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Biomedical subjects

L Gui

Publications and source records attributed to L Gui.

At least 19 recordsLinked to original sources
PubMed2001

Molecular cloning and characterization of chemokine-like factor 1 (CKLF1), a novel human cytokine with unique structure and potential chemotactic activity.

Cytokines are small proteins that have an essential role in the immune and inflammatory responses. The repertoire of cytokines is becoming diverse and expanding. Here we report the identification and characterization of a novel cytokine designated as chemokine-like factor 1 (CKLF1). The full-length cDNA of CKLF1 is 530 bp long and a single open reading frame encoding 99 amino acid residues. CKLF1 bears no significant similarity to any other known cytokine in its amino acid sequence. Expression of CKLF1 can be partly inhibited by interleukin 10 in PHA-stimulated U937 cells. Recombinant CKLF1 is a potent chemoattractant for neutrophils, monocytes and lymphocytes; moreover, it can stimulate the proliferation of murine skeletal muscle cells. These results suggest that CKLF1 might have important roles in inflammation and in the regeneration of skeletal muscle.

Amino Acid Sequence↗
PubMed2001

[Reduction gonioplasty for the prominent mandibular angle. Report of 38 cases].

The one-stage curved osteotomy of the mandibular angle without resection of the masseter was used for 38 patients suffering from prominent mandibular angle from december 1996 to november 1997 at our department of plastic and cranio-maxillo-facial surgery. The preoperative strategy and surgical procedure are described. These 38 cases had a low rate of complications and usually good cosmetic results. Technical refinements that have improved the results are analyzed. At the present time the one-stage curved osteotomy of the mandibular angle is a simple and more reliable method for the surgical correction of the prominent mandibular angle, which is preferred by us to the other techniques: resection of the masseter alone or with straight cutting of the mandibular angle, simple straight cutting of the mandibular angle, multistaged osteotomy of the mandibular angle.

Adolescent↗
PubMed2001

Identification and functional assessment of endothelial P1H12.

Monoclonal antibody P1H12 recognizes circulating endothelial cells and endothelia of all sizes of blood vessels. To identify the protein recognized by P1H12, we expressed a cDNA library in CHO cells and sequenced the cDNA from positive cells. The P1H12 sequence was identical, except at several bases, to that reported for melanoma cell surface antigen MUC18/CD146. Aggregation assays demonstrated that CD146 mediates Ca(++)-independent homotypic endothelial cell adhesion. P1H12 mAb abrogated interactions between human microvascular endothelial cells (HMVECs) but not between human umbilical vein endothelial cells (HUVECs). P1H12 mAb abrogated P1H12-positive (CHO(P1H12))-association with HMVECs or HUVECs. CD146 distribution is sparser on HUVECs than on HMVECs. These data imply that HMVECs and HUVECs express the CD146 binding partner but that CD146 is functional (or at sufficient density) only on HMVECs. HMVEC monolayers treated with soluble P1H12 mAb showed increased permeability to albumin, with accompanying changes in actin, paxillin, FAK, and caveolin distribution and changes in tyrosine phosphorylation of FAK. Stimulation with P1H12 mAb led to redistribution of NF-kappa B to the nucleus. P1H12 mAb bound to beads inhibited closure of wounded endothelial monolayers. CD146 thus joins VE-cadherin and PECAM-1 as a molecule that mediates homotypic endothelial cell adhesion. CD146 has both structural functions and signaling functions important for endothelial monolayer integrity.

Animals↗
PubMed2001

[The pathology and DNA quantitative study of renal clear cell carcinoma in children].

OBJECTIVE: To investigate the pathological features of renal clear cell carcinoma (RCCC) in children and its relationship to the DNA content of cancer cells and DNA ploidy. METHODS: The pathologic morphology of 4 cases of RCCC in children were observed. Using image analysis instruments the quantity of tumor cell DNA was measured. RESULTS: The cytoplasm of the tumor cells were clear in all four cases. Papillary structures were present in these tumors, of which the papillary structure in two cases was over 50%, three cases had small calcified bodies with prominent bleeding and necrosis. Around tumor the glomerular and tubular of kidney always is normal the average DNA index was 1.31. They presented diploidy, high diploidy or subtetraploidy. CONCLUSIONS: The specific features of most RCCC in children are clear cytoplasm, most contain papillary structures, calcified bodies, often with bleeding and necrosis. Around tumor the glomerular and tubular of kidney is always normal. The DNA contents of cancer cells present diploidy, high diploidy or subtetraploidy.

Carcinoma, Renal Cell↗
PubMed2000

Crystallization and preliminary X-ray analysis of earthworm fibrinolytic enzyme component A from Eisenia fetida.

