Biomedical subjects

Y C Lin

Publications and source records attributed to Y C Lin.

At least 91 records · Page 5Linked to original sources

PubMed2000

Lack of mutations of BCL6 and BCL10 genes in mucosa-associated lymphoid tissue lymphomas of the orbital adnexa.

Knowledge regarding the molecular pathogenesis and progression of mucosa-associated lymphoid tissue (MALT) lymphomas of ocular adnexa is limited. Eleven cases of ocular MALT lymphoma were analyzed by clonal rearrangement of antigen receptor genes using Southern blot hybridization. Polymerase chain reaction-single stranded conformational polymorphism analysis and DNA sequencing was utilized to analyze the mutations of BCL6 and BCL10 genes. Clonal rearrangement of immunoglobulin heavy genes was found in all 11 patients. No point mutation was found in BCL6 or BCL10 genes in any of the samples analyzed. We suggest that mutations of BCL6 and BCL10 genes are rare in low-grade MALT lymphoma of ocular adnexa and are unlikely to be involved in the pathogenesis of the disease. But the role of alterations of both BCL6 and BCL10 genes in the disease progression of low-grade MALT lymphoma require additional study.

Adaptor Proteins, Signal Transducing↗

PubMed2000

An early vision-based snake model for ultrasound image segmentation.

Due to the speckles and the ill-defined edges of the object of interest, the classic image-segmentation techniques are usually ineffective in segmenting ultrasound (US) images. In this paper, we present a new algorithm for segmenting general US images that is composed of two major techniques; namely, the early-vision model and the discrete-snake model. By simulating human early vision, the early-vision model can capture both grey-scale and textural edges while the speckle noise is suppressed. By performing deformation only on the peaks of the distance map, the discrete-snake model promises better noise immunity and more accurate convergence. Moreover, the constraint for most conventional snake models that the initial contour needs to be located very close to the actual boundary has been relaxed substantially. The performance of the proposed snake model has been shown to be comparable to manual delineation and superior to that of the gradient vector flow (GVF) snake model.

Algorithms↗

PubMed2000

Anxiolytic effect of seed of Ziziphus jujuba in mouse models of anxiety.

The aim of the present study was to investigate the ethanolic extract of Semen Ziziphi jujuba (SZJE) induced anxiolytic effect. The SZJE was orally administered to male ICR mice, at 0.5, 1.0 and 2. 0 g/kg, 30 min before the behavioral evaluation in the black and white test (BWT) and elevated plus maze (EPM). The SZJE at the dosage 0.5-2.0 g/kg increased the first time entry, total changes and times spent in the white chamber of the BWT. The SZJE at the dosage 0.5-1.0 g/kg increased the percentage of time-spent and the percentage of arm entries in the open arms of the EPM and decreased the percentage of time-spent and the percentage of arm entries in the closed arms of the EPM. Furthermore, the SZJE at the dosage of 1. 0 g/kg prolonged the hexobarbital-induced sleeping time in mice and decreased the locomotor activity in rats. These results suggested that SZJE possessed anxiolytic effect at lower dose and sedative effect at higher dose.

Animals↗

PubMed2000

Clusterin may be involved in rat liver allograft tolerance.

Little is known about the possible role of complement inhibitors on tolerance induced by liver allografts. Clusterin, which is a plasma glycoprotein, inhibits cytolytic membrane attack complex (MAC) of complement by binding to soluble C5b-7 complex. The role of clusterin in relation to the naturally achieved tolerance in a rat orthotopic liver transplantation (OLT) has not been investigated before. Here we determined the kinetics of clusterin expression at different post-transplantation time points in a tolerogenic model (DA-PVG) where rejection was naturally overcome without any immunosuppressive drugs in comparison with the syngenic OLT model (DA-DA). Peripheral blood and liver tissues were taken from OLT at various post-operative time points. A strong expression of soluble clusterin was observed on post-transplantation day 7, which occurred at the peak of the rejection in this tolerogenic OLT model. The expression of clusterin remained strong even after tolerance was achieved. The intensity of clusterin expression was much stronger when compared with the syngenic OLT (DA-DA) model after OLT. A strong expression of clusterin mRNA was also observed in the tolerogenic model on post-OLT day (POD) 7 and the expression persisted when compared with the syngenic model on post-OLT day 60. Our data have shown that the strongest levels of clusterin during the reaction phase in tolerogenic OLT may be involved in tolerance induction.

