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B Su

Publications and source records attributed to B Su.

At least 91 records · Page 5Linked to original sources
PubMed1996

[Phylogenetic relationships among six species of Macaca inferred from ribosomal DNA variations].

Restriction maps of ribosomal DNA repeating units of six species of Macaca (M. mulatta, M. facsicularis, M. arctoides, M. assamensis, M. thibetana, M. nemestrina) and two outgroup species, Rhinopithecus bieti and Hylobates leucogenys, were constructed with 15 restriction endonucleases and 28S, 18S rDNA probes cloned from human, M. arctoides shares a common restriction map with M. assamensis. Phylogenetic tree derived from the neighbor-joining was somewhat different that derived from the maximum likelihood methods using the NEIGHBOR and RESTML program in PHYLIP version 3.5c. However, the consensus of our phylogenetic trees supports the viewpoint that M. facsicularis and M. mulatta were maybe diverged first in the genus Macaca. Further studies using DNA sequencing method are required to resolve the phylogeny of the genus Macaca.

Animals↗
PubMed1996

[A new way for inbred strain mice genetic monitoring and the discovery of sex-linkaging RAPD markers].

We used 21 10 bp random primers to amplify DNA for four colonies of BALB/ c mice, four individuals of C 57 BL mice, and four individuals of Kunming stock mice. The amplified band patterns were different between BALB/c and C 57 BL mice in the products of 13 primers, and 8 primer products showed difference between BALB/c and Kunming stock mice. These results indicated that we can easily distinguish different strains of mice by RAPD method. For the four colonies of BALB/c mice, the genetic background of Chengdu colony. Shanghai colony and Beijing colony were homogeneous at all RAPD markers, however, in Kunming colony, there were two BALB/c individuals were disclosed different amplified patterns by 4 primers, showing that these two Kunming BALB/c mice maybe suffer genetic contamination or mutation some time. An unexpected phenomenon discovered in this study is that sex specific amplification bands were amplified by primer OPG 2, OPE 4, OPE 9 in all male mice. Although an 1.2 kb band were disclosed by both OPG 2 and OPE 4 in male mice, cross RAPD and not hybridization showed that the two bands were not homologous.

Animals↗
PubMed1995

Identification of galactitol 2-phosphate and galactitol 3-phosphate in the lens of galactose-fed rats.

Production of unusual phosphorylated metabolites in the lens is one of several changes caused by hyperglycemia. Sorbitol 3-phosphate (Sor-3P) and fructose 3-phosphate (Fru-3P) are two such compounds identified in the diabetic lens, and galactitol 2-phosphate (Gal-2P) and galactitol 3-phosphate (Gal-3P) are identified here in the galactosemic lens. These new compounds are the first example of galactitol metabolism in mammalian tissue other than liver. Sor-3P and Fru-3P are also present in the galactosemic lens, apparently synthesized directly from their precursors, sorbitol and fructose, which are elevated in the lens due to increased flux of glucose through the aldose reductase (AR) pathway. The NADPH necessary to support this increased flux is derived from activation of the hexose monophosphate shunt (HMPS), which is clearly demonstrated by a large increase in the concentration of sedoheptulose 7-phosphate (Sed-7P), a HMPS-specific metabolite. Additionally, during 3 weeks of galactose feeding, there is a dramatic increase in lenticular concentrations of galactitol, sorbitol, galactose, and fructose and a sharp decrease in inositol. Glucose remains unchanged. A precipitous loss of both phosphorylated and nonphosphorylated metabolites occurs after 3 weeks, possibly due to lens rupture.

Animals↗
PubMed1995

Phylogenetic relationships among two species of golden monkey and three species of leaf monkey inferred from rDNA variation.

Restriction maps of rDNA repeats of five species of Colobinae and three outgroup taxa, Hylobates leucogenys, Macaca mulatta, and Macaca irus, were constructed using 15 restriction endonucleases and cloned 18S and 28S rRNA gene probes. The site variation between Rhinopithecus roxellana and Rhinopithecus bieti is comparable to that between Presbytis françoisi and Preshytis phayrei, implying that R. bieti is a valid species rather than a subspecies of R. roxellana. Phylogenetic analysis on the 47 informative sites supports the case for Rhinopithecus being an independent genus and closely related to Presbytis. Furthermore, branch lengths of the tree seem to support the hypothesis that the leaf monkeys share some ancestral traits as well as some automorphic characters.

