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Biomedical subjects

M Li

Publications and source records attributed to M Li.

At least 433 records · Page 24Linked to original sources
PubMed2000

[B7 and DC vaccines induced anti-tumor immunity against murine T-lymphocyte leukemia L615].

OBJECTIVE: To study the effect of B7 and DC vaccines in inducing anti-tumor immunity in murine T-lymphocyte leukemia L615. METHODS: In vivo, murine mortality and survival were observed to compare the difference between B7 and DC vaccine in inducing immunoprotection against the subsequent challenge of live L615 cells;in vitro, specific cytotoxic assay and MLR were performed to test the specific cytotoxicity and proliferative activity of effective T cells. RESULTS: Both vaccines could efficiently improve T cell mediated anti-leukemic immunity in syngenic hosts, and DC vaccine was revealed to be more efficient. In vitro observations showed that both vaccines could induce tumor specific cytotoxicity and proliferative activity of effective T cells. CONCLUSION: DC vaccine is promising in tumor immunotherapy owing to its safety, efficiency and convenience.

Animals↗
PubMed2000

[In vitro induction of autologous T cell killing by heat treated human chronic myelogenous leukemia cells].

OBJECTIVE: To investigate the potential of autologous T cell killing of heat treated chronic myelogenous leukemia (CML) cells (autologous tumor killing, ATK). METHODS: (51)Cr release assay was used to measure the ATK activity of autologous T cells against CML cells treated with 42 degrees C for 30 minutes (heat) or 37 degrees C for 30 minutes (non-heat). The phenotypes of T cells and heat shock protein 70 (HSP70) expression of CML cells were measured by flow cytometry (FCM). T cells from the CML patients were stimulated and expanded by autologous mixed lymphocyte/tumor cell cultures (MLTC). RESULTS: ATK activity of autologous T cells to the non-heated and heated CML cells were found in 4 (19.05%) and 10 (47.62%) of the 21 cases, respectively. The ATK activity of interleukin-2 (IL-2) stimulated autologous T cells against heated CML cells was markedly higher than that of unstimulated autologous T cells against non-heated CML cells (P < 0.001). FCM analysis showed that no HSP70 was expressed on the CML cell membranes whether heated or non-heated, but intracellular HSP70 expressions were (83.42 +/- 5.65)% and (78.34 +/- 6.32)% pre- and post-heated, respectively. The phenotypes of T cells stimulated and expanded in MLTC were TCRgammadelta - CD(3)(+), mostly CD(8)(+), with some activation markers (CD(25) and HLA-DR) expression. The ATK activities of these T cells against the heated and non-heated CML cells and K562 cells were (51.25 +/- 4.26)%, (36.52 +/- 3.83)% and (2.92 +/- 1.19)%, respectively. CONCLUSIONS: ATK activity of autologous T cells against CML cells could be induced or enhanced by heat treatment of the CML cells particularly of T cells stimulated with IL-2. This ATK activity was not associated with gammadelta T cells or HSP70 expression of CML cells.

Adolescent↗
PubMed2000

[Responses induced by dopamine in Xenopus laevis oocytes injected with mRNA from heat injured rat striatum].

Poly(A)(+) mRNA isolated from the striatum of normal rats and heat injured rats by RNAgents Total RNA Isolation System and PolyTract mRNA RNAgents Isolation Systems was microinjected into Xenopus laevis oocytes to express functional neurotransmitter receptors. Membrane currents were recorded by the conventional patch clamp technique for measuring the relative amounts of mRNA encoding dopamine receptor in order to study the change in dopamine receptors in heat injured rat striatum. There was no change in resting membrane potentials of the oocytes before and after mRNA injection. Dopamine induced membrane currents were shown to be mediated through Cl( ). The oocytes injected with mRNA from heat injured rat striatum were less sensitive to dopamine than those injected with mRNA from normal rats ( P<0.05). The above result showed that heat injury affected gene expression and signal transduction of dopamine receptors in rat striatum.

Animals↗
PubMed2000

[Antitumor activity of the lysates prepared from anti-CD3 antibody activated killer cells].

