PubMed Health⌕ Search

Biomedical subjects

C Sun

Publications and source records attributed to C Sun.

At least 91 records · Page 5Linked to original sources
PubMed2000

[The effects of suicide gene therapy system on adenoid cystic carcinoma of salivary gland in athymic mice].

OBJECTIVE: To study the effects of HSV-tk/GCV system on adenoid cystic carcinoma (ACC) in vivo. METHODS: The cell strain of ACC-M (highly metastatic to the lung) was inoculated into the flank of nude mice, then treated with HSV-tk/GCV system. RESULTS: The system can inhibit the tumor growth greatly, moreover this function has bystander effect. CONCLUSION: HSV-tk/GCV system can be to treat ACC.

Animals↗
PubMed2000

[The effect of protein kinase C on the invasive behavior of human salivary adenoid cystic carcinoma in vitro].

OBJECTIVE: To explore the relationship between protein kinase C (PKC) and invasion/metastasis of salivary adenoid cystic carcinoma and to explore the possibility of treatment against invasion/metastasis of the tumor cell by PKC inhibitor. METHODS: SACC-83 cell line cells were treated by endogenous PKC inhibitor BS-PKCI extracted from bovine spermatozoa and exogenous PKC inhibitor H(7), while the adhesion to basement membrane, movement (expressed by the cell numbers moving out from agarose drop and the furthest distance) and invasive capacity in vitro were observed. RESULTS: (1) The two inhibitors suppressed significantly adhesion of the tumor cell to basement membrane (P < 0.05). (2) The two inhibitors suppressed significantly movement of the tumor cells (P < 0.05). (3) The two inhibitors suppressed significantly invasive capacity of the tumor cells in vitro (P < 0.01). CONCLUSIONS: There was a close relationship between PKC and invasion/metastasis of salivary adenoid cystic carcinoma; the two PKC inhibitor suppressed significantly adhesion, movement and invasive capacity of SACC - 83 cell line cells in vitro.

Carcinoma, Adenoid Cystic↗
PubMed2000

[Cytochrome P450IA1 and the genetic susceptibility to esophageal carcinoma].

OBJECTIVES: To explore the susceptibility to esophageal carcinoma (EC) in different population with different cytochrome P450 IA1 (CYPIA1) genotype, and study the synergistic effects between CYPIA1 and smoking. METHODS: A case-control study (case = 111, control = 114) was used to compare the frequency of CYPIA1 genotype between EC and controls with a PCR method. RESULTS: The distribution of three genotypes of CYPIA1 in EC and controls was significantly different (chi(2) = 19.35, P < 0.01). There was a synergistic effect between the mutation of CYPIA1 4,889 site and smoking (SIA = 1.56), and a significant dose-response effect was observed. The risk of individual whose CYPIA1 4,889 site is mutated was 3 times higher than those not mutated. CONCLUSIONS: The mutation of CYPIA1 ,89 site maybe one of important host susceptible factors of EC, and the risk would increase significantly in smokers.

Aged↗
PubMed2000

[Regulation effect of curcumin on blood lipids and antioxidation in hyperlipidemia rats].

The regulation effects of curcumin on lowering blood lipids and antioxidation were studied in the hyperlipoidemia model Wistar rats fed with high fat diet for 4 weeks. The hyperlipoidemia model rats were then separated into four groups: normal diet group, normal diet + curcumin (5 g/kg) group, high-fat diet group and high-fat diet + curcumin group. The rats were fed with experimental diets for another 4 weeks respectively. The results indicated that curcumin decreased the serum levels of cholesterol and triglyceride and increased the serum level of apolipoprotein A. Curcumin decreased TBA value and improved total antioxidation capability. The activities of SOD and GSH-PX in liver were enhanced. After taking normal diet for four weeks, the blood fat and cholesterol levels of the hyperlipoidemia rats recovered. But in the normal diet + curcumin group, the same results could be found in two weeks.

Animals↗
PubMed2000

[Effect of chromium gluconate on body weight, serum leptin and insulin in rats].

In order to observe the effect of chromium on rat body weight, serum leptin and insulin, eight groups of rats were randomly fed diets (basal diet or high-fat diet) with different levels of chromium gluconate [proximally Cr(III) 1,2 and 3 mg/kg BW]. All rats were weighted once a week. By the end of the 8th week, all rats were decapitalized and the levels of serum leptin and insulin were tested by RIA method. The ratio of liver, spleen, kidney and testickle to body weight were calculated. The average body weight and the levels of leptin and insulin of high-fat-diet groups were significantly higher than those of the basal-diet group (P < 0.05), but the insulin and leptin of groups with chromium were significantly lower than their corresponding control groups without chromium(P < 0.05). It was concluded that chromium could cause weight loss slightly and reduce the levels of insulin and leptin.

