Biomedical subjects

W Hong

Publications and source records attributed to W Hong.

At least 91 records · Page 5Linked to original sources

PubMed1998

A novel synaptobrevin/VAMP homologous protein (VAMP5) is increased during in vitro myogenesis and present in the plasma membrane.

cDNA clones encoding a novel protein (VAMP5) homologous to synaptobrevins/VAMPs are detected during database searches. The predicted 102-amino acid VAMP5 harbors a 23-residue hydrophobic region near the carboxyl terminus and exhibits an overall amino acid identity of 33% with synaptobrevin/VAMP1 and 2 and cellubrevin. Northern blot analysis reveals that the mRNA for VAMP5 is preferentially expressed in the skeletal muscle and heart, whereas significantly lower levels are detected in several other tissues but not in the brain. During in vitro differentiation (myogenesis) of C2C12 myoblasts into myotubes, the mRNA level for VAMP5 is increased approximately 8- to 10-fold. Immunoblot analysis using antibodies specific for VAMP5 shows that the protein levels are also elevated approximately 6-fold during in vitro myogenesis of C2C12 cells. Indirect immunofluorescence microscopy and immunoelectron microscopy reveal that VAMP5 is associated with the plasma membrane as well as intracellular perinuclear and peripheral vesicular structures of myotubes. Epitope-tagged versions of VAMP5 are similarly targeted to the plasma membrane.

Amino Acid Sequence↗

PubMed1998

Molecular analysis of Ewing's sarcoma: another fusion gene, EWS-E1AF, available for diagnosis.

Ewing's sarcoma, one of the most malignant tumors of children and young adults, expresses specific chimeric genes, e.g. EWS-FLI-1, EWS-ERG, EWS-ETV1 and EWS-FEV. In this paper, we extensively characterized a new fusion gene, EWS-EIAF by means of whole cDNA sequencing, RNA blot analysis, DNA blot analysis and chromosomal analysis, and showed it to be available for the diagnosis of Ewing's sarcoma and to participate in the oncogenesis of Ewing's sarcoma. Furthermore, we conducted a genetic analysis of Ewing family tumors in conjunction with immunohistochemical analysis and ultrastructural analysis. Our results demonstrate some limitations of both genetic analysis and histopathological analysis, and establish the relationship between neurogenic phenotypes and chimera genes.

Adenovirus E1A Proteins↗

PubMed1998

Alpha-SNAP but not gamma-SNAP is required for ER-Golgi transport after vesicle budding and the Rab1-requiring step but before the EGTA-sensitive step.

N-ethylmaleimide-sensitive factor (NSF) and soluble NSF attachment proteins (SNAPs) have been implicated in diverse vesicular transport events; yet their exact role and site of action remain to be established. Using an established in vitro system, we show that antibodies against alpha-SNAP inhibit vesicle transport from the ER to the cis-Golgi and that recombinant alpha-SNAP enhances/stimulates the process. Cytosol immunodepleted of alpha-SNAP does not support normal transport unless supplemented with recombinant alpha-SNAP but not gamma-SNAP. In marked contrast, cytosol immunodepleted of gamma-SNAP supports ER-Golgi transport to the normal level. Neither antibodies against gamma-SNAP nor recombinant gamma-SNAP have any effect on ER-Golgi transport. These results clearly establish an essential role for alpha-SNAP but not gamma-SNAP in ER-Golgi transport. When the transport assay is performed with cytosol immunodepleted of alpha-SNAP, followed by incubation with cytosol immunodepleted of a COPII subunit, normal transport is achieved. In marked contrast, no transport is detected when the assay is first performed with cytosol depleted of the COPII subunit followed by alpha-SNAP-depleted cytosol, suggesting that alpha-SNAP is required after a step that requires COPII (the budding step). In combination with cytosol immunodepleted of Rab1, it is seen that alpha-SNAP is required after a Rab1-requiring step. It has been shown previously that EGTA blocks ER-Golgi transport at a step after vesicle docking but before fusion and we show here that alpha-SNAP acts before the step that is blocked by EGTA. Our results suggest that alpha-SNAP may be involved in the pre-docking or docking but not the fusion process.

