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C H Lin

Publications and source records attributed to C H Lin.

At least 91 records · Page 5Linked to original sources
PubMed2000

Synthesis and structure determination of 6-methylbenzo[a]pyrene-deoxyribonucleoside adducts and their identification and quantitation in vitro and in mouse skin.

Activation of the moderate carcinogen 6-methylbenzo[a]pyrene (6-CH(3)BP) by one-electron oxidation to form DNA adducts was studied. Iodine oxidation of 6-CH(3)BP in the presence of dGuo produces BP-6-CH(2)-N(2)dGuo, BP-6-CH(2)-N7Gua and a mixture of 6-CH(3)BP-(1&3)-N7Gua, whereas in the presence of Ade the adducts BP-6-CH(2)-N1Ade, BP-6-CH(2)-N3Ade, BP-6-CH(2)-N7Ade and 6-CH(3)BP-(1&3)-N1Ade are obtained. Furthermore, for the first time an aromatic hydrocarbon radical cation afforded an adduct with dThd, the stable adduct BP-6-CH(2)-N3dThd. Formation of these adducts indicates that the 6-CH(3)BP radical cation has charge localized at the 6, 1 and 3 position. When 6-CH(3)BP was activated by horseradish peroxidase in the presence of DNA, two depurinating adducts were identified, BP-6-CH(2)-N7Gua (48%) and 6-CH(3)BP-(1&3)-N7Gua (23%), with 29% unidentified stable adducts. In the binding of 6-CH(3)BP catalyzed by rat liver microsomes, the same two depurinating adducts, BP-6-CH(2)-N7Gua (22%) and 6-CH(3)BP-(1&3)-N7Gua (10%), were identified, with 68% unidentified stable adducts. In 6-CH(3)BP-treated mouse skin, the two depurinating adducts, BP-6-CH(2)-N7Gua and 6-CH(3)BP-(1&3)-N7Gua, were identified. Although quantitation of these two adducts was not possible due to coelution of metabolites on HPLC, they appeared to be the major adducts found in mouse skin. These results show that 6-CH(3)BP forms depurinating adducts only with the guanine base of DNA, both in vitro and in mouse skin. The weaker reactivity of 6-CH(3)BP radical cation vs. BP radical cation could account for the weaker tumor-initiating activity of 6-CH(3)BP in comparison to that of BP.

Adenine↗
PubMed2000

Antiplatelet activity of Staphylococcus aureus lipoteichoic acid is mediated through a cyclic AMP pathway.

In this study, Gram-positive Staphylococcus aureus lipoteichoic acid (LTA) dose dependently (0.1-1.0 microg/mL) and time dependently (10-60 min) inhibited platelet aggregation in human platelets stimulated by agonists (i.e., thrombin and collagen). LTA also dose dependently inhibited intracellular Ca(2+) mobilization in human platelets stimulated by collagen. In addition, LTA (0.5 and 1.0 microg/mL) dose dependently increased the formation of cyclic AMP but not cyclic GMP in platelets. LTA (0.5 and 1.0 microg/mL) did not significantly increase the production of nitrate within a 10-min incubation period. Rapid phosphorylation of a platelet protein of M(r) 47,000, a marker of protein kinase C activation, was triggered by PDBu (0.03 microM). This phosphorylation was dose dependently inhibited by LTA (0.5 and 1.0 microg/mL) within a 10-min incubation period. Furthermore, LTA (0.5 and 1.0 microg/mL) also inhibited platelet aggregation induced by PDBu (0.03 microM) in human platelets. These results indicate that the antiplatelet activity of LTA may be involved in the increase of cyclic AMP, leading to inhibition of intracellular Ca(2+) mobilization and protein kinase C activity. Therefore, LTA-mediated alteration of platelet function may contribute to bleeding diathesis in septicemic and endotoxemic patients.

Alprostadil↗
PubMed2000

The antiplatelet activity of tetramethylpyrazine is mediated through activation of NO synthase.