Animals↗
PubMed2000

[Expressions of five protein kinase C isoforms in salivary adenoid cystic carcinoma].

OBJECTIVE: The protein kinase C (PKC) family of isoforms plays the key role in the regulation of cellular events, including cell proliferation, differentiation and canceration. Previous work from our laboratory has shown the alteration of PKC and its inhibitor activities in salivary adenoid cystic carcinoma (SACC) [Sun Changfu, et al. West China Journal of Stomatology, 1998, 16(3): 201-203]. This study aimed to further explore the relationship between PKC isoforms and canceration of SACC. METHODS: Expressions of five isoforms of PKC (alpha, beta I, beta II, epsilon and delta) were examined in cytosolic and membranous fraction of specimen homogenates from SACCs and were compared with the adjacent normal tissues by immunoblotting. Equal amounts of cytosolic and membrane protein from control and experimental groups were simultaneously subjected to sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE), transferred to nitrocellulose membranes, and reacted with first and second antibodies; Color development and image analysis were performed. RESULTS: 1. Cytosolic PKC-alpha, PKC-beta I, and PKC-beta II were expressed in SACCs and adjacent normal tissues. The Expressions of these three cytosolic isoforms were reduced significantly in SACCs compared with the adjacent normal tissues; 2. Membranous PKC-alpha was only detected in SACCs and the membranous translocation of cytosolic PKC-alpha was also seen. 3. The expressions of PKC-epsilon and PKC-delta were not detected in both SACCs and adjacent normal tissues. CONCLUSION: There was close relationship between changes of expression of PKC isoforms (alpha, beta I, beta II) and carcinogenesis of SACC. We postulated that there may be relationship between the membranous translocation of PKC-alpha and hematogenous lung metastasis in SACC.

Carcinoma, Adenoid Cystic↗
PubMed2000

[Giant cell reparative granuloma of the skull].

OBJECTIVE: To investigate the clinical course, histologic feature, diagnosis, differential diagnosis and treatment of giant cell reparative granuloma (GCRG). METHODS: Three cases of GCRG, which arose in the skull, were collected from 1987 to 1999 and analyzed clinicopathologically. RESULTS: Two patients had the lesion in the temporal bone and one in the orbit. One patient with GCRG had a recurrence after incomplete surgical resection. Histologically, all of three cases were characterized by fibroblastic proliferation with osteoclast-like giant cell rich areas, hemorrage, and newly formed bone or osteoid trabeculae. GCRG appeared as a typical bony lytic lesion on computed tomography (CT) and as low signal intensity on both T1 and T2 weighted images on magnetic resonance imaging (MRI). CONCLUSION: GCRG is an uncommon nonneoplastic lesion that typically arises in mandible and maxilla and its involvement in skull is rare. Although behaves benignly, GCRG may be locally aggresive. It is usually misdiagnosed for a giant cell tumor (GCT). Diagnosis of GCRG is based on typical histologic features as well as clinical information. Complete surgical resection is believed to be the most suitable treatment for GCRG and long-term follow-up by CT scanning is essential.

Adult↗
PubMed2000

[Surgical treatment of malignant esophageal tumors in PUMC Hospital].

OBJECTIVE: To study how to prolong the postoperative survival time of the patients with malignant esophageal tumors. METHODS: The clinical data of 1,098 patients with malignant esophageal tumors from 1961 to 1992 were retrospectively analyzed. The deletion of fragile histamine triplet(FHIT) gene(a tumor suppressor gene) in 30 fresh esophageal samples obtained in 1996 was detected with PCR and RT-PCR. RESULTS: The resectability was raised gradually and the operative morbidity and mortality decreased year-by-year, but there was no significant improvement on the postoperative 5-year survival rate. Delayed diagnosis and ir-radical resection influenced the long term survival. The deletion of cDNA of FHIT gene was 64.2% in esophageal cancer and 20% in the resected margin of the cancer. CONCLUSIONS: High atypical hyperplasia in esophageal epithelium and deletion of FHIT gene in esophageal cancer and its resected margin are pathological and molecular markers for early diagnosis of esophageal cancer respectively, and the latter may be one of the molecular markers for the resection. Early diagnosis and treatment, radical resection, and postoperative nutritional support are essential for the improvement of the postoperative survival time of the patients.

Acid Anhydride Hydrolases↗
PubMed1999

Isolation and mapping of rFUS6, a rice orthologue of Arabidopsis thaliana FUS6.