This study was directed at the antitumor activity of the lysates prepared from CD3McAb activated killer cells. We separated the peripheral blood monocytes(PBMC) from normal adults. The PBMC were induced by monoclonal antibody specific for CD3(CD3McAb) and activated by rIL-2. The CD3McAb-activated killer cells (CD3AK) were smashed by ultrasonic wave, along with frozen and thawed three times, then the lysates were obtained by centrifugation. The lysates were tested for antitumor activity in vivo and in vitro. The results revealed that the inhibition rate of the lysates that acted on mice solid tumor hepatoma 22(H22) was 68.20% and the killing activity of the lysates on K562 and Raji were 83.32%, and 66.83% respectively. The results of this experiment suggested that the lysates prepared from CD3McAb-activated killer cells is one of probable agents that might apply to biotherapy for tumors.

Animals↗
PubMed2000

[A study on the shape of nose of the Jingpo people in China].

The objective of this survey was to provide data for clinical plastics of nose, medical aesthetics and cosmetology, anthropology, nationality study and medical jurisprudence. We carried out a somatological survey on the nose of 611 Jingpo people living in Yunnan. The survey covered 277 males (aged 15 to 60 years) and 334 females (aged 13 to 55 years). The findings of the features of nose are as follows: the Nasal Root Height is high (average 55.83%); the Nasal Tip Direction is forward (average 81.17%); the Nasal Base is horizontal (average 79.17%); the Alae Nasi is slightly projecting (average 91.83%); the Nasal Profile is straight (average 74.83%). The type of the Nasal Index is middle (70.0-84.9). The average of the Nasal Height (NH) of both male and female is 49.09 mm, the average of the Nasal Length (NL) is 41.99 mm, the average of the Nasal Breadth (NB) is 36.44 mm, the average of the Nasal Index is 74.93, but there is significant difference between male and female. The average of the Nasal Depth (ND) is 14.59 mm, the average of the Nasal Deep Index is 40.19; there is no significant difference between male and female. There is no difference between adults and youths, but there is marked difference between adults and teenagers, suggesting that the development of the nose of the Jingpo people tends to end up in youth.

Adolescent↗
PubMed2000

[Study of accuracy of one-piece casted and laser welded bridges].

OBJECTIVE: To assess whether laser welded bridge be fit for the clinical usage, this study compares the accuracy of laser welded multi-unit bridges with one-piece casted bridges. METHODS: A precise stainless mold which was 20 mm length composed of two abutments (one premolar and one molar) and one pontic (two missed teeth) was made. 5 wax patterns of four-unit FPD frame-works in one-piece casting based on the mold were made. After that, they were invested with inner (Bellavest) and outer investment (phosphate and gypsum). Then they were casted with CW-PA (Ni-Cr-Nb) alloys. The other 5 wax patterns of four-unit FPD frameworks were invested and casted in two halves. Each couple of frameworks were ultra-sonic washed in distilled water and inserted to the standard metal FPD mold accurately. Laser welding machine (DL-2002) was used to weld each couple of frameworks at 305V, 20 ms. Both groups of specimens were tested on their mesiodistal span dimensions and the diameters of alloy crowns. Then they were inserted to their original stainless mold, where the marginal fitness was examined. RESULTS: 1. The one-piece casted fixed multi-unit bridge couldn't be inserted to abutments completely because of distortion, while the laser welded bridge could be inserted to abutments completely. The average marginal opening of laser welded bridges was about 74 microns and conformed to clinical standard of fitness. 2. Mesiodistal dimensions of one-piece casted bridges at the inner, bottom and top margins were 19.5600 +/- 0.3877 mm, 41.2206 +/- 0.4140 mm, 41.0598 +/- 0.3379 mm respectively; while those of laser welded bridges were 20.2950 +/- 0.1191 mm, 41.9625 +/- 0.0788 mm, 42.0584 +/- 0.1089 mm, which were obviously close to metal abutments (P < 0.05). 3. The alloy crowns' diameters of one-piece casted bridges were examined as following, the premolar: phi IJ = 9.8386 +/- 0.0567 mm, phi LK = 9.9596 +/- 0.0548 mm, the molar: phi EF = 11.7948 +/- 0.0252 mm, phi HG = 11.9412 +/- 0.0763 mm; The alloy crowns' diameters of laser bridges were as following, the premolar: phi IJ = 9.7927 +/- 0.0636 mm, phi LK = 9.9438 +/- 0.0726 mm, the molar: phi EF = 11.8287 +/- 0.0863 mm, phi HG = 11.8893 +/- 0.1049 mm. There was no significant difference between the two groups (P < 0.05). CONCLUSION: Laser welding greatly improve the fitness of multi-unit fixed bridges.

