Biomedical subjects

C H Wen

Publications and source records attributed to C H Wen.

7 recordsLinked to original sources

PubMed1999

Genotoxicity of water samples from Dianchi lake detected by the Vicia faba micronucleus test.

Dianchi Lake covers about a 300 km2 area. Kunming city on the edge of the lake is surrounded by industrial establishments. Farm land surrounds the remaining areas of the lake. The lake water is polluted by the Kunming city municipal sewage from 3 million inhabitants, the industrial effluent and farm runoff. Water samples were collected from 12 sites along the shore of the lake during the dry (May) and rainy (August) seasons for genotoxicity testing with the Vicia micronucleus assay during the year 1995. Genotoxicity in terms of micronuclei (MCN) frequencies in the root tip cells of Vicia showed a consistent elevated frequency of MCN over the control sample at the 0.05-0.01 levels of significance in both seasons. The MCN frequencies of sites A (Daguanhe), B (Gaoqiao) and C (Xiyuan) were 3.5-4 times as high as the control values (5.25/1000 cells) in the dry season. In the rainy season, the MCN frequencies of water samples from most of the 12 sites were relatively lower than those of the dry season except sites J (Haikou), and K (Kunyang). The average MCN frequency of the dry season samples was 14.97 per 1000 cells and that of the rainy season samples was 12.24 per 1000 cells while the average control value was around 5.00/1000 cells.

Biological Assay↗

PubMed1999

Tradescantia bioassays for the determination of genotoxicity of water in the Panlong River, Kunming, People's Republic of China.

The Panlong river passes through Kunming City and receives a large quantity of municipal sewage and wastewater from industrial effluent. Along the river, 20 sites were selected to collect water samples to assess the genotoxicity using two Tradescantia assays, the micronucleus (Trad-MCN) and the stamen-hair-mutation (Trad-SHM) assays. The lowest frequencies in the Trad-MCN assay and the Trad-SHM assay are 3.19 MCN/100 tetrads and 1.32 M/1000 stamen hairs, respectively. In the water samples obtained from the Songhua Reservoir, the MCN frequencies and mutation rates are not statistically significantly different from the data found for the negative control (2.49 MCN/100 tetrads and 0.71 M/1000 stamen hairs). Among the other water samples, 19 in Trad-MCN assay and 17 in Trad-SHM assay show significantly higher genotoxicity than the control. The highest genotoxicity was in samples No. 19 for the MCN assay (8.73 MCN/100 cells), over three times higher than the negative control, and in sample No. 11 for the SHM assay (4.30 M/1000), six times higher than the negative control, and were about the same as for the positive control (10.0 mg/l NaN3, 9.28 MCN/100 tetrads and 7.44 SHM/1000 stamen hairs), respectively. The peak frequencies for the Trad-MCN assays were observed in the water samples obtained from the sites that were near industrial and municipal wastewater that ran into the river as effluent. In general, the frequency of MCN and SHM mutations increased where the river passed through Kunming. The Trad-MCN assay seemed more sensitive than that of the Trad-SHM assay in detecting genotoxicity of the river water pollution.

Biological Assay↗

PubMed1998

Differential effects of peptide histidine isoleucine (PHI) and related peptides on stimulation and suppression of neuroblastoma cell proliferation. A novel VIP-independent action of PHI via MAP kinase.

The growth rate of rodent embryonic neuroblasts and human neuroblastoma cell lines is regulated in part by autocrine or paracrine actions of neuropeptides of the family that includes vasoactive intestinal peptide (VIP), peptide histidine isoleucine (PHI), and pituitary adenylate cyclase-activating peptide (PACAP). These peptides act via seven transmembrane G-protein-linked receptors coupled to cAMP elevation, phospholipase C activation, intracellular Ca2+ release, and/or of mitogen-activated protein (MAP) kinase activation. Here we investigated the action of these peptides on the mouse neuroblastoma cell line Neuro2a. PHI and VIP inhibited proliferation at concentrations as low as 10(-13) M and 10(-10) M, respectively. In contrast, PACAP action was biphasic, with stimulation occurring at subnanomolar doses and inhibition at higher doses. Peptide actions were studied further by measuring cAMP and ERK1/2 MAP kinase activity and by assessing 3H-thymidine incorporation in conjunction with a panel of signal transduction pathways inhibitors. The data obtained indicated that the PHI-inhibitory and PACAP-stimulatory activities were mediated by corresponding changes in activity of the MAP kinase pathway and independent of protein kinase A (PKA) or protein kinase C (PKC). In contrast, the inhibitory actions of VIP and PACAP were specifically blocked by antagonists of PKA. Northern blot analysis revealed gene expression for only the PACAP-preferring (PAC1) receptor. However, binding experiments using 125I-labeled PACAP27, PHI, and VIP, demonstrated the presence of PACAP-preferring sites, bivalent VIP/PACAP sites, and PHI-binding sites that did not interact with VIP. The studies demonstrate potent regulatory actions of PACAP, PHI, and VIP on neuroblastoma cell proliferation which appear to be mediated by multiple subsets of receptors which differentially couple to MAP kinase and PKA signaling pathways.

