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Biomedical subjects

Q Tian

Publications and source records attributed to Q Tian.

At least 37 records · Page 2Linked to original sources
PubMed1999

Control of auxin-regulated root development by the Arabidopsis thaliana SHY2/IAA3 gene.

The plant hormone auxin controls many aspects of development and acts in part by inducing expression of various genes. Arabidopsis thaliana semidominant shy2 (short hypocotyl) mutations cause leaf formation in dark-grown plants, suggesting that SHY2 has an important role in regulating development. Here we show that the SHY2 gene encodes IAA3, a previously known member of the Aux/IAA family of auxin-induced genes. Dominant shy2 mutations cause amino acid changes in domain II, conserved among all members of this family. We isolated loss-of-function shy2 alleles including a putative null mutation. Gain-of-function and loss-of-function shy2 mutations affect auxin-dependent root growth, lateral root formation, and timing of gravitropism, indicating that SHY2/IAA3 regulates multiple auxin responses in roots. The phenotypes suggest that SHY2/IAA3 may activate some auxin responses and repress others. Models invoking tissue-specificity, feedback regulation, or control of auxin transport may explain these results.

Amino Acid Sequence↗
PubMed1999

[Cloning of a new cDNA: responded to all-trans retinoic acid in HL-60 cell differentiation].

In this paper a new type of cDNA fragment named as W-1 gene was first cloned and sequenced from ATRA induced HL-60 cells by using differential display PCR (DD-PCR) and DNA sequencing techniques. These differentially expressing products of the gene responding to ATRA were further confirmed by Northern blotting analysis. The results showed that the expressing level of this gene induced by ATRA (10(-6) mol.L-1) for 16 hrs was much higher than that in the control HL-60 cells, but its expression in HL-60 was reduced to an unestimable level after induction of ATRA (10(-6) mol.L-1) for 24 hrs. It suggests that ATRA may increase the expression of W-1 gene during the early stage of HL-60 cell differentiation. The exact mechanism of action is being studied further.

Antineoplastic Agents↗
PubMed1999

[Expression of ET-1 and Pr ET-1 mRNA in kidney of early diabetic rats].

The purpose of this study was to explore the role of endothelin 1 (ET-1) and pr ET-1 mRNA in kidney of early diabetic rats. The location and level of ET-1 were determined by immuno-histochemical staining; ET-1 cDNA probe was used for in situ hybridization. The expressions of ET-1 and ET-1 mENA in the kidneys of 24 early diabetic rats were detected by microscopy and Mia-2000 patho-image-analysis system. The results revealed that the ET-1 mRNA and ET-1 were principally distributed in the glomerular endothelial cells, mesangial cells, smooth muscle cells of vessels, epithelial cell lining tubules and collecting ducts, showing no difference in the distribution over kidney, but the expressions of ET-1 and ET-1 mRNA were higher in the renal medulla. The levels of ET-1 and ET-1 mRNA in glomeruli significantly decreased at week 1 and week 2(P < 0.05), but increased at week 4(P < 0.05). However, the levels of ET-1 and ET-1 mRNA continually increased from week 1 to week 4 in the medulla of diabetic rats. These data suggest that ET-1 and ET-1 mRNA may induce the glomerular hyperperfusion and damage the tubulointerstitial of the kidneys in early diabetic rats.

Animals↗
PubMed1998

Modification of Ran GTPase-activating protein by the small ubiquitin-related modifier SUMO-1 requires Ubc9, an E2-type ubiquitin-conjugating enzyme homologue.

Covalent modification of the Ran GTPase-activating protein RanGAP1 with the ubiquitin-related protein SUMO-1 promotes its association with Nup358, a component of the cytoplasmic fibrils emanating from the nuclear pore complex (1,2). In Xenopus egg extracts, Nup358 can be found in a complex with Ubc9 (3), a structural homologue of the E2-type ubiquitin-conjugating enzymes (UBCs). Here we show that a subset of the human homologue of Ubc9 (HsUbc9) colocalizes with RanGAP1 at the nuclear envelope. HsUbc9 forms thiolester conjugates with recombinant SUMO-1, but not with recombinant ubiquitin, indicating that it is functionally distinct from E2-type UBCs. Finally, HsUbc9 is required for the modification of RanGAP1 by SUMO-1. These results suggest that HsUbc9 is a component of a novel enzymatic cascade that modifies RanGAP1, and possibly other substrates, with SUMO-1.