Dental Abutments↗
PubMed2000

[Study on the morphological processing of classical swine fever virus in cultured cells].

An infected mode between the Thiverval strain and Chinese strain of CSFV and MPK cells are established. The morphological structure and processing of different strains(T strain, C strain and F strain) of CSFV were studied by ultra-thin section electron microscopy. The virions of CSFV are roughly round and approximately 70 nm in diameter with a 40 nm core, and are wraped by membrane. The distinctive pathway of the maturation and release of CSFV are observed. Virons on different deverloping state and the pathologic changes of host cells have also been reported in this paper.

Animals↗
PubMed2000

[Gene cloning and expression of prolyl endopeptidase from Aeromonas punctata].

Prolyl endopeptidase gene was cloned from Aeromonas punctata subsp. Punctata(ST-78-3-3) using activity screening method and the 3.3 kb DNA fragment containing PEP gene was sequenced. DNA sequence from 20-2092 bp was ORF region coding 690 amino acids of prolyl endopeptidase. It was a new PEP gene through gene search. The genetic engineered E. coli BL21/pGEM-PEP overexpressing recombinant Aeromonas punctata prolyl endopeptidase(apPEP) was constructed. Cultured in YH medium, the expressed apPEP was about 30% of total cellular protein, the activity was 112 times more than that of wild strain. Expressed apPEP was mainly soluble intracellular protein, about 5% of apPEP was secreted to medium. Non-reduced SDS-PAGE analysis showed it's monomer with molecular weight about 76 kD, which corresponded with prediction by gene sequence. Recombinant apPEP was purified after tube culture, the purity reached 90% and specific activity was 67 U/mg.

Aeromonas↗
PubMed2000

[Preparation and characterization of McAbs against lactate dehydrogenase of Plasmodium falciparum].

OBJECTIVE: To prepare and characterize the monoclonal antibodies(McAbs) against lactate dehydrogenase of the Plasmodium falciparum(LDHp). METHODS: BALB/c mice were immunized with purified recombinant LDHp and McAbs against LDHp were prepared according to the protocol of hybridoma technique. The McAbs were characterized by ELISA and Western blot analysis. RESULTS: Two McAbs against LDHp antigen were obtained. Both McAbs were IgG2b. The titer of two McAbs(2A5, 1H10) in the ascites was 1:25,600 and 1:12,800, and in supernatant were 1:512,1:256 respectively. The result of ELISA indicated that two McAbs reacted only with P. falciparum, and did not react with normal human red blood cells, P. vivax, Toxoplasma gondii, Schistosoma japonicum. It is recognized 33 kDa protein which was defined as LDHp by Western blot analysis. CONCLUSION: Two hybridoma cell lines secreting high titer of McAbs against LDHp with high specificity were established.

Animals↗
PubMed2000

[The effect of transforming growth factor-beta 1 on the secretion of collagen type IV in cultured human trabecular cells].

PURPOSE: To investigate the effect of transforming growth factor-beta 1 (TGF-beta 1) on the expression of collagen type IV in cultured human trabecular cells. METHODS: On the basis of successful culture of human trabecular cells, we detected the content of collagen type IV in the media and covers of trabecular cells, treated with TGF-beta 1 (1 ng/ml), by using enzyme-linked immunosorbent assay(ELISA) and immunohistochemical techniques respectively. RESULTS: ELISA method demonstrated that, in the first four days, there was statiscally significant difference between TGF-beta 1 treated and control groups with the collagen type IV content of 187.50 +/- 29.01 pg/ml and 93.75 +/- 20.50 pg/ml respectively, then in the second four days, there was no statistically significant difference between experimental group of 128.75 +/- 52.02 pg/ml and control group of 91.25 +/- 21.36 pg/ml. Neither statistical difference was found between two treated groups, nor was between two control groups. Immunohistochemical techniques showed, the positive staining of collagen type IV was stronger in cell covers of experimental group treated with TGF-beta 1 for 12 days than that of control group. CONCLUSION: TGF-beta 1 can increase the expression of collagen type IV in cultured trabecular cells, it may be among causes of abnormal accumulation of extracellular matrices in trabecular meshwork of eyes with primary open angle glaucoma.

