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Biomedical subjects

L Lin

Publications and source records attributed to L Lin.

At least 145 records · Page 8Linked to original sources
PubMed1997

DQ microsatellite association studies in three ethnic groups.

Polymorphism at the level of three microsatellite markers (DQCAR, DQCARII, G51152) located in the HLA-DQ region was characterized in 78 10th International Histocompatibility Workshop B-cell lines, 718 random Japanese Asians, 99 Norwegian Caucasians and 95 New Guinean Aborigines with established HLA-DRB1, -DQA1 and -DQB1 typing. DQCAR, DQCARII, and G51152 result in 13, 13, and 11 alleles respectively. All three markers were in tight linkage disequilibrium with HLA-DRB1, -DQA1 and -DQB1. DRB1, DQA1, DQCARII, DQCAR, DQB1, and G51152 haplotypes could be defined for all subjects. In fact, DQ microsatellite typing data could predict DQA1 and DQB1 genotypes with high accuracy and may be used as a simple first pass HLA-DQ typing method. The haplotype data was also used to determine recombination in the DRB1-DQA1 (about 80 kb), DQA1-DQCARII (about 4.5 kb), DQCARII-DQCAR (about 7.5 kb), DQCAR-DQB1 (about 1-1.5 kb) and DQB1-G51152 (about 20-25 kb) genomic segments and the relative rate of slippage microsatellite mutations for DQCAR, DQCARII, and G51152. This led us to conclude that recombination is more frequent in the DRB1-DQA1 and DQCAR-DQCARII segments, thus suggesting cross-overs within small genomic segments are not proportional to genetic distance. We also observed that DQCAR had a higher mutation rate than DQCARII or G51152 and that 1 or 2 CA slippage mutations were arising more frequently from large size microsatellite alleles.

DNA, Satellite↗
PubMed1997

The validity of screening for post-traumatic stress disorder and major depression among Vietnamese former political prisoners.

The aim of this study was to investigate the validity of the Harvard Trauma Questionnaire (HTQ) and the depression sub-scale of the Hopkins Symptom Checklist-25 (HSCL-25) in screening for post-traumatic stress disorder (PTSD) and major depressive disorder (MDD) among Vietnamese former political prisoners (POWs). The study population included Vietnamese POWs (n = 51) who migrated to the Boston metropolitan area between January 1990 and July 1992 under the Special Released Re-education Center Detainees Resettlement Program. The criterion validity of the HTQ in assessing PTSD and of the depression sub-scale of the HSCL-25 in assessing MDD is supported by the results. Consideration of an appropriate cut-off score should include examination of the utility of a given screening instrument for PTSD or MDD within different settings, such as refugee camps vs. countries of third asylum.

Adult↗
PubMed1997

Mechanism of the acceleration of CO2 production from pyruvate in liver mitochondria by HCO3-.

To investigate the mechanism by which HCO3- accelerates pyruvate metabolism in guinea pig liver mitochondria, we measured continuously, at pH 7.4 and 37 degrees C, 13C16O2 production from [1-13C]pyruvate by mass spectrometry and NADH concentration by fluorescence and analyzed total malate, citrate, and beta-hydroxybutyrate produced by standard biochemical methods. When [1-13C]pyruvate is added to the mitochondrial suspension, 13C16O2 concentration rises steeply in the first seconds and then slows to a steady lower rate. Carbonic anhydrase (CA) eliminates this initial phase, which shows that decarboxylation of pyruvate produces CO2, not HCO3-, and it does this more rapidly than it can equilibrate without CA. HCO3- (25 mM) increased 13C16O2 production, O2 consumption and total malate and citrate production and decreased NADH concentration and total beta-hydroxybutyrate production. After obtaining the total amount of 13C16O2, malate, citrate, and beta-hydroxybutyrate produced, we calculated that the addition of 25 mM HCO3- to the suspension medium increased the amount of pyruvate decarboxylated by pyruvate dehydrogenase (PDH) 16% and increased the amount carboxylated by pyruvate carboxylase 300%. This supports our initial proposal that HCO3- accelerates the pyruvate carboxylation, which in turn consumes ATP directly and NADH and acetyl CoA secondarily, all of which increase PDH activity. However, we found no acceleration of pyruvate decarboxylation by 0.5 and 1 microM free Ca2+ concentration, unless the mitochondria were uncoupled and ATP was added.