Adenosine Triphosphate↗
PubMed1998

[Pathological characteristics of gonads in nine patients with true hermaphroditism].

OBJECTIVE: To investigate the gonadal histopathology of true hermaphroditism and its correlation with the clinical features. METHODS: Clinico-pathological materials and chromosomal karyotypes from 9 true hermaphroditisms were reviewed. RESULTS: Seven out of 9 patients aged 5-21 years had been raised as females, and the other two were raised as males. Ovotestis was the most common form of the abnormal gonads, 2 out of 9 patients had bilateral ovotestes, 7 had unilateral ovotestes (5 in right side, 2 in left side). In the 7 patients with unilateral ovotestis, 6 had a contralateral ovary and one had a contralateral testis. Microscopically, the ovarian tissue of 11 ovotestes, including 6 biopsies from contralateral ovaries were normal, with many primordial follicles and a few growing follicles. In two of the patients, aged over 15 years, evidence of ovulation was observed. In comparison, the testicular tissue of the ovotestis and one left inguinal testis was histologically abnormal. Two of the 9 patients conceived and delivered normal infants by cesarean section after surgical treatment. CONCLUSION: Identification of the gonadal histopathology in these cases is important in order to make a correct scheme for the treatment.

Adolescent↗
PubMed1997

Percutaneous vasal sperm aspiration and intrauterine insemination in the treatment of obstructive azoospermia.

OBJECTIVE: To treat obstructive azoospermia by using sperm recovered from percutaneous vasal sperm aspiration in IUI. DESIGN: Clinical study. SETTING: Institutional clinic in Jinan. PATIENT(S): Six men with obstructive azoospermia, three of whom were treated with percutaneous vasal sperm aspiration and IUI; sperm recovered from this procedure were used for IUIs. INTERVENTION(S): Spermatozoa used for intrauterine injection were retrieved by percutaneous vasal sperm aspiration and incubated at 37 degrees C for 40 to 60 minutes. MAIN OUTCOME MEASURE(S): Normal pregnancy. RESULT(S): Intrauterine insemination was performed in three patients for one or two cycles, with motile spermatozoa. There was one successful term delivery. CONCLUSION(S): Percutaneous vasal sperm aspiration can be used successfully to recover sperm in men with obstructive azoospermia for use in IUI. The technique is simple and less traumatic than an open surgical procedure.

Female↗
PubMed1997

Marrow-mesenchyme connections in the fetal and newborn tympanum. A new entity.

Examinations of 41 human fetal, 8 infant, and 8 juvenile temporal bones prepared for light microscopic evaluation revealed direct connections between the hematopoietic bone marrow and the unresolved mesenchyme in the middle ear. The connections first appeared at 15 weeks of gestation and became bridged by fibrous tissue, in most cases, by the postpartum age of 10 months. Between 16 and 18 months after birth, the marrow-mesenchyme connections gradually disappeared. The areas in which the connections were most numerous were the anterior epitympanum, the sinus tympani medial to the stapedius muscle, and transitory bone that occupies the area that will become the aditus of the antrum. Immunohistochemical staining demonstrated the existence of mature leukocytes in these connections. These connections may help protect the middle ear against bacterial invasion during the postnatal period.

Bone Marrow↗
PubMed1997

[The effect of smoking and passive smoking on thiocyanate content in saliva].

The saliva thiocyanate contents were determined among smokers and passive smokers. The saliva thiocyanate contents of passive smokers in smoking environment and non-smoking environment were compared. The results showed that the saliva thiocyanate in smoking environment was higher than that in non-smoking environment (P<0.01). The results indicate that the saliva thiocyanate detecting is a direct and sensitive index for evaluating the hazard of passive smoking.

Environmental Exposure↗
PubMed1997

[Study of spectrometer calibration experiment research].

