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C T Lin

Publications and source records attributed to C T Lin.

At least 73 records · Page 4Linked to original sources
PubMed1998

Isolation and investigation of canine phosducin as a candidate for canine generalized progressive retinal atrophies.

A subtractive cDNA cloning strategy was used to isolate canine retina-specific genes. Canine phosducin cDNA was cloned from a canine subtracted retinal cDNA library and was analysed as a candidate for canine generalized progressive retinal atrophies (gPRA). Canine phosducin cDNA is 1230 bp in length encoding 245 amino acids. The nucleotide and amino acid sequences of canine phosducin are highly conserved when compared with those of five other mammalian species, namely human, cat, cow, rat, and mouse. Northern blot analysis demonstrated that the mRNA transcript for phosducin was approximately 1.3 kb in size and was present in canine retina, but showed no visible signals in 13 other canine tissues. The phosducin gene was examined for polymorphisms in a total of 101 pedigree dogs of eight breeds, including normal, obligate gPRA carriers, and gPRA-affected dogs, by single-stranded conformation polymorphisms (SSCP) analysis. Polymorphisms in the phosducin gene were detected only in the 3' untranslated region of the gene in two breeds of dogs: allelic heterozygous polymorphisms in miniature poodles suffering from one form of gPRA (progressive rod-cone degeneration, prcd), and a different polymorphism in a single normal Irish wolfhound. The polymorphisms of phosducin in prcd-affected miniature poodles did not segregate with the autosomal recessive form of gPRA. Heterozygous inheritance of the polymorphisms suggests that phosducin is very unlikely to carry the mutation causing prcd, so phosducin was probably excluded as a candidate for prcd-affected miniature poodles in this study.

Amino Acid Sequence↗
PubMed1998

Topics in microbial risk assessment: dynamic flow tree process.

Microbial risk assessment is emerging as a new discipline in risk assessment. A systematic approach to microbial risk assessment is presented that employs data analysis for developing parsimonious models and accounts formally for the variability and uncertainty of model inputs using analysis of variance and Monte Carlo simulation. The purpose of the paper is to raise and examine issues in conducting microbial risk assessments. The enteric pathogen Escherichia coli O157:H7 was selected as an example for this study due to its significance to public health. The framework for our work is consistent with the risk assessment components described by the National Research Council in 1983 (hazard identification; exposure assessment; dose-response assessment; and risk characterization). Exposure assessment focuses on hamburgers, cooked a range of temperatures from rare to well done, the latter typical for fast food restaurants. Features of the model include predictive microbiology components that account for random stochastic growth and death of organisms in hamburger. For dose-response modeling, Shigella data from human feeding studies were used as a surrogate for E. coli O157:H7. Risks were calculated using a threshold model and an alternative nonthreshold model. The 95% probability intervals for risk of illness for product cooked to a given internal temperature spanned five orders of magnitude for these models. The existence of even a small threshold has a dramatic impact on the estimated risk.

Analysis of Variance↗
PubMed1998

BCECF in single cultured cells: inhomogeneous distribution but homogeneous response.

Using confocal laser scanning microscopy with a dual-wavelength laser system, the behaviour of BCECF [(2',7'-bis-2-carboxyethyl)-5-(and-6)carboxyfluorescein] was investigated in a variety of cell lines. Selection of a small area for monitoring allowed discrimination between various intracellular organelles, whose identity was established by vital staining. It was found that, after loading the cells with BCECF, both the nucleus and the mitochondria showed a higher level of fluorescence than the cytoplasm. Calibration of the pH-sensitivity of these fluorescence signals using the nigericin method yielded identical curves, as did exposure of the cells to NH4Cl. These studies suggest that BCECF, despite its inhomogeneous intracellular distribution, reports the pH of only one cellular compartment, the cytosol.

Ammonium Chloride↗
PubMed1998

Familial macrothrombocytopenia with granulocyte inclusion: a clinical and laboratory problem.

