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Biomedical subjects

R Li

Publications and source records attributed to R Li.

At least 415 records · Page 23Linked to original sources
PubMed1996

[A study of the immunopathology of Mooren's ulcer].

OBJECTIVE: The study was designed to investigate the immunopathology of bulbar conjunctive adjacent to Mooren's ulcer of the cornea and to evaluate the roles of immune regulation status, the adhesive action of conjunctival cells and leucocytes in the pathological tissue in the pathogenesis of the lesion. METHOD: 15 limbal conjunctival specimens from 14 patients with the progressive Mooren's ulcer were examined by using immunohistochemical stainings for T-lymphocyte and its subsets (Pan-T, TH and TS), B-lymphocyte, intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function associated antigen-1 (LFA-1). RESULT: The ratio of T-helper to T-suppressor cells (TH/TS) in Mooren's ulcer group was significantly higher than that in the normal group, ICAM-1 was strongly expressed on conjunctival cells, whereas LFA-1 was strongly expressed in infiltrating leukocytes. CONCLUSION: The immune hyperfunction at the peripheral corneal lesion and its adjacent bulbar conjunctiva possibly is the direct cause of the pathogenesis of Mooren's ulcer. Simultaneously, the mutual action of ICAM-1 and LFA-1 might play an important role in the development of the disease.

Adult↗
PubMed1996

Gene localization and expression of thienamycin cyclase gene in Streptomyces lividans TK24.

Transformants of S. lividans TK24 were obtained by transforming a recombinant plasmid p6BC12 harboring the thienamycin cyclase gene into it. An antibacterial substance could be detected by the conversion of fermentation broth of the Y3 block mutant and the purified Y3 mutant intermediate with a cell-free extract of S. lividans TK24 transformant. Paper chromatographic analysis showed that the conversion product of Y3 fermentation broth with cell-free extract of S. lividans TK24 was thienamycin and an unstable antibacterial substance was a product of Y3 intermediate with cell-free extract of the transformants. This result indicated that the thienamycin cyclase gene was expressed in S. lividans TK24 and complemented the deficiency in the Y3 block mutant. Restriction analysis of p6BC12 was carried out and the restriction map was constructed. The thienamycin cyclase gene was localized on a 0.9 kb PstI-HinCII fragment from a bioconversion result. The 1.0 kb IPNS homologous DNA fragment in plasmid p6BC12 was excluded from the cyclase activity.

Genes, Bacterial↗
PubMed1996

Amplification, cloning, and sequence comparison of the growth hormone gene for carp (Cyprinus carpio) by the polymerase chain reaction.

Total RNA was isolated from carp pituitary gland. The first strand cDNA was synthesized using oligo(dT) 12-18 as a primer, the total RNA as a template, and AMV reverse transcriptase. Next the polymerase chain reaction (PCR) was performed using the first strand cDNA as a template, the synthetic 29 oligonucleotides as primer and Taq DNA polymerase (94 degrees C, 60 s; 55 degrees C, 30 s; 72 degrees C, 50 s; 35 cycles). After PCR amplification, the products were cloned into an E. coli expression vector (PBluescript II KS+/-). The result of the sequence analysis and the restriction map shows that an open reading frame of the carp growth hormone gene contains 630 base pairs which code for a polypeptide of 210 amino acids including 22 amino acids of the signal peptide and 188 amino acids of the nature growth hormone. Nucleotide sequence and amino acid sequence of our carp growth hormone gene are the same as Koren's carp GH cDNA in the coded region. Compared with Chao's carp GH cDNA, the homology of nucleotide sequence and amino acid sequence for our carp growth hormone gene is 95.6% and 96.7%, respectively, in the coded region.

Amino Acid Sequence↗
PubMed1996

[Fertilization in vitro and embryo transfer by combined long-acting gonadotropin releasing hormone agonist and gonadotropin for superovulation in patients with refractory polycystic ovary syndrome].