Animals↗

PubMed1997

An image capture and communication system for emergency computed tomography.

An image capture and communication system for emergency computed tomography (CT) is presented. The system, named ICCS, integrates CT scanners, personal computers (PC), network systems, an IBM API gateway and an IBM mainframe platform. The ICCS was implemented in the emergency unit in the Taichung Veterans General Hospital (TCVGH) and has received considerable support from the doctors, nurses and staff of the TCVGH emergency unit who have shown great interest in ICCS. This is because ICCS allows physicians in the emergency unit to examine patients' images on image viewing stations immediately after the patients are CT scanned. It also makes remote consultation possible for doctors who can stay where they are and consult with radiologists through the system and a hot line without leaving the emergency unit. This advantage greatly reduces the consultation time and saves many unnecessary trips between the emergency unit and the Department of Radiology.

Emergency Service, Hospital↗

PubMedDate not supplied

Orthogonal subspace projection-based approaches to classification of MR image sequences.

Orthogonal subspace projection (OSP) approach has shown success in hyperspectral image classification. Recently, the feasibility of applying OSP to multispectral image classification was also demonstrated via SPOT (Satellite Pour 1'Observation de la Terra) and Landsat (Land Satellite) images. Since an MR (magnetic resonance) image sequence is also acquired by multiple spectral channels (bands), this paper presents a new application of OSP in MR image classification. The idea is to model an MR image pixel in the sequence as a linear mixture of substances (such as white matter, gray matter, cerebral spinal fluid) of interest from which each of these substances can be classified by a specific subspace projection operator followed by a desired matched filter. The experimental results show that OSP provides a promising alternative to existing MR image classification techniques.

Brain↗

PubMedDate not supplied

An economical, personal computer-based picture archiving and communication system.

Taichung Veterans General Hospital has been developing a hospital-wide picture archiving and communication system (PACS) since 1993. A personal computer-based environment was implemented to reduce costs (only $2,500 for each view station) and take advantage of distributed system techniques. Other features of the PACS are automatic image acquisition, hierarchic storage management, efficient image transmission, robust fault tolerance, and user-friendly image manipulation. The system is integrated with the hospital information system so that Chinese-language patient data can be automatically transferred. A four-tier storage hierarchy and a multipath search strategy are used to improve reliability and efficiency. Image compression and efficient image transmission techniques (autorouting and prefetching) are used to reduce the response time. Robust fault tolerance is achieved with fault-tolerant hardware, image replication, and a system watchdog. User-friendly image manipulation features include easy adjustment of the brightness, contrast, or quality of the displayed image; several windows for image display; and image measurement capability. The PACS currently supports computed tomography, ultrasound, magnetic resonance imaging, computed radiography, and digital fluoroscopy; almost all appropriate personal computers in the hospital can be used as view stations. Users are satisfied with the quality, reliability, and performance of the system.

Humans↗

PubMedDate not supplied

Consulting with radiologists outside the hospital by using Java.

A Java-based teleradiology system that makes use of the Internet has been developed. Using this system, an on-call, off-duty radiologist can make diagnoses and perform consultations easily by reviewing the transferred images at home. The image accessibility of the system allows a hospital with such a system to assist an affiliated rural hospital without a full-time radiologist. The system consists of three components: the image server subsystem, the database server subsystem, and the client subsystem. All client subsystems of the system are designed to be symmetric. Users may retrieve images, manipulate them, and perform remote consultations. In addition, a user may add annotations to an image area of interest. Screen synchronization is achieved by means of the command-passing technique and local command execution to reduce the network bandwidth and transmission demands; user interaction is achieved by means of a synchronized indicator for pointing out areas of interest and dialog windows for conversation. Because Java programs can run on heterogeneous platforms, the need for system maintenance and user training is minimized. Although the drawback of Internet bandwidth still exists, the system enables platform-independent teleradiology via the Internet and allows easy and cost-effective remote consultation.

Humans↗