Biomedical subjects

L Liao

Publications and source records attributed to L Liao.

At least 37 records · Page 2Linked to original sources

PubMed2000

[Genetic polymorphism of 10 STR loci on chromosome 9 and its forensic application in Chinese population].

OBJECTIVE: To have a thorough knowledge of the genetic polymorphism of 10 short tandem repeats loci of chromosome 9 in Chinese population and its application in forensic science. METHODS: The 9 STR tetrameric loci and one trimeric tandem repeat locus were chosen from Genome Databank. Eighty-three EDTA-blood samples were collected from the unrelated family in Baiyin city, Gansu province. DNA was extracted by Chelex method and amplified by the polymerase chain reaction(PCR). The PCR products were analyzed by PAGE electrophoresis. RESULTS: The polymorphisms of all 10 STR loci have been obtained in Chinese Han population. The 10 STR loci follow the Mendel ns law. CONCLUSION: The data of all 10 STR loci is beneficial to understanding the population genetics of them in Chinese Han population.

Chromosomes, Human, Pair 9↗

PubMed2000

[Mixing of Cunninghamia lanceolata with Michelia macclurei and restoration of self-sustaining mechanism in G. lanceolata plantation].

The formation of self-sustaining mechanism is one of the major objectives for the sustainable management of plantations. In this study, the incorporation of different proportions of native Michelia macclurei into Cunninghamia lanceolata plantation was practiced to restore the degraded C. lanceolata plantation, and the comparison of nutrient cycling characteristics and soil nutrient concentrations was made among four types of plantation stand with different mixed rate of native M. macclurei representing four different restoration stages of degraded C. lanceolata plantations. With the increase of the proportion of M. macclurei in the plantation, the litterfall and returned nutrients N, P, K, Ca and Mg increased. The nutrient cycling efficiency increased significantly, e.g., that of N and Mg increased from about 0.1 for the degraded pure C. lanceolata plantation to above 0.5 for the pure M. macclurei plantation. Soil organic matter and nutrients also elevated. It is suggested that the self-sustaining mechanism of the C. lanceolata plantation forest gradually reformed as the proportion of native M. macclurei mixed in the plantation increased. The criteria to determine the proportion of native broad-leaved tree species mixed in C. lanceolata plantations for the purpose of sustainable management should be based on whether the self-sustaining mechanism was reformed and whether the soil nutrient status was improved.

Biomass↗

PubMed2000

[Decomposition process of Chinese fir stump roots and changes of nutrient concentration].

With space as a substitute for time, the changes of the density of stump sapwoods and heartwoods, and the releasing process of major nutrients during the decomposition of Chinese fir stump roots were investigated. The yearly loss rate of the densities of sapwoods and heartwoods was 2.767 x 10(-2) and 2.255 x 10(-2) respectively during decomposition. The contents of N and P in sapwoods and roots decreased continually, while those in heartwoods increased during the first stage of decomposition, and then decreased. The K concentration in stump roots decreased remarkably during first two years, and the content of organic substances decreased during the whole decomposition process. The N, P and K concentrations in roots, were higher than those in stump sapwoods and heartwoods at the beginning of decomposition, but bet content of organic substance was opposite.

Abies↗

PubMed2000

[Bioproductivity of Castanopsis hysrix-Cyclobalanopsis glauca-Machilus pauhoi community in Huitong, Hunan].

Based on the mean DBH measurements of sample trees, the bioproductivity of subtropical Castanopsis hysrix-Cyclobalanopsis glauca-Machilus pauhoi community in Huitong, Hunan province was studied by regression analysis (y = a(D2.H)b). The results showed that the total biomass of the forest was 451.02 t.hm-2, and the component biomass of tree, shrub, liana and litter layer was 426.76, 17.76, 1.80 and 4.70 t.hm-2, respectively. The net production and average production of tree layer were 34.46 and 13.32 t.hm-2.yr-1, respectively.

