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Biomedical subjects

C Lin

Publications and source records attributed to C Lin.

At least 73 records · Page 4Linked to original sources
PubMed2001

Selective enhancement of l-type calcium currents by corticotropin in acutely isolated rat amygdala neurons.

The modulation of voltage-dependent calcium currents (I(Ca)) by corticotropin was studied in acutely dissociated rat amygdala neurons using whole-cell, patch-clamp recording techniques. Application of corticotropin(1-24) or corticotropin(4-10) increased I(Ca) in a concentration-dependent manner, with half-maximal effective concentrations of 65 and 176 nM and maximal increases of approximately 75% and approximately 50%, respectively. Nimodipine (1 microM) reduced the I(Ca) by approximately 30%. Subsequent application of corticotropin in the presence of nimodipine failed to produce an enhancement of I(Ca), suggesting that corticotropin acts selectively on L-type channels. In addition, corticotropin-mediated enhancement of I(Ca) after exposure to omega-conotoxin-GVIA and omega-agatoxin-IV was not significantly different from that observed in the control neurons, ruling out the involvement of N- and P/Q-type channels. The effect of corticotropin was mimicked by forskolin and (S(p))-cyclic adenosine 3',5'-monophosphothioate [(S(p))-cAMPS] and was significantly enhanced in the presence of phosphodiesterase or protein phosphatase inhibitors. On the other hand, the effect of corticotropin was markedly reduced in neurons intracellularly dialyzed with (R(p))-cAMPS, a regulatory site antagonist of cAMP-dependent protein kinase (PKA) or by extracellular perfusion of KT 5720, a catalytic site antagonist of PKA. Taken together, these results show for the first time that corticotropin enhances voltage-dependent Ca(2+) currents in brain neurons and that this increase is mediated through L-type channels and involves a cAMP-dependent mechanism.

Adrenocorticotropic Hormone↗
PubMed2001

Exercise tolerance and quality of life in elderly patients with chronic atrial fibrillation.

BACKGROUND: Atrial fibrillation is the most common arrhythmia affecting the elderly. Although the risk of cardioembolic stroke is well defined, the effects of chronic atrial fibrillation on exercise tolerance and quality of life have been less well quantified. METHODS: We compared a group of 52 elderly patients with chronic atrial fibrillation to a group of 48 control patients in sinus rhythm. Each patient underwent an interview that incorporated the Short Form-36 Health Survey (SF-36) to quantify individual perceptions on quality of life. In addition each person underwent physiologic testing that included a Modified Bruce Protocol exercise tolerance test, 24-hour ambulatory monitor test, and an echocardiogram. RESULTS: Both groups were elderly, 77 vs 76 years of age (P=0.35). The two groups had similar ejection fractions, 55.4% vs 58.4% (P=0.10). The atrial fibrillation patients demonstrated a higher level of comorbidity based on the Charlson Comorbidity Index, 2.46 vs 1.57 (P=0.03). On formal exercise testing there was no statistical difference in exercise duration between the two groups 9.0 vs 10.1 minutes (P=0.24). Similarly the Physical Summary Score (PCS) and the Mental Summary Score (MCS) of the SF-36 quality of life survey did not demonstrate a statistical difference between the two groups. PCS: 43.0 vs 45.9 (P=0.24); MCS: 52.5 vs 55.7 (P=0.07). CONCLUSIONS: Despite a higher level of comorbidity, elderly, ambulatory patients with chronic atrial fibrillation demonstrate similar exercise tolerance and report similar quality of life to a group of age-matched control patients in sinus rhythm. There is a cohort of patients in chronic atrial fibrillation in whom a strategy of rate control and anticoagulation may be appropriate.

Aged↗
PubMed2001

[Non-invasive prenatal diagnosis of Duchenne muscular dystrophy].

OBJECTIVE: This paper was designed to investigate the feasibility of non-invasive prenatal diagnosis of Duchenne muscular dystrophy(DMD). METHODS: The nucleated red blood cells(NRBC) were separated with percoll using a discontinuous density gradient method. The cells were smeared on microscope slides using a cyto-centrifuge and then stained by Wright- Giemsa. NRBCs were detected and individually retrieved into glass capillary pipettes using a micromanipulator under microscopic observation. The whole genome of a single cell was amplified by improved primer extension preamplification(PEP). The procedures for making prenatal diagnosis of DMD and determining the origin of NRBCs proceeded at the same time using sex determination and linkage analysis of several STR loci of dystrophin. Genotypes were analyzed by amplifying the 9 STR fragments using fluorescence-PCR technique and NRBCs origin was further determined. RESULTS: A case of DMD in male fetus was diagnosed. CONCLUSION: With the use of the method reported, the non-invasive prenatal diagnosis of DMD is possible.