Animals↗

PubMed2000

Identification of the indoleamine 2,3-dioxygenase nucleotide sequence in a rat liver transplant model.

A tryptophan catabolizer, indoleamine 2,3-dioxygenase (IDO) is highly expressed in the placenta and plays an essential role in maternal tolerance. Recent data have shown that the administration of an IDO inhibitor blocked not only maternal tolerance but also liver allograft tolerance. However, little is known about the induction of IDO in liver allografts, although a gene specific for tryptophan 2,3-dioxygenase (TDO) is believed to be expressed in the liver. In the present study, we investigated whether IDO is induced in liver allografts. Synthetic oligonucleotide primers based on the mouse IDO cDNA sequence were used to amplify RNA derived from livers of donor, syngeneic or allogeneic OLT rats. RNA encoding IDO was induced in the rat allogeneic liver after orthotopic liver transplantation (OLT), but not in syngeneic OLT. The rat nucleotide sequence of the RT-PCR products obtained from OLT livers revealed identities of 89% homology to the mouse IDO and of 68% to the human IDO. This study demonstrated the presence of RNA encoding IDO in allogeneic OLT livers, which may be involved in the immune response after liver transplantation.

Amino Acid Sequence↗

PubMed2000

Telomerase activity in peripheral blood for diagnosis of hepatoma.

BACKGROUND: Telomerase activity may be used as a molecular marker for the detection of circulating hepatoma cells in blood of patients with hepatoma. METHODS: Telomerase activity in peripheral blood from hepatocellular carcinoma (HCC) patients was assessed by using a highly sensitive and non-radioisotope telomerase polymerase chain reaction (PCR) ELISA. Initially, tissue telomerase activity was measured in the hepatoma and non-tumour portions by using PCR ELISA within the same specimen, to compare its sensitivity with the conventional telomeric repeat amplification protocol (TRAP) method. Second, telomerase activity was measured in the peripheral blood obtained from patients with HCC, patients with chronic liver disease and in healthy controls. RESULTS: Of the 17 HCC patients, telomerase activity was found to be positive in 14 (82%) by using TRAP and 15 (88%) by using PCR ELISA, indicating that PCR ELISA is a reliable tool for the measurement of telomerase activity. By using the Telomerase PCR ELISA assay, telomerase activities in the peripheral blood of 20 HCC patients was 1.65 +/- 0.78 units. This was significantly greater than the results obtained for 20 chronic liver disease patients (0.43 +/- 0.36 units) and 20 healthy controls (0.39 +/- 0.14 units; P < 0.0001).When the arbitrary cut-off level was set at 0.7 units (maximum value of healthy controls + 0.1), the positive frequency of telomerase activity was 25% for chronic liver disease and 80% for HCC patients (sensitivity 80%, specificity 75%). Among the HCC patients, high telomerase activity in the peripheral blood was shown at stage III HCC with vascular invasion (2.10 +/- 0.62 units, n = 9). This was significantly higher than patients at stage II of HCC (1.28 +/- 0.72 units, n = 11, without vascular invasion; P = 0.012). CONCLUSION: These results suggest that peripheral blood telomerase activity, which may reflect haematogenous micrometastasis, is potentially a practical diagnostic/predictive marker of HCC.

Biomarkers, Tumor↗

PubMed2000

Production of activated carbons from pyrolysis of waste tires impregnated with potassium hydroxide.

Activated carbons were produced from waste tires using a chemical activation method. The carbon production process consisted of potassium hydroxide (KOH) impregnation followed by pyrolysis in N2 at 600-900 degrees C for 0-2 hr. The activation method can produce carbons with a surface area (SA) and total pore volume as high as 470 m2/g and 0.57 cm3/g, respectively. The influence of different parameters during chemical activation, such as pyrolysis temperature, holding time, and KOH/tire ratio, on the carbon yield and the surface characteristics was explored, and the optimum preparation conditions were recommended. The pore volume of the resulting carbons generally increases with the extent of carbon gasified by KOH and its derivatives, whereas the SA increases with degree of gasification to reach a maximum value, and then decreases upon further gasification.