Antibodies↗

PubMed1998

Protein transport from the endoplasmic reticulum to the Golgi apparatus.

As the first step of protein transport along the biosynthetic (secretory/exocytotic) pathway, transport from the endoplasmic reticulum (ER) to the Golgi apparatus has received much attention over the past several decades. The general structural organization underlying this transport process is becoming more defined. The major protein components participating in the budding, pre-docking, and docking/fusion events have been identified and their mechanistic aspects investigated. Conceptually, it is now clear that protein export from the ER is a selective process. Although much remains to be defined or refined, the general picture of this transport step has now emerged.

Animals↗

PubMed1998

The recycling pathway of protein ERGIC-53 and dynamics of the ER-Golgi intermediate compartment.

To establish recycling routes in the early secretory pathway we have studied the recycling of the ER-Golgi intermediate compartment (ERGIC) marker ERGIC-53 in HepG2 cells. Immunofluorescence microscopy showed progressive concentration of ERGIC-53 in the Golgi area at 15 degreesC. Upon rewarming to 37 degreesC ERGIC-53 redistributed into the cell periphery often via tubular processes that largely excluded anterograde transported albumin. Immunogold labeling of cells cultured at 37 degreesC revealed ERGIC-53 predominantly in characteristic beta-COP-positive tubulo-vesicular clusters both near the Golgi apparatus and in the cell periphery. Concentration of ERGIC-53 at 15 degreesC resulted from both accumulation of ERGIC-53 in the ERGIC and movement of ERGIC membranes closer to the Golgi apparatus. Upon rewarming to 37 degreesC the labeling of ERGIC-53 in the ERGIC rapidly returned to normal levels whereas ERGIC-53's labeling in the cis-Golgi was unchanged. Temperature manipulations had no effect on the average number of ERGIC-53 clusters. Density gradient centrifugation indicated that the surplus ERGIC-53 accumulating in the ERGIC at 15 degreesC was rapidly transported to the ER upon rewarming. These results suggest that the ERGIC is a dynamic membrane system composed of a constant average number of clusters and that the major recycling pathway of ERGIC-53 bypasses the Golgi apparatus.

Albumins↗

PubMed1998

[Treatment of 129 patients with advanced and recurrent malignant ovarian germ cell tumor].

OBJECTIVE: To investigate the improved treatment for advanced malignant germ cell tumors of the ovary. METHODS: 129 patients with advanced and recurrent germ cell tumor of the ovary treated from 1958 to 1993 were retrospectively analyzed. The results of malignant nondysgerminomatous germ cell tumor of the ovary treated from 1958-1983 were compared with those treated with the supplement of VAC (Vincristine + ActinomycinD + Cyclophosphamide), PVB (Cisplatin + Vinblastine + Bleomycin) or BEP (Bleomycin + Etoposide + Cisplatin) combined chemotherapy from 1984-1993. RESULTS: The overall 5-year survival rate was 30% (39/129) of advanced and recurrent germ cell tumor of the ovary. The 5-year survival rates of dysgerminoma and nondysgerminomatous germ cell tumor of the ovary were 68% (19/28) and 20%(20/101), respectively. The 5-year survival rate of patients with malignant nondysgerminomatous germ cell tumor of the ovary was raised from 3% (1/40) to 42% (15/36) in the recent years. The institution of combination chemotherapy is critical for the improvement with BEP regimen as the best among the three. CONCLUSIONS: The endodermal sinus tumor of the ovary stands first in the incidence of malignant germ cell tumors of the ovary in China. To improve the prognosis of advanced malignant germ cell tumor of the ovary, BEP regimen is the most effective at present.

Adolescent↗

PubMed1998

[Detection of human cytomegalovirus infection in pregnant women and their fetuses by nested polymerase chain reaction].