OBJECTIVE: To investigate the efficacy of the treatment for polycystic ovary syndrome (PCOS) patients by combined long acting gonadotropin-releasing hormone agonist (GnRHa) and gonadotropin. METHODS: Nineteen women with PCOS who had failed to conceive on treatment with conventional fertilization in vitro-embryo transfer (IVF-ET) protocol underwent 26 cycles of IVF-ET by combined long-acting and gonadotropin stimulation. A self-control group consisted of 19 PCOS women who had received 19 treatment cycles with conventional IVF-ET stimulation protocol more than 6 months previously. RESULTS: A comparison of these two groups showed that treatment with combined long-acting GnRHa and gonadotropin improved the in vitro fertility rate (76.2%) and pregnancy rate (38.5%). CONCLUSION: Patients with refractory PCOS should be referred for IVF-ET, using long-acting GnRHa before gonadotropin as the stimulation protocol.

Adult↗
PubMed1996

[Cloning and sequencing the isopenicillin N synthetase(IPNS) gene from Streptomyces cattleya].

Great homology existed between IPNS genes from surphur-containing beta-lactam antibiotics producers including procaryotes and eucaryotes. A DNA homologous band was confirmed in S. cattleya by Southern blot analysis using IPNS gene from S. lipmanii as a probe. A recombinant plasmid containing the cyclase gene involved in thienamycin biosynthesis and IPNS gene was obtained by complementary cloning with mutant from S. cattleya. DNA sequencing revealed that the IPNS gene of S. cattleya consists of 963 bp encoding a protein of 321 amino acids with ATG as start codon, TGA as stop codon. Pairwise comparison of the predicted amino acid sequences showed 56% and 64% similarity with IPNSs of S. clavuligerus and S. lipmanii, respectively.

Amino Acid Sequence↗
PubMed1996

[Dynamic assay of oleanolic acid in Aralia taibaiensis Z. Z. Wang et H. C. Zheng].

The dynamic assay on oleanolic acid (OA) in Aralia taibaiensis shows that the plant has a higher OA level. The level in root cortex is 4.74%-10.81% and peak stages are mid-May to late June and late August to mid-September the level in stem barks is 3.59%-12.06% and peak period is between mid-May and late July, the level in leaves increases throughout the life time ranging from 2.41% to 6.66% and peak level is 6.66% around mid-September.

Drugs, Chinese Herbal↗
PubMed1996

[Subcellular localization of blood group substances ABH in human gastrointestinal tracts].

Authers investigated subcellular localization of ABH substances in normal human stomach, duodenum and transverse colon by post-embedding immunogold method using monoclonal antibodies specific for A, B and H antigens. The immunoreactivity was usually restricted to the following organelles: mucigen granules of epithelical cells of gastric mucosa, zymogenic granules of chief cells of the gastric gland, both mucigen granules and Golgi cisternae of neck mucous cells of the gastric gland and of epithelial cells of the duodenum mucosa as well as the Brunner's gland. ABH antigens were also visualized in microvilli of absorptive cells and mucigan granules of goblet cells of the transverse colon. The results suggested that ABH substances in those cells were produced in Golgi cisternae and were transfered to secreting granules, then were secreted with mucus. The mosaic distribution of ABH substances in cells and the effect of embedding resins on ABH antigens and the ultrastructure of cells were discussed.

ABO Blood-Group System↗
PubMed1996

A one-hand operation gun for transrectal prostate biopsy.