Air Pollutants, Occupational↗

PubMed2000

Antisense IL-10 abrogates the inhibitory effects of IL-10 production by transfected tumor cells.

Interleukin-10 (IL-10) is a pleiotropic cytokine that has a variety of downregulatory effects on immunologic and inflammatory processes. Ectopic tumor expression of IL-10 inhibited tumor growth, and local administration of antisense IL-10 significantly reversed the effects of IL-10 transfection in P815 mastocytoma. Tissue inhibitors of metalloproteinase (TIMPs) have been associated with decreased tumorigenesis and reduced metastasis, and TIMPs were increased in the region surrounding P815/IL-10 tumors and reduced in antisense IL-10-treated mice. In addition, the antisense IL-10 group had the largest tumor volume and poorest survival when compared with the P815/IL-10 control or sense groups. In summary, our data suggest that, in a mouse model, antisense IL-10 has substantive effects in reducing IL-10 translation and inhibiting IL-10-mediated TIMP upregulation, and, by doing so, allows IL-10-transfected mastocytoma to grow unchecked. Thus, ectopic tumor expression of IL-10 inhibits tumor growth, and antisense IL-10 administration in vivo reverses this protective effect.

Animals↗

PubMed2000

GP-83 and GP-39, two glycoproteins secreted by human epididymis are conjugated to spermatozoa during maturation.

Surface glycoconjugates of spermatozoa are modified during epididymal maturation, which is closely related to the development of sperm function. In addition, recognition of surface glycoconjugates is one of very critical events in sperm-oocyte interaction. The binding of carbohydrate-specific lectins to the human sperm surface during epididymal maturation has been investigated. However, the glycoproteins responsible for lectin binding in sperm maturation are not well documented. This study used wheat germ agglutinin (WGA), peanut agglutinin (PNA) and concanavalin A (Con-A) to identify sperm maturation-related glycoproteins in human epididymis. Histochemical localization revealed that the binding sites of WGA, PNA and Con-A were mainly in the principal cells and luminal contents of the human epididymis, but not in the interstitial regions. Each lectin displayed a fairly distinct regional localization. On Western blots probed with WGA and Con-A, glycoproteins of 83 kDa (GP-83) and 39 kDa (GP-39) were identified in the sperm extracts, epididymal fluid and tissue extracts of the corpus and cauda epididymides, but not in the caput. PNA identified GP-83 in the same manner as WGA and Con-A, but did not recognize GP-39. These results suggest that lectin-binding glycoproteins GP-83 and GP-39 found on mature spermatozoa may be secreted by the principal cells of corpus and cauda epididymis, and conjugated to spermatozoa during their transit in human epididymis.

Binding Sites↗

PubMed2000

Purification of GP-83, a glycoprotein secreted by the human epididymis and conjugated to mature spermatozoa.

Epididymal secretions are critical for mammalian spermatozoa to acquire both forward motility and an ability to recognize and penetrate oocytes. Previous studies identified two glycoproteins, GP-83 and GP-39, which were secreted by the human epididymis and may be related to maturation of sperm function. In this study, GP-83 was purified from human seminal fluid by DEAE-ion exchange, gel filtration chromatography and preparative gel elution. The isoelectric point (pI) of purified GP-83 was 6.57. Monospecific antiserum to GP-83 was induced in male New Zealand rabbits and confirmed on immunoblots. GP-83 was found in fluid, tissue and sperm extracts of corpus and cauda epididymis, but not in the caput. Immunohistochemical localization identified GP-83 in the luminal contents and in the supranuclear region and cell membrane of principal cells of the corpus and cauda epididymis. GP-83 was found on the anterior acrosome in ejaculated spermatozoa, and shifted to the equatorial region after capacitation and the acrosome reaction.

Acrosome Reaction↗

PubMed2000

Rare complication of massive hemorrhage in neurofibromatosis with arteriovenous malformation.