OBJECTIVES: To evaluate the applicability of nested polymerase chain reaction (PCR) and restriction endonucleases analyses (REA) for the diagnosis of human cytomegalovirus (HCMV) in pregnant women and their fetuses. METHODS: Nested PCR and REA, virus isolation, anti-HCMV-IgM and anti-HCMV-IgA were used for detection of HCMV in peripheral blood of pregnant women, umbilical blood and tissues of stillbirths. RESULTS: Among 367 pregnant women, the HCMV infections rate in the first, second and third trimester of gestation were 8.6%, 1.6% and 7.0%, respectively. The nested PCR had significantly higher detective rate (4.9%) than that of virus isolation (3.0%, P < 0.025). Among 6 samples of maternal HCMV DNA positive blood, 3 matched umbilical samples were HCMV DNA positive as well. Of these 3 cases, HCMV intrauterine infection was considered. HCMV was detected with all measurements in both maternal and umbilical blood except in 1 paired samples specific-IgM were negative. HCMV DNA was found in the lung tissue of one of the 28 stillbirds. CONCLUSION: The diagnostic specificity and sensitivity of HCMV can be raised by nested PCR.

Cytomegalovirus↗

PubMed1998

[The clinical features and management of borderline ovarian tumors].

OBJECTIVE: To study the clinical features and management of borderline ovarian tumor (BOT). METHODS: Retrospectively study 70 cases of BOT. RESULTS: Age 16-76 years old, average 45.6 year old; histological type: mucinous 46(65.7%), serous 21(30%); stage: I 46 (65.7%), II 1(1.4%), III 11(15.7%), IV 0%, relapse 12(17.1%). Tumor marker: elevated CA125 11/21, carcinoembryonic antigen (CEA) 6/10. TREATMENT: all patients were operated, 45 were given adjuvant therapy. OUTCOME: No evidence of disease (NED) 45, with evidence of disease (WED) 4, died of disease (DOD) 11, died of intercurrent disease (DID) 10. 11 patients who were given conservative surgery were NED, there were 2 long term CR among 16 patients with residual disease who were given adjuvant treatment. The 5, 10, 20 and 30-year survival is 90.0%, 87.1%, 87.1% and 85.6% respectively. COX hazard regression model analysis showed that histological type (r = 24.825), stage (r = 2.236) and residual disease (r = 2.083) were the main factors which impact on the prognosis of BOT. CONCLUSIONS: (1) The proportion of mucinous tumor is higher than that of serous tumor in this group; (2) Surgery is the proved only effective treatment of BOT till now, without any residual disease is expected; (3) Adjuvant therapy can't improve the prognosis of BOT; (4) CA125 and CEA can be two effective tumor markers in monitoring of BOT.

Adolescent↗

PubMed1998

[Treatment of malignant germ cell tumors of the ovary: a clinical analysis of 233 cases].

OBJECTIVE: To evaluate the treatment methods of malignant germ cell tumors of the ovary. METHODS: Two hundred thirty three patients with malignant germ cell tumors of the ovary treated during 1958 through 1993 were retrospectively analyzed. The number of patients in different stage of the disease was as follows: stage I, 94; stage II-IV, 43; recurrence or metastasis, 96. Unilateral salpingo-oophorectomy was performed in 78 patients, or total abdominal hysterectomy and bilateral salpingo-oophorectomy with or without omentectomy and appendectomy was performed in 151 cases, and biopsy in 4 cases. Operation alone was done in 17 cases, operation plus radiotherapy with or without chemotherapy in 65, operation plus chemotherapy in 151 cases. RESULTS: Of the 233 patients 127 were disease-free. The number of survivors in stage I patients was 78, in stage II-IV was 17. There were 32 cases with recurrence and metastasis. The overall 5-year survival rate was 55.6%. The 5-year survival rate differed between dysgerminoma and nondysgerminomatous tumurs being 84.2% for the former and 44.6% for the latter. In patients with nondysgerminomatous tumors, chemotherapy with PVB and BEP regimens gave a 5-year survival rate of 66.0% and 73.3%, respectively. CONCLUSION: Malignant germ cell tumors of the ovary is very sensitive to chemotherapy. The PVB and BEP regimens result in excellent response in these patients. Complete remission and preservation of fertility can be obtained in patients with early tumors. Preoperative chemotherapy and postoperative adjuvant chemotherapy can improve survival in patients with advanced tumors.