3-Hydroxybutyric Acid↗
PubMed1997

[Antagonistic effect of calcitonin gene related peptide on arrhythmia in rats].

Premature ventricular contraction (PVC), ventricular tachycardia (VT) and ventricular fibrillation (VF) were developed by endothelin-1 (ET-1) injected into the coronary ostia at the dose of 900 pmol/kg in anesthetized rats. No arrhythmia was elicited but blood pressure fell temporarily by calcitonin gene related peptide (CGRP), the injection into the coronary ostia. After pretreatment with CGRP incidence and severity of arrhythmia decreased at the same ET-1 dose. Arrhythmia score in CGRP 1200 pmol/kg + ET-1 group was lower than that in ET-1 group (P < 0.01). The results revealed that antiarrhythmic effect of CGRP may be partially brought about by its antagonistic effect against ET-1 induced arrhythmia.

Animals↗
PubMed1997

[Effect of dietary fiber on antioxidation in rats].

The antioxidative effect of cellulose, wheat bran and pectin was studied in rats. Wistar rats (40) were randomly divided into 4 groups, 3 groups were fed with the fibers at a level of 10% in weight, the 4th group consumed stock food as control. After 3 months' feeding, MDA in serum and in RBC membrane of the 3 treated groups were significantly lower than that of the control group. The RBC membrane fluidity was significantly increased. It is suggested that these three kinds of dietary fibers can reduce the level of lipid peroxidation and inhabit free radical injury to RBC membrane in rats.

Animals↗
PubMed1997

[Advance in medical robot].

In this paper, we describe the basic divisions of medical robot, and at the same time their applications filed and developing trend are also been given. Finally some views of the development of medical robot in China are presented.

Microsurgery↗
PubMed1997

[Effects of HE particles on medicinal plant Agastache rugosus (Fisch. et Mey.) O. Ktze].

The biological effect of HE particles on the seeds of Agastache rugosus was probed in experiments on board a retrievable satellite. The result shows that the germination rate of the seeds pierced by HE particles radiation appears rather low. The seeds hit by HE particles (piercing radiation or not) start to germinate two days earlier than those in the control group, and the first leaf emerges four to five days earlier than that in the control group. The resultant seedlings grow markedly faster. Variations take place in the nuclear types of chromosome. The yield of essential oils becomes slightly higher. No marked changes have been observed in the major chemical components of these oils.

Chromosomes↗
PubMed1997

[Glutamate causes release of nitric oxide from chicken spinal cord in vitro].

Nitric oxide (NO) has been identified to have profound effects on many systems, especially the neural tissues. Many studies suggest that NO mediate the neurotoxicity of glutamate (Glu). In order to determine in vitro whether Glu causes release of NO from chicken spinal cord, different concentrations of Glu (0.1, 0.5, 1.0 mmol.L-1) were added to the primary cultured chicken spinal cord cells, and the quantity of NO- (the metabolism product of NO) in medium was detected. The result shows that Glu can enhance obviously the concentration of NO in primary cell cultures (212% compared with the control). If the spinal cord cells were pretreated with NO synthases (NOS) inhibitor--L-NOARG, the [NO-] was decreased compared with those treated with Glu only, and, on the contrary, the viability of cells was increased. All of the results above indicate that NO may play an important role in the neurotoxicity of Glu on nervous cells. It might be that Glu can instigate the activity of NO synthases, then induce a series of changes within cell and finally lead to the toxic effect on cells.

Animals↗
PubMed1997

Dynamic and conventional spin-echo MR of pituitary microlesions.