Tetramethylpyrazine (TMPZ) is an active ingredient of a Chinese herbal medicine (Ligusticum wallichii Franchat). In this study, TMPZ (50-200 microM) significantly increased production of nitrate and cyclic GMP in human platelets within a 15-min incubation period. TMPZ concentration-dependently inhibited intracellular Ca2+ mobilization in human platelets stimulated by collagen (5 microg/ml). Furthermore, TMPZ concentration (50 and 200 microM)- and time (15 and 30 min)-dependently triggered endothelial-type constitutive nitric oxide synthase (ecNOS) protein expression in human platelets. These results indicated that TMPZ at micromolar concentrations stimulated nitric oxide production in human platelets via a novel mechanism that activated ecNOS protein expression.

Blood Platelets↗
PubMed2000

Airway obstruction caused by a congenital epiglottic cyst.

Congenital epiglottic cyst is a rare affliction with potential for airway obstruction. A newborn boy was referred to our department for evaluation of respiratory distress and inspiratory stridor 7 h after birth. Through a transnasal fiberoptic laryngoscopy examination, a diagnosis of an obstructive upper laryngeal cyst was made. Immediate endoscopic surgery was performed 20 h after birth to completely remove the lesion. Two days after surgery, the patient resumed normal breathing pattern and showed no further episodes of stridor or airway obstruction.

Airway Obstruction↗
PubMed2000

Localization of unconventional myosins V and VI in neuronal growth cones.

Class V and VI myosins, two of the six known classes of actin-based motor genes expressed in vertebrate brain (Class I, II, V, VI, IX, and XV), have been suggested to be organelle motors. In this report, the neuronal expression and subcellular localization of chicken brain myosin V and myosin VI is examined. Both myosins are expressed in brain during embryogenesis. In cultured dorsal root ganglion (DRG) neurons, immunolocalization of myosin V and myosin VI revealed a similar distribution for these two myosins. Both are present within cell bodies, neurites and growth cones. Both of these myosins exhibit punctate labeling patterns that are found in the same subcellular region as microtubules in growth cone central domains. In peripheral growth cone domains, where individual puncta are more readily resolved, we observe a similar number of myosin V and myosin VI puncta. However, less than 20% of myosin V and myosin VI puncta colocalize with each other in the peripheral domains. After live cell extraction, punctate staining of myosin V and myosin VI is reduced in peripheral domains. However, we do not detect such changes in the central domains, suggesting that these myosins are associated with cytoskeletal/organelle structures. In peripheral growth cone domains myosin VI exhibits a higher extractability than myosin V. This difference between myosin V and VI was also found in a biochemical growth cone particle preparation from brain, suggesting that a significant portion of these two motors has a distinct subcellular distribution.

Animals↗
PubMed2000

On-line identification of depurinating DNA adducts in human urine by capillary electrophoresis--fluorescence line narrowing spectroscopy.

The benzo[a]pyrene (BP)-derived 7-(benzo[a]pyren-6-yl)guanine (BP-6-N7Gua) depurinating one-electron oxidation adduct was identified in the urine extracts of coal-smoke-exposed humans for the first time. Urine samples were prepared by solid-phase extraction and reversed-phase high-performance liquid chromatography. Subsequently, the BP-6-N7Gua adduct was identified on-line with capillary electrophoresis-- fluorescence line narrowing spectroscopy (CE-FLNS) at 4.2 K. The daily excretion of BP-6-N7Gua in human urine of individuals exposed to coal smoke was approximately 226 pmol per micromol of creatinine. Due to the high level of excretion we propose that BP-6-N7Gua adducts found in urine could serve as effective biomarkers for risk assessment of BP exposure. The results demonstrate that CE-FLNS allows for on-line separation and DNA adducts identification in complex fluid extracts.

Benzopyrenes↗
PubMed2000

Autonomous induction of proliferation, JNK and NF-alphaB activation in primary resting T cells by mobilized CD28.

Induction of proliferation in primary resting T cells requires engagement of both the antigen-specific TCR and the co-stimulatory receptor CD28. Here we report that CD28 functions as an autonomous mitogenic receptor which is mobilized by TCR signaling through cytoskeletal rearrangement. Shortcutting of TCR-dependent CD28 recruitment by stimulation with monoclonal antibodies specific for mobilized CD28 results in maximum proliferation and IL-2 secretion in primary resting T cells without activation of ZAP-70, a central component of the TCR's signal transduction machinery. Engagement of mobilized CD28 fully activates the c-Jun N-terminal kinase cascade and translocation of NF-alphaB, two key targets of signal integration in co-stimulation. We propose a two-step activation model for co-stimulation in primary resting T cells in which antigen recognition recruits co-stimulatory receptors which then autonomously transduce signals promoting T cell proliferation.

