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Biomedical subjects

W Hong

Publications and source records attributed to W Hong.

At least 109 records · Page 6Linked to original sources
PubMed1997

The mammalian homolog of yeast Sec13p is enriched in the intermediate compartment and is essential for protein transport from the endoplasmic reticulum to the Golgi apparatus.

The role of COPII components in endoplasmic reticulum (ER)-Golgi transport, first identified in the yeast Saccharomyces cerevisiae, has yet to be fully characterized in higher eukaryotes. A human cDNA whose predicted amino acid sequence showed 70% similarity to the yeast Sec13p has previously been cloned. Antibodies raised against the human SEC13 protein (mSEC13) recognized a cellular protein of 35 kDa in both the soluble and membrane fractions. Like the yeast Sec13p, mSEC13 exist in the cytosol in both monomeric and higher-molecular-weight forms. Immunofluorescence microscopy localized mSEC13 to the characteristic spotty ER-Golgi intermediate compartment (ERGIC) in cells of all species examined, where it colocalized well with the KDEL receptor, an ERGIC marker, at 15 degrees C. Immunoelectron microscopy also localized mSEC13 to membrane structures close to the Golgi apparatus. mSEC13 is essential for ER-to-Golgi transport, since both the His6-tagged mSEC13 recombinant protein and the affinity-purified mSEC13 antibody inhibited the transport of restrictive temperature-arrested vesicular stomatitis virus G protein from the ER to the Golgi apparatus in a semi-intact cell assay. Moreover, cytosol immunodepleted of mSEC13 could no longer support ER-Golgi transport. Transport could be restored in a dose-dependent manner by a cytosol fraction enriched in the high-molecular-weight mSEC13 complex but not by a fraction enriched in either monomeric mSEC13 or recombinant mSEC13. As a putative component of the mammalian COPII complex, mSEC13 showed partially overlapping but mostly different properties in terms of localization, membrane recruitment, and dynamics compared to that of beta-COP, a component of the COPI complex.

Animals↗
PubMed1997

Endoplasmic reticulum retention mediated by the transmembrane domain of type II membrane proteins Sec12p and glucosidase 1.

The yeast Sec12p, a type II protein localized to the yeast endoplasmic reticulum (ER), is similarly localized to the ER when expressed in mammalian cells. Replacing the transmembrane domain of the plasma membrane molecule dipeptidyl peptidase IV (D4) with that of Sec12p or the ER-localized enzyme glucosidase 1 resulted in the ER retention of the chimeric molecules, as assessed by immunocytochemical localization and the persistence of pulse-labeled proteins in the endoglycosidase H-sensitive form. Retention is not due to gross misfolding as these chimeras remained enzymatically active. Density gradient analysis revealed that the ER-localized chimeric molecules form high molecular weight oligomers quickly after synthesis. The type II transmembrane domain of ER proteins could therefore mediate retention in the ER.

Animals↗
PubMed1997

[China-made paclitaxel in the treatment of advanced ovarian cancer: a clinical analysis of 32 cases].

OBJECTIVE: To study the effect and toxicities of China-made paclitaxel in the treatment of advanced epithelial ovarian carcinoma. METHODS: Thirty-two patients were divided into two groups. single paclitaxel group (SPG): paclitaxel was only given to twelve untreated patients or those who had been given only one course of chemotherapy at a dose of 175 mg/m2 in 5% glucose 500 ml, i.v. for 3 hours; and combined paclitaxel group (CPG): paclitaxel 135 mg/m2 in 5% glucose 55 ml, i.v. for 3 hours on day 1 plus cisplatin 70-80 mg/m2 or carboplatin 300 mg/m2, i.v. on day 2, was administered to 20 patients with persistent or recurrent tumor after platinum based chemotherapy. Four weeks were defined as one course in both groups. At least two courses were given except those with tumor progression after one course. RESULTS: The overall response rate was 39%. It was 27% and 45% in the SPG and CPG. The chief side effects were moderate myelosuppression, peripheral neuropathy (myalgia, arthralgia, peripheral neuritis), severe alopecia, etc., but no hypersensitivity. One patient died from intestinal perforation. CONCLUSIONS: China-made paclitaxel is effective as in treating ovarian carcinoma especially for platinum-resistant patients. The toxic effects are tolerable to the patients.

