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W L Lin

Publications and source records attributed to W L Lin.

At least 91 records · Page 5Linked to original sources
PubMed1992

Mitogenic, chemotactic, and synthetic responses of rat periodontal ligament fibroblastic cells to polypeptide growth factors in vitro.

The mitogenic, chemotactic, and synthetic responses of rat periodontal ligament (PDL) fibroblastic cells to epidermal growth factor (EGF), transforming growth factor-beta (TGF-beta), recombinant human platelet-derived growth factor (rhPDGF)-AB, rhPDGF-BB, natural (n) PDGF-AB, and insulin-like growth factor-I (IGF-I) were examined in vitro using PDL cells obtained from the coagulum of healing tooth sockets. PDGFs and IGF-I have potent and comparable mitogenic effects on PDL fibroblastic cells. The maximum mitogenic effect of PDGFs was observed at the concentration of 10 ng/ml, whereas that of IGF-I was seen at concentrations higher than 100 ng/ml. In contrast, EGF induced moderate, and TGF-beta inhibitory mitogenic responses. The combination of rhPDGF-AB with either EGF or TGF-beta demonstrated comparable mitogenic potency, equivalent to the level of PDGF alone regardless of the mitogenic effect of other growth factors. The combination of rhPDGF-AB and IGF-I, however, showed a synergistic effect revealing the highest mitogenic effect among all individual growth factors as well as any combinations of the growth factors tested. Similarly, PDL fibroblastic cells demonstrated strong chemotactic responses to both IGF-I and PDGFs. The maximum effect was observed by IGF-I at concentrations higher than 10 ng/ml, followed by rhPDGF-BB at 0.1 ng/ml, rhPDGF-AB and nPDGF at concentrations ranging from 0.1 to 1 ng/ml. TGF-beta revealed no, and EGF slightly increased, chemotactic effects. IGF-I slightly enhanced the synthesis of total protein, whereas other factors had no significant effect. However, both rhPDGF-AB and TGF-beta stimulated collagen synthesis. On the other hand, IGF-I showed no effect on collagen synthesis, while EGF suppressed collagen synthesis. These findings suggest that rhPDGF-BB and IGF-I stimulate proliferation and chemotaxis of PDL fibroblastic cells. In addition, the combination of these growth factors further increases the mitogenic effect. rhPDGF-AB also stimulates collagen synthesis by PDL fibroblastic cells. Thus, rhPDGF-BB and IGF-I may have important roles in promotion of PDL healing, and consequently, may be useful for clinical application in periodontal regenerative procedures.

Animals↗
PubMed1992

Analysis of ragweed allergens recognized by monoclonal antibody 8-5 using two-dimensional gel electrophoresis and immunoblotting.

A series of MoAbs against major allergens (Amb a I and Amb a II) of the short ragweed pollen is reported by this laboratory. One of these MoAbs, 8-5, showed strong reactivity to Amb a II, weak reactivity to Amb a I-B and I-C, and no reactivity to Amb a I-B2 of the short ragweed pollen by SDS-PAGE and immunoblotting. In the present study, ragweed allergens recognized by MoAb 8-5 were further analyzed by two-dimensional gel electrophoresis and immunoblotting. The results showed that MoAb 36-6, which has been identified to be reactive with Amb a I only, reacted mainly with components with MW of about 39 kD, which corresponded to creatine kinase charge standards from -14 to -20 in both the Amb a I-B and I-C preparation and the crude extract of the short ragweed pollen. However, MoAb 8-5 showed strong reactivity to components with about the same MW but charge standards from -8 to -13 in Amb a II and the crude extract of the short ragweed pollen. Furthermore, a weak positive reactivity of MoAb 8-5 to components with MW of about 39 kD and charge standards from -8 to -14 in Amb a I-B and I-C was also observed. It was thus concluded that MoAb 8-5 reacted with Amb a II only.(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗
PubMed1992

Ultrastructural immunocytochemical localization of chondroitin sulfate proteoglycan in Bruch's membrane of the rat.