Animals↗
PubMed2000

Rapid diagnosis and quantification of herpes simplex virus with a green fluorescent protein reporter system.

A genetically modified cell line (Vero-ICP10-EGFP) was constructed for detection of herpes simplex virus (HSV) by a simple, rapid and direct method. The cell line was developed by stable transfection of Vero cell with a plasmid encoding the green fluorescent protein (GFP) driven by the promoter of the HSV-2 ICP10 gene. As early as 6 h after infection with HSV, fluorescence-emitting cells can be observed under a fluorescence microscope. A single infected cell emitting fluorescence can be observed with soft agar overlay by inverted fluorescence microscopy. No induction of detectable fluorescence was seen following infections with human cytomegalovirus (HCMV), varicella zoster virus (VZV), coxsackievirus A16 and enterovirus 71. Analysis by flow cytometry also demonstrated that intensity of the triggered fluorescence is proportional to the titer of HSV inoculated. Taken together, this novel GFP reporter system could become a useful means for rapid detection and quantification of HSV in clinical specimens.

Animals↗
PubMed2000

Rapidly progressive fibrosing interstitial nephritis associated with Chinese herbal drugs.

Rapidly progressive fibrosing interstitial nephritis after a slimming regimen containing aristolochic acid has been identified as Chinese herbs nephropathy (CHNP). From 1995 to 1998, we observed 12 Chinese people from different areas of Taiwan who underwent renal biopsy for unexplained renal failure. Medical history gave no clue to the causes of impaired renal function except for the ingestion of traditional Chinese herbs. Although these patients ingested herbal drugs from various sources for different purposes, their renal biopsy samples showed amazingly similar histological findings, with extensive hypocellular interstitial fibrosis and atrophy and loss of tubules in all cases. Glomeruli were apparently intact. They also had similar clinical features, such as normal or mildly elevated blood pressure, early and severe anemia, low-grade proteinuria, glycosuria, and insignificant urinary sediments. Renal function deteriorated rapidly in most patients despite discontinuation of the herbal medicines. Seven patients underwent dialysis, and the remainder experienced slowly progressive renal failure. Bladder carcinoma was found in one patient. Morphologically and clinically, the nephropathy in our patients was similar to CHNP, reported in Belgium. Because of the complexity and unknown types of herbs used in different clinical situations, unidentified phytotoxins other than aristolochic acid might be responsible for this unique disease entity. We conclude that the relation of this nephropathy to the consumption of Chinese herbs is striking. Using uncontrolled herbal remedies carries a high risk for developing interstitial renal fibrosis and urothelial malignancy.

Adult↗
PubMed2000

Substrate-induced exposure of an energy-coupling motif of a membrane transporter.

BtuB is an outer membrane protein responsible for the uptake of vitamin B12 by Escherichia coli. It belongs to a family of bacterial transport proteins that derive energy for transport by coupling to the trans-periplasmic energy-coupling protein TonB. Using site-directed spin labeling and EPR we investigated the structure and substrate-induced changes in the TonB box, a highly conserved region in all TonB dependent transporters that may couple to TonB. In the absence of substrate, the line widths and collision parameters from EPR are consistent with this domain existing in a structured helical conformation that contacts the barrel of the transporter. Addition of substrate converts this segment into an extended structure that is highly dynamic, disordered and probably extended into the periplasm. This structural change demonstrates that the TonB box cycles between sequestered and accessible states in a substrate-dependent fashion. In a transport defective mutant of BtuB, this conformational cycle is disrupted and the TonB box appears to be extended even in the absence of substrate. These data suggest that the TonB box extends into the periplasm and interacts with TonB only in

Amino Acid Motifs↗
PubMed2000

Lipopolysaccharide enhances bradykinin-induced signal transduction via activation of Ras/Raf/MEK/MAPK in canine tracheal smooth muscle cells.

