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Biomedical subjects

R Lu

Publications and source records attributed to R Lu.

At least 73 records · Page 4Linked to original sources
PubMed1999

[A study on the loss of heterozygosity of multiple tumor suppressor genes in gastrointestinal metaplasia].

OBJECTIVE: To investigate the role of multiple tumor suppressor gene abnormality in gastrointestinal metaplasia (IM). METHODS: The loss of heterozygosity (LOH) of YNZ22, APC, MCC and DCC genes was examined by PCR-RFLP technique in 60 IM cases. RESULTS: LOH of YNZ22, APC, MCC and DCC genes were found in 19.4% (6/31), 12.0% (3/25), 13.0% (3/23) and 4.3% (2/47) respectively. IM was classified into types I, II and III. It was found that the LOH rates of each tumor suppressor gene of type III IM were higher than those of types I & II IM, but the difference was not significant (P > 0.05). Two cases of type III IM were found to also have 2 gene alterations (APC, MCC or YNZ22, MCC) respectively. All LOH were found in IM of adjacent carcinoma. None were found in IM of cancer-free patients. CONCLUSION: The alteration of tumor suppressor gene may play a role in the development and carcinogenesis of IM.

DNA↗
PubMed1999

[Morphological changes and electrophysiological study of motor neuron of spinal cord following delayed repair of peripheral nerve injury].

OBJECTIVE: Following the delayed repair of peripheral nerve injury, the cell number of anterior horn of the spinal cord and its ultrastructural changes, motorneuron and its electrophysiological changes were investigated. METHODS: In 16 rabbits the common peroneal nerves of both sides being transected one year later were divided into four groups randomly: the degeneration group and regeneration of 1, 3 and 5 months groups. Another 4 rabbits were used for control. All transected common peroneal nerves underwent epineural suture except for the degeneration group the electrophysiological examination was carried out at 1, 3 and 5 months postoperatively. Retrograde labelling of the anterior horn cells was demonstrated and the cells were observed under light and electronmicroscope. RESULTS: 1. The number of labelled anterior horn cell in the spinal cord was 45% of the normal population after denervation for one year (P < 0.01). The number of labelled cells increased steadily from 48% to 57% and 68% of normal values at 1, 3 and 5 months following delayed nerve repair (P < 0.01). 2. The ultrastructure of the anterior horn cells of the recover gradually after repair. 3. With the progress of regeneration the latency become shortened, the conduction velocity was increased, the amplitude of action potential was increased. CONCLUSION: Following delayed repair of injury of peripheral nerve, the morphology of anterior horn cells of spinal cord and electrophysiological display all revealed evidence of regeneration, thus the late repair of injury of peripheral nerve was valid.

Animals↗
PubMed1999

[Light and electron microscope observations of heart and vascular tissues in animals acutely infected with tubercle bacilli].

The objective of this study was to observe the heart and vascular pathological lesions of some animals acutely infected with H37Rv tubercle bacilli. C57 BL/6N mice and rabbits were used for the establishment of the models. Light sections were stained with HE, Z-N, MCT and BCGS-P. Ultrathin sections were stained with uranyl and lead citrate and examined by electron microscope. The results showed that tubercle bacilli were present in heart and vascular tissues. Myocardial fibre, pericardium and vascular tissues had various degrees of lesions. The lesions of myocardial fibre and pericardium were more serious than that of the vascular tissues. These findings suggest that the toxin of the tubercle bacilli can damage the tissues of the infected animals, and the excessive reproduction can be also a factor detrimental to the infected tissues.

Acute Disease↗
PubMed1999

[Deletion analysis and functional studies of the promoter from commelina yellow mottle virus].