Adolescent↗

PubMed1998

[Diagnostic evaluation of magnetic resonance urography in urinary tract dilatation and obstruction].

OBJECTIVE: To evaluate the diagnostic value of magnetic resonance urography (MRU). METHODS: Two hundred and one patients were examined, 92 patients with urinary tract dilatation using a modified, heavily T2-weighted fast spin-echo pulse sequence and fat-suppression pulse aid. Postprocedure processing was performed with a maximum-intensity-projection (MIP) algorithm. RESULTS: In the 92 patients with urinary tract dilatation, 86 had obstructive urinary tract dilatation 6 non-obstructive urinary tract dilatation. In the 86 patients, 14 had ureteral carcinoma, 19 calculus, and 13 benign stricture, 23 congenital ureteral stricture/or with anomalies, 7 ureteral obstructive caused by extrinsic pelvis disease, and 10 bladder carcinoma involved ureter. In the 6 patients, 5 had nervous bladder. MR urography provided the high-resolution image of the urinary tract and determined the presence of obstruction. CONCLUSION: MR urography is a reliable noninvasive method for depicting the urinary tract.

Adolescent↗

PubMed1998

[Thyroid cancer during pregnancy].

OBJECTIVE: To study the diagnosis and treatment of thyroid cancer during pregnancy. METHOD: 12 pregnant patients with thyroid cancer were retrospectively analysed. RESULT: Diagnosis was dependent on the clinical manifestation, the examination of B-ultrasonic and the fine-needle aspiration biopsy of thyroid, 4 patients who asked for ending pregnancy were operated on after abortion, 6 patients with early and middle pregnancy were operated on during pregnancy, and 2 patients with late pregnancy were operated on after delivery. No patients showed recurrence of cancer, and their children were healthy, and the shape and function of the children's thyroid were normal. CONCLUSION: Pregnant patients with thyroid cancer during early and middle pregnancy should be operated on in time, and late pregnant patients should be operated on after delivery. All patients should take levothyroxine.

Adult↗

PubMed1997

The mammalian protein (rbet1) homologous to yeast Bet1p is primarily associated with the pre-Golgi intermediate compartment and is involved in vesicular transport from the endoplasmic reticulum to the Golgi apparatus.

Yeast Bet1p participates in vesicular transport from the endoplasmic reticulum to the Golgi apparatus and functions as a soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) associated with ER-derived vesicles. A mammalian protein (rbet1) homologous to Bet1p was recently identified, and it was concluded that rbet1 is associated with the Golgi apparatus based on the subcellular localization of transiently expressed epitope-tagged rbet1. In the present study using rabbit antibodies raised against the cytoplasmic domain of rbet1, we found that the majority of rbet1 is not associated with the Golgi apparatus as marked by the Golgi mannosidase II in normal rat kidney cells. Rather, rbet1 is predominantly associated with vesicular spotty structures that concentrate in the peri-Golgi region but are also present throughout the cytoplasm. These structures colocalize with the KDEL receptor and ERGIC-53, which are known to be enriched in the intermediate compartment. When the Golgi apparatus is fragmented by nocodazole treatment, a significant portion of rbet1 is not colocalized with structures marked by Golgi mannosidase II or the KDEL receptor. Association of rbet1 in cytoplasmic spotty structures is apparently not altered by preincubation of cells at 15 degrees C. However, upon warming up from 15 to 37 degrees C, rbet1 concentrates into the peri-Golgi region. Furthermore, rbet1 colocalizes with vesicular stomatitis virus G-protein en route from the ER to the Golgi. Antibodies against rbet1 inhibit in vitro transport of G-protein from the ER to the Golgi apparatus in a dose-dependent manner. This inhibition can be neutralized by preincubation of antibodies with recombinant rbet1. EGTA is known to inhibit ER-Golgi transport at a stage after vesicle docking but before the actual fusion event. Antibodies against rbet1 inhibit ER-Golgi transport only when they are added before the EGTA-sensitive stage. These results suggest that rbet1 may be involved in the docking process of ER-derived vesicles with the cis-Golgi membrane.