Neurofibromatosis is rare in the general population. Its clinical manifestations are systemic and variable. The clinical presentation of cutaneous lesions is even more variable. Some patients have giant tumors in the trunk or limbs (so-called "elephant neurofibromatosis"). The pathological findings are diffuse neurofibromatosis of the nerve trunk associated with overgrowth of subcutaneous tissue and skin. The associated vascular malformations make most surgeons hesitant to address them because bleeding to death is possible if the bleeding is not well controlled. According to the authors' experience in treating this complication of neurofibromatosis, they noted that there are three key points to reducing the amount of hemorrhage to a minimal level: (1) hypotensive anesthesia, (2) preliminary sutures around the lesion, (3) ligation of the limited numbers of feeding vessels in the vascular malformation of the neurofibroma. Ligating these pedicles can decrease bleeding during resection of the neurofibroma, as demonstrated in their patient.

Arteriovenous Malformations↗

PubMed2000

Single-agent docetaxel in metastatic breast cancer patients pre-treated with anthracyclines and paclitaxel: partial cross-resistance between paclitaxel and docetaxel.

The purpose of this study was a retrospective analysis of docetaxel in a cohort of anthracyclines and paclitaxel pretreated patients with metastatic breast cancer. From July 1998 to June 1999, 24 consecutive patients were included for this study. The regimen consisted of docetaxel 75 mg/m2 in combination with a 3-day schedule of dexamethasone every 3 weeks until disease progression or unacceptable toxicity. The median age of patients was 53 (ranged 32-67) years with a median performance status of 2. Twenty of the 24 patients (84%) had measurable disease. The median number of organs involved was 2 (range 1-4). A total of 146 cycles chemotherapy were given with a mean of 6. There was a 25% (six of 24) overall response rate including one complete response, 37.5% stable disease and 37.5% progressive disease. The major toxicity included grade 3-4 leukopenia (41.7%) and eight episodes of infection. No treatment-related death was observed. The responders included patients refractory to or resistant to prior paclitaxel treatment. The median survival and median time to disease progression was 12 and 9 months, respectively. We conclude that docetaxel has a modest activity in breast cancer patients pre-treated with anthracyclines and paclitaxel, indicating a partial cross-resistance between paclitaxel and docetaxel.

Adult↗

PubMed2000

Shortening of cardiac action potentials in endotoxic shock in guinea pigs is caused by an increase in nitric oxide activity and activation of the adenosine triphosphate-sensitive potassium channel.