Animals↗
PubMed1995

31P-nuclear magnetic resonance evidence of an activated hexose-monophosphate shunt in hyperglycemic rat lenses in vivo.

Using 31P-nuclear magnetic resonance spectroscopy, we have identified elevated concentrations of sedoheptulose-7-phosphate (S-7-P) in lenses from three animal models of hyperglycemia: streptozotocin-induced diabetic rats, galactose-fed rats, and xylose-fed rats. This observation provides a unique and independent confirmation of the activation of the hexose monophosphate shunt (HMPS) pathway in the hyperglycemic lens in vivo. While the elevation in concentration of S-7-P was very dramatic, the other HMPS metabolites in these tissues were below the threshold of detection, as expected for the HMPS pathway near equilibrium. In terms of nonenzymatic glycation, these results suggest that the only HMPS metabolite of importance in the hyperglycemic rat lens is S-7-P. Although in the diabetic lens its role appears to be relatively minor, in the galactosemic lens this compound may be an important contributor to the increased production of advanced glycosylation end products.

Animals↗
PubMed1995

[Effect of low dose rhTNF-alpha on immune function of lymphocytes in burned rats].

SD rats (200-230 g body weight) were randomly divided into three groups: (1) sham burn; (2) burn; (3) burn plus rhTNF-alpha. Third degree burn of 30% TBSA on the trunk was produced in groups 2 and 3. Intravenous rhTNF-alpha(10 micrograms/kg) was administered 6 hours postburn and once daily thereafter for 5 days in group 3. At 5 days postburn, splenic lymphocytes obtained from all the animals were used for the determination of distribution of T lymphocyte subsets with flowcytic analysis and activity of IL-2(Gills method). The results indicated that low dose rhTNF-alpha in vivo could improve distribution of splenic T lymphocyte subsets in burned rats by increasing the numbers of W3/25(Th) and decreasing the number of OX-8(Ts), and the ratio of W3/25/OX-8 was raised. In vitro the proliferation response of T lymphocytes to ConA was enhanced and the activity of IL-2 was increased by 108%, 149% and 168%, respectively, in group 3 compared with that in group 2. However, a dose-dependent effect, in that a small dose (< or = 10 ng/2.5 x 10(6) cells) of rhTNF-alpha improved the immune function of T lymphocytes, while a higher dose inhibited T lymphocyte immune function. These findings showed that rhTNF-alpha improved not only the distribution of T lymphocyte subsets but also their immune activity.

Animals↗
PubMed1995

[Large-scale culture of human keratinocytes].

We propose a modification of the conventional keratinocyte subculture method, showing a significant improvement in the colony growth capacity of subcultured keratinocytes. This method utilized mouse 3T3 fibroblasts and MCDB153 medium, and it has been shown that they could improve the colony growth of human keratinocytes. Compare with the conventional procedure, this culture method was shorter in time, and resulted in a higher colony growth capacity of cells, reaching confluence 3 days earlier. In the treatment of extensively burned patients using cultured epidermal sheets, the time required for their production remains the main problem. Thus, the significantly reduced time to obtain confluent keratinocyte sheets with our method is very important for the treatment of large burn wounds.

3T3 Cells↗
PubMed1995

[Expression of p53 gene protein in squamous cell carcinoma and precancerous lesion of vulva].

OBJECTIVES: To investigate the relationship between p53 gene protein expression and vulvar carcinoma. METHODS: Expression of p53 gene mutative protein was determined by immunohistochemical technique in 17 specimens of vulva squamous cell carcinoma, 11 of atypical hyperplasia, 22 of lichen sclerosus et atrophicus, 34 of hyperplastic dystrophy, 48 of mixed dystrophy. Normal skin samples from abdomen and legs, and adjacent tissues of vulvar cancer were served as controls. RESULTS: All specimens of normal skin showed no p53 gene mutative protein expression. However, p53 protein positive rates were 52.9% (9/17) in carcinoma group, 54.5% (6/11) in atypical hyperplasia, 13.6% (3/22) in lichen sclerosus et atrophicus group, 20.8% (10/48) in mixed dystrophy, 14.7% (5/34) in hyperplastic dystrophy. CONCLUSIONS: p53 gene mutative protein had a higher expression rate in vulva squamous cell carcinoma and precancerous lesion than that in various types of vulva dystrophy (P < 0.01). These data suggested that overexpression of p53 gene mutative protein may be related to the oncogenesis of vulva malignancy.