Two monoclonal antibodies (Mab 4D5 and 2D6) raised against the core protein of a basement membrane chondroitin sulfate proteoglycan from Reichert's membrane of the rat, were used for ultrastructural immunoperoxidase localization of this protein in Bruch's membrane of the rat. Immunoreactivity for both antibodies was found in the basal lamina (basement membrane) of the choriocapillary endothelium and retinal pigment epithelium, in collagen fibers in the collagenous zones, and surrounding the elastic layer.

Animals↗
PubMed1991

Occurrence of epidermal growth factor-binding sites during differentiation of cementoblasts and periodontal ligament fibroblasts of the young rat: a light and electron microscopic radioautographic study.

Occurrence of epidermal growth factor (EGF)-binding sites during differentiation of cementoblasts and periodontal ligament (PDL) fibroblasts was investigated using radioautography after I. V. injection of 125I-EGF to 14-day-old rats. During differentiation of cementoblasts, a very low level of EGF-binding sites was present on the mesenchymal cells in dental follicle proper, precementoblasts, and cementoblasts. On the other hand, during differentiation of PDL fibroblasts, numerous EGF-binding sites were observed on the undifferentiated paravascular cells and on the perifollicular mesenchymes representing the major source of PDL fibroblast precursor cells. Also heavy labeling was observed throughout their differentiation to PDL fibroblasts, as well as during full synthetic activity as mature cells. Quantitative analysis of the light microscopic radioautographs revealed that these cells demonstrated approximately 4 grains per 100 microns 2 of cell area. These results suggest that EGF plays an important role in differentiation of PDL fibroblasts, but not in that of cementoblasts. Furthermore, the well-known in vivo effect of EGF in producing precocious eruption of teeth may be a consequence of a more extensive effect of EGF throughout differentiation of PDL fibroblasts as well as during full synthetic activity as mature cells.

Animals↗
PubMed1991

Breakdown of the blood-retinal barrier in S-antigen-induced uveoretinitis in rats.

Experimental autoimmune uveoretinitis was induced in Lewis rats by footpad injection of purified, bovine retinal soluble antigen (S-antigen) with complete Freund's adjuvant. Control animals received adjuvant only. At the peak of ocular inflammation the animals received an intravenous injection of the tracer horseradish peroxidase, and the eyes were removed and processed for peroxidase cytochemistry. A breakdown of the blood-retinal barrier occurred at the level of the retinal venules. Peroxidase reaction product was demonstrable in the interendothelial tight junctions and in the perivascular spaces. Heavy infiltration of inflammatory cells was also found in and around the venular wall. The endothelial cells of venules and capillaries were hypertrophied and showed swollen endoplasmic reticulum and Golgi apparatus as well as increased numbers of ribosomes and cytoplasmic fibrils; pericytes and smooth-muscle cells showed a similar synthetic phenotype and the basal lamina of these cells was thickened.

Animals↗
PubMed1991

Immunocytochemical localization of gamma-glutamyl transpeptidase in porcine ciliary epithelium.

Our previous work on cultured bovine ciliary epithelial cells indicated that gamma-glutamyl transpeptidase (GGTP) activity is primarily associated with the non-pigmented epithelial cells and is virtually absent in the pigmented epithelial cells [Ng and Shichi, (1987) J. Ocular Pharmacol. 3, 341-348]. We have now investigated the localization of GGTP in porcine ciliary processes by immunocytochemical methods using goat anti-rat GGTP serum detected by rabbit anti-goat IgG secondary antibodies conjugated to fluorescein isothiocyanate or horseradish peroxidase, or biotin-conjugated secondary antibodies and streptavidin (Auroprobe). The non-pigmented cells were labeled uniformly and intensely by fluorescent antibodies, while only the plasma membrane (on the stroma side) was labeled in the pigmented cells. Immunoperoxidase reactions demonstrated that only the plasma membrane was labeled also in non-pigmented cells. The apparent uniform labeling of the cytoplasm of non-pigmented cells by fluorescent antibodies was attributed to the extensively infolded plasma membrane. The peroxidase reaction product was not found in the mitochondria, nucleus or endoplasmic reticulum of non-pigmented or pigmented cells. Immunogold labeling indicated that antigenic sites are associated with the plasma membrane infoldings (vitreous side) of non-pigmented cells, and the plasma membrane (stroma side) of pigmented cells. For enzymatic localization of GGTP activity in ciliary epithelial cells, non-pigmented and pigmented epithelial cells were carefully separated from fresh porcine ciliary body and homogenized to isolate microsomal fractions containing vesicles of plasma membrane and endoplasmic reticulum. The specific activity of microsomes from non-pigmented cells was 23 times higher than that of microsomes from pigmented cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Immunoblot analysis of components of Penicillium notatum recognized by human IgE antibodies.