Biomass↗

PubMed2000

[Protein secretion from drug-resistant bacteria--a suitable target for new antibiotics].

This paper reviewed the pathways of bacterial protein secretion and discussed the targets of pathogenic bacteria for antibiotics. Inhibition of protein secretion could lead to the growth decline, morphological alteration, and reduction of bacterial virulence, as well as the deprivation of their drug resistant. It was concluded that protein secretion could be a suitable target for new antibiotic agents.

Anti-Bacterial Agents↗

PubMed2000

[Nutrient retranslocation in fine roots of Cunninghamia lanceolata, Alnus cremastogyne and Kalopanax septemlobum in the mixed plantations--a pilot study].

Comparison of N, P and K concentrations in live and dead fine roots of Cunninghamia lanceolata, Alnus cremastogyne and Kalopanax septemlobum showed that the fine roots of A. cremastogyne had a stronger ability of N retranslocation than K. septemlobum's, but no N translocation occurred in C. lanceolata's. P retranslocation could be found in the fine roots of the all test tree species except C. lanceolata. As for K, it could translocate from fine roots to tree bodies of all these tree species before senescence. Based on the analysis on the difference of N, P, and K concentrations in live fine roots of each pair of tree species in the mixtures, it was suggested that N and K could respectively transfer from the root system of A. cremastogyne and K. septemlobum to the fine roots of C. lanceolata, and the mechanism could be clarified through exploring the ecological process of root-soil interface.

Biological Transport↗

PubMed2000

[Dynamics of phenolics content of Chinese fir stump-roots and the rhizosphere soil and it's allelopathy].

Studies on the releasing pattern of phenolics during the decomposition of Chinese fir stump-root and on its allelopathy show that the phenolics contents in stump-roots decreased with their decomposition. Roots had a higher content of phenolics than heart stumps, and edge stumps had the least. The phenolics was released during decomposition, and accumulated in the soils around stump-roots. Pot culture experiment showed that phenolics affected the germination of Chinese fir seeds. The correlation analysis between the density of Chinese fir stump-root and the tree height and base diameter (BD) of its saplings proved that Chinese fir stump-roots had a negative impact on the growth of the next generation of Chinese fir plantations. It is suggested that the traditional operation of Chinese fir plantations should be reformed, and the stump-roots should be cleared from woodland before reforestation.

Phenols↗

PubMed2000

A study of Hodgkin/Reed-Sternberg cells using single cell polymerase chain reaction.

OBJECTIVE: To investigate the characteristics of Hodgkin/Reed-Stemberg (H/R-S) cells found in patients with various types of Hodgkin's disease (HD). METHODS: H/R-S cells were micropicked from frozen sections of tissues affected by HD. The DNA from these cells was amplified by polymerase chain reaction (PCR) using immunoglobulin heavy chain gene FR III a/JH primers and light chain gene family-specific primers. RESULTS: A total of 52/135 (35.8%) isolated cells showed the specific products in the reactions. IgH and V kappa 4 rearrangements were repeatedly found in many cells from a lymphocyte predominance type sample; repeated V kappa 4 and individual IgH/V kappa 2,4 rearrangements and individual IgH, V lambda 3/ V kappa 4 rearrangements were found in two different cases of the nodular sclerosis type; repeated IgH/ V lambda 3 and individual V lambda 2,4 rearrangements, repeated V kappa 2,4 rearrangements, repeated V kappa 4 and individual IgH/ V kappa 3 rearrangements, repeated IgH and individual V kappa 3/ V lambda 4 rearrangements were detected in 3 cases of the mixed cellularity type. Repeated and individual IgH rearrangements were found in other 2 cases. CONCLUSION: The H/R-S cells isolated from the lymphocyte predominance subtypes of HD have IgH and V lambda 4 gene rearrangements. This suggests that the lymphocyte predominance type is a proliferation of neoplastic B cells. The cells isolated from the mixed cellularity and nodular sclerosis types derive from B lineage cells at various stages of differentiation because of the presence of their IgH, kappa and/or lambda gene rearrangements. To our knowledge, this is the first time that the lambda gene rearrangement was detected in H/R-S cells.