Earthworm fibrinolytic enzyme component A, a protein which functions both as a direct fibrinolytic enzyme and a plasminogen activator, was purified from the earthworm Eisenia fetida. Diffraction-quality single crystals of the protein were grown by the hanging-drop vapour-diffusion technique with ammonium sulfate as a precipitant. The crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 40.6, b = 127.5, c = 129.2 A and three molecules per asymmetric unit. The data set reached a resolution of 1.95 A.

Animals↗
PubMed1999

Sickle cell anemia as a possible state of enhanced anti-apoptotic tone: survival effect of vascular endothelial growth factor on circulating and unanchored endothelial cells.

The biologic processes of apoptosis and angiogenesis are linked in endothelial biology because some endothelial cell growth factors also exert anti-apoptotic effects. We studied whether apoptosis is occurring in circulating endothelial cells (CEC) that have lost the survival signals derived from anchorage to extracellular matrix. Consistent with this expectation, 64% +/- 16% of CEC from normal donors showed evidence of apoptosis (by morphology and TdT-mediated dUTP nick end labeling [TUNEL] assay). However, only 30% +/- 15% (P <.001 v normal) of CEC from donors with sickle cell anemia were apoptotic. Vascular endothelial growth factor (VEGF) levels were significantly (P =.001) higher in plasma of sickle donors (120.1 +/- 81.4 pg/mL) than that of normal donors (37.6 +/- 34.6 pg/mL), and there was an inverse correlation between VEGF and CEC apoptosis (r =. 612, P =.001). Consistent with stimulation by VEGF, CEC from sickle donors exhibited increased expression of alphavbeta3. In vitro experiments showed that VEGF inhibits apoptosis for cultured endothelial cells that are kept unanchored and not allowed to re-establish attachment to extracellular matrix, thus demonstrating that VEGF provides survival signals independent of its ability to promote matrix reattachment. These data suggest the hypothesis that sickle cell anemia is a state of enhanced anti-apoptotic tone for endothelial cells. If true, this has implications for disease pathobiology, particularly the development of neovascularizing retinopathy.

Adult↗
PubMed1999

Preparation and Characterization of Nanoscopic Organic Semiconductor of Oxovanadium Phthalocyanine.

Nanoscopic particles of oxovanadium phthalocyanine (VOPc, phase-II) with different particle sizes are prepared by aggregation of VOPc molecules in the presence of surfactants for the first time. A size effect in the region of nanoscale was observed in the UV-visible spectra. The photoconductivity of the nanoscopic VOPc is much higher than that of bulk VOPc. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

VEGF prevents apoptosis of human microvascular endothelial cells via opposing effects on MAPK/ERK and SAPK/JNK signaling.

Vascular endothelial growth factor (VEGF), an endothelial cell-specific mitogen, promotes endothelial cell survival and angiogenesis. We recently showed that VEGF can support the growth of human dermal microvascular endothelial cells (HDMEC) and human umbilical vein endothelial cells in serum-free medium. Reasoning that VEGF might be modulating apoptotic signal transduction pathways, we examined mechanisms involved in the anti-apoptotic effect of VEGF on starvation- and ceramide-induced apoptosis in HDMEC. We observed that VEGF ameliorated the time-dependent increase in apoptosis, as demonstrated by morphologic observations, TUNEL assay, and DNA fragmentation. On the other hand, basic fibroblast growth factor only partially prevented apoptosis in serum-starved HDMEC; platelet-derived growth factor-BB was completely ineffective. VEGF activated the phosphorylation of extracellular signal regulated kinase (ERK)1 (p44 mitogen-activated protein kinase; MAPK) and ERK2 (p42 MAPK) in a time- and concentration-dependent manner. Both the VEGF-induced activation and its anti-apoptotic effect were prevented by the specific MAPK/ERK inhibitor PD98059. The presence of VEGF also inhibited the sustained activation of stress-activated protein kinase/c-jun-NH2-kinase (SAPK/JNK) caused by serum starvation and ceramide treatment. Activation of the MAPK pathway together with inhibition of SAPK/JNK activity by VEGF appears to be a key event in determining whether an endothelial cell survives or undergoes programmed cell death.

Apoptosis↗
PubMed1999

[Intraoral one-stage curved osteotomy for prominent mandibular angle].

OBJECTIVE: This paper presents a new method of osteotomy for the prominent mandibular angle (PMA). METHODS: Two modifications have been made to the conventional procedures. The first is the one-stage curved osteotomy of the mandibular angle. The second is non-resection of the masseter muscle. The surgical procedure has been performed through an intraoral approach with a direct field of vision. RESULTS: From December 1996 to December 1997, a total of thirty-eight patients suffering from PMA have been operated on by this method with satisfactory results. The follow-up is 3 to 12 months. CONCLUSION: This method is a very simple and ideal procedure with much less complications for surgical treatment of PMA.

Adolescent↗
PubMed1998

Tissue factor expression by endothelial cells in sickle cell anemia.

