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A K Ching

Publications and source records attributed to A K Ching.

5 recordsLinked to original sources
PubMed2001

Expression of human BRE in multiple isoforms.

BRE, a putative stress-modulating gene, found able to down-regulate TNF-alpha-induced NF-kappaB activation upon overexpression, is now shown in human cells expressed as multiple mRNA isoforms. A total of six isoforms are produced by alternative splicing predominantly at either end of the gene. Predicted from the cDNA sequences of these isoforms, three of them (alpha(a), alpha(b), and alpha(c)) code for BRE of different C-terminus, and the other three (beta(a), beta(b), and beta(c)) may possibly be the nonfunctional counterparts. All human cells examined coexpress all the predominant splice variants, albeit at different ratios. Comparing with normal cells, immortalized human cell lines uniformly express higher levels of BRE. Interestingly, peripheral blood monocytes responded to LPS by down-regulating the expression of all the BRE isoforms, which was however less obvious in the cell line counterpart, THP-1. Isoform alpha(a), which codes for the canonical BRE with a C-terminal peroxisomal targeting sequence, is the most abundant transcript. We propose that the function of BRE and its isoforms is to regulate peroxisomal activities.

Animals↗
PubMed2000

Strand bias in Ig somatic hypermutation is determined by signal sequence within the variable region.

Ig genes undergo hypermutation with a nucleotide preference of A over T for mutation on the coding strand. As only with concomitant strand bias can such nucleotide bias be observed, Ig gene hypermutation is generally accepted as a strand-specific process, for which the mechanistic basis remains unknown. It has previously been shown that different non-Ig sequences replacing the LVJ region of an Ig transgene to various extents are targeted for hypermutation with similar mutation frequencies. However, the nucleotide bias characteristic of Ig hypermutation was not found in two of the three such sequences studied. To test whether it is the DNA sequences of the non-Ig substrates that determine the pattern of nucleotide bias in hypermutation or whether the LVJ sequence may contain element(s) that confer strand bias, we have added back all the replaced LVJ sequences to one of the transgenes, L(kappa)-Vgpt*, that expresses no strand bias in hypermutation and studied the outcome. The results show that the gpt sequence in the presence of the complete LVJ sequence hypermutates differently from the same sequence in L(kappa)-Vgpt* where 84% of the LVJ was replaced. The main difference is the resumption of strand bias characteristic of Ig hypermutation. Thus, whether or not a substrate sequence manifests strand bias in hypermutation is not inherently determined by the substrate DNA sequence. This indicates the presence of special element(s) within the LVJ that confer strand bias.

Animals↗
PubMed1995

BibleCard: network-based virtual database for laboratory information.

The clinical laboratory's use of computers has evolved beyond the single minicomputer stand-alone system. Our laboratory information system is now part of an institutional network. The laboratory also uses smaller systems and workstations for a wide variety of functions, often with much data duplication among systems. We have been developing a network-based virtual database for laboratory test information. This system uses World Wide Web standards for hypertext and multimedia displays, which allows for the display of information retrieved from various department computer sources without the necessity of data duplication, modification of existing systems, or centralization of data. The medical technologists can continue to write testing procedures on their word processors. Maintenance of reference values, specimen requirements, etc., can continue as a laboratory information system function. Yet information from all of these disparate sources can be viewed in a consolidated format that has platform independence.

Chemistry, Clinical↗
PubMedDate not supplied

Cytoplasmic tutor: a program for teaching interpretation of a microscope-based laboratory test.

Antibodies to cytoplasmic antigens can be identified with a microscope-based indirect immunofluorescence assay that uses a mouse stomach-kidney substrate. The antibodies are diagnostic markers in chronic active hepatitis, primary biliary cirrhosis, pernicious anemia, and other autoimmune diseases. We describe the development and features of an image-based computer program for teaching medical technologists and other health care workers the proper interpretation of cytoplasmic fluorescence staining patterns. The program, called Cytoplasmic Tutor, is written in Microsoft Visual Basic for Windows and runs on an 80486 microcomputer. it is based on a library of digital images, with key features described by overlays of text. The images were collected and processed with a computer-based fluorescence video microscopy system assembled in our laboratory.

Animals↗