PURPOSE: To determine whether dynamic traditional spin-echo MR imaging, with the use of routine T1 parameters during contrast infusion, is superior to standard MR imaging after contrast administration for detecting microlesions of the pituitary gland. METHODS: Sixty-four patients with pituitary microlesions 3 to 10 mm in diameter were examined with a dynamic traditional spin-echo technique; that is, a typical T1 spin-echo sequence of 500-600/20-25/2 (repetition time/echo time/excitations), 3-mm-thick sections, 16-cm field of view, 256 x 128 matrix, and a scan time ranging from 2 minutes to 2 minutes 40 seconds during contrast infusion. In addition, standard imaging with unenhanced and contrast-enhanced spin-echo sequences were obtained. The three sequences were evaluated retrospectively and graded for gland-lesion contrast conspicuity, lesion homogeneity, and delineation of lesion margin. RESULTS: The dynamic sequence was judged to be better than the standard enhanced sequence for depicting microlesions in 42% to 47% of patients. Lesions were identified only on the dynamic study in an additional 1% to 14% of patients. Lesions were seen equally well on the standard and dynamic sequences only in 16% to 23% of cases. The standard postcontrast sequence was judged better in 12.5% to 17% of cases, with lesions identified only on the standard sequence in an additional 8% to 9%. CONCLUSION: Dynamic traditional spin-echo MR imaging improved lesion detection and provided increased clarity over standard sequences after contrast infusion. Both sequences are important, since lesions were detected only on the dynamic sequence in 11% to 14% of patients and only on the standard sequence in 8% to 9% of patients.

Adenoma↗
PubMed1997

Hepatitis G viral RNA in serum and in peripheral blood mononuclear cells and its relation to HCV-RNA in patients with clotting disorders.

The hepatitis G virus (HGV) has recently been identified as a new member of the Flaviviridae family. Infection by this virus is thought to be associated with blood borne hepatitis. In this study, the presence of HCV- and HGV-RNAs in serum or plasma (175 patients) and in peripheral blood mononuclear cells (PBMC) (133 patients) was investigated in patients with clotting disorders using a sensitive reverse transcriptase polymerase chain reaction (RT-PCR). HGV-RNA was detected in serum of 26 patients (14.8%). In apparently healthy blood donors, serum HGV-RNA was detected in 4 of 358 individuals investigated (1.12%). Ninety two percent of the 26 serum HGV-RNA positive patients had coinfection with the hepatitis C virus (HCV), especially with HCV genotype 1b, the most common genotype in Belgium. Of these coinfected patients, 15 (62.5%) showed elevated serum ALT levels. Two patients who were solely infected with HGV had normal serum ALT.HGV-RNA in PBMC was found in 18 patients, of whom 3 were negative for serum HGV-RNA. As in case of HCV, HGV-RNA in PBMC is preferentially sensitive to interferon treatment. Nevertheless, rapid reappearance of HGV-RNA in PBMC was observed after cessation of treatment. In one patient, persistent serum ALT elevation seems to be associated with continued HGV viremia, despite the disappearance of serum HCV-RNA.

Adolescent↗
PubMed1997

Muscle characteristics in effort angina before and after CABG.

Seven males with effort angina undertook graded ergometer tests and had muscle biopsies taken from their vastus lateralis muscle before, and three and six months after coronary bypass surgery. Muscle fibre composition (percentage of slow twitch fibres), ubiquinone (vitamin Q), and oxidative and fermentative enzyme activities were determined. After six months, muscle ubiquinone and oxidative enzymes were still depressed, indicating sustained muscle trauma. The only peripheral changes were that muscle lactate dehydrogenase and its skeletal muscle-specific subunits and isozymes were increased 35% to 40% (P < 0.001) three to six months postsurgery. Onset of blood lactate accumulation (2.0 mmol/L), symptom-limited ('maximal') exercise and peak blood lactate increased linearly over time (r = 0.52, P < 0.05; r = 0.63, P < 0.01; and r = 0.76, P < 0.001, respectively). It is suggested that the initial physical performance increase was due to improved circulatory capacity, oxygen delivery and lactate efflux, whereas the increased fermentative capacity ('anaerobic power') first contributed after a lag of three or more months. Whether the muscle histochemical changes reflected a healing process (recovery) is speculative.

Angina Pectoris↗
PubMed1997

Global regulatory considerations for unified assay specifications.

When developing a biotechnology product for global registration, there are several aspects to evaluate in an effort to unify specifications. These include differences between the United States, Europe and Japan, and Rest-of-World (ROW) countries with regard to the respective regulatory guidelines and pharmacopoeias in force, the state-of-the-art of product testing analytical methods, and the interval between submitting a registration dossier to different countries. In terms of regulatory guidelines, one country may have a monograph or required specifications for particular tests, for example the potency that a product has to meet before clinical trials can be initiated. For pharmacopoeias, different assay methods are required for sterility, general safety, and pyrogen testing, so that one may have to test a specific lot of a product at two or three different times to evaluate the same parameter, because of specific testing differences required for each country's pharmacopoeia. In addition, the state of analytical methods is always evolving and better analytical techniques become available. Sometimes, from starting with one set of tests, and based on the time in development, new tests may be added to the existing list of release specifications, because new analytical techniques have become available. Examining the global registration approval process for Betaseron, (interferon beta-1b) illustrates when specifications were able to be unified and when they were not.