Female↗
PubMed2001

Mechanism-based inactivation of CYP2D6 by 5-fluoro-2-[4-[(2-phenyl-1H-imidazol-5-yl)methyl]-1-piperazinyl]pyrimidine.

SCH 66712 [5-fluoro-2-[4-[(2-phenyl-1H-imidazol-5-yl)methyl]-1-piperazinyl]pyrimidine] caused a time- and NADPH-dependent loss of CYP2D6 activity. The inactivation of human liver (HL) microsomal dextromethorphan O-demethylase activity, a prototype marker for CYP2D6, was characterized by a K(I) of 4.8 microM and a maximal rate constant of inactivation (k(inact)) of 0.14 min(-1). The inactivation of the recombinant CYP2D6 in Supersomes (r-CYP2D6) was characterized by a K(I) of 0.55 microM and a k(inact) of 0.32 min(-1). Extensive dialysis of the SCH 66712-inhibited enzyme failed to restore the activity to control levels (dialyzed reaction mixture lacking SCH 66712) for both HL microsomes and r-CYP2D6. Addition of glutathione, superoxide dismutase, or mannitol to the reaction mixture failed to protect CYP2D6 against SCH 66712-NADPH-catalyzed inactivation. Addition of quinidine, a reversible inhibitor of CYP2D6, to a preincubation mixture consisting of SCH 66712, HL microsomes, or Supersomes and NADPH partially protected CYP2D6 from inactivation. SCH 66712 also inhibited HL microsomal CYP3A4, CYP2C9, and CYP2C19; however, the concentrations required to inhibit those isoforms were 5- to 10-fold higher than those required to inhibit CYP2D6. These results demonstrate that SCH 66712 is a potent and fairly selective mechanism-based inhibitor of CYP2D6.

Chromatography, High Pressure Liquid↗
PubMed2001

[The antioxidative effect of procyanidins from pine bark in vitro].

OBJECTIVE: To assess the antioxidative effect of procyanidins from pine bark on free radical damage. METHODS: Hemolysis, Malonaldehyde(MDA) level of mice liver homogenates, the conformation changes of irradiated plasmid PUC18 were used as indexes. RESULTS: Procyanidins could reduce the hemolysis degree of human RBC induced by H2O2 significantly(P < 0.01), reduce the MDA level of mice liver homogenate initiated by VitC/Fe2+ remarkably(P < 0.01), and reduce the degree of single-strain break of plamid PUC18 induced by 60Co gamma significantly(P < 0.01). CONCLUSION: Procyanidins had good antioxidative function. It can prevent RBC membrane, plasmid DNA suffering from oxygen free radical damage in vitro.

Animals↗
PubMed2001

[Nucleotide sequence of the noncoding regions of measles virus stain CC-47 and comparison with other measles viruses].

BACKGROUND: To determine the nucleotide sequence of noncoding regions of Measles virus strain Changchun-47 (CC-47) and to compare them with other measles virus for revealing some vaccine-related information. METHODS: Six overlapped fragments, that covers complete genome of CC-47 were amplified by using RT-PCR, all of the amplified fragments have been cloned and sequenced. RESULTS: Seven noncoding regions lie in the genome sequence of CC-47 separated by six structure genes. The noncoding regions of CC-47 contain 1791 nucleotides totally. Comparing of the noncoding regions of CC-47 with other wild type strains and five Edmonston-derived vaccine strains, four nucleotide substitutions were shared by nearly all vaccine strains. Two of these were in the genomic 3 terminal transcriptional control region: position 26 (U->G), 42 (U->G); the other were in the F mRNA 5 -untranslated region of M/F intergenic region. These site substitutions may influence the efficiency of mRNA synthesis, processing, and translation, as wel l as genome replication and encapsidation. CONCLUSIONS: The nucleotide substitutions shared by different genotype measles virus vaccine strains may be related to virus growth in semipermissive cell or process of attenuation, which provide useful data for molecular epidemiology of measles virus. The nucleotide substitutions for attenuation were involved in several regions other than one definite region.

3' Untranslated Regions↗
PubMed2001

[Detecting human papillomavirus type 6/11 with fluorescence quantitative PCR].