Cells, Cultured↗
PubMed2000

[Intracytoplasmic injection with sperm from ejaculation, epididymis and testis in treating different male infertility with oligo-asthenozoospermia or azoospermia ].

OBJECTIVE: To retrospectively study 400 intracytoplasmic sperm injection (ICSI) cycles by using three different sources of sperm. METHOD: Different male infertility with oligo-asthenozoospermia or azoospermia was treated by ICSI using sperm from ejaculation, epididymis and testis. RESULTS: In the ejaculation group (n = 277), the fertilization rate was 69.6% and the clinical pregnancy rate 28.9%. In the 104 cycles using epididymal sperm, the fertilization and clinical pregnancy rate was 65.9% and 37.5% respectively. And the fertilization and clinical pregnancy of testis sperm (n = 19) was 65.7% and 21.1%. The difference of fertilization and clinical pregnancy rate among the three groups were not significant. CONCLUSIONS: Male infertility of different causes can be treated by ICSI. The outcome has nothing to do with the common parameter of semen except that the sperm motility is 0, but the effectiveness of ICSI should be studied by long-term observation.

Adult↗
PubMed2000

[Expression of inducible nitric oxide synthase in human esophageal biopsies from carcinoma and precancerous lesions].

OBJECTIVE: To investigate the possible role of inducible nitric oxide synthase (iNOS) in esophageal carcinogenesis. METHODS: iNOS expressions in normal epithelial cells(NC), hyperplastic cells(HC), atypical hyperplastic cells(AHC) from grade I to III, carcinoma in situ(CIS), squamous cell carcinoma(SCC), and adenocarcinoma(ADC) were detected with immunohistochemistry. RESULTS: The positive rates of immunohistochemistry staining was 0 for NC, 2.5% for HC, 4.0%, 7.5% and 2.5% for AHC grade I to III respectively, 1.4% for CIS, 8.5% for SCC and 71.4% for ADC. CONCLUSIONS: There is a high expression of iNOS in human esophageal adenocarcinomas. Frequent expression of iNOS may be a potential event in ADC carcinogenesis. There is no correlation between iNOS and SCC carcinogenesis.

Adenocarcinoma↗
PubMed1999

A polyclonal antibody to protein disulfide isomerase induces platelet aggregation and secretion.

Monoclonal mouse antiplatelet antibodies against a variety of platelet surface components can activate platelets, causing platelet aggregation and secretion. The mechanism involves binding of the Fab domain to a platelet surface antigen, and the activation occurs through an interaction of the Fc domain with the platelet FcgammaRII receptor. There is almost no information on FcgammaRII receptor-dependent activation of platelets by polyclonal rabbit antibodies. We presently report that a polyclonal rabbit antibody to a platelet surface antigen, protein disulfide isomerase, induces platelet aggregation and secretion. These effects are seen with concentrations of the antiprotein disulfide isomerase antibody as low as 25 to 40 microg/mL. Fab and F(ab')2 preparations of the rabbit antiprotein disulfide isomerase antibody do not cause aggregation. Fab made from the rabbit antiprotein disulfide isomerase antibody as well as a monoclonal antibody to the FcgammaRII (IV.3) receptor block the aggregation and secretion responses. Aggregation and secretion are inhibited by an antiglycoprotein IIbIIIa antibody, which blocks fibrinogen binding and wortmannin, an inhibitor of phosphoinositide 3-kinase. Aspirin, prostaglandin E1, and Ethylenediamine-tetraacetic acid (EDTA) also block the platelet responses. These data suggest that activation of platelets by polyclonal antibodies occurs by mechanisms similar to those found with activating monoclonal antibodies.