OBJECTIVE: To investigate the roles of nitric oxide and adenosine triphosphate (ATP)-sensitive potassium channels (KATP) in the shortening of cardiac action potential in endotoxic shock. DESIGN: Prospective animal study with concurrent controls. SETTING: University animal research laboratory. SUBJECTS: Adult Hartley guinea pigs, weighing 300-400 g. INTERVENTIONS: Guinea pigs were anesthetized and mechanically ventilated for 6 hrs. Lipopolysaccharide (LPS) or saline (sham group) were given intravenously. Drug effects were examined at the end of 6 hrs. MEASUREMENTS AND MAIN RESULTS: Plasma nitrate concentration was measured hourly, while guanosine 3',5'-cyclic monophosphate (cGMP) content and action potential duration at 90% of repolarization (APD90) of papillary muscle were examined every 2 hrs in the 6-hr endotoxemia in both the sham and the LPS-treated groups. The basal levels of these three variables showed no difference in the two groups. In the sham group, these variables did not change significantly (n = 14 for plasma nitrate determination; n = 5 for cGMP content measurement; n = 5-14 for APD90 measurement; all p > .05). But in the LPS-treated group, both plasma nitrate concentration and cGMP content of papillary muscle showed time-dependent increases and they were significantly higher than those in the sham group (at the 6th hr, plasma nitrate: 42.6 +/- 7.7 vs. 21.8 +/- 3.1 micromol/L, both n = 14, p < .01; cGMP: 1.52 +/- 0.15 vs. 0.73 +/- 0.08 pmol/mg protein, both n = 5, p < .01). In contrast, APD90 revealed a time-dependent decrease compared with that in the sham group (at the 6th hr, 137.1 +/- 52 vs. 188.2 +/- 4.8 msecs, both n = 14, p < .001). In the following 60-min in vitro recording of action potentials after the end of 6-hr endotoxemia, the shortened APD90 in the LPS-treated group did not recover and remained shorter compared with that in the sham group, in which the APD90 showed no significant changes (at the 60th min, 165.1 +/- 5.7 vs. 200.2 +/- 3.8 msecs, each n = 14, p < .01). However, in the presence of glibenclamide, a specific KATP blocker (100 micromol/L; n = 10), the APD90 could be reversed almost completely to the same value as that in the sham group (n = 14) (196.6 +/- 3.5 vs. 200.2 +/- 3.8 msecs; p > .05), despite glibenclamide having no effect on the APD90 in the sham group. In the LPS-treated group, NG-nitro-L-arginine methyl ester (1 mmol/L; n = 4), methylene blue (10 micromol/L; n = 5), and aminoguanidine (100 micromol/L; n = 4) significantly prolonged the shortened APD90 (192.5 +/- 3.1, 195.0 +/- 3.3, and 176.5 +/- 3.3 msecs, respectively; p < .01, p < .01, and p < .05, respectively, compared with that without these agents, 165.1 +/- 5.7 msecs, n = 14). These agents had negligible effects on the APD90 in the sham group (all p > .05). Furthermore, 8-bromoguanosine-3',5'-cyclic monophosphate (500 micromol/L; n = 5) decreased APD in intact papillary muscle (mean reduction of APD90, 13.5 +/- 3.5%, n = 5; p < .05), an effect abolished by pretreatment with glibenclamide (100 micromol/L; n = 5) that did not have an effect by itself. CONCLUSIONS: In this experimental model, we provide reasonably convincing evidence to suggest that in endotoxic shock, an increase in nitric oxide activity may activate KATP, which plays a major role in the shortening of APD, presumably through a cGMP-dependent pathway.

Action Potentials↗

PubMed2000

Electrophysiologic characteristics and ablation of an atypical atrial flutter in the right atrium.

Subeustachian isthmus-dependent typical atrial flutter has been well studied. We demonstrate a case with atypical atrial flutter involving only the base of the right atrium around the inferior vena cava. Entrainment pacing and mapping studies documented a distinct circuit traversing the subeustachian isthmus, propagating through the posterobasal right atrium, and skirting the inferior vena cava. Successful radiofrequency ablation of the arrhythmia was accomplished by creating a linear lesion at the subeustachian isthmus. Mapping of the inferior vena cava region and the demonstration of concealed entrainment are essential steps in establishing the mechanism of the atypical atrial flutter.

Atrial Flutter↗

PubMed2000

Analysis of 16S rRNA and 51-kilodalton antigen gene and transmission in mice of Ehrlichia risticii in virgulate trematodes from Elimia livescens snails in Ohio.

Operculate snails (the family Pleuroceridae: Elimia livescens) were collected between June and October 1998 from a river in central Ohio where repeated cases of Potomac horse fever (PHF) have occurred. Of collected snails, consistently 50 to 80% carried a combination of cercariae and sporocysts of digenetic virgulate trematodes. The trematodes obtained from each snail were pooled and tested for Ehrlichia risticii, the agent of PHF, by nested PCR using primers specific to the 16S rRNA gene. Out of a total of 209 trematode pools, 50 pools were found to be positive by PCR. The DNA sequence of the 16S rRNA gene identified in one trematode pool was identical to that of the type strain of E. risticii, and the sequence of the gene identified in another pool differed from that of the type strain by 1 nucleotide. Comparison of the deduced amino acid sequence of the partial 51-kDa antigen gene from various sources revealed that Maryland, Ohio (except Ohio 081), and Kentucky strains are in a cluster distinct from the sequences obtained from sources in California and Oregon. Ohio 081 was shown previously by antigenic composition analysis to be distinct from other groups. However, all sequences examined were not segregated according to their sources: horse blood or infected trematodes. E. risticii was found to be transmittable from trematodes to mice and was subsequently passaged from infected mice to additional mice, as determined by PCR analysis. Our findings suggest the evolution of E. risticii in the natural reservoir in separate geographic regions and persistent infection of trematode populations with E. risticii during summer and early fall. The study also suggests that the mouse can be used to isolate E. risticii from the infected trematode.