OBJECTIVE: To develop a new automatic biopsy device (ABD) that enables a radiologist to obtain multiple samples with one hand and free the other hand to handle the ultrasonic scanner for continuous monitoring. MATERIALS AND METHODS: The new ABD developed by us in April 1994 enabled a radiologist to complete all the biopsy procedures including loading and reloading the spring system, firing the device, emptying the specimen, selecting the depth of needle advancement, and multiple sampling, simply by pressing 3 buttons in turn with his/her right thumb. Using this new ABD, transrectal prostate biopsy under the guidance of transrectal ultrasonic imaging was performed in 60 consecutive cases of prostate diseases. Each biopsy procedure was completed by a single radiologist, who was able to obtain multiple specimens with one biopsy needle, using only one hand and freeing the other hand for the manipulation of the ultrasonic scanner for guidance. RESULTS: A total of 265 satisfactory core tissue specimens of 285 needle passes (93%) were obtained from the 60 patients. Definite pathologic diagnoses were made for all the 60 patients (100%). No serious biopsy-related complications were observed. The main complications were hematuria in 24 of 60 (40%) patients and fever in 5 (8.3%). CONCLUSION: On the basis of our experience with the 60 patients, this new ABD can be operated smoothly and effectively with the right hand, while the left hand is freed to handle the ultrasonic transducer for continuous monitoring.

Biopsy, Needle↗
PubMed1996

[The progress of morphological research on the parabrachial nucleus].

In this paper, the progress of morphological research on the PBN, the cytoarchitecture of the PBN, and the fiber connections between the PBN and the spinal, the brainstem, the forebrain and the other nucleus were summarized. Its function in the relationship between the meridian and the internal organ was also assumed.

Animals↗
PubMed1996

The expression of c-erbB-1 and c-erbB-2 oncogenes in basal cell carcinoma and squamous cell carcinoma of skin.

The expression of c-erbB-1 and c-erbB-2 oncogenes were investigated by immunohistochemistry using monoclonal antibodies to c-erbB-1 and c-erbB-2 protein in 43 cases of basal cell carcinoma (BCC) and 26 cases of squamous cell carcinoma (SCC). We found that the expression of c-erbB-1 oncogene in all BCC increased by different degrees and the expression of c-erbB-2 oncogene in BCC was significantly reduced or lost when compared to that in normal epidermal cells. Furthermore, apparent negative and positive relationships were observed respectively between the tumor differentiation and the expression of c-erbB-1 and c-erbB-2 oncogenes in SCC. It is suggested that the abnormal expression of c-erbB-1 and c-erbB-2 oncogenes in BCC and SCC may play a role in the development of skin tumors. The pattern of the c-erbB-1 and c-erbB-2 oncogenes expression in SCC may assist in distinguishing the biological behavior and prognosis of SCC.

Adolescent↗
PubMed1996

[Subcellular location of blood group substances ABH using transmission electron microscopical immunocytochemistry technique].

The subcellular location of blood group substances ABH was studied by using transmission electron microscopical immunocytochemistry. The cells were the epithelial cells of both mucous membranes and glands of normal human stomach, duodenum and transverse colon. Both cellular ultrastructure and antigens should be well preserved in transmission electron microscopical immunocytochemistry. In this paper, various fixatives, embedding media and immunostaining methods were investigated and compared. The results indicate that the solution containing 2% paraformaldehyde and 0.2% glutaraldehyde (2PG) is the best fixative and Epon 812 medium is the best embedding medium for preserving ABH antigens and protecting cellular ultrastructure. Post-embedding immunogold staining technique is superior to pre-embedding immunoperoxidase staining.

ABO Blood-Group System↗
PubMed1996

[Distribution of Bacillus thuringiensis in soils of north and south of China].

221 isolates of Bacillus thuringiensis were isolated in 1491 soil samples from North and South of China. H-serotypes and larvicidal characters of all Bt isolates have been identified. The rate of Bt-harbouring soil sample and the rate of Bt isolates in Northeast and Neimeng were in 12.6% and 17.2% respectively. Predominant serotypes were H4, H10, H3, H13, H5 and H29. The most fertile Bt-harbouring area was the Heilongjiang Province with rate of Bt-harbouring sample of 21.4% and rate of Bt isolate of 29.4%. Rate of Bt-harbouring sample and rate of Bt isolate in Northwest area were 6.6% and 7.1% respectively. Main serotypes were H4, H5, H19, H10 and H3. In four provinces of Southern China, both rates above were 18.6% and 29.5%, but frequency of Bt distribution was varied seriously in different distinct. Predominant serotypes in soils from Southern China were H3 and H5. Results of bioassay showed that the percentage of strains high active to Heliothis armigera and Plogioidera versicolora were 1.6% and 1.1% in soils from North of China. In contrast to North of China, Bt strains active to H. armigera were 5.3% and none of Bt was effective to P. versicolora in South of China. A strain H27-05 was high toxic to H. armigera and showed temperate toxicity to P. versicolora.