Animals↗
PubMed1997

Detection of differentially expressed genes in methylnitrosourea-induced rat mammary adenocarcinomas.

In this study, altered gene expression in five methylnitrosourea (MNU)-induced rat mammary adenocarcinomas was investigated using a newly developed competitive cDNA library screening assay. In order to detect the differentially expressed cDNA transcripts, three cDNA libraries (rat mammary, rat liver, and rat kidney) with over 18,000 clones were differentially screened with competing normal and neoplastic mammary cDNA probes. Ninety-eight clones indicated by competitive hybridization to be differentially expressed in tumors were verified by dot-blot hybridization analysis. Of these clones, 45 were found to be overexpressed while 53 were underexpressed in tumors. Forty-five of the confirmed clones were further analyzed by single-pass cDNA sequence determination. Four clones showed homology with cytochrome oxidase subunit I, polyoma virus PTA noncoding region, cytoplasmic beta-actin, and mouse secretory protein containing thrombospondin motifs. Further investigation into the potential roles of these identified genes should contribute significantly to our understanding of the molecular mechanism(s) of rat mammary tumorigenesis.

Adenocarcinoma↗
PubMed1997

[Mean corpuscular volume and red blood cell volume distribution width in the diagnosis of iron deficiency anemia in pregnancy].

OBJECTIVE: To evaluate the value of combined measurement of mean corpuscular volume (MCV) and red blood cell volume distribution width (RDW) in the diagnosis of iron deficiency anemia in pregnancy. METHODS: Hemoglobin concentration (HGB), MCV, RDW, serum iron concentration (Fe), total iron binding capacity (TIBC) and transferrin saturation percentage (TS%) were simultaneously assayed in 605 pregnant women at prenatal examination. The results in different groups were analysed. RESULTS: There were 68 cases in iron deficiency anemia group, 57 cases in non-iron deficiency anemia group and 480 pregnant women in normal group. RDW was significantly increased and MCV greatly decreased in iron deficiency anemia group as compared with that in normal group and non-iron deficiency anemia group. There were no differences in both MCV and RDW between normal group and non-iron deficiency anemia group. CONCLUSIONS: Low MCV and high RDW were the characteristic changes of iron deficiency anemia in pregnancy. We recommend the use of RDW and MCV in the initial classification of anemia in pregnancy.

Adult↗
PubMed1996

Identification of a (CUG)n triplet repeat RNA-binding protein and its expression in myotonic dystrophy.

Myotonic dystrophy (DM) is an autosomal dominant neuromuscular disease that is associated with a (CTG)n repeat expansion in the 3'-untranslated region of the myotonin protein kinase (Mt-PK) gene. This study reports the isolation and characterization of a (CUG)n triplet repeat pre-mRNA/mRNA binding protein that may play an important role in DM pathogenesis. Two HeLa cell proteins, CUG-BP1 and CUG-BP2, have been purified based upon their ability to bind specifically to (CUG)8 oligonucleotides in vitro. While CUG-BP1 is the major (CUG)8-binding activity in normal cells, nuclear CUG-BP2 binding activity increases in DM cells. Both CUG-BP1 and CUG-BP2 have been identified as isoforms of a novel heterogeneous nuclear ribonucleoprotein (hnRNP), hNab50. The CUG-BP/hNab50 protein is localized predominantly in the nucleus and is associated with polyadenylated RNAs in vivo. In vitro RNA-binding/photocrosslinking studies demonstrate that CUG-BP/hNab50 binds to RNAs containing the Mt-PK 3'-UTR. We propose that the (CUG)n repeat region in Mt-PK mRNA is a binding site for CUG-BP/hNab50 in vivo, and triplet repeat expansion leads to sequestration of this hnRNP on mutant Mt-PK transcripts.

Amino Acid Sequence↗