COP9 complex is one of the most important components that act in repressing photomorphogenesis in Arabidopsis thaliana. FUS6 has been identified as one of eight subunits of the COP9 complex in Arabidopsis. Using Arabidopsis Fus6 cDNA as a probe, we screened a rice root cDNA library and a rice genomic library. A 1730-bp cDNA was obtained, which has an open reading frame corresponding to 441-amino-acid. This 441 amino acids putative protein has 67% identity with Arabidopsis COP11/FUS6 (AtFUS6) and 40% identity with human GPS1, an AtFUS6 orthologue. So we designated this novel gene as rFUS6. The 6.2-kb genomic sequence of rFUS6 was also obtained. Sequence comparison showed that the rFUS6 gene had six exons and five introns. Sequence inspection of the 5'-flanking region revealed the presence of some potential light-regulated cis-elements such as a G-box, GT-1 binding sites, and a TGACG motif. Southern hybridization with rice total DNA showed that rFUS6 was perhaps a single copy gene. The rFUS6 locus was mapped by hybridization with a rice BAC library membrane and the results showed that rFUS6 had a locus at 16.3 cM of chromosome 1.

Amino Acid Sequence↗
PubMed1999

NMR structure and mutagenesis of the inhibitor-of-apoptosis protein XIAP.

The inhibitor-of-apoptosis (IAP) family of proteins, originally identified in baculoviruses, regulate programmed cell death in a variety of organisms. IAPs inhibit specific enzymes (caspases) in the death cascade and contain one to three modules of a common 70-amino-acid motif called the BIR domain. Here we describe the nuclear magnetic resonance structure of a region encompassing the second BIR domain (BIR2) of a human IAP family member, XIAP (also called hILP or MIHA). The structure of the BIR domain consists of a three-stranded antiparallel beta-sheet and four alpha-helices and resembles a classical zinc finger. Unexpectedly, conserved amino acids within the linker region between the BIR1 and BIR2 domains were found to be critical for inhibiting caspase-3. The absence or presence of these residues may explain the differences in caspase inhibition observed for different truncated and full-length IAPs. Our data further indicate that these residues may bind to the active site and that the BIR domain may interact with an adjacent site on the enzyme.

Amino Acid Sequence↗
PubMed1999

The Ig fold of the core binding factor alpha Runt domain is a member of a family of structurally and functionally related Ig-fold DNA-binding domains.

BACKGROUND: CBFA is the DNA-binding subunit of the transcription factor complex called core binding factor, or CBF. Knockout of the Cbfa2 gene in mice leads to embryonic lethality and a profound block in hematopoietic development. Chromosomal disruptions of the human CBFA gene are associated with a large percentage of human leukemias. RESULTS: Utilizing nuclear magnetic resonance spectroscopy we have determined the three-dimensional fold of the CBFA Runt domain in its DNA-bound state, showing that it is an s-type immunoglobulin (Ig) fold. DNA binding by the Runt domain is shown to be mediated by loop regions located at both ends of the Runt domain Ig fold. A putative site for CBFB binding has been identified; the spatial location of this site provides a rationale for the ability of CBFB to modulate the affinity of the Runt domain for DNA. CONCLUSIONS: Structural comparisons demonstrate that the s-type Ig fold found in the Runt domain is conserved in the Ig folds found in the DNA-binding domains of NF-kappaB, NFAT, p53, STAT-1, and the T-domain. Thus, these proteins form a family of structurally and functionally related DNA-binding domains. Unlike the other members of this family, the Runt domain utilizes loops at both ends of the Ig fold for DNA recognition.

Animals↗
PubMed1999

A novel calmodulin-like protein gene in rice which has an unusual prolonged C-terminal sequence carrying a putative prenylation site.

A rice cDNA encoding a novel calmodulin-like protein was identified. It has 38 additional amino acids at the C-terminus of a complete, typical calmodulin (CaM) sequence of 149 amino acids. The four C-terminal amino acid residues form a CAAL motif which could be a site for protein prenylation and may subsequently cause the protein to become membrane associated. RT-PCR analysis confirmed that such a combined protein gene truly exists in rice. Sequence analysis of its genomic counterpart showed that there is an intron located at junction of the normal CaM sequence and the 38 C-terminal amino acids. This introduces a potential stop codon for normal CaM if an alternative splicing mechanism is involved. Southern blot analysis of rice genomic DNA revealed that there is only one locus for this gene. The northern blot analysis showed that this gene is highly expressed in rice roots, shoots and flowers. The distribution of this protein demonstrates the functional importance of this novel CaM-like protein in rice.

Amino Acid Sequence↗
PubMed1999

Assessment of chromosome 8 copy number in cervical cancer by fluorescent in situ hybridization.