The differential diagnosis of familial macrothrombocytopenia and idiopathic thrombocytopenic purpura (ITP) may be difficult owing to the similarities in their clinical and laboratory presentations, but it is important because of dissimilarities in their management and prognosis. We investigated two families with familial macrothrombocytopenia and granulocyte inclusion. The probands of both families presented with mild bleeding tendency, macrothrombocytopenia, normal bone marrow, and increased percentages of platelet-associated immunoglobulin G (IgG) and reticulated platelets. ITP had been misdiagnosed in both patients initially. Both probands failed to respond to steroid therapy. Family study revealed an autosomal dominant pattern of heredity in both families, with absence of Alport's syndrome-like features (hearing impairment, congenital cataract, and interstitial nephritis). All thrombocytopenic family members showed blue cytoplasmic inclusions in neutrophils on peripheral blood smears. Ultrastructurally, distinct granulocyte inclusions comprising clusters of rough endoplasmic reticulum, smooth endoplasmic reticulum, and polysomes were detected, without the presence of parallel filaments. The clinical, laboratory, and hereditary findings were consistent with a diagnosis of Sebastian platelet syndrome in both families. In conclusion, caution should be exercised when interpreting the percentages of platelet-associated IgG in thrombocytopenic patients, as overinterpretation may lead to misdiagnosis of macrothrombocytopenia as ITP. Family history is important, as familial ITP is rare, and careful examination of blood smears is essential.

Adult↗
PubMed1997

A method for generating subtractive cDNA libraries retaining clones containing repetitive elements.

Here we describe a two-stepped photobiotin-based procedure to enrich a target (canine retinal) cDNA library for tissue specific clones without removing those containing repetitive ( SINE ) elements, despite the presence of these elements in the driver population. In a first hybridization excess SINE elements were hybridized to a driver (canine cerebellar) cDNA. In a second hybridization target cDNA was added to this reaction. The resulting cDNA library was enriched for retinal specific clones, but contained the same ratio of clones with SINE elements found in the unsubtracted library.

Animals↗
PubMed1997

A cruciform-dumbbell model for inverted dimer formation mediated by inverted repeats.

Small inverted repeats (small palindromes) on plasmids have been shown to mediate a recombinational rearrangement event in Escherichia coli leading to the formation of inverted dimers (giant palindromes). This recombinational rearrangement event is efficient and independent of RecA and RecBCD. In this report, we propose a cruciform-dumbbell model to explain the inverted dimer formation mediated by inverted repeats. In this model, the inverted repeats promote the formation of a DNA cruciform which is processed by an endonuclease into a linear DNA with two hairpin loops at its ends. Upon DNA replication, this linear dumbbell-like DNA is then converted to the inverted dimer. In support of this model, linear dumbbell DNA molecules with unidirectional origin of DNA replication (ColE1 ori ) have been constructed and shown to transform E.coli efficiently resulting in the formation of the inverted dimer. The ability of linear dumbbell DNA to transform E.coli suggests that the terminal loops may be important in bypassing the requirement of DNA supercoiling for initiation of replication of the ColE1 ori.

DNA↗
PubMed1997

Regulation of the long terminal repeat in visna virus by a transcription factor related to the AML/PEBP2/CBF superfamily.

The long terminal repeats of maedi visna virus strain 1514 contain a consensus AP-1 binding site which has been shown to be important in controlling virus transcription. However, this consensus site is absent in strain EV-1. Here, we have compared the ability of oligonucleotides corresponding to LTR sequences from EV-1 with those from 1514 to bind transcription factors in competitive gel retardation assays and activate reporter gene expression. The experiments demonstrated no observable binding of AP-1 to the EV-1-derived sequences and significant differences in the abilities of the 1514 and EV-1 sequences to activate transcription. However, both viral sequences interacted with a second, previously undetected, transcription factor. This factor gave specific gel shifts which were competed by an oligonucleotide containing the consensus sequence for the AML/PEBP2/CBF family of transcriptional factors, but not by control AP-1 or OCT-1 oligonucleotides. The factor was therefore denoted AML (vis). A second AML (vis) site, noted upstream of the TATA box proximal AP-1 site, gave single shifts which were competed by the downstream AML (vis) oligonucleotide. Both sites were functional in transfection assays. In gel shift retardation assays, polyclonal antisera directed against known runt domain proteins were able to supershift part of the AML (vis) binding activity in nuclear extracts from physiologically relevant cell types. The results thus suggest that the AML (vis) binding factor belongs to the AML/PEBP2/CBF family of transcription factors and may be important in controlling virus replication in these and other strains of ruminant lentiviruses.