BACKGROUND: To study the human paillomavirus type 6/11 (HPV6/11) infectious status of patients with vaginitis. METHODS: Fluorescence quantitative PCR (FQ-PCR) was used to measue HPV 6/11 DNA in 129 secretion samples. RESULTS: 47 samples were positive with a positive rate of 36.43%; 39 of 47 samples had over 105 copy/ml of the virus. CONCLUSIONS: Middle and old aged patients do not go to hospital until their virus infectious state becomes serious. FQ-PCR is suitable for clinical application because of its high sensitivity, rapidity and accuracy.

Adult↗
PubMed2001

[Herpesviridae and laryngeal neoplasia].

OBJECTIVE: To investigate the relationship between herpesviridae and malignant or benign laryngeal diseases. METHOD: 128 paraffin-embedded laryngeal squamous cell carcinoma and laryngeal epithelium hyperplastic lesions were detected by polymerase chain reaction (PCR) and PCR-ISH for herpesviridae. RESULT: HSV-1 was detected in 10 cases by PCR, among them 3 were laryngeal squamous cell carcinoma (LSCC), 1 was carcinoma in situ(CIS), 4 were laryngeal polyps and 2 were laryngeal keratosis. Except 1 LSCC and 1 CIS 8 of 10 cases were positive while detected by PCR-ISH. In benign diseases, signals were shown from basal layer to superficial cell; in malignant lesions, the signals were scattered in the diseases. CONCLUSION: Most of laryngeal diseases were not related to herpesviridae, but HSV-1 may acts as initiator in the development of a few cases.

Carcinoma, Squamous Cell↗
PubMed2001

[Resection of gastric carcinoma with preserving of the spleen and pancreas and functional clearance lymph nodes of the spleen hillus and splenic artery].

OBJECTIVE: To study the practical effects of the preserved spleen and pancreas and functional, clearance of lymph nodes of the spleen hillus and splenic artery for gastric carcinoma. METHODS: Spleen and pancreatic involvement was retrospectively reviewed in 439 cases of resectable carcinoma of the gastric cardia, gastric corpus and total stomach. During gastric operation, 2 ml methylene blue was injected into the subserosal space of the gastric cardia or corpus to observe the spreading of lymphatic flow of the stomach in 54 cases. The No10, No11 lymph node metastasis rates, postoperative complications and survival rates were observed in 63 case of gastric carcinoma that had received gastrectomy with preservation of the spleen and pancreas (PSP) and functional clearance of lymph nodes of the spleen hillus and splenic artery. RESULTS: Invasion of gastric cancer into the pancreas and spleen occurred in 5.7% (25/439) and 2.3% (10/439) respectively. Methylence blue was injected into the subserosal space of the stomach without diffusion into the spleen and pancreas. The No10, No11 lymph node metastasis rates of PSP, pancreas preservation (PR) and pancreas and spleen resection (PSR) were 17.5% (11/63), 19.1% (12/63); 20.8% (45/216), 25% (54/216); 20% (6/30), 23% (7/30), respectively (P > 0.05). The occurrence of postoperative complications and mortality was lower in patients with PSP than those with spleen and parts of pancreas resected, whereas the survival rate was higher in patients with PSP. The 5-year and 10-year survival rates of gastric carcinoma in stage II, III a were markedly improved in patients with PSP. CONCLUSIONS: PSP for patients with gastric cancer is safe and functional resectable. The occurrence of postoperative complications is lower and the survival rates are higher in patients with PSP than those with spleen and part of pancreas resected. PSP is beneficial to those with gastric carcinoma in stage II, IIIa.

Adult↗
PubMed2000

Mode-specific energy disposal in the four-atom reaction OH + D2 --> HOD + D.

Experiments, employing crossed molecular beams, with vibrational state resolution have been performed on the simplest four-atom reaction, OH + D2 --> HOD + D. In good agreement with the most recent quantum scattering predictions, mode-specific reaction dynamics is observed, with vibration in the newly formed oxygen-deuterium bond preferentially excited to v = 2. This demonstrates that quantum theoretical calculations, which in the past decade have achieved remarkable accuracy for three-atom reactions involving three dimensions, have progressed to the point where it is now possible to accurately predict energy disposal in four-atom reactions involving six dimensions.