The role of the vascular endothelium in activation of the coagulation system, a fundamental homeostatic mechanism of mammalian biology, is uncertain because there is little evidence indicating that endothelial cells in vivo express tissue factor (TF), the system's triggering mechanism. As a surrogate for vessel wall endothelium, we examined circulating endothelial cells (CEC) from normals and patients with sickle cell anemia, a disease associated with activation of coagulation. We find that sickle CEC abnormally express TF antigen (expressed as percent CEC that are TF-positive), with 66+/-13% positive in sickle patients in steady-state, 83+/-19% positive in sickle patients presenting with acute vasoocclusive episodes, and only 10+/-13% positive in normal controls. Repeated samplings confirmed this impression that TF expression is greater when sickle patients develop acute vasoocclusive episodes. Sickle CEC are also positive for TF mRNA, with excellent concurrence between antigen and mRNA expression. The TF expressed on the antigen-positive CEC is functional, as demonstrated by a binding assay for Factor VIIa and a chromogenic assay sensitive to generation of Factor Xa. By establishing that endothelial cells in vivo can express TF, these data imply that the vast endothelial surface area does provide an important pathophysiologic trigger for coagulation activation.

Anemia, Sickle Cell↗
PubMed1998

Complementation of an Escherichia coli polypeptide deformylase mutant with a gene from Clostridium acetobutylicum ATCC 824.

The Clostridium acetobutylicum ATCC 824 DNA containing the 3' end of a PriA homolog, deformylase (def), and the 5' end of formyltransferase (fmt) has been cloned, sequenced, and used to complement an Escherichia coli mutant. While def and fmt have been found sharing an operon in other organisms, the presence of a third gene within a putative operon has not previously been found.

Amidohydrolases↗
PubMed1998

Peanut lectin-binding sites and mucins in benign and malignant colorectal tissues associated with schistomatosis.

An immunohistochemical and histochemical comparative study was carried out in benign and malignant colorectal tissues with and without schistosomiasis. This included a quantitative determination of peanut lectin (PNA)-binding sites and proliferating cell nuclear antigen (PCNA) expression and histochemical detection of mucin changes. 133 cases were studied, including 70 cases of colorectal carcinoma associated with schistosomiasis (CCS) and 63 cases of colorectal carcinoma without schistosomiasis (CC). Significant differences were found in the type of mucin-containing carcinomas (MC) between CCS and CC. 65% of non-tumorous mucosa adjacent to MC of the CCS group expressed PNA-binding sites, significantly higher than those of the MC in the CC group (31%). The non-tumorous mucosa in cases of MC of the CCS group also showed a high percentage of sialomucin-predominant secretion (69%, vs 38% in MC of the CC group). Consistently, the presence of PNA-binding sites in MC tumors of the CCS group was increased, compared with that in the same subtype in the CC group (respectively 65% and 31% of strong positivity for PNA). However, no differences in expression of PNA and mucin changes were demonstrated in the surrounding mucosa and tumorous tissues of non-mucin-containing carcinomas (NMC) between CCS and CC. The expression of PCNA was not different between CCS and CC and their subtypes. Our findings suggest a close relationship between mucin-containing colorectal carcinomas and schistosomiasis japonica.

Colorectal Neoplasms↗
PubMed1997

Labeling of recombinant protein for NMR spectroscopy: global and specific labeling of the rat liver fructose 2,6-bisphosphatase domain.

Methods for the efficient use of the 13C-labeled nutrients, glucose and histidine, in the production of recombinant protein were developed to provide the large amount of sample required for NMR studies. The nutrient requirements were reduced by determining the minimum amount of these metabolites needed during both the growth and the induction phases of the BL21(DE3) and newly constructed BL21(DE3) histidine auxotrophic Escherichia coli cultures. These methods were developed using the separate bisphosphatase domain of rat liver 6-phosphofructo-2-kinase/ fructose-2,6-bisphosphatase, which is expressed to high levels in the pET3a/BL21 (DE3) bacterial system. Use of the optimized expression methods reduced the requirements for the labeled nutrients, glucose and histidine, by 90 and 93.8%, respectively. The savings realized by use of the minimized media and modified induction protocols were obtained without significant reduction of the yield of purified protein. Comprehensive study of the bisphosphatase domain by NMR spectroscopy requires large amounts of protein because of its low solubility and the short lifetime (2-3 days) of the NMR samples. The significant reduction in the costs of labeled protein samples realized by the optimized expression methods can meet these sample requirements in a cost-effective way, and thereby, allow NMR studies of the bisphosphatase domain to proceed.

Animals↗
PubMed1996

Autoregulation of iclR, the gene encoding the repressor of the glyoxylate bypass operon.

The aceBAK operon was partially induced by a multicopy plasmid which carried the promoter region of the gene which encodes its repressor, iclR. Gel shift and DNase I analyses demonstrated that IclR binds to its own promoter. Disruption of iclR increased the expression of an