Gene Rearrangement↗

PubMed2000

[Study on the production of beta-mannanase by Bacillus M50].

Bacillus sp. M50 produced beta-mannanase efficiently in the medium composed of 4% konjac powder, 1.0% (NH4)2SO4 and 0.35% Na2CO3. Fermentation of beta-mannanase by Bacillus sp. M50 has been carried out in 100 L tank. The temperature, ventitation quantity and agitation speed were 30-32 degrees C, 1:0.75 vvm and 220 r/min respectively. the fermentation cycle was 28 h and the highest beta-mannanase activity was 330 u/mL. The optimal temperature and pH for beta-mannanase reaction were 50 degrees C and 6.0 respectively. It was stable at pH 4.0-7.0 and below 50 degrees C. The activity of the enzyme was strongly inhibited by Fe3+, Al3+, EDTA, Hg2+ and slightly stimulated by Ba2+, Mn2+. Treatment of ramie-fibers with crude enzyme preparations from Bacillus sp. M50 showed a good degradation for hemicellulose of ramie-fibers residues.

Bacillus↗

PubMed1999

Integrated mapping package--a physical mapping software tool kit.

We have developed an integrated physical mapping computer software package (IMP), originally designed to support the physical mapping of human chromosome 13 and expanded to support several gene-identification projects based on the positional candidate approach. IMP displays map data in a form that provides useful guidelines to the end users. An integrated map with high resolution and confidence is constructed from different types of mapping data, including hybridization experiments, STS-based PCR assays, genetic linkage mapping, cDNA localization, and FISH data. The map is also designed to provide suggestions for specific experiments that are required to obtain maps with even higher resolution and confidence. To this end, the optimization employs multiple constraints that take into account already established STS "scaffold" maps. This software thus serves as an important general tool kit for physical mapping, sequencing, and gene-hunting projects.

Algorithms↗

PubMed1999

Detection of circulating antigens and antibodies in Toxocara canis infection among children in Chengdu, China.

In order to determine the seroprevalence of Toxocara spp. infection in children from Chengdu, we performed an enzyme-linked immunosorbent assay (ELISA) and sandwich ELISA (S-ELISA) with excretory-secretory antigens isolated from second-stage larvae of Toxocara canis (TES-Ag ELISA). The seroprevalences of T. canis antibodies in the children from rural areas, urban districts, and urban districts with recent Ascaris lumbricoides infection were 17.7% (59/333), 2.1% (4/186), and 2.6% (1/38), respectively. Among 63 suspected patients with symptoms of T. canis infection, 31 had positive antibodies. The inhibition assay showed an apparent inhibiting capacity of TES-Ag for the antibody against T. canis larvae. The result of S-ELISA demonstrated that circulating antigens of T. canis larvae could be detected in part of the serum with positive antibodies and that the detection rate for circulating antigens in the sera could be improved by polyethylene glycol-acid treatment. This is the first epidemiological study to confirm the existence of T. canis infection and Toxocara-larvae migrans in Chengdu by the combination of TES-Ag ELISA and S-ELISA.

Animals↗

PubMed1999

A method for isolation and purification of nematode larvae.

A new apparatus for isolating, purifying, and collecting larvae of nematodes is described. Results of collecting larvae with Baermann's traditional method and the pasteur pipette cotton plug method are compared to those obtained with the device in this research note. It is simple, easy to use, and a more effective apparatus for the isolation, purification, and collection of nematode larvae.

Animals↗

PubMed1999

[Nucleotide sequence analysis for high variance region of hepatitis C virus in patients with hemodialysis].