Bacterial lipopolysaccharide (LPS) was found to induce inflammatory responses and to enhance bronchial hyperreactivity to several contractile agonists. However, the implication of LPS in the pathogenesis of bronchial hyperreactivity was not completely understood. Therefore, in this study, we investigated the effect of LPS on mitogen-activated protein kinase (MAPK) activation associated with potentiation of bradykinin (BK)-induced inositol phosphates (IPs) accumulation and Ca(2+) mobilization in canine cultured tracheal smooth muscle cells (TSMCs). LPS stimulated phosphorylation of p42/p44 MAPK in a time- and concentration-dependent manner using a Western blot analysis against a specific phosphorylated form of MAPK antibody. Maximal stimulation of the p42 and p44 MAPK isoforms occurred after 7 min-incubation and the maximal effect was achieved with 100 microg ml(-1) LPS. Pretreatment of TSMCs with LPS potentiated BK-induced IPs accumulation and Ca(2+) mobilization. However, there was no effect on the IPs response induced by endothelin-1, 5-hydroxytryptamine, and carbachol. In addition, pretreatment with PDGF-BB enhanced BK-induced IPs response. These enhancements by LPS and PDGF-BB might be due to an increase in BK B(2) receptor density (B(max)) in TSMCs, characterized by competitive inhibition of [(3)H]-BK binding using B(1) and B(2) receptor-selective reagents. The enhancing effects of LPS and PDGF-BB were attenuated by PD98059, an inhibitor of MAPK kinase (MEK), suggesting that the effect of LPS may share a common signalling pathway with PDGF-BB in TSMCs. Furthermore, overexpression of dominant negative mutants, H-Ras-15A and Raf-N4, significantly suppressed p42/p44 MAPK activation induced by LPS and PDGF-BB, indicating that Ras and Raf may be required for activation of these kinases. These results suggest that the augmentation of BK-induced responses produced by LPS might be, at least in part, mediated through activation of Ras/Raf/MEK/MAPK pathway in TSMCs.

Animals↗
PubMed2000

Chromosomal changes and clonality relationship between primary and recurrent hepatocellular carcinoma.

BACKGROUND & AIMS: Hepatocellular carcinoma (HCC) is highly malignant and prone to recur after surgical treatment. Differentiation between a true relapse of HCC and a second primary tumor is of clinical importance. However, no convenient method is currently available. METHODS: Comparative genomic hybridization (CGH) was used to analyze 31 pairs of initial and recurrent HCC samples obtained from patients undergoing 2 consecutive surgeries. The resulting chromosomal aberration profiles were used as genomic fingerprints to determine tumor clonalities and their relationships. RESULTS: Eleven recurrent tumors with high clonal relationship (CR) values (>0.95) were found to be relapsed HCCs, and 11 tumors with CR values close to 0 were found to be second primary HCCs. The other 9 paired samples had inconclusive CR values between 0.95 and 0.4. Two were confirmed by hepatitis B virus integration and X chromosome inactivation analysis to be de novo cancers (CR values, 0.35 and 0. 23, respectively). Initial HCCs that subsequently relapsed accumulated more chromosomal aberration events than those that developed de novo HCC (mean, 16.1 +/- 4.5 vs. 5.4 +/- 4.8 events; P < 0.01). Also, they more frequently showed gains on chromosome arms 3q, 6p, 8q, and 17q and losses on 4q and 16p. CONCLUSIONS: CGH is useful for chromosomal aberration study and tumor clonality analysis. More and characteristic genomic changes in the initial HCC suggest that subsequent tumor recurrence is a true relapse.

Adult↗
PubMed2000

Protein N-arginine methylation in subcellular fractions of lymphoblastoid cells.

Arginine methylation in RNA-binding proteins containing arginine- and glycine-rich RGG motifs is catalyzed by specific protein arginine N-methyltransferase in cells. We previously showed that lymphoblastoid cells grown in the presence of an indirect methyltransferase inhibitor, adenosine dialdehyde (AdOx), accumulated high level of hypomethylated protein substrates for the endogenous protein methyltransferases or recombinant yeast arginine methyltransferase [Li, C. et al. (1998) Arch. Biochem. Biophys. 351, 53-59]. In this study we fractionated the lymphoblastoid cells to locate the methyltransferases and the substrates in cells. Different sets of hypomethylated methyl-accepting polypeptides with wide range of molecular masses were present in cytosolic, ribosomal, and nucleus fractions. The methylated amino acid residues of the methyl-accepting proteins in these fractions were determined. In all three fractions, dimethylarginine was the most abundant methylated amino acid. The protein-arginine methyltransferase activities in the three fractions were analyzed using recombinant fibrillarin (a nucleolar RGG protein) as the methyl-accepting substrate. Fibrillarin methylation was strongest in the presence of the cytosolic fraction, followed by the ribosomal and then the nucleus fractions. The results demonstrated that protein-arginine methyltransferases as well as their methyl-accepting substrates were widely distributed in different subcellular fractions of lymphoblastoid cells.