Spectrometer calibration is very important for quantitative research of imaging spectral remote sensing. After spectral calibtation and radiometric calibration, it was known that the average shift of wavelength of SE590 channels was 8nm, and the linear response was depended on the change of energy recieved by SE590, and spectral response resolution was unreasonable beyond 950nm range. At last, the calibration results were proved by the field experiment measurement data.

English Abstract↗
PubMed1996

Synergistic effects of Vg1 and Wnt signals in the specification of dorsal mesoderm and endoderm.

In amphibians, dorsoventral asymmetry is established by cortical rotation, a cytoplasmic rearrangement in the egg which activates a dorsal determinant on one side of the zygote. This determinant has been proposed to be either Vgl, an endodermally derived molecule that can directly induce ectoderm to form dorsal mesoderm, or a member of the Wnt family, which patterns the ectoderm such that it forms dorsal mesoderm in response to ventral inductive signals. In this study, we have investigated whether the endogenous dorsal determinant(s) functions as a direct inducer of dorsal mesoderm (Vg1-like) or whether it acts to pattern the response of ectoderm to inductive signals (Wnt-like). We report here that cortical rotation enhances both the dorsal-inductive activity of endodermal cells and the response of ectodermal cells to endogenous inductive signals and that both of these activities are required for notochord induction in ectoderm/endoderm recombinants. While ectopically expressed Xwnt-8b can substitute for the dorsalizing signals activated in either ectoderm or endoderm, and can allow notochord formation in recombinants, Vg1 alone is not sufficient to induce notochord in ectodermal explants in the absence of signals activated by cortical rotation. Coexpression of Xwnt-8b along with Vg1 restores ectodermal competence to form notochord. Finally, in endodermal explants, ectopically expressed Xwnt-8b, but not Vg1, can divert the fate of ventral endodermal cells along a dorsal pathway. Thus, while Vg1 is most likely required for induction of mesoderm in vivo, our data suggest that a maternal Wnt-like signal acts synergistically with Vg1 to specify a dorsal fate not only in the mesoderm, but also in the endoderm.

Animals↗
PubMed1996

Characterization of GMP-17, a granule membrane protein that moves to the plasma membrane of natural killer cells following target cell recognition.

Cytotoxic lymphocytes are characterized by their inclusion of cytoplasmic granules that fuse with the plasma membrane following target cell recognition. We previously identified a cytotoxic granule membrane protein designated p15-TIA-1 that is immunochemically related to an RNA-recognition motif (RRM)-type RNA-binding protein designated p40-TIA-1. Although it was suggested that p15-TIA-1 might be derived from p40-T1A-1 by proteolysis, N-terminal amino acid sequencing of p15-TIA-1 immunoaffinity purified from a natural killer (NK) cell line by using monoclonal antibody (mAb) 2G9 revealed that p15-T1A-1 is identical to the deduced amino acid sequence of NKG7 and GIG-1, cDNAs isolated from NK cells and granulocyte-colony-stimulating factor-treated mononuclear cells, respectively. Epitope mapping revealed that mAb 2G9 recognizes the C terminus of p15-T1A-1 and p40-T1A-1. The deduced amino acid sequence of p15-T1A-1/NKG7/GIG-1 predicts that the protein possesses four transmembrane domains, and immuno-electron microscopy localizes the endogenous protein to the membranes of cytotoxic granules in NK cells. Given its subcellular localization, we propose to rename-this protein GMP-17, for granule membrane protein of 17 kDa. Immunofluorescence microscopy of freshly isolated NK cells confirms this granular localization. Target cell-induced NK cell degranulation results in translocation of GMP-17 from granules to the plasma membrane, suggesting a possible role for GMP-17 in regulating the effector function of lymphocytes and neutrophils.

Amino Acid Sequence↗
PubMed1996

Investigation on inhibition of biological effects of endothelin.