Carcinoma, Squamous Cell↗
PubMed1995

Synergistic inhibition of human cell-mediated cytotoxicity by complement component antisera indicates that target cell lysis may result from an enzymatic cascade involving granzymes and perforin.

A widely accepted theory of lymphocyte-mediated cytotoxicity (CMC) proposes that upon effector cell (EC) and target cell (TC) interaction, release of perforin, serine proteases and other lytic moieties contained within cytoplasmic granules results in TC lysis. Complement activation and the activation of the various enzymatic activities associated with cytotoxic granules have strikingly similar modes of action and both lead to pore formation in their respective targets. We report here that by using antisera to early and late complement components we were able to inhibit CTL, NK and ADCC cytotoxicity up to 100%, even though binding of EC to TC was unaffected. Furthermore, we showed that addition of C1q or C1s (two serine proteases) antisera to C9 antisera, at titers too low to inhibit separately, resulted in synergistic inhibition of CMC. Anti-C1s together with anti-C1q (or anti-C8 with anti-C9) did not result in synergy. This finding supports a cascade model of activation for lytic molecules released from EC. In addition, we demonstrated that anti-C1q and anti-C1s bind to proteins in the 30-kD region and anti-C9 binds to proteins in the 70-kD region, coinciding with published molecular weights of granzymes and perforin, respectively. Finally, lytic ability of purified granules was also inhibited by complement antisera, further suggesting that activation occurs outside of TC. Taken as a whole, these data indicate that TC lysis may be the result of a cascade of events involving granzymes and perforin, analogous to that seen with the complement system.

Antibodies, Monoclonal↗
PubMed1994

JNK2 contains a specificity-determining region responsible for efficient c-Jun binding and phosphorylation.

The transcriptional activity of c-Jun is augmented through phosphorylation at two sites by a c-Jun amino-terminal kinase (JNK). All cells express two distinct JNK activities, 46 and 55 kD in size. It is not clear which of them is the more important c-Jun kinase and how they specifically recognize c-Jun. The 46-kD form of JNK was identified as a new member of the MAP kinase group of signal-transducing enzymes, JNK1. Here, we report the molecular cloning of the 55-kD form of JNK, JNK2, which exhibits 83% identity and similar regulation to JNK1. Despite this close similarity, the two JNKs differ greatly in their ability to interact with c-Jun. JNK2 binds c-Jun approximately 25 times more efficiently than JNK1, and as a result has a lower Km toward c-Jun than JNK1. The structural basis for this difference was investigated and traced to a small beta-strand-like region near the catalytic pocket of the enzyme. Modeling suggests that this region is solvent exposed and therefore is likely to serve as a docking site that increases the effective concentration of c-Jun near JNK2. These results explain how two closely related MAP kinases can differ in their ability to recognize specific substrates and thereby elicit different biological responses.

Amino Acid Sequence↗
PubMed1994

Molecular cloning of the human angiotensin II type 2 receptor cDNA.

A human adult lung cDNA library was screened and one full-length human angiotensin II type 2 receptor (hAT2R) clone was isolated and characterized. The hAT2R cDNA clone contains a 1089-base-pair open reading frame which encodes a protein of 363 amino acid residues. The hAT2R is approximately 92% identical in sequence to the rat and mouse AT2R sequences. Specific binding of [125I]CGP42112A was demonstrated in membranes from COS-7 cells transiently transfected with the hAT2R cDNA. Scatchard analysis and ligand displacement profiles were typical of the AT2R. Northern analysis demonstrated that the hAT2R mRNA was abundantly expressed in human adult lung and in human fetal kidney. Additionally, the hAT2R mRNA was just detectable in human adult heart and aorta. In contrast, the rat AT2R mRNA was abundantly expressed in the rat brain and just detectable in the rat lung.