Adenosine↗
PubMed2000

Immediate Camitz opponensplasty in acute thenar muscle injury.

Thenar function impairment or destruction is not uncommon in hand crush injury or thumb avulsion injury. Although complete evaluation of thenar muscle function is difficult during an emergency setting because of skeletal instability and pain, if left untreated the injured hand may result in deficiency of opposition and may require secondary reconstruction. When the palmaris longus tendon is available from the open wound, a Camitz opponensplasty can be performed in the emergency operation setting even as an augmentation procedure for opposition if there is any suspicion of thenar muscle impairment. Seven patients with such injuries who underwent immediate Camitz opponensplasty were assessed to have an 80% angle of separation, a 90% angle of circumduction, and an 88% Kapandji test of the normal opposite hand. An emergency Camitz procedure provided a reliable, immediate one-stage reconstruction of thenar function.

Amputation, Traumatic↗
PubMed2000

Filleted toe flap for chronic forefoot ulcer reconstruction.

Chronic plantar and dorsal forefoot ulcer may result from injury, structural deformity, and abnormal sensation or circulation. It is not uncommon that the distal portion of the affected toes is deficient functionally in these patients. A filleted toe flap from the expendable functionless toe can provide a durable, stable, and sensate skin flap of 4 to 5.5 cm for coverage of the forefoot defect. In this report, five cases of dorsal forefoot defects and four cases of plantar forefoot defects due to ischemia (N = 3), trophic change (N = 2), and diabetes (N = 4) were treated with filleted toe flaps. One flap failed due to postoperative deep infection. The other eight filleted toe flaps survived but 2 patients underwent secondary amputations 7 months and 2 two years later because of secondary diabetic foot infections.

Adult↗
PubMed2000

A prospective trial of lansoprazole triple therapy for pediatric Helicobacter pylori infection.

BACKGROUND: Triple therapy with a proton-pump inhibitor and two antibiotics is widely used in the treatment of Helicobacter pylori infection in adults. Experience with such therapy in the pediatric population is limited. This was a prospective, nonrandomized, open-label trial to evaluate safety and efficacy of a combination of lansoprazole, clarithromycin, and amoxicillin in symptomatic children with H. pylori infection. METHODS: Children with H. pylori gastritis diagnosed by endoscopy performed for persistent nausea, vomiting, recurrent abdominal pain, and diarrhea with consistent histology were treated with the regimen of 0.45 mg/kg per day lansoprazole divided into two doses (maximum dose, 15 mg twice daily), amoxicillin 40 mg/kg per day in two doses (maximum dose, 1.0 g twice daily), and 250 mg clarithromycin twice daily (<10 years old) or 500 mg twice daily (>10 years old) for 2 weeks. Pre- and posttreatment endoscopic biopsy specimens were graded for the severity of gastritis and H. pylori density by a blinded pathologist. A questionnaire for assessing the severity of symptoms at the time of initial and second endoscopy were completed by patient and/or parent. RESULTS: Thirty-two children (age range, 1-25 years; mean age, 11 years; 19 females, 13 males) were treated with this regimen during an 18-month period. H. pylori organisms with varying grades of gastritis were present in tissue specimens of all patients. Only 28 children had follow-up endoscopy, which showed eradication of H. pylori in 15 (54%) children. Histologic symptoms of gastritis improved after therapy in the whole group. Overall, symptoms of vomiting, abdominal pain, diarrhea, anorexia, and halitosis significantly improved (P < 0.05). Minor adverse effects of therapy occurred in 25% of patients. CONCLUSIONS: Symptoms, histologic, and endoscopic findings improved after triple therapy in children with H. pylori gastritis; however, eradication of bacteria was achieved in only 56% of children.

2-Pyridinylmethylsulfinylbenzimidazoles↗