Adult↗
PubMed1996

GS28, a 28-kilodalton Golgi SNARE that participates in ER-Golgi transport.

Little is known about the integral membrane proteins that participate in the early secretory pathway of mammalian cells. The complementary DNA encoding a 28-kilodalton protein (p28) of the cis-Golgi was cloned and sequenced. The protein was predicted to contain a central coiled-coil domain with a carboxyl-terminal membrane anchor. An in vitro assay for endoplasmic reticulum-Golgi transport was used to show that p28 participates in the docking and fusion stage of this transport event. Biochemical studies established that p28 is a core component of the Golgi SNAP receptor (SNARE) complex.

Amino Acid Sequence↗
PubMed1996

A novel chimera gene between EWS and E1A-F, encoding the adenovirus E1A enhancer-binding protein, in extraosseous Ewing's sarcoma.

Ewing's sarcoma/PNET, a tumor of the bone and soft tissue, is one of the most common causes of tumor death among youths. This tumor does not have specific phenotypes, but does have characteristic chromosomal translocations. Furthermore, the expression of EWS/FLI-1 or EWS/ERG chimeric genes was found to be generated through a t(11;22)(q24;q12) or a t(21;22)(q22;q12) translocation. In this study, we identified a new chimera gene between the transactivation domain of EWS and E1A-F, encoding the adenovirus E1A enhancer-binding protein. Since E1A-F is known to activate matrix metalloproteinase genes, the chimera gene may possibly be involved in tumor progression and could be a novel tumor marker for Ewing's sarcoma/PNET.

Adenovirus E1A Proteins↗
PubMed1996

Cytotoxicity of KDEL-terminated ricin toxins correlates with distribution of the KDEL receptor in the Golgi.

DNAs encoding ricin toxin A chain (RTA), with or without a C-terminal endoplasmic reticulum retention signal KDEL, were subcloned into pGEX2T bacterial expression plasmid. After transformation of JM105 E. coli cells and induction with isopropylthio-beta-galactoside (IPTG), fusion proteins were bound to an immobilized glutathione matrix and recombinant ricin A chains released with thrombin. Both recombinant wild-type RTA and RTA with KDEL had immunological reactivity and catalytic activity indistinguishable from plant RTA. The bacterial RTA products reassociated with plant ricin B chain (RTB) similarly to plant RTA. Cell cytotoxicities were measured on seven cell lines for each A-chain and heterodimer. Although KDEL sequences enhanced cytotoxicity in most cases, significant variability was observed. In each case, addition of KDEL enhanced A-chain cytotoxicity more than holotoxin cytotoxicity. Three cell lines showed reduced KDEL enhancement of both RTA and ricin cytotoxicity. The concentration of KDEL receptor was examined on each cell line by immunofluorescence microscopy with an antireceptor monoclonal antibody. Differences in sensitivity to KDEL-containing toxins correlated with altered distribution of KDEL receptor between endoplasmic reticulum (ER) and Golgi compartments.

Amino Acid Sequence↗
PubMed1996

The mammalian ARF-like protein 1 (Arl1) is associated with the Golgi complex.

A rat cDNA clone was isolated which encodes a protein displaying characteristics of a ras-like small GTPase. The deduced amino acid sequence shows the highest amino acid identity (79%) with the Drosophila ARF-like protein 1 (dArl1) among all the known members of the ras-like small GTPase superfamily. The encoded protein was tentatively named rat Arl1 (rArl1). Northern blotting analysis revealed that the rArl1 gene is ubiquitously expressed in rat tissues. Recombinant rArl1 fused to glutathione-S-transferase (GST) to create GST-rArl1 binds GTP-gamma-S in a dose-dependent manner. Polyclonal antibodies raised against two unique rArl1 peptides recognized a 22 kDa protein in total NRK cell lysate. Immunofluorescence microscopy of NRK cells revealed discrete perinuclear labelling that could be competed out by GST-rArl1 but not GST. Examination of 8 additional cell lines revealed a similar labelling, suggesting that the antigen recognised by the antibodies is conserved and widely-expressed. Co-localization experiments in NRK cells with antibodies to mannosidase II and a newly identified cis-Golgi protein, p28, showed that rArl1 is localized to the Golgi complex. When cells were treated with nocodazole, the Golgi complex marked by mannosidase II and p28 was fragmented into punctate structures scattered throughout the cell, in which rArl1 was colocalized. Treatment with brefeldin A (BFA) resulted in the redistribution of rArl1 and mannosidase II into the cytoplasm and endoplasmic reticulum, respectively. The kinetics of the redistribution of rArl1 in response to BFA differ from those of ARF and beta-COP, two components of non-clathrin coated vesicles.