Adult↗
PubMed1994

The genomic organization and functional analysis of the promoter for the human angiotensin II type 1 receptor.

We have cloned and characterized several human angiotensin II type 1 receptor (hAT1R) cDNAs by utilizing the 5'-RACE procedure. Sequence analysis demonstrated that human AT1 receptors are encoded by at least four distinct mRNA transcripts sharing an identical open reading frame, but differing in their organization of 5'-untranslated sequences. Therefore, even though multiple alternatively spliced forms of hAT1R mRNA are transcribed, they are all translated into identical receptors since the entire open reading frame of this receptor is harbored on a single exon. None of these exons coding for 5'-untranslated sequence is expressed in a tissue specific manner. By comparing the 5'-RACE cDNA clones with our hAT1R genomic clones, the organization of the hAT1R gene was determined. The human AT1 gene is comprised of at least four exons and spans at least 60 kb. Several putative promoter regions were characterized by utilizing primer extension and luciferase reporter gene constructs transfected into human adrenal cells. These results indicate that we have cloned a functional promoter for the hAT1R gene. Furthermore, this promoter harbors an adrenal specific response element.

Adenocarcinoma↗
PubMed1994

JNK is involved in signal integration during costimulation of T lymphocytes.

T lymphocyte activation and interleukin-2 (IL-2) production require at least two signals, generated by phorbol ester (TPA) and Ca2+ ionophore or costimulation of the T cell receptor (TCR) and the CD28 auxiliary receptor. We investigated how these stimuli affect mitogen activated protein (MAP) kinases. Full activation of the MAP kinases that phosphorylate the Jun activation domain, JNK1 and JNK2, required costimulation of T cells with either TPA and Ca2+ ionophore or antibodies to TCR and CD28. Alone, each stimulus resulted in little or no activation. Similar to its effect on IL-2 induction, cyclosporin A (CsA) inhibited the synergistic activation of JNK, and a competitive inhibitor of Jun phosphorylation by JNK inhibited IL-2 promoter activation. By contrast, the MAP kinases ERK1 and ERK2 were fully activated by TPA or TCR stimulation and were not affected by Ca2+, CD28, or CsA. Hence, integration of signals that lead to T cell activation occurs at the level of JNK activation.

Animals↗
PubMed1994

Ly-6A is required for T cell receptor expression and protein tyrosine kinase fyn activity.

To characterize the function of the Ly-6A antigen in T cell activation, antisense Ly-6 RNA was expressed in a stably transfected antigen-specific T cell clone. Reduced Ly-6A expression results in inhibition of responses to antigen, anti-TCR (anti-T cell receptor) crosslinking and concanavalin A plus recombinant interleukin 1 and causes impairment of in vitro fyn tyrosine kinase activity. More substantial reduction of Ly-6A results in reduction of TCR expression. Analysis of mRNA species indicates that the reduction is specific for the TCR beta chain. These data demonstrate that Ly-6A may regulate TCR expression and may be involved in early events of T cell activation via regulation of fyn tyrosine kinase activity.

Animals↗
PubMed1994

JNK1: a protein kinase stimulated by UV light and Ha-Ras that binds and phosphorylates the c-Jun activation domain.

The ultraviolet (UV) response of mammalian cells is characterized by a rapid and selective increase in gene expression mediated by AP-1 and NF-kappa B. The effect on AP-1 transcriptional activity results, in part, from enhanced phosphorylation of the c-Jun NH2-terminal activation domain. Here, we describe the molecular cloning and characterization of JNK1, a distant relative of the MAP kinase group that is activated by dual phosphorylation at Thr and Tyr during the UV response. Significantly, Ha-Ras partially activates JNK1 and potentiates the activation caused by UV. JNK1 binds to the c-Jun transactivation domain and phosphorylates it on Ser-63 and Ser-73. Thus, JNK1 is a component of a novel signal transduction pathway that is activated by oncoproteins and UV irradiation. These properties indicate that JNK1 activation may play an important role in tumor promotion.

Amino Acid Sequence↗