Journal Article↗
PubMed2000

An improved analytical procedure for determination of total actual acidity (TAA) in acid sulfate soils

An improved analytical procedure is proposed for the determination of total actual acidity (TAA) in acid sulfate soils. The proposed method involves the use of a superior extracting solution, 0.5 M BaCl2, instead of the 1 M NaCl used by Konsten et al. (Konsten CJM, Brinkman R, Andriesse W. A field laboratory method to determine total potential and actual acidity in acid sulfate soils. In: Dost H, editor. Selected papers of the Dakar Symposium on Acid Sulfate Soils. Wageningen: ILRI Publication 44, 1988:106-134.) and improved experimental design to obtain correction factors for calculating TAA. The introduction of a multi-choice procedure also enables increased accuracy of analytical results to be obtained if more accurate TAA estimation is required.

Journal Article↗
PubMed2000

Enhancing effects of Thai edible plants on 2-amino-3, 8-dimethylimidazo(4,5-f)quinoxaline-hepatocarcinogenesis in a rat medium-term bioassay.

Boesenbergia pandurata (Zingiberaceae), Languas galanga (Zingiberaceae) and Citrus hystrix (Rutaceae) are edible plants that are commonly used as flavors or condiments in various Thai food dishes. They are known to exert strong anti-promoting activity in a test of tumor promoter-induced Epstein-Barr virus (EBV) activation. In the present study their effects on hepatocarcinogenesis were investigated in a medium-term bioassay using F344 male rats. C. hystrix significantly enhanced 2-amino-3,8-dimethylimidazo(4, 5-f)quinoxaline-associated preneoplastic liver cell focus development while B. pandurata and L. galanga had borderline effects. The results suggest that C. hystrix as well as B. pandurata and L. galanga may contain agents augmenting the hepatocarcinogenicity of 2-amino-3,8-dimethylimidazo(4,5-f)quinoxaline.

Animals↗
PubMed2000

Gene replacement with the human BRCA1 locus: tissue specific expression and rescue of embryonic lethality in mice.

We have generated transgenic mice that harbor a 140 kb genomic fragment of the human BRCA1 locus (TgN x BRCA1GEN). We find that the transgene directs appropriate expression of human BRCA1 transcripts in multiple mouse tissues, and that human BRCA1 protein is expressed and stabilized following exposure to DNA damage. Such mice are completely normal, with no overt signs of BRCA1 toxicity commonly observed when BRCA1 is expressed from heterologous promoters. Most importantly, however, the transgene rescues the otherwise lethal phenotype associated with the targeted hypomorphic allele (Brca1DeltaexllSA). Brca1-/-; TgN x BRCA1GEN bigenic animals develop normally and can be maintained as a distinct line. These results show that a 140 kb fragment of chromosome 17 contains all elements necessary for the correct expression, localization, and function of the BRCA1 protein. Further, the model provides evidence that function and regulation of the human BRCA1 gene can be studied and manipulated in a genetically tractable mammalian system. Oncogene (2000) 19, 4085 - 4090

Animals↗
PubMed2000

Effects of arctiin on PhIP-induced mammary, colon and pancreatic carcinogenesis in female Sprague-Dawley rats and MeIQx-induced hepatocarcinogenesis in male F344 rats.

Chemopreventive effects of arctiin, a lignan isolated from Arctium lappa (burdock) seeds, on the initiation or post initiation period of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) induced mammary carcinogenesis in female rats and on 2-amino-3, 8-dimethylimidazo[4,5-f]quinoxaline (MeIQx)-associated hepatocarcinogenesis in male rats were examined. In experiment 1, female Sprague-Dawley (SD) rats were given intragastric doses of 100 mg/kg body wt of PhIP once a week for 8 weeks as initiation. Groups of 20 rats each were treated with 0.2 or 0.02% arctiin during or after PhIP initiation. Control rats were fed 0.2 or 0.02% arctiin, or basal diet alone during the experimental period. Animals were killed at the end of week 48. Although the incidence of mammary carcinomas did not significantly differ among the PhIP-treated groups, multiplicity was significantly decreased in rats given 0.2 (0.7+/-0.7, P<0.05) or 0.02% (1.0+/-1.1, P<0.05) arctiin after PhIP initiation as compared with the PhIP alone controls (2.1+/-2.5). The average number of colon aberrant crypt foci was also significantly decreased in these two groups. Pancreas acidophilic foci were induced in PhIP treated animals with slight decrease in the multiplicity with arctiin during the initiation phase. For liver carcinogenesis, groups of 15 male F344 rats were given a single intraperitoneal injection of diethylnitrosamine (DEN) and starting 2 weeks later, they were administered 0.03% MeIQx in the diet, MeIQx together with 0.5% arctiin, 0.1% arctiin or basal diet for 6 weeks. They were subjected to two-third partial hepatectomy 3 weeks after DEN initiation and killed at the end of week 8 for glutathione S-transferase placental form (GST-P) immunohistochemistry. The numbers and areas of preneoplastic GST-P positive foci were elevated by the treatment with MeIQx, and further increased by the simultaneous treatment with arctiin. These results indicate that arctiin has a protective effect on PhIP-induced carcinogenesis particularly in the mammary gland in the promotion period. On the other hand, it may have a weak co-carcinogenic influence on MeIQx-induced hepatocarcinogenesis. In addition, the results suggested that PhIP is a weak pancreatic carcinogen in female SD rats, targeting acinar cells.