Commelina Yellow Mottle Virus(CoYMV) is a double-stranded, circular DNA virus and its promoter could direct GUS gene specifically expressing in phloem tissue of transgenic tobacco plants. To determine the optimal promoter sequence for pholem-specific gene expression, CoYMV promoter was deleted from its 5 end to form promoter fragments with 5 different lengths. Chimeric GUS genes were constructed using the promoter deletion based on the binary vector pBI121. Transgenic tobacco plants evidenced by PCR analysis were obtained with each kind of chimeric GUS gene structure by Agrobacterium mediated transformation. The results of GUS activity assay and histo-chemical staining showed that most of the chimeric GUS genes were expressed in transgenic plants. The GUS activity with the promoter deleted to -870 bp was about 78% higher than that of the full length promoter(1040 bp) and was a little higher than that of the promoter deleted to -585 bp, but the difference is not significant. The GUS activity reduced significantly when the promoter was deleted to -447 bp or -232 bp, whereas the property of phloem-specific expression pattern was still retained. When the promoter was deleted to -44 bp, just upstream adjacent to the TATA box, its tissue-specificity was lost and the activity was reduced to undetectable level. These results suggest that the region between -870 bp-232 bp and downstream of -232 bp of CoYMV promoter could be responsible for promoter activity and tissue specific expression, respectively. A negative regulation sequence might exist upstream of -870 bp of the CoYMV promoter. Therefore, we recommend that the optional CoYMV promoter sequence for phloem specific expression could be downstream from -870 bp or -585 bp. In comparison with CaMV 35S promoter, the GUS activity when driven by -870 bp CoYMV promoter was about 70% of that when driven by the 35S promoter. Considering the fact that 35S promoter-GUS gene is constitutively expressed, while the CoYMV promoter-GUS gene is expressed only in phloem tissues, the activity of the latter in phloem may be the same with or even higher than that of the 35S promoter.

Badnavirus↗
PubMed1999

[Molecular cloning and sequencing of outer capsid protein gene of rice dwarf virus and its expression in Escherichia coli].

The S2 full-length cDNA of rice dwarf phytoreovirus which enocodes the viral outer capsid protein was cloned and its complete nucleotide sequence was determined. The results showed that S2 is 3512 bp long with a large open reading frame which encodes a protein of 1116 amino acids. It shares 94.6% and 95.4% identity with RDV of Japanese H isolate in terms of nucleotide and amino acid sequences, respectively, and it also shows some homology with VP2 of rotavirus at the level of amino acid sequence. The search of deduced RDV S2 amino acid sequence in Blast network found that there were 4 leucine-rich motifs in P2 protein, and ten amino acids within the hydrophibic region at amino-terminus could form an alpha-helix. Predicted secondary structure of S2 cDNA indicated that a hairpin and a stem loop are present in the 5'-end within 50 bp, and a stem loop in the 3'-end within 50 bp. RDV S2 partial and full-length sequences were then cloned into expression vector pET-11d & pTrcHisC. SDS-PAGE and Western blot proved that amino- and carborn-termini of P2 were successfully expressed in E. coli.

Amino Acid Sequence↗
PubMed1999

Study of loss of heterozygosity at DCC and APC/MCC genetic loci of gastric cancer.

In order to assess the role of the changes of DCC and APC/MCC genes in the development and progression of gastric cancer, the loss of heterozygosity (LOH) of these genetic loci was investigated in 45 surgical specimens of gastric cancer with PCR-RFLP. The rate of LOH was 30.0% (9/30) at APC/MCC gene and 33.3% (15/45) at DCC gene. LOH was found in both intestinal and gastric types of gastric cancer and the rate of LOH of DCC gene was significantly higher in stages III to approximately IV gastric cancer (48.0%) than in stages I to approximately II (15.0%) (P<0.05). LOH of APC/MCC gene could be found in both early and advanced stages of gastric cancer. These findings suggest that changes of DCC and APC/MCC genes are involved in the development and progression of the intestinal and gastric types of gastric cancer.

Adenocarcinoma↗
PubMed1998

Transgenic knockout mice exclusively expressing human hemoglobin S after transfer of a 240-kb betas-globin yeast artificial chromosome: A mouse model of sickle cell anemia.

Sickle cell anemia (SCA) and thalassemia are among the most common genetic diseases worldwide. Current approaches to the development of murine models of SCA involve the elimination of functional murine alpha- and beta-globin genes and substitution with human alpha and betas transgenes. Recently, two groups have produced mice that exclusively express human HbS. The transgenic lines used in these studies were produced by coinjection of human alpha-, gamma-, and beta-globin constructs. Thus, all of the transgenes are integrated at a single chromosomal site. Studies in transgenic mice have demonstrated that the normal gene order and spatial organization of the members of the human beta-globin gene family are required for appropriate developmental and stage-restricted expression of the genes. As the cis-acting sequences that participate in activation and silencing of the gamma- and beta-globin genes are not fully defined, murine models that preserve the normal structure of the locus are likely to have significant advantages for validating future therapies for SCA. To produce a model of SCA that recapitulates not only the phenotype, but also the genotype of patients with SCA, we have generated mice that exclusively express HbS after transfer of a 240-kb betas yeast artificial chromosome. These mice have hemolytic anemia, 10% irreversibly sickled cells in their peripheral blood, reticulocytosis, and other phenotypic features of SCA.