Animals↗
PubMed1997

Storage effect on dentine structure and on resultant composite bond strengths.

This study evaluates the effects of a food simulating solution (75 vol% ethanol/water) and an artificial saliva (Moi-Stir) on dentine structure and chemistry, using scanning electron microscopic examination and Fourier transform infra-red (FTIR) microscopic characterization. The effect on the bonding of composites to the conditioned dentine were evaluated by shear bond strength (SBS) tests. Three adhesive/composite systems were examined: Tenure/Marathon One, Scotchbond Multi-Purpose/Z100, and Optibond/Herculite XRV. Control specimens were stored in either distilled water or tested without storage. Dentine surface exposure to ethanol resulted in partial loss of the smear layer and of plugs, as well as possible perturbation of collagen. Dentine surfaces exposed to artificial saliva or to distilled water had no evidence of any change from normal appearance of the smear layer. The measured FTIR spectra for most specimens conditioned in these two liquids appeared to be similar to those obtained from fresh dentine. SBS data were analysed using ANOVA and the Tukey LSD test. The SBS value for the non-preconditioned control (23.0 +/- 3.7 MPa) or for the dentine preconditioned in distilled water (22.9 +/- 4.2 MPa) was significantly higher (P < 0.05) than that for dentine pre-conditioned in ethanol (20.0 +/- 3.5 MPa). The SBS (13.3 +/- 3.4 MPa) of all bonding systems was reduced by 40-50% (P < 0.001) when artificial saliva pre-conditioned dentine was used. The failure mode at the dentine-bonding agent interface for the artificial saliva group was adhesive in nature. This is in contrast to the complex cohesive fracture mode found in the control groups and in most ethanol conditioned groups. Dentine structure and chemistry, shear bond strength, and the subsequent debonded mode can be significantly affected by exposure to oral environment prior to conditioning.

Adhesiveness↗
PubMed1997

Cloning of canine rom-1 and its investigation as a candidate gene for generalized progressive retinal atrophies in dogs.

Generalized progressive retinal atrophy (gPRA) represents a genetically heterogenous group of retinal degenerations affecting pedigree dogs. Currently, we are using a candidate gene approach in an attempt to identify mutations causing gPRA in dogs. Here we report the cloning, sequencing and analysis of canine rom-1, a structural gene of the rod photoreceptor. Single-stranded conformation polymorphism (SSCP) analysis was used to look for polymorphisms segregating with gPRA in the English cocker spaniel, Labrador retriever, miniature poodle, miniature long-haired dachshund, Tibetan terrier, miniature schnauzer, Cardigan Welsh corgi and Irish wolfhound. Further investigation involved DNA sequencing and restriction fragment length polymorphism (RFLP) analysis. Our studies revealed the presence of three polymorphisms, none of which segregated with disease phenotype. Haplotype analysis identified four rom-1 alleles. Our results indicate that rom-1 is unlikely to be a cause of gPRA in the breeds of dog examined.

Animals↗
PubMed1997

Co-localization of endogenous and exogenous p53 proteins in nasopharyngeal carcinoma cells.

Recently, we have established nine nasopharyngeal carcinoma (NPC) cell lines in which only one cell line showed the p53 mutation. For investigation of the p53 mutation in this line, immunostaining using anti-p53 antibody was applied and showed the presence of p53 protein in the cytoplasm but not in the nucleus. Single strand conformation polymorphism analysis of the p53 gene showed one normal and one additional DNA band. Cloning and sequencing of PCR-amplified DNA showed an AGA (arginine) to ACA (threonine) heterozygous point mutation at codon 280. Transfection of the p53 DNA binding sequence and chloramphenicol acetyltransferase assay revealed loss of transcriptional activation function of endogenous p53 protein. Co-localization of the endogenous and the transfected exogenous p53 protein by polyclonal antibodies to anti-p53 protein revealed strong exogenous p53 staining in the transfected nuclei and weak staining of endogenous p53 protein in the cytoplasm. We concluded that (a) a heterozygous point mutation at codon 280 was identified in the NPC-TW 06 cell line; (b) the point mutation may cause the stagnation of mutant p53 protein in the cytoplasm, and loss of its transcriptional activation function; (c) endogenous and exogenous p53 protein can be co-localized at the same time in the transfected cells; and (d) 280 mutant p53 protein in NPC cells does not cause a decrease or increase in sensitivity to chemotherapy.