OBJECTIVE: To investigate the route of transmission for hepatitis C virus (HCV) infection in patients on hemodialysis (HD). METHODS: Nucleotide sequence of high variance region (HVR) of HCV was analyzed with nucleotide sequencing technique in 15 HD patients, and its homology was compared. RESULTS: Comparison of the nucleotide sequences of HCV HVR in 15 HD patients showed that their homologies in isolates 8, 12 and 14 reached 97.50%, 95.00% in isolates 4, 5 and 10, and more than 80.00% in isolates 1, 3 - 8 and 10 - 14. Clinical data showed that all these patients were hemodialyzed in the same room with the same HD machine. Isolates 2 and all others were 61.25% - 66.25% in homology, and 57.50% - 67.50% in isolates 9 and all others, and both the patients had histories of large-quantity blood transfusion. CONCLUSION: Blood transfusion was the primary risk factor for HCV infection in HD patients, but iatrogenic transmission of HCV through HD environment could also exist.

Adult↗

PubMed1999

[Studies on ACE gene insertion/deletion polymorphism, serum ACE activity, and diabetic retinopathy in type II diabetic patients].

To clarify the relationship among angiotensin 1-converting enzyme(ACE) gene insertion/deletion(I/D) polymorphism, serum ACE activity, and diabetic retinopathy in Type II diabetic patients, we examined 36 healthy controls, 40 Type II diabetic patients without diabetic retinopathy, and 68 Type II diabetic patients with diabetic retinopathy. All of patients suffered from Type II diabetes beyond 5 years and matched in age and body mass index. An insertion/deletion polymorphism of ACE gene was identified by polymerase chain reaction(PCR). Serum ACE activity was determined using spectrophotometry. The distribution of DD, ID, and II genotypes of the ACE gene did not differ among the three groups (16.7%, 33.3%, and 50.0% in the healthy controls; 22.5%, 35.0%, and 42.5% in Type II diabetic patients patients without diabetic retinopathy; and 20.6%, 30.9%, and 48.5% in Type II diabetic patients with diabetic retinopathy; respectively). The frequency of ACE I/D genotypes was not significantly different between non-proliferative retinopathy and proliferative retinopathy of Type II diabetic patients with diabetic retinopathy (P > 0.05). Serum ACE activity of three groups was similar (P > 0.05). These results do not support the hypothesis that the DD genotype of the ACE gene would be a clinically useful genetic marker for predicting the development of diabetic retinopathy in Type II diabetic patients. There is no association between ACE gene I/D polymorphism and the prognosis of diabetic retinopathy in Type II diabetic patients. ACE may not involve in forming diabetic retinopathy in Type II diabetic patients.

Adult↗

PubMed1999

[Relationship between serum angiotensin I-converting enzyme activity and diabetic nephropathy in patients with type II diabetes].

To clarify the relationship between serum angiotensin I-converting enzyme (ACE) activity and Type II diabetic patients with or without diabetic nephropathy. We examined 36 healthy controls, 58 Type II diabetic patients without diabetic nephropathy, and 50 Type II diabetic with diabetic nephropathy. The diabetic duration of all of Type II diabetic patients was more than 5 years. All patients matched well in age and BMI. An insertion/deletion polymorphism of ACE gene was identified by polymerase chain reaction(PCR). Serum ACE activity was determined using spectrophotometry. Although the distribution of DD, ID, and II genotypes of the ACE gene did not differ among the three groups, serum ACE activity was significantly higher in Type II diabetic patients with diabetic nephropathy than in that without diabetic nephropathy(P < 0.05), especially in the groups with D allele of ACE gene. Serum ACE activity had no difference between healthy controls and Type II diabetic patients without diabetic nephropathy. There is no association between serum ACE activity and Type II diabetic patients without diabetic nephropathy in any genotype of ACE gene. The increasing serum ACE activity plays a role in the initiation of diabetic nephropathy or may serve as a risk marker for later development of overt diabetic nephropathy in Type II diabetic patients.