Components of the crude extract of Penicillium notatum recognized by human IgE antibodies (Abs) were investigated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. The allergenic components were identified with sera from 19 allergic patients and 20 blood donors. The allergen-Ab complexes were visualized by 125I-labeled monoclonal antihuman IgE and autoradiography. A total of 11 allergenic components, ranging in molecular weights (MWs) from 94,000 to 20,000 daltons, were identified. Heterogeneity in the IgE-binding patterns of the serum samples tested was also observed. However, the major allergen appears to be the component with an MW of about 68,000 daltons that was recognized by IgE Abs in 56% of the 39 sera analyzed. Furthermore, the component with an MW of about 64,000 daltons that was recognized by IgE Abs in 46% of the sera analyzed was also considered as an important allergen. Results obtained from this study will be useful in additional characterization of allergens of P. notatum and related fungal species.

Allergens↗
PubMed1991

Dose-dependent reduced haloperidol/haloperidol ratios in schizophrenic patients.

Plasma haloperidol (HAL) and reduced HAL (RHAL) concentrations were measured in 113 Chinese schizophrenic patients. Daily doses of HAL ranged from 8 to 65 mg. Samples were obtained under steady-state conditions and drawn 10-12 hours after the bedtime dose and before the morning dose. In all, 313 blood samples were collected. Multiple samples were obtained at the same doses in 63 patients and at two or three different doses in 31 patients. HAL and RHAL concentrations were assayed by high performance liquid chromatography. Interpatient variation in plasma HAL levels at a given dosage was up to sixfold. However, there was a high positive correlation between plasma levels and daily dosages with the equation of HAL plasma level (ng/ml) = 0.88 x dosage (mg/day) -0.56 or 46.0 x dosage (mg/day/kg) + 0.28. The expected values are about 15-55% higher than those obtained from non-Chinese patients as reported in the literature. The RHAL/HAL ratios were dose-dependent. The greater the dose used, the higher the ratio. An upper therapeutic limit of plasma HAL level is suggested to be 25 ng/ml, which can be achieved at dosages about 30 mg/day in most Chinese patients. Based upon the dose-dependent increase in RHAL/HAL ratios, the importance of RHAL in determining the therapeutic benefit of HAL treatment is discussed.

Adolescent↗
PubMed1991

The 40-kilodalton allergen of Candida albicans is an alcohol dehydrogenase: molecular cloning and immunological analysis using monoclonal antibodies.

To characterize the 40-kilodalton (kD) major allergen of Candida albicans (C. albicans), six monoclonal antibodies (MoAbs) against this allergen were generated. In SDS-polyacrylamide gel electrophoresis and immunoblot analysis, these MoAbs showed four different reaction patterns to antigens of six different Candida species. With the exception of one MoAb, other MoAbs were resistant to periodate treatment indicating non-carbohydrate epitopes were probably being recognized by these MoAbs. These MoAbs were used in the molecular cloning and immunological analysis of the gene coding for the 40-kD allergen. Nucleotide sequence determination of the two lambda gt11 cDNA clones obtained showed that the 40-kD allergen is an alcohol dehydrogenase (ADH) which shares a 70% amino acid sequence homology with the ADH isozyme I of Saccharomyces cerevisiae. This finding was confirmed by positive immunological response of the lysates of the clones obtained and a preparation of ADH of Saccharomyces cerevisiae to various MoAbs and to IgE antibodies in sera of allergic patients.

Alcohol Dehydrogenase↗
PubMed1991

Increased immunoreactivity of collagen types I, III and V, fibronectin and TGF-beta in retinal vessels of rats with experimental autoimmune uveoretinitis.