Amino Acid Sequence↗

PubMed2000

Alteration of substrate and inhibitor specificity of feline immunodeficiency virus protease.

Feline immunodeficiency virus (FIV) protease is structurally very similar to human immunodeficiency virus (HIV) protease but exhibits distinct substrate and inhibitor specificities. We performed mutagenesis of subsite residues of FIV protease in order to define interactions that dictate this specificity. The I37V, N55M, M56I, V59I, and Q99V mutants yielded full activity. The I37V, N55M, V59I, and Q99V mutants showed a significant increase in activity against the HIV-1 reverse transcriptase/integrase and P2/nucleocapsid junction peptides compared with wild-type (wt) FIV protease. The I37V, V59I, and Q99V mutants also showed an increase in activity against two rapidly cleaved peptides selected by cleavage of a phage display library with HIV-1 protease. Mutations at Q54K, I98P, and L101I dramatically reduced activity. Mutants containing a I35D or I57G substitution showed no activity against either FIV or HIV substrates. FIV proteases all failed to cut HIV-1 matrix/capsid, P1/P6, P6/protease, and protease/reverse transcriptase junctions, indicating that none of the substitutions were sufficient to change the specificity completely. The I37V, N55M, M56I, V59I, and Q99V mutants, compared with wt FIV protease, all showed inhibitor specificity more similar to that of HIV-1 protease. The data also suggest that FIV protease prefers a hydrophobic P2/P2' residue like Val over Asn or Glu, which are utilized by HIV-1 protease, and that S2/S2' might play a critical role in distinguishing FIV and HIV-1 protease by specificity. The findings extend our observations regarding the interactions involved in substrate binding and aid in the development of broad-based inhibitors.

Amino Acid Sequence↗

PubMed2000

Molecular cloning and sequence analysis of canine acidic ribosomal phosphoprotein P0 cDNA.

Acidic ribosomal phosphoprotein P0 has been widely used as an estradiol-independent housekeeping gene. Expression of acidic ribosomal phosphoprotein P0 in canine prostate was detected and canine specific cDNA was cloned. Total cellular RNA was isolated from normal young (5 month-old) canine prostate tissue. Total cDNAs were synthesized from total cellular RNAs by reverse transcription assay. Primers used in polymerase chain reaction were designed from published human ARP0 cDNA sequences and utilized to amplify 562 base-pair (bp) canine acidic ribosomal phosphoprotein P0 cDNA. Nucleotide sequences of canine ARP0 cDNA clones were determined on both strands. Canine ARP0 cDNA and their deduced amino acid sequences share very high homology to ARP0 orthologs from other vertebrate species including human, mouse, rat, chicken, and bovine.

Amino Acid Sequence↗

PubMed2000

Influence of polyvinylpyrrolidone on the outcome of intracytoplasmic sperm injection.

OBJECTIVE: To assess the effectiveness of a procedure for intracytoplasmic sperm injection (ICSI) modified so as not to use polyvinylpyrrolidone (PVP) and to examine clinical outcome. STUDY DESIGN: Seventy-seven cycles of ICSI were performed over a one-year period. PVP was used for sperm immobilization in 39 of these cycles and was eliminated from the other 38 cycles. Difference in fertilization rate, cleavage rate, parthenogenetic activity, clinical pregnancy rate, ongoing pregnancy rate and grading of preembryos between the two groups was compared. RESULTS: The non-PVP group had a higher fertilization rate (57.63% vs. 84.43%, P < .001) and better preembryo quality (chi 2 = 6.80, P = .009) than the PVP group. There was no significant difference in cleavage rate, parthenogenetic activity, clinical pregnancy rate and ongoing pregnancy rate between the two groups. CONCLUSION: Performing ICSI without PVP may improve the fertilization rate and preembryo grading. However, further study with a larger cohort is necessary to determine whether the modified procedure can increase the pregnancy rate.

Adult↗