ADP-Ribosylation Factors↗
PubMed1996

[Sixty years of study on history of medicine of Chinese minorities].

This paper is divided into three parts for the description of history of minority medicine: 1. Liberal period (before 1980), only a few papers were published, mostly individual study. 2. Foundation period (1980-1987), more papers were published, dealing with all aspects of the subject in an organized basis. 3. Flourishing period (1988-1995), an unprecedented and comprehensive development, both quantitatively and qualitatively. An independent branch of the science, History of Minority Medicine, is formed during this period.

China↗
PubMed1996

[Primary malignant melanoma of the vagina: a report of 22 cases].

In this paper, 22 patients from 1973 through 1994 with primary malignant melanoma are retrospectively analyzed. Vaginal bleeding, discharge and a tumor mass were the chief complaints. The most common site of the tumor origin was the lower third of the anterior and postrior vaginal wall. The 5-year survival rate of 18 previously untreated patients was 11% (2/18). Of the 18 patients, 9 in stage I treated by surgery and postoperative chemothreoapy and/or radiotherapy survived for an average of 33 months. Two of the 9 patients receiving radical surgery survived for more than 5 years. None of the remaining 9 patients in stage II-IV treated with chemotherapy and/or radiotherapy survived longer than 2 years. The survival time differed significantly in patients with and without pelvic lymph node metastasis (7 versus 41 months) and in those with and without vascular tumor thrombi (13 versus 43 months). Mitotic index of tumor cells and lymphocytic infiltration were of no prognostic value.

Adult↗
PubMed1995

Retardation of a surface protein chimera at the cis Golgi.

Dipeptidyl peptidase IV (D4) and the alpha subunit of human chorionic gonadotrophin (alpha hcg) are plasma membrane and secretory proteins, respectively. In the course of studies to understand mechanisms involved in transport along the exocytotic pathway, the ectoplasmic domain of D4 was replaced by the mature polypeptide of alpha hcg, resulting in the membrane anchored chimera, D4 alpha hcg. Surprisingly, when transfected into Chinese hamster ovary (CHO) and Madin-Darby canine kidney (MDCK) cells, strong perinuclear Golgi staining was predominant, in addition to the expected surface staining. By following the biogenesis and transport of the molecule, it was established that newly synthesized D4 alpha hdg is eventually transported to the cell surface but only after a significant retardation in the Golgi apparatus. The compartment of retardation was identified as the early or cis Golgi, before the medial Golgi, where resistance to endoglycosidase (endo) H is conferred. As a result of the transport retardation of the chimera, we were able to document the appearance of an endo D sensitive intermediate, which is usually too transient to be apparent in normal cells. The retardation of this chimera in the cis Golgi complements our previous report in which the D4 molecule with its transmembrane domain replaced by that of aminopeptidase N resulted in retardation in the trans Golgi/trans Golgi network in MDCK and CHO cells [Low, S. H., Tang, B. L., Wong, S. H., & Hong, W. (1994) J. Biol. Chem. 269, 1985-1994).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

A role for retinoblastoma protein in potentiating transcriptional activation by the glucocorticoid receptor.