Animals↗
PubMed1999

Maspin plays an important role in mammary gland development.

Maspin is a unique member of the serpin family, which functions as a class II tumor suppressor gene. Despite its known activity against tumor invasion and motility, little is known about maspin's functions in normal mammary gland development. In this paper, we show that maspin does not act as a tPA inhibitor in the mammary gland. However, targeted expression of maspin by the whey acidic protein gene promoter inhibits the development of lobular-alveolar structures during pregnancy and disrupts mammary gland differentiation. Apoptosis was increased in alveolar cells from transgenic mammary glands at midpregnancy. However, the rate of proliferation was increased in early lactating glands to compensate for the retarded development during pregnancy. These findings demonstrate that maspin plays an important role in mammary development and that its effect is stage dependent.

Animals↗
PubMed1999

Human 76p: A new member of the gamma-tubulin-associated protein family.

The role of the centrosomes in microtubule nucleation remains largely unknown at the molecular level. gamma-Tubulin and the two associated proteins h103p (hGCP2) and h104p (hGCP3) are essential. These proteins are also present in soluble complexes containing additional polypeptides. Partial sequencing of a 76- kD polypeptide band from these complexes allowed the isolation of a cDNA encoding for a new protein (h76p = hGCP4) expressed ubiquitously in mammalian tissues. Orthologues of h76p have been characterized in Drosophila and in the higher plant Medicago. Several pieces of evidence indicate that h76p is involved in microtubule nucleation. (1) h76p is localized at the centrosome as demonstrated by immunofluorescence. (2) h76p and gamma-tubulin are associated in the gamma-tubulin complexes. (3) gamma-tubulin complexes containing h76p bind to microtubules. (4) h76p is recruited to the spindle poles and to Xenopus sperm basal bodies. (5) h76p is necessary for aster nucleation by sperm basal bodies and recombinant h76p partially replaces endogenous 76p in oocyte extracts. Surprisingly, h76p shares partial sequence identity with human centrosomal proteins h103p and h104p, suggesting a common protein core. Hence, human gamma-tubulin appears associated with at least three evolutionary related centrosomal proteins, raising new questions about their functions at the molecular level.

Amino Acid Sequence↗
PubMed1999

Casein kinase 2 binds and phosphorylates the nucleosome assembly protein-1 (NAP1) in Drosophila melanogaster.

The nucleosome assembly protein-1 (NAP1) was originally identified in HeLa cells as a factor facilitating the in vitro assembly of nucleosomes. However, in yeast cells NAP1 is required in the control of mitotic events induced by the Clb2/p34(CDC28). Here, we show that Drosophila NAP1 is a phosphoprotein that is associated with a kinase able to phosphorylate NAP1. By using an in-gel kinase assay we found that this kinase displays a molecular mass of 38 kDa. Following purification and peptide microsequencing, we identified the kinase phosphorylating NAP1 as the alpha subunit of casein kinase 2 (CK2). With the help of a series of NAP1 segments and synthetic peptides, we assigned the CK2 phosphorylation sites to residues Ser118, Thr120, and Ser284. Interestingly, Ser118 and Thr120 are located within a PEST domain, while Ser284 is adjacent to the nuclear localization signal. Substitution of the identified phosphoresidues by alanine was found to reduce considerably the ability of CK2 to phosphorylate NAP1. The enhanced ability of CK2 to phosphorylate phosphatase-treated NAP1 extracted from Drosophila embryos and the similar tryptic phospho-peptide pattern of in vivo labelled NAP1 and in vitro labelled NAP1 with CK2 indicate that NAP1 is a natural substrate of CK2. Further analysis revealed that both CK2alpha and beta subunits are associated with NAP1 but we found that only the catalytic alpha subunit establishes direct contact with NAP1 on two distinct domains of this protein. The location of CK2 phosphorylation sites in NAP1 suggests that their phosphorylation can contribute to a PEST-mediated protein degradation of NAP1 and the translocation of NAP1 between cytoplasm and nucleus.

Amino Acid Motifs↗