Animals↗
PubMed1995

In vitro antimalarial activity of chalcones and their derivatives.

A series of chalcones and their derivatives have been synthesized and identified as novel potential antimalarials using both molecular modeling and in vitro testing against the intact parasite. A large number of chalcones and their derivatives were prepared using one-step Claisen-Schmidt condensations of aldehydes with methyl ketones. These condensates were screened in vitro against both chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum and shown to be active at concentrations in the nanomolar range. The most active chalcone derivative, 1-(2,5-dichlorophenyl)-3-(4-quinolinyl)-2-propen-1-one (7), had an IC50 value of 200 nM against both a chloroquine-resistant strain (W2) and a chloroquine-sensitive strain (D6). The resistance indexes for all compounds were substantially lower than for chloroquine, suggesting that this series will be active against chloroquine-resistant malaria. Structure-activity relationships (SAR) of the chalcones in the context of a homology-based model structure of the malaria trophozoite cysteine protease, the most likely target enzyme, are presented.

Animals↗
PubMed1995

Hematopoietic and lung abnormalities in mice with a null mutation of the common beta subunit of the receptors for granulocyte-macrophage colony-stimulating factor and interleukins 3 and 5.

Gene targeting was used to create mice with a null mutation of the gene encoding the common beta subunit (beta C) of the granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin 3 (IL-3; multi-CSF), and interleukin 5 (IL-5) receptor complexes (beta C-/- mice). High-affinity binding of GM-CSF was abolished in beta C-/- bone marrow cells, while cells from heterozygous animals (beta C+/- mice) showed an intermediate number of high-affinity receptors. Binding of IL-3 was unaffected, confirming that the IL-3-specific beta chain remained intact. Eosinophil numbers in peripheral blood and bone marrow of beta C-/- animals were reduced, while other hematological parameters were normal. In clonal cultures of beta C-/- bone marrow cells, even high concentrations of GM-CSF and IL-5 failed to stimulate colony formation, but the cells exhibited normal quantitative responsiveness to stimulation by IL-3 and other growth factors. beta C-/- mice exhibited normal development and survived to young adult life, although they developed pulmonary peribronchovascular lymphoid infiltrates and areas resembling alveolar proteinosis. There was no detectable difference in the systemic clearance and distribution of GM-CSF between beta C-/- and wild-type littermates. The data establish that beta C is normally limiting for high-affinity binding of GM-CSF and demonstrate that systemic clearance of GM-CSF is not mediated via such high-affinity receptor complexes.

Animals↗
PubMed1995

Intercellular adhesion molecule-2 (CD102) binds to the leukocyte integrin CD11b/CD18 through the A domain.

The interactions between the leukocyte-specific beta 2-integrins cluster of differentiation (CD) Ag CD11/CD18 and their ligands, the intercellular adhesion molecules (ICAMs), play important roles in many adhesion-dependent leukocyte functions. ICAM-1 is known to be a ligand for both CD11a/CD18 and CD11b/CD18. ICAM-2, whose two extracellular Ig domains show the highest homology to the two NH2-terminal domains of ICAM-1, has been previously shown to be a ligand for CD11a/CD18. We recently found that a 22-amino acid CD11a/CD18-binding peptide, P1, derived from the first domain of ICAM-2, also binds to purified CD11b/CD18. In the present study, we demonstrate that the ICAM-2 protein interacts with CD11b/CD18, and the binding is through the CD11b A domain.

Animals↗