Adult↗

PubMed1999

[Determination of chlorogenic acid in chrysanthemum morifolium Ramat.flower].

OBJECTIVE: To determine the contents of chlorogenic acid in flower of Chrysanthemum morifolium. METHOD: Column: Nova-Pak C18, 4 microns, 4.6 mm x 250 mm, mobile phase: MeOH-0.1 mol.L-1 NaH2PO4(pH 2.65)30:70, detection wavelength: 328 nm. RESULTS: Flowers of 20 batches bought from the market were analysed. Contents of chlorogenic acid were 0.060%-0.467%. CONCLUSION: Chlorogenic acid is a suitable component for the quality control of C. morifolium.

Chlorogenic Acid↗

PubMed1998

Thrombin stimulates vascular smooth muscle cell polyamine synthesis by inducing cationic amino acid transporter and ornithine decarboxylase gene expression.

Thrombin, a serine protease, is a potent mitogen for vascular smooth muscle cells (SMCs), but its mechanism of action is not known. Since L-ornithine is metabolized to growth-stimulatory polyamines, we examined whether thrombin regulates the transcellular transport and metabolism of L-ornithine by vascular SMCs. Treatment of SMCs with thrombin initially (0 to 2 hours) decreased L-ornithine uptake, whereas longer exposures (6 to 24 hours) progressively increased transport. Kinetic studies indicated that thrombin-induced inhibition was associated with a decrease in affinity for L-ornithine, whereas stimulation was mediated by an increase in transport capacity. Thrombin induced the expression of both cationic amino acid transporter (CAT)-1 and CAT-2 mRNA. Furthermore, thrombin stimulated L-ornithine metabolism by inducing ornithine decarboxylase (ODC) mRNA expression and activity. The stimulatory effect of thrombin on both L-ornithine transport and ODC activity was reversed by hirudin, a thrombin inhibitor, and was mimicked by a 14-amino acid thrombin receptor-activating peptide. Thrombin also markedly increased the capacity of SMCs to generate putrescine, a polyamine, from extracellular L-ornithine. The thrombin-mediated increase in putrescine production was reversed by N(G)-methyl-L-arginine, a competitive inhibitor of cationic amino acid transport, or by alpha-difluoromethylornithine (DFMO), an ODC inhibitor. DFMO also inhibited thrombin-induced SMC proliferation. These results demonstrate that thrombin stimulates polyamine synthesis by inducing CAT and ODC gene expression and that thrombin-stimulated SMC proliferation is dependent on polyamine formation. The ability of thrombin to upregulate L-ornithine transport and direct its metabolism to growth-stimulatory polyamines may contribute to postangioplasty restenosis and atherosclerotic lesion formation.

Amino Acid Transport Systems, Basic↗

PubMed1998

[A longitudinal study on growth model and velocity of term small for gestation age].

To probe into the vegetal pattern and find out the key period of promoting normal growth of term small for gestational age (TSGA), a longitudinal study on growth model and velocity of TSGA was conducted from Jan 1993 to June 1997. The body weight and length of 150 children of TSGA (57 boys, 93 girls) and 152 children as controls (58 boys, 94 girls) were measured from the 1st month to 36th month. The growth model was analysed by multilevel models. The result showed that there was a difference between the growth models of TSGA and controls. During 8 and a half months (center month), the weight, length of controls were 1.19 kg, 3.46 cm greater than those of TSGA; the weight, length of boys were 0.34 kg, 1.08 cm more than those of girls respectively. The growth velocity of TSGA was similar to that of controls. The maximal growth velocity was observed during the first 6 monthes after birth. The order of growth velocity from high to low was 1 mo. > 2 mo. > 3 mo. in length and weight, showing that children of TSGA have their own growth model. Their growth velocity should be monitored attentively. If low velocity appears one should search for the cause and adopt apropriate measures to ensure their growth in accordance with their "own track".

Body Height↗