The Saccharomyces cerevisiae SNF2/SWI2 protein is essential for the regulated expression of a variety of genes. A human SWI2/SNF2 homologue, hBrm, is a positive participant in glucocorticoid-receptor-mediated transcription, but its mechanism of action is not known. The retinoblastoma protein, RB, has also been shown to stimulate the transcription of several genes, although the target for RB has not been identified in any of these transcriptional events. Here we show that RB upregulates glucocorticoid-receptor-mediated transcription. The effect of either RB or hBrm is dependent on the presence of the other. Furthermore, we demonstrate that RB and hBrm interact with one another in vitro and in vivo. These results highlight a new role for RB, which is to interact with hBrm in order to potentiate glucocorticoid-receptor-activated transcription.

Amino Acid Sequence↗
PubMed1995

Additive interactions between propofol and ketamine when used for anesthesia induction in female patients.

BACKGROUND: Propofol and ketamine may be paired for anesthesia induction and for total intravenous anesthesia. The nature of any sedative interactions occurring between propofol and ketamine are unknown. The combination when used for anesthesia induction in female patients was studied. METHODS: Quantal dose-response curves were determined in 180 female patients to whom the drugs were administered individually and in combination. Two minutes after administering the drugs, two endpoints were assessed. First, loss of response to verbal command (hypnosis) and then, in those who failed to respond to this endpoint, loss of response to a 5-s transcutaneous tetanus (anesthesia). Interactions were analyzed by fitting the data to a mathematical model in which response was analyzed in terms of the doses of the two drugs and an additional term included to describe nonadditive interactions. The incidences of apnea, arterial pressure, and heart rate changes during the first 5 min were recorded. RESULTS: At the hypnotic endpoint, the ED50s were 1.10 mg/kg propofol (95% CIs 0.93-1.27), 0.39 mg/kg ketamine (95% CIs 0.27-0.46), and the combination of 0.63 mg/kg propofol and 0.21 mg/kg ketamine (95% CIs 0.53/0.18-0.73/0.24). At the anesthetic endpoint, the ED50s were 1.85 mg/kg propofol (95% CIs 1.58-2.36) 0.66 mg/kg ketamine (95% CIs 0.58-0.77), and the combination of 1.05 mg/kg propofol and 0.35 mg/kg ketamine (95% CIs 0.88/0.29-1.27/0.42). The effects were additive at both endpoints; there was no evidence of an interaction. The ED50s for apnea were 1.61 mg/kg propofol (95% CIs 1.39-1.94), greater than 0.85 mg/kg ketamine and for the combination 1.50 mg/kg propofol and 0.50 mg/kg ketamine (95% CIs 1.15/0.38-3.09/1.03). The addition of ketamine did not significantly alter the ED50 for apnea of propofol. There was a significant difference in the arterial pressures among the three groups (P < 0.001). Using the combination, the cardiostimulant effects of ketamine balanced the cardiodepressant effects of propofol. There was no change in arterial pressure or heart rate after the noxious stimulus. CONCLUSIONS: When using the combination, doses were additive at hypnotic and anesthetic endpoints. Ketamine had no influence on the incidence of apnea after propofol, and the net hemodynamic effects were minimal.

Adult↗
PubMed1995

Monoclonal antibody HFD9 identifies a novel 28 kDa integral membrane protein on the cis-Golgi.

We have raised a monoclonal antibody (mAb) (HFD9) that detects a 28 kDa protein (p28) enriched in the Golgi membrane. p28 was localized to the perinuclear Golgi region in all cell lines thus far examined. Its Golgi localization was confirmed by its colocalization with Golgi markers using indirect immunofluorescence microscopy. Immunogold labelling demonstrates that the majority of p28 was localized on the cis-Golgi and its associated structures. Two independent experiments demonstrate that the p28 epitope recognized by mAb HFD9 is exposed to the cytosol. Extraction of Golgi membranes with a variety of reagents revealed that p28 behaves like an integral membrane protein. mAb HFD9 thus defines a novel 28 kDa integral membrane protein on the cis-Golgi. To our knowledge, p28 represents the first integral membrane protein of the Golgi system identified via the antibody approach whose epitope is cytoplasmically-oriented and highly-conserved. Monoclonal antibody HFD9 will thus provide a useful tool for further studies on the cis side of the Golgi, which is not well characterised due to the lack of good markers.

Antibodies, Monoclonal↗
PubMed1995

Cell type differences in Golgi retention signals for transmembrane proteins.