Biopsy↗
PubMed1997

Autopsy findings on patients with AIDS in Taiwan.

At National Taiwan University Hospital, from 1986 to 1996, autopsies were performed on 16 patients with acquired immunodeficiency syndrome. There were 15 men and 1 woman. Fourteen of these male patients had contracted the disease as a result of sexual practice, among which 9 were homosexual, 1 was bisexual and 4 were heterosexual. One of the patients had become infected by sharing a syringe during intravenous drug use. The female was a sex worker. Among these patients, only 2 had been tested for HIV before developing AIDS. On autopsy, lymphoid depletion and thymus atrophy were found in all patients. Testicular atrophy was noted in all the male patients. Three patients died of malignant lymphoma. Twelve patients died of opportunistic infections and 1 committed suicide. The initial opportunistic infection was usually oral candidiasis. Pneumocystis carinii pneumonia (PCP) was the most common opportunistic infection developed in the early stage while cytomegalovirus (CMV) infection was the most common one found in the late stage. Mycobacterium infection had developed in 8 patients. Six patients had disseminated Kaposi's sarcoma (KS) and 4 of them were homosexual. In 4 patients, biopsy specimens were proved to have KS associated viral (HHV-8) genome. Malignant lymphoma was found in 4 cases, all were of high grade B cell type. Epstein-Barr virus (EBV) encoding small RNA (EBER1) was demonstrated in all the lymphomas. In conclusion, (1) the prevalence of tuberculosis (38%) in patients with AIDS in Taiwan is high; (2) the most common opportunistic infections in this series are candidiasis, PCP and CMV infections; (3) the incidence of AIDS related non-Hodgkin's lymphoma in Taiwan has increased since 1995.

AIDS-Related Opportunistic Infections↗
PubMed1997

The mechanism of Epstein-Barr virus infection in nasopharyngeal carcinoma cells.

To investigate the relationship between Epstein-Barr virus (EBV) and nasopharyngeal carcinoma (NPC) cells, we examined the pathway of EBV infection in NPC cell lines. We used immunolocalization to investigate the EBV receptor (C3d-R) and polymeric immunoglobulin receptor [secretory component (SC) protein]. We incubated IgA anti-EBV and EBV particles with NPC cells and observed the EBV DNA signal by in situ polymerase chain reaction hybridization and polymerase chain reaction plus Southern blotting. We also colocalized SC protein and EBV RNA in NPC biopsy specimens. Results showed that: 1) NPC cells did not express the EBV receptor but did express SC protein in each line; 2) SC protein was also expressed in some tumor cells but not in untransformed squamous metaplastic epithelia in NPC biopsy specimens; 3) EBV could infect NPC cells through an EBV-IgA and SC complex and retained an EBV viral genome in their nuclei; SC expression could be down-regulated by EBV proteins; and 4) in biopsy specimens, a fraction of tumor cells showed SC protein expression; only a portion of tumor cells contained EBV, and of these cells only a few expressed SC protein. These findings indicate that EBV cannot infect untransformed nasopharyngeal squamous metaplastic epithelia but can enter NPC cells through IgA-mediated endocytosis.

Carcinoma↗
PubMed1997

Phrenic nerve transfer in the repair of brachial plexus injuries: an animal model.