Amino Acid Sequence↗

PubMed1997

A SNARE involved in protein transport through the Golgi apparatus.

In eukaryotic cells, the Golgi apparatus receives newly synthesized proteins from the endoplasmic reticulum (ER) and delivers them after covalent modification to their destination in the cell. These proteins move from the inside (cis) face to the plasma-membrane side (trans) of the Golgi, through a stack of cisternae, towards the trans-Golgi network (TGN), but very little is known about how proteins are moved through the Golgi compartments. In a model known as the maturation model, no special transport process was considered necessary, with protein movement along the Golgi being achieved by maturation of the cisternae. Alternatively, proteins could be transported by vesicles or membrane tubules. Although little is known about membrane-tubule-mediated transport, the molecular mechanism for vesicle-mediated transport is quite well understood, occurring through docking of SNAREs on the vesicle with those on the target membrane. We have now identified a protein of relative molecular mass 27K which is associated with the Golgi apparatus. The cytoplasmic domain of this protein or antibodies raised against it quantitatively inhibit transport in vitro from the ER to the trans-Golgi/TGN, acting at a stage between the cis/medial- and the trans-Golgi/TGN. This protein, which behaves like a SNARE and has been named GS27 (for Golgi SNARE of 27K), is identical to membrin, a protein implicated earlier in ER-to-Golgi transport. Our results suggest that protein movement from medial- to the trans-Golgi/TGN depends on SNARE-mediated vesicular transport.

Animals↗

PubMed1997

N-Ethylmaleimide-sensitive factor (NSF) and alpha-soluble NSF attachment proteins (SNAP) mediate dissociation of GS28-syntaxin 5 Golgi SNAP receptors (SNARE) complex.

Golgi soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) GS28 and syntaxin 5 can be reciprocally coimmunoprecipitated from Golgi extracts, suggesting that they exist in a protein complex. When Golgi extract is preincubated with soluble NSF attachment proteins (alpha-SNAP) and N-ethylmaleimide-sensitive factor (NSF) under conditions that allow ATP hydrolysis by NSF, GS28 and syntaxin 5 become dissociated. GS28 and syntaxin 5 remain in a protein complex when Golgi extract is preincubated with similar amounts of alpha-SNAP and NSF under conditions that prevent ATP hydrolysis by NSF, suggesting that ATP hydrolysis by NSF is necessary for dissociating the GS28-syntaxin 5 complex. Since preincubation of Golgi extract with either alpha-SNAP or NSF alone has no effect on the GS28-syntaxin 5 complex, a concerted action of alpha-SNAP and NSF therefore mediates the dissociation of the GS28-syntaxin 5 complex. Furthermore, GS28 but not syntaxin 5 is capable of binding to immobilized alpha-SNAP when the GS28-syntaxin 5 complex is dissociated.

Animals↗

PubMed1997

GS15, a 15-kilodalton Golgi soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) homologous to rbet1.