The immunoreactivity of types I, III and V collagen, fibronectin and transforming growth factor-beta (TGF-beta) was studied by an immunogold labeling method in retinal vessels of rats with experimental autoimmune uveoretinitis (EAU) induced by retinal S-antigen. The basal lamina of retinal capillaries in normal rats showed low immunoreactivities for the extracellular matrix components and TGF-beta. However, at the peak of inflammation (day 13-16 postimmunization), labeling of all three types of collagen and fibronectin increased considerably in the basal lamina of retinal vessels. TGF-beta immunoreactivity was detected mainly in the vascular endothelium and the pericytes. The results suggest that TGF-beta synthesized by the endothelial cells and pericytes may regulate the synthesis and composition of extracellular matrix components in the vascular basal lamina during the course of EAU development.

Animals↗
PubMed1991

[The urinary screening and identification of amphetamines in clinical toxicology laboratory--VGH].

Amphetamines abuse has recently become a problem in this country. Four case identification, we used Emit-d.a.u. amphetamine assay to screen the amphetamines in human urine, and then confirmed them by gas chromatography-ion trap detector (GC-ITD). From January 1989 to August 1990, 267 urinary samples were requested by the physicians for amphetamine identification. Six samples were accompanied with drug powders used by the patients. Among the 267 samples, 79 were confirmed for the presence for both of methamphetamine and amphetamine. Neither the presence of amphetamine nor methamphetamine itself was detected. Among the six packs of drug powder tested, methamphetamine but not amphetamine was detected in four. We found that fenfluramine and diethylpropion would have false positive amphetamine reactions in Emit-d.a.u. assay. All the samples originated from 34 hospitals were widely distributed in the country. Other drugs concomitantly used included ethanol, morphine, flunitrazepam and ephedrine. Since methamphetamine can be metabolized to amphetamine but not vers versa, our study confirmed the abuse of methamphetamine not amphetamine in this country.

Amphetamines↗
PubMed1990

Plasma catecholamine metabolites in schizophrenics: evidence for the two-subtype concept.

Plasma homovanillic acid (pHVA) and plasma methoxyhydroxyphenyl glycol (pMHPG), as well as plasma haloperidol, were measured in 33 schizophrenic patients before and during 6 weeks of haloperidol treatment. Good responders had higher baseline pHVA values compared with poor responders (17.4 +/- 8.8 ng/ml, n = 22 versus 11.4 +/- 5.0 ng/ml, n = 11, p less than 0.05). A higher than 15 ng/ml pretreatment pHVA level was associated with a more consistent clinical response to the subsequent treatment. Differential pHVA changes during treatment were also found between good and poor responders. Within the good responder group, a significant decline in pHVA over time was found. By contrast, pHVA showed a transient increase in the poor responder group. Plasma MHPG changes showed a similar pattern during treatment in good responders, although no significant differences in baseline values were found between the good (n = 13) and poor (n = 9) responders, and pMHPG showed no change during treatment in poor responders. Significant correlations between baseline pHVA and pMHPG values were found in 22 patients. Good responders and poor responders did not differ significantly in terms of age, duration of illness, severity of presenting symptoms, haloperidol dose, or plasma drug concentration. Two hypothetical subtypes of schizophrenia and both dopamine and norepinephrine systems involved in schizophrenic psychopathology are proposed.

Adult↗
PubMed1990

An improved scheme for the identification of antigens recognized by specific antibodies in two-dimensional gel electrophoresis and immunoblotting.

This paper describes an improved scheme for the identification of antigens in crude extracts recognized by specific antibodies when analyzed by a combination of two-dimensional gel electrophoresis and immunoblotting. First, protein components in gels are electrophoretically transferred to a polyvinylidene difluoride membrane which does not shrink or change dimensions in organic solvents. The efficiency of transfer and the localization of sample proteins on the membrane are checked and recorded by staining the blotting membrane with Fast Green FCF and recording the profile on a transparency. After blocking and the immunoassay, the results are recorded by photography. The sites of immune reaction are marked and the same membrane is restained briefly with Coomassie Brilliant Blue R-250 for the protein profile. Thus antigens in complex mixtures, recognized by antibodies of interest, can easily be identified from the restained membrane. If the whole protein profile is not well demonstrated, when used in combination with the profile recorded on the transparency, spots appearing on the restained membrane can still be used as useful landmarks in the final unequivocal antigenic identification. This improved scheme circumvents problems arising from membrane shrinkage and difficulties in accurately matching immunoreactive spots by conventional procedures and thus provides an accurate, simple and fast approach in the identification of antigens after immunoblotting.