The effects of a series of substances on the biological function of endothelin (ET) are reported. The substances used are: synthetic inhibitors of endothelium derived relaxing factors (EDRFs), inhibitor of big-endothelin converting enzyme phosphoramidon, antiserum of endothelin, antagonists of endothelin A receptor BQ123 and JKC301, and two Chinese anti-snake venom herb medicines Lobelia radicans Thumb and Taris polyphylla Smith var. chinensis (Franch) Hara. The results showed that inhibiting the production of nitric oxide (NO) could stimulate ET release from vascular endothelium, elevate plasma ET and increase blood pressure. These changes could be reversed by L-arginine (L-Arg), the substrate of nitric oxide synthase (NOS). The amount of ET released by arterial endothelium could be increased or inhibited by inhibiting or stimulating the synthesis of prostacyclin (PGI2). The plasma ET level and blood pressure in both SHR and WKY rats could be decreased by giving phosphoramidon (PhR). The above results indicate that the biological effects of ET could be antagonized by inhibiting the synthesis or release of ET, decreasing the level of plasma ET, blocking the binding of ET with its receptor and using some Chinese anti-snake venom herb medicines.

Animals↗
PubMed1995

Fas-activated serine/threonine kinase (FAST) phosphorylates TIA-1 during Fas-mediated apoptosis.

We have identified a serine/threonine kinase that is rapidly activated during Fas-mediated apoptosis. Fas-activated serine/threonine kinase (FAST) is phosphorylated on serine and threonine residues in Jurkat cells. In response to Fas ligation, it is rapidly dephosphorylated and concomitantly activated to phosphorylate TIA-1, a nuclear RNA-binding protein that has been implicated as an effector of apoptosis. Phosphorylation of TIA-1 precedes the onset of DNA fragmentation, suggesting a role in signaling downstream events in the apoptotic program. Our results introduce Fast and TIA-1 as components of a molecular cascade involved in signaling Fas-mediated apoptosis.

Amino Acid Sequence↗
PubMed1995

The RNA-binding protein TIAR is translocated from the nucleus to the cytoplasm during Fas-mediated apoptotic cell death.

We have determined the structure, intracellular localization, and tissue distribution of TIAR, a TIA-1-related RNA-binding protein. Two related isoforms of TIAR, migrating at 42 and 50 kDa, are expressed in primate cells. Unlike TIA-1, which is found in the granules of cytotoxic lymphocytes, TIAR is concentrated in the nucleus of hematopoietic and nonhematopoietic cells. Because TIAR can trigger DNA fragmentation in permeabilized thymocytes, it is a candidate effector of apoptotic cell death. Consistent with this possibility, we have found that the expression and intracellular localization of TIAR change dramatically during Fas-mediated apoptosis. TIAR moves from the nucleus to the cytoplasm within 30 min of Fas ligation. Redistribution of TIAR precedes the onset of DNA fragmentation and is not a nonspecific consequence of nuclear disintegration. Cytoplasmic redistribution of TIAR is not observed during cellular activation triggered by mitogens such as concanavalin A or phytohemagglutinin. Our results suggest that cytoplasmic redistribution of TIAR may be a general feature of the apoptotic program.

Antibodies, Monoclonal↗
PubMed1995

GABAergic axons in the ventral forebrain of the rat: an electron microscopic study.

The ventral forebrain, including the ventral striatum, the ventral pallidum and the substantia innominata, is an important region involved in the functions of the basal ganglia and the limbic system, as well as the magnocellular corticopetal neurons of the nucleus basalis of Meynert. Although previous studies have shown that this region is richly innervated by GABAergic fibers, little is known with respect to the relative densities of GABAergic to non-GABAergic axon terminals in this region. To address this issue, we have developed a specific rabbit antiserum to GABA and used a postembedding immunocytochemical reaction to analyse the distribution of GABA-like immunoreactive axon terminals in the rat ventral striatum, ventral pallidum and substantia innominata. Of all axon terminals that form identifiable synapses within single ultrathin sections taken from these regions, 11.6% in the ventral striatum, 85.5% in the ventral pallidum and 64.8% in the substantia innominata were GABAergic. Differences were also found in the distribution patterns of these terminals with respect to the size of their synaptic target dendrites. These findings are consistent with previous findings that a majority of inputs to the ventral striatum are excitatory, and that a majority of inputs to the ventral pallidum are inhibitory. Our results provide a first approximation of the anatomical substrate for the physiology and pharmacology of GABA actions in the ventral forebrain region. These results also show that GABA may play an important role in the substantia innominata, where both the cholinergic and the non-cholinergic magnocellular corticopetal neurons reside within a neuropil innervated by many different non-cholinergic fibers.

Animals↗