Anemia, Sickle Cell↗
PubMed1998

Molecular cloning of the gene for the human prostaglandin transporter hPGT: gene organization, promoter activity, and chromosomal localization.

Prostaglandins (PGs) play diverse and important roles in human health and disease. We recently identified the first known PG transporter cDNA in the rat (PGT) and human (hPGT). To aid in the analysis of any possible human disease caused by mutations in PGT, we have cloned and characterized the hPGT gene. The gene exists as a single copy in the human genome and is comprised of 14 exons distributed over approximately 95 kb. Two introns disrupt putative trans-membrane spans of the coding region; each of these sites is near a highly conserved charged residue. The approximately 250 bp immediately 5' to the start of exon 1 contain a TATAAA sequence (TATA box), a transcription initiation (Inr) consensus (CTCANTCT), two Sp 1 sequences (GGGCGG), and a cAMP response element (CGGCGTCA). Ligation of approximately 3.5 kb of 5' flanking sequence to a luciferase reporter yielded > 15-fold activity above background when expressed in A549 human lung epithelial cells. PCR-based monochromosomal somatic cell hybrid mapping and fluorescence in situ hybridization localized hPGT to chromosome 3q21. Three microsatellites were identified, one of which was demonstrated to be polymorphic in unrelated individuals and may be useful in evaluating PGT as a candidate gene in human disease.

Alleles↗
PubMed1998

Targeted disruption of the ubiquitous CNC-bZIP transcription factor, Nrf-1, results in anemia and embryonic lethality in mice.

The CNC-basic leucine zipper (CNC-bZIP) family is a subfamily of bZIP proteins identified from independent searches for factors that bind the AP-1-like cis-elements in the beta-globin locus control region. Three members, p45-Nf-e2, Nrf-1 and Nrf-2 have been identified in mammals. Expression of p45-Nf-e2 is largely restricted to hematopoietic cells while Nrf-1 and Nrf-2 are expressed in a wide range of tissues. To determine the function of Nrf-1, targeted disruption of the Nrf-1 gene was carried out. Homozygous Nrf-1 mutant mice are anemic due to a non-cell autonomous defect in definitive erythropoiesis and die in utero.

Amino Acid Sequence↗
PubMed1998

Fractal behavior of length change in human mitotic chromosome.

Sixty-six cells were examined for chromosome length change, with half of them (33) in the early-metaphase and the other half in the pre-metaphase. The 22 couples of chromosomes (excluding sex chromosomes) in each cell were analyzed. The differences of chromosome length between the two phases were demonstrated and the correlation dimension of each chromosome was calculated. It was suggested that the mitosis of human chromosome possessed the feature of chaotic decrease. This offers a new approach to the research of the dynamic process of the mitosis.

Chromosome Banding↗
PubMed1998

The herpesvirus transactivator VP16 mimics a human basic domain leucine zipper protein, luman, in its interaction with HCF.

In human cells infected with herpes simplex virus (HSV), viral gene expression is initiated by the virion protein VP16. VP16 does not bind DNA directly but forms a multiprotein complex on the viral immediate-early gene promoters with two cellular proteins: the POU domain protein Oct-1 and host cell factor (HCF; also called C1, VCAF, and CFF). Despite its apparent role in stabilizing the VP16-induced transcription complex, the natural biological role of HCF is unclear. Only recently HCF has been implicated in control of the cell cycle. To determine the role of HCF in cells and answer why HSV has evolved an HCF-dependent mechanism for the initiation of the lytic cycle, we identified the first human ligand for HCF (R. Lu et al., Mol. Cell. Biol. 17:5117-5126, 1997). This protein, Luman, is a member of the CREB/ATF family of transcription factors that can activate transcription from promoters containing cyclic AMP response elements (CRE). Here we provide evidence that Luman and VP16 share two important structural features: an acidic activation domain and a common mechanism for binding HCF. We found that Luman, its homolog in Drosophila, dCREB-A (also known as BBF-2), and VP16 bind to HCF by a motif, (D/E)HXY(S/A), present in all three proteins. In addition, a mutation (P134S) in HCF that prevents VP16 binding also abolishes its binding to Luman and dCREB-A. We also show that while interaction with HCF is not required for the ability of Luman to activate transcription when tethered to the GAL4 promoter, it appears to be essential for Luman to activate transcription through CRE sites. These data suggest that the HCF-Luman interaction may represent a conserved mechanism for transcriptional regulation in metazoans, and HSV mimics this interaction with HCF to monitor the physiological state of the host cell.

