_final_versio

    Fast measurement of SEP for monitoring spinal cord during scoliosis

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    Recently there has been considerable interest in the use of somatosensory evoked potential (SEP) for monitoring the functional integrity of the spinal cord during surgery such as scoliosis. This paper describes a monitoring system and signal processing algorithms, which consist of an artificial neural network filter and a wavelet signal enhancer developed to enhance the signal-to-noise ratio (SNR) of surface recorded SEP. Our system allows fast detection of change in SEP's peak latency, amplitude and signal waveform, which are the main parameters of interest during intra-operative procedures.published_or_final_versionThe 20th IEEE Engineering in Medicine and Biology Society Conference Proceedings, Hong Kong, China, 29 October - 1 November 1998, v. 4, p. 2239-224

    Hepatocyte-specific activation of NF-κB does not aggravate chemical hepatocarcinogenesis in transgenic mice

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    The NF-κB signalling pathway plays important roles in liver organogenesis and cardnogenesis. Mouse embryos deficient in IKKβ die in mid-gestation, due to excessive apoptosis of hepatoblasts. Although activation of the NF-κB signalling pathway has been demonstrated in human hepatocellular carcinoma, the role of NF-κB is controversial. Here, we have generated transgenic mice in which a constitutively active form of IKKβ was expressed in a hepatocyte-specific manner. Using electrophoretic mobility shift assay, we documented increased NF-κB activities and up-regulated levels of NF-κB downstream target genes, Bcl-xL and STAT5, in the transgenic mouse livers. These results confirmed that the NF-κB pathway was activated in the livers of the transgenic mice. However, there was no significant difference in tumour formation between transgenic and wild-type mice up to an age of 50 weeks. When we treated the transgenic mice with the chemical carcinogen diethylnitrosamine (DEN), we observed no significant differences in the incidence and size of liver tumours formed in these mice with and without DEN treatment at 35 weeks of age, suggesting that the activated NF-κB pathway in the livers of the transgenic mice did not enhance hepatocarcinogenesis. Interestingly, some of the transient transgenic embryos (E12.5) had abnormal excessive accumulation of nucleated red blood cells in their developing livers. In summary, NF-κB activation in hepatocytes did not significantly affect chemical hepatocarcinogenesis. In addition, the TTR/IKKCA transgenic mice may serve as a useful model for studying the role of NF-κB activation in hepatocarcinogenesis as well as inflammatory and metabolic diseases. Copyright © 2008 Pathological Society of Great Britain and Ireland.postprin

    Promoter hypermethylation and histone hypoacetylation contribute to pancreatic-duodenal homeobox 1 silencing in gastric cancer

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    Background and Aims: The expression of pancreatic-duodenal homeobox 1 (PDX1) in gastric cancer is aberrantly reduced. The aim of this study was to elucidate the regulation of DNA methylation and histone acetylation at the promoter for PDX1 silencing in gastric cancer. Methods: PDX1 expression in response to demethylation and acetylation was detected in human gastric cancer cell lines by reverse transcription-polymerase chain reaction (PCR) and western blot. Four CpG islands within the 5#-flanking region of PDX1 gene were analyzed with their transcription activities being detected by dual luciferase assay. Promoter hypermethylation was identified in gastric cancer cell lines and cancer tissues by methylation-specific PCR or bisulfite DNA sequencing PCR analysis. Histone acetylation was determined by chromatin immunoprecipitation (ChIP) assay. Results: Demethylation by 5′-aza-2′-deoxycytidine (5′-aza-dC) and/or acetylation by trichostatin A (TSA) restored PDX1 expression in gastric cancer cells. Hypermethylation was found in four CpG islands in six of seven cancer cell lines. However, only the distal CpG island located in the promoter fragment of PDX1, F383 (c.22063 to 21681 nt upstream of the ATG start codon) displayed significant transcriptional activity that could be suppressed by SssI methylase and increased by 5′-aza-dC and TSA. More than 70% of the single CpG sites in F383 were methylated with hypermethylation of F383 fragment more common in gastric cancerous tissues compared with the paired normal tissues (P < 0.05). ChIP assay showed F383 was also associated with low hypoacetylation level of the histones. Conclusion: Promoter hypermethylation and histone hypoacetylation contribute to PDX1 silencing in gastric cancer. © The Author 2010. Published by Oxford University Press. All rights reserved.postprin

    Directed differentiation of human pluripotent stem sells for the generation of high-order kidney organoids

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    Our understanding in the inherent properties of human pluripotent stem cells (hPSCs) have made possible the development of differentiation procedures to generate three-dimensional tissue-like cultures, so-called organoids. Here we detail a stepwise methodology to generate kidney organoids from hPSCs. This is achieved through direct differentiation of hPSCs in two-dimensional monolayer culture toward the posterior primitive streak fate, followed by induction of intermediate mesoderm-committed cells, which are further aggregated and cultured in three-dimensions to generate kidney organoids containing segmented nephron-like structures in a process that lasts 20 days. We also provide a concise description on how to assess renal commitment during the time course of kidney organoid generation. This includes the use of flow cytometry and immunocytochemistry analyses for the detection of specific renal differentiation markers
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