Antibodies, Monoclonal↗
PubMed1990

Immunogold localization of basal laminar heparan sulfate proteoglycan in rat brain and retinal capillaries.

Heparan sulfate proteoglycan was localized in the basal lamina of the brain and retinal capillaries, using an antibody to the core protein of the proteoglycan and a postembedding immunogold labeling method at the ultrastructural level. Gold particles appeared to be randomly distributed in the basal lamina of both types of capillaries, in contrast to discrete ruthenium red-staining sites near the endothelial plasma membrane, as shown in previous studies of the retinal vessel. The present study not only agrees with previous biochemical and immunofluorescence studies, but also provides a more precise localization of the antigen. Furthermore, the method can be useful for quantitative studies.

Animals↗
PubMed1990

Genomic structure of the human proliferating cell nucleolar protein P120.

A gene for human proliferating cell nucleolar protein p120 has been isolated from a human genomic library using p120 cDNA as a probe. The gene spanned 12 kilobase pairs and was composed of 15 exons and 14 introns. Unusual splice junction sequences, (AT) and (AC), instead of (GT) and (AG), respectively, were located at the splice sites for intron F. The 5' flanking region was analyzed for putative cis-acting factor binding sites. The region contained a TATA-like sequence and the CCAAT box. CAT assays indicated that the region -2532 /+ 102 was necessary for transcription. Two specific areas at -1444/-1224 and -537/-278 were shown to be important for transcription. Two "GC" boxes and two "GC"-rich sequences were observed Other sites upstream of these sites were analyzed for homology to other gene control regions.

Base Sequence↗
PubMed1990

Cross-reactivity among antigens of different air-borne fungi detected by ELISA using five monoclonal antibodies against Penicillium notatum.

Cross-reactivity among antigens of 12 genera of air-borne fungi, 13 species of Penicillium, and 5 species of Aspergillus was studied by ELISA using five monoclonal antibodies (MoAbs) against Penicillium notatum. Epitopes recognized by all the five MoAbs were susceptible to treatment of mild periodate oxidation and may therefore be associated with carbohydrates. Furthermore, our results showed that there is cross-reactivity among antigens of Penicillium, Aspergillus, and Eurotium species. By using these MoAbs, cross reactivity was not detected between antigens of Penicillium notatum and antigens of Fusarium solani, Alternaria porri, Cladosporium cladosporoides, Curvularia species, Nigrospora species, Aureobasidium pullulans, Wallemia species, Rhizopus arrhizus, and Candida albicans. Cross-reactivity among antigens of 11 species of Penicillium and 5 species of Aspergillus could be detected by ELISA using one of the five MoAbs (MoAb P15). The fact that there may be cross-reactivity among antigens of closely related fungi species should be considered in the diagnosis and treatment of mold allergic diseases.

Air Microbiology↗
PubMed1990

Immunogold localization of basement membrane molecules in rat retinal capillaries.

Vascular basement membrane contains laminin, fibronectin, proteoglycan and collagens. These molecules have been identified in various tissues by immunolabeling methods and biochemical analyses. We have previously localized laminin, fibronectin and type IV collagen to the basement membrane of rat retinal vessels at the ultrastructural level using an immunoperoxidase method. In this study, we use an immunogold method to re-examine the distribution of these molecules and also to study the localization of heparan sulfate proteoglycan and types I, III and V collagen in the retinal capillary basement membrane. Gold labeling for laminin, type IV collagen and proteoglycan were found diffusely on the basement membrane of the endothelium and pericyte, while that for fibronectin and type V collagen was spotty and variable and that for types I and III collagen was negligible. The segment of basement membrane between the endothelial cell and pericyte appeared less reactive to anti-laminin and anti-type IV collagen than the membrane between the pericyte and perivascular neuroretina. The immunogold method may be useful in quantitative studies of thickened basement membranes under abnormal conditions.

Animals↗