The transmembrane domain of Golgi resident proteins such as beta-galactoside alpha 2,6-sialyltransferase (ST) and N-acetylglucosaminyltransferase 1 (NT) contain a Golgi retention signal which confers Golgi retention to reporter proteins appended to them in the appropriate context. Thus, chimeras of the cell surface protein dipeptidyl peptidase IV containing the transmembrane domain of ST and NT are retained in the Golgi apparatus in MDCK and COS cells, as assessed by indirect immunofluorescence microscopy. Transfection of these chimeric constructs into CHO cells, however, results in their transport to vesicular structures which do not colocalize with that of an endogenous Golgi marker, mannosidase II. Furthermore, the staining pattern of these structures are not affected by brefeldin A. Biochemical analysis of the transgene products in pulse-chase experiments revealed that the chimeric proteins eventually become resistant to endoglycosidase H, suggesting that they are transported beyond the medial Golgi and therefore the vesicular structures are likely to be post-Golgi. The vesicular structures colocalized well with a lysosomal marker, cathepsin D, and also with internalized FITC-dextran chased into the lysosomal compartment. Monitoring the cell surface appearance of the chimeric protein suggests that the majority is transported directly to the lysosomal compartment. Golgi retention can be completely restored for ST and improved for NT by the inclusion of sequences flanking the transmembrane domain. Our results reflect cell type differences in the interpretation of the transmembrane domain Golgi retention signal, established that general Golgi retention of type II glycosyltransferases requires the hydrophilic flanking sequence as well as the transmembrane domain, and demonstrate that proteins which escape Golgi retention may be channeled to the lysosomal pathway.

Animals↗
PubMed1995

[Analysis of heavy chain immunoglobulins gene and T-cell receptor delta gene in children with acute leukemia].

IgH gene, TCR delta gene rearrangements and Tal-1 gene deletion were analysed by using PCR, Southern blot and DNA sequencing methods in newly diagnosed BM samples from children with AL. The DNAs from leukemic cells in 102 children were detected with PCR. The results showed that IgH gene rearrangement mainly occurred in B Precursor ALL (37/49). Six PCR products were further analysed by DNA sequencing. Less homogene and bias of JH gene usage were found in analysed DNA sequences. V delta 2-D delta 3 rearrangement of 78 samples from ALL was analysed with PCR method. V delta 2-D delta 3 rearrangements mainly observed in B precursor ALL and related HAL. V delta 2-D delta 2-N-D delta 3 rearrangement was found in a sequence of PCR product. Three cases of Tal-1 gene deletion were observed in all studied 70 samples of AL. They all were in stage I of thymus differentiation. We conclud that PCR detection of those genes are useful in the diagnosis of clonality of AL, DNA sequencing of PCR products is the base of preparing clonal specific probes, and dynamic analysis of IgH gene rearrangement using PCR may be helpful in detection of residual clones.

Child↗
PubMed1995

[Dysgerminoma of the ovary: a clinical retrospective analysis of 60 cases].

OBJECTIVE: To study the treatment methods and the prognostic factors of pure dysgerminoma of the ovary. METHODS: Sixty cases histologically confirmed pure ovarian dysgerminoma treated in our hospital, from May 1959 to Oct. 1992 were retrospectively analysed. Factors mainly studied were: age, symptoms, clinical staging and treatment methods. RESULTS: The median age of this series was 21. The main symptoms were abdominal mass, pain and distension. Thirty two out of 60 cases were stage I, 2 were stage II, 5 were stage III and 21 with recurrences or persistence of the disease. All cases excepting one case received surgery alone were treated by surgery combined with external radiotherapy or chemotherapy. Nine cases died of the disease. The actual 5-year survival rate was 85.17%. The survival rate for patients with postoperative adjuvant chemotherapy is 95% and that for patients with radiotherapy is 76.1%; no statistic significance was shown. CONCLUSIONS: In pure ovarian dysgerminoma surgery combined with radiotherapy or chemotherapy showed high complete remission rates and excellent survival rates. For younger patients and those with gestation desires as well as patients with advanced diseases, adjuvant chemotherapy following surgery might be a better choice.

Adolescent↗