Cervical carcinoma is a malignancy which typically occurs at the transformation zone between squamous and glandular epithelium. The vast majority falls into two histologic types, squamous cell and adenocarcinoma. In an effort to identify a subset of cervical cancer characterized by chromosome 8 trisomy, a biomarker extensively explored by this laboratory, we conducted a study of formalin-fixed, paraffin-embedded materials of cervical cancer. A total of 24 cases of cervical cancer were identified from the archives of the Rhode Island Hospital. Fluorescent in situ hybridization (FISH) using a chromosome 8 centromere enumeration probe was conducted to assess the chromosome 8 copy number in these specimens. Hybridization signals were scored among tumor cells in a blinded fashion. Tumors with >/=15% of cells with three signals were scored as trisomic. Of 24 cases studied, 23 were informative. Of the 23 informative cases, 12 (52.2%) were found to be trisomic. Eleven cases (47.8%) were disomic. The frequency of trisomy in a control chromosome 17 probe was 13.0% (3/23). Selected clinicopathologic characteristics of the tumors were also reviewed. The frequency of trisomy 8 among cases of invasive squamous cell carcinoma was 44.4% (8 of 18 tumors) and that of invasive adenocarcinoma was 80% (4 of 5 tumors). The sole tumor which was both trisomic 8 and amplified for the HER-2/neu oncogene was found to be an invasive adenocarcinoma. While the sample size in this pilot study is not large, the data obtained thus far clearly demonstrate that FISH is an appropriate technique for detecting chromosomal trisomies and that a subset of cervical cancer exists that is characterized by chromosome 8 trisomy. Further exploration of this biomarker is warranted.

Adenocarcinoma↗
PubMed1999

Inflammatory modulation of calcium-activated potassium channels in canine colonic circular smooth muscle cells.

BACKGROUND & AIMS: The characteristics of colonic circular smooth muscle slow waves are altered during inflammation. The aim of this study was to examine whether inflammation modulates the open-state probability of Ca2+-activated K+ (KCa) channels in these cells to contribute to these alterations. METHODS: The experiments were performed on freshly dissociated single smooth muscle cells from the canine colon using standard patch clamp methods. Inflammation was induced by mucosal exposure to ethanol and acetic acid. RESULTS: Inflammation decreased the open-state probability of large-conductance KCa (BK) channels in the cell-attached and excised inside-out configurations. The voltage sensitivity of the channels was also reduced during inflammation. Inflammation had no significant effect on the large, medium, and small conductances or the unitary current levels of channel openings. However, it decreased the maximum number of simultaneous channel openings. The channels were Ca2+-dependent and were blocked by tetraethylammonium and charybdotoxin in normal and inflamed cells. CONCLUSIONS: Inflammation decreases the open-state probability of BK channels. This may partially reverse the decrease in duration and amplitude of slow waves and depolarization of membrane potential seen in inflammation.

Animals↗
PubMed1999

Analyses of isoamylase gene activity in wild-type barley indicate its involvement in starch synthesis.

The notion of debranching enzyme activity as a participant in starch synthesis is gaining acceptance. Inconsistent reports from mutant analyses implicate either isoamylase or pullulanase as a determinant in amylopectin formation and whether wild-type plants utilize one or the other, or both, of these debranching enzymes in starch synthesis is unclear. Recent results on the sul mutant in maize suggest that both forms of debranching enzymes might be involved in amylopectin formation. We wished to find out if isoamylase takes part in starch synthesis by comparing isoamylase gene activity under three conditions: (1) during starch accumulation in developing sink tissues; (2) during starch degradation in germinating seeds; (3) in ectopic expression after applying sucrose, a starch precursor. We isolated the gene for barley isoamylase, isol, and analysed its expression and regulation in germinating seeds, developing endosperm and vegetative tissues, and compared the isoamylase gene expression in sink tissues from three different species. Our results indicate that isoamylase gene activity is involved in starch synthesis in wild-type plants and is modulated by sucrose.

Amino Acid Sequence↗
PubMed1999

Proximal myotonic myopathy: clinical and molecular investigation of a Norwegian family with PROMM.

Proximal myotonic myopathy (PROMM) was first described in 1994 as a multisystem disorder with similarity to myotonic dystrophy (DM), but without the abnormal (CTG)n expansion in the DM protein kinase (DMPK) gene. The inheritance is autosomal dominant and the clinical features include myotonia, proximal muscle weakness and cataract. Linkage analysis in nine German PROMM families has indicated the possibility of linkage to DM2 locus on chromosome 3. We report a Norwegian PROMM family in which the proband was clinically diagnosed as DM but without the (CTG)n expansion. Using an intragenic marker we showed that the DMPK gene did not segregate with the disease in this family. All family members are heterozygous for the R894X mutation in CLCN1 gene. Linkage analysis could not be performed, but haplotyping probably excludes the DM2 locus as the disease locus in this family. The present family emphasises that myalgia is a prominent symptom in PROMM and the clinical differences may be explained by genetic heterogeneity. This family will be reinvestigated along with the identification of candidate genes or regions in larger PROMM families.

Adult↗