Bet1p plays an essential role in vesicular transport from the endoplasmic reticulum (ER) to the Golgi in yeast, and it functions as a vesicle soluble N-ethylmaleimide-sensitive factor protein receptor (v-SNARE). A mammalian protein related to Bet1p has been reported previously and was referred to as rbet1. We have now identified a new mammalian protein that is homologous to rbet1 (28% amino acid identity). mRNA for this rbet1 homologue is widely expressed in rat tissues. Affinity-purified polyclonal antibodies raised against recombinant protein specifically recognized a 15-kilodalton integral membrane protein highly enriched in Golgi membranes. Indirect immunofluorescence microscopy revealed that this protein is specifically associated with the Golgi apparatus in diverse cell types. Biochemical characterization established that this protein behaves like a SNARE and was named GS15 (Golgi SNARE with a size of 15 kilodaltons). These properties raise the possibility that GS15 is a novel SNARE mediating a yet to be defined transport event associated with the Golgi apparatus.

Amino Acid Sequence↗

PubMed1997

Association of U2 snRNP with the spliceosomal complex E.

In metazoans, the E complex is operationally defined as an ATP-independent spliceosomal complex that elutes as a single peak on a gel filtration column and can be chased into spliced products in the presence of an excess of competitor pre-mRNA. The A complex is the first ATP-dependent functional spliceosomal complex. U1 snRNP first binds tightly to the 5'splice site in the E complex and U2 snRNP first binds tightly to the branch site in the A complex. In this study, we have generated and characterized a monoclonal antibody (mAb 4G8) directed against SAP 62, a component of U2 snRNP and a subunit of the essential mammalian splicing factor SF3a. We show that this antibody is highly specific for SAP 62, detecting only SAP 62 on Western blots and immunoprecipitating only SAP 62 from nuclear extracts. The anti-SAP 62 antibody also immunoprecipitates U2 snRNP and the A complex. Significantly, however, we find that the E complex is also efficiently immunoprecipitated by the anti-SAP 62 antibody. This antibody does not cross-react with any E complex-specific components, indicating that SAP 62 itself is associated with the E complex. To determine whether other U2 snRNP components are associated with the E complex, we used antibodies to the U2 snRNP proteins B"and SAP 155. These antibodies also specifically immunoprecipitate the E complex. These observations indicate that U2 snRNP is associated with the E complex. However, we find that U2 snRNP is not as tightly bound in the E complex as it is in the A complex. The possible significance of the weak association of U2 snRNP with the E complex is discussed.

Animals↗

PubMed1997

Specificities of anti-sialyl-Tn and anti-Tn monoclonal antibodies generated using novel clustered synthetic glycopeptide epitopes.

The fine specificities of MAbs generated using novel synthetic clustered STn and Tn glycopeptides as immunogens were compared with the anti-TAG-72 antibodies B72.3 and CC49. Hapten inhibition experiments demonstrated the specificity of several of the MAbs for STn and Tn expressed on ovine submaxillary mucin and tumor derived MUC-1 mucin. Amongst the STn specific MAbs only the B195.3 MAb shows absolute dependence on the presence of sialic acid and specificity to the simple disaccharide NANAA alpha2-6-GalNAc. Identification of tumor associated carbohydrate epitopes in cluster and monomer configurations are possible using MAbs detecting the defined structure specificities described herein.

Animals↗

PubMed1997

Detection of Epstein-Barr virus DNA in virus-infected cells by electron microscopic in situ hybridization.

We describe a procedure for in situ hybridization using a biotinylated Epstein-Barr virus (EBV) sequence with detection at the light and electron microscopic levels. In situ hybridization using an immunogold-silver staining detection system was used to identify biotinylated DNA probes in cell smears and in Lowicryl K4M-embedded EBV-infected and -noninfected cell lines. At the light microscopic level, the reaction product of hybridized EBV DNA sequence seemed to be located mainly in the nuclei. The labelling was dependent on the cell strains. However, at the electron microscopic level, the reaction product was evident as spots or clusters distributed not only in the nuclei of EBV-infected cells but also in the cytoplasm and extracellular particles. These findings suggest that immature particles in the cytoplasm contain EBV DNA. This procedure can be applied to the observation and identification of virus infection.

Biotinylation↗