UNLABELLED: Ten young mongrel dogs underwent unilateral denervation of the brachial plexus. In six dogs, a 2-cm segment of phrenic nerve autograft was sutured to either the resected musculocutaneous nerve or the radial nerve. A hemoclip was applied to either musculocutaneous or radial nerve in the control groups. Five months postoperatively, the grafted musculocutaneous nerve demonstrated less fibrous tissue and less muscle atrophy of the biceps when compared to the control group with clipped nerve. In the group with the grafted radial nerve, the electromyographic findings of multiphasic action potential and muscle contraction from electric stimulation suggested reinnervation of the radial nerve. IN CONCLUSION: phrenic nerve transfer may be used to repair specific damages to nerve trunk with histological, electromyographic and clinical recovery.

Animals↗
PubMed1997

Clonal versus polyclonal Epstein-Barr virus infection in nasopharyngeal carcinoma cell lines.

In most nasopharyngeal carcinoma (NPC) biopsy specimens, the Epstein-Barr virus (EBV), particularly in the terminal repeat region genomic structure, reveals a clonal pattern. To evaluate this phenomenon in vitro, we infected EBV-negative NPC cell lines, which express secretory component (SC) protein on their cell surface, with EBV particles. The viral particles were obtained either from a subcloned single cell or from the original B95-8 cell line. EBV infection was performed by incubating IgA anti-EBV and EBV particles with NPC cells and confirmed by direct in situ PCR hybridization. Southern blot analysis of EBV terminal repeat in EBV-infected NPC cell lines was performed using a Xhol 1.9-kb DNA fragment from the right terminus of the EBV genome as a probe. We found that all four NPC cell lines (ie, NPC-TWO1; 03, 04, and 06) expressed SC protein on their surfaces and could be infected by EBV through the EBV IgA-SC complex. Southern blot analysis in the single cell-subcloned B95-8 cell line showed a clonal EBV terminal repeat with a higher molecular size; whereas the original B95-8 line revealed the polyclonal EBV DNA pattern. A similar clonal EBV genomic pattern with lower molecular size was seen in all EBV-infected NPC cell lines. For comparison, six NPC biopsy specimens were also examined; of these, five showed a single band, and the remaining showed one major band and several lower molecular-sized bands. The EBV genomic DNA in the infected cells was shown to be an episomal form. We conclude, therefore, that a single (clonal) form of EBV genome can be obtained from a mixed population of epithelial tumor cells, even when they are infected by multiple virions with single or multiple form(s) of the EBV genomic pattern.

Animals↗
PubMed1996

A system for the analysis of seat support surfaces using surface shape control and simultaneous measurement of applied pressures.

A system for the design and analysis of seat support and buttock tissue interfaces has been developed. It has the ability to control the seating surface shape while measuring the pressure applied to the buttocks by the surface. Pressures are measured over an 11 x 12 rectangular array of support elements using silicon pressure sensors mounted in a swiveling head atop each support element. Control of surface shape is mediated by selective linear translation of the support elements along their respective vertical axes. Closed-loop control of the system allows for the dynamic formulation of a support surface on the basis of programmable criteria. The system is intended to function as a research tool to facilitate the study of the relationships between support surface shape and interface pressure, and support surface shape and soft tissue distortion. The purpose of this paper is to present the system instrumentation and the rationale behind its design and development. The paper also presents the results of several tests to evaluate the accuracy and performance of the system. This evaluation included a pilot study on 10 able-bodied subjects. The results of these system evaluations indicate that the system is capable of making repeatable and precise measurements of pressure and surface element position and can formulate support surface shapes that satisfy specified optimization criteria.

Back↗
PubMed1996

Canine infectious cyclic thrombocytopenia found in Taiwan.

Here were report the first canine infectious cyclic thrombocytopenia (CICT) found in Taiwan. Platelet-specific inclusions were detected in the blood smear of a military working dog. To identify the etiologic agent, the patient's blood was transmitted to three six-month-old German Shepherd dogs. The Ehrlichia platys-like inclusions were observed six to eight days after inoculation. Indirect fluorescent antibody test showed that the serum from the patient reacted specifically with the microorganisms within the platelets. Typical hematologic manifestations of E. platys infection, cyclic parasitemia and concomitant thrombocytopenia, were observed in these dogs. The prevalence of CICT in north Taiwan was also studied, and the incidence was 8.9% (4 out of 45) in civilian dogs and 97.1% (34 out of 35) in dogs from a heavily tick infested kennel.

Animals↗