Animals↗
PubMed1998

[Effects of tea polyphenol on blood lipid and antioxidation in vivo in aged rats].

OBJECTIVE: To study the ability of tea polyphenol to lowering blood lipid and antioxidation in the aged rats. METHODS: The SD rats were divided into three groups, i.e., control group and two trial groups fed with 1% and 2% tea polyphenol for six weeks, respectively. RESULTS: Tea polyphenol could reduce serum level of lipid peroxide and increase the ratio of high-density lipoprotein cholesterol (HDL-C) to total cholesterol (TC), and significantly lower serum level of lipid peroxide in rats. Activities of superoxide dismutase in red blood cells of rats fed with 2% tea polyphenol were significantly higher than those in control ones. CONCLUSION: Tea polyphenol can enhance antioxidation in vivo in the aged rats.

Aging↗
PubMed1998

[Effects of different vascular beds on the microstructural components and intimal hyperplasia of autogenous vein grafts in dogs].

In order to investigate the effect of vascular beds on the vascular wall of autogenously grafted vein, femoral veins were reversely placed in between the cut ends of collateral femoral arteries in 11 dogs with atraumatic technique. The grafted veins were covered with vivid muscle or skin respectively after being assured to be patent, and investigated by histomorphologic method and computerized image analysis technique at postoperative intervals of 1 week, 4 weeks and 16 weeks. The results showed that: 1. One graft developed pseudoaneurysm at 1 week, and two grafts were occulded in skin-covered group, whereas, no complications occurred in muscle-covered group. 2. Intimal thickening of grafts in skin-covered group was much more obvious than that in the muscle-covered group (P < 0.05). 3. The relative contents of microstructural components of the graft wall showed no significant difference quantitatively between the two groups. So, the conclusion was: 1. Subcutaneous transplantation appeared to be a potential causative factor in inducing short-term excessive dilatation and long-term intimal hyperplasia of vein graft. 2. Muscular covering is of priority in blood vessel graft.

Animals↗
PubMed1998

[Investigation of intrauterine microbes after intrauterine operation].

OBJECTIVE: To explore the postoperative changes in the cultures of ureaplasma urealyticum (UU), mycoplasma hominis (Mh), L-form bacteria (L-form), anaerobic bacteria (Ana) and chlamydia trochomatis (CT) after intrauterine operation. METHODS: Four groups of patients were set up: group 1, induced abortion; group 2, intrauterine device (IUD) insertion; group 3, penicillin i.m. after IUD insertion; group 4, oral lincomycin after IUD insertion. Intrauterine secretion were aspirated to identify the above microbes before operation and within 1 week of ending of menstrual bleeding for 4 consecutive postoperative cycles. Bacteria-carrier was defined as at least one of the 5 microbes detected. RESULTS: No difference was shown in the incidence of bacteria-carrier (IBC) among the 4 groups preoperation. The IBC tended to be the highest in the first menstrual cycle postsurgery in all the 4 groups, then decreased. Compared with preoperation, there were significantly higher IBC in the 3 IUD groups (P < 0.05) except group 1. CONCLUSION: IUD is a major factor for intrauterine microbes existing after operation, and the natural body defense system can help to get rid of the organism by time. Small doses and short period of penicillin or lincomycin administration proved not effective in clearing the intrauterine microbes after IUD insertion.

Abortion, Induced↗
PubMed1998

[A computer system for bone age measurement of hand radiographs].

OBJECTIVE: This study was to development a computer system for assessing bone age which would analyse children's growth level accurately and quickly. METHODS: It used the standards of estimating skeletal maturity for Chinese (CHN) scoring method to assess the bone age of Chinese children. We applied image enhancement techniques for imprving the quality of the hand-wrist radiographs, while an automated system was developed to implement this method. RESULTS: Users could get a clear and reliable radiograph through image processing, compare each bone of the hand-wrist radiograph with that of the scanned image of the standard radiographs, then generate the stage of bone maturity. The computer would give out individual and total bone score and a value of bone age. CONCLUSION: This system implemented evaluation of bone age rapidly and accurately, it would help orthodontist to choose the best time of treatment.

Age Determination by Skeleton↗