Animals↗
PubMed2000

Capillary gel electrophoresis: separation of major erythrocyte membrane proteins.

A new separation method of human erythrocyte membrane proteins by sodium dodecyl sulfate capillary gel electrophoresis (SDS-CGE) is described. In this method, a replaceable gel matrix was used. Seven major erythrocyte membrane proteins, alpha-and beta-spectrin, ankyrin 2.1, band 3 (anion-exchanger), 4.1a and b, and 4.2 (pallidin), were separated and identified by SDS-CGE method. High reproducible migration times of these proteins (inter-assay coefficients of variation less than 2%), as well as quantification (inter-assay coefficients of variation less than 11%) were obtained. This new SDS-CGE method may provide important diagnostic evidence for hereditary spherocytosis. It can be a powerful diagnostic tool in place of SDS polyacrylamide gel electrophoresis for erythrocyte membrane protein analysis.

Electrophoresis, Capillary↗
PubMed2000

The interaction of calmodulin with alternatively spliced isoforms of the type-I inositol trisphosphate receptor.

A 592-amino acid segment of the regulatory domain of the neuronal type-I inositol 1,4,5-trisphosphate receptor (IP(3)R) isoform (type-I long, amino acids1314-1905) and the corresponding 552-amino acid alternatively spliced form present in peripheral tissues (type-I short, amino acids 1693-1733 deleted) were expressed as glutathione S-transferase fusion proteins. These domains encompass a putative calmodulin (CaM) binding domain and two protein kinase A phosphorylation sites. Both long and short fusion proteins retained the ability to bind CaM in a Ca(2+)-dependent manner as measured by CaM-Sepharose chromatography or a dansyl-CaM fluorescence assay. Both assays indicated that the short fusion protein bound twice the amount of CaM than the long form at saturating concentrations of CaM. In addition, the binding of the short form to CaM-Sepharose was inhibited by phosphorylation with protein kinase A, whereas the binding of the long form was unaffected. Full-length cDNAs encoding type-I long, type-I short, and type-III IP(3)R isoforms were expressed in COS cells, and the Ca(2+) sensitivity of [(3)H]IP(3) binding to permeabilized cells was measured. The type-I long isoform was more sensitive to Ca(2+) inhibition (IC(50) = 0.55 microM) than the type-I short (IC(50) = 5.7 microM) or the type-III isoform (IC(50) = 3 microM). In agreement with studies on the fusion proteins, the full-length type-I short bound more CaM-Sepharose, and this binding was inhibited to a greater extent by protein kinase A phosphorylation than the type-I long IP(3)R. Although type-III IP(3)Rs did not bind directly to CaM-Sepharose, hetero-oligomers of type-I/III IP(3)Rs retained the ability to interact with CaM. We conclude that the deletion of the SII splice site in the type-I IP(3)R results in the differential regulation of the alternatively spliced isoforms by Ca(2+), CaM, and protein kinase A.

Alternative Splicing↗
PubMed2000

Structure and function of hepatitis C virus NS3 helicase.

Hepatitis C Virus helicase activity has been mapped to the COOH-terminal 450 residues of the NS3 protein. Due to its complexity and presumed essentiality for viral replication, the helicase is an attractive target for drug discovery. The elucidation of the atomic structure of the HCV NS3 helicase in complex with oligonucleotide and with ADP has helped clarify our understanding of potential sites for inhibitor binding. Molecular details of the mechanism of this enzyme, and in particular, a better understanding of the mechanism by which ATP hydrolysis is coupled to unwinding of double-stranded substrate may facilitate more efficient structure-based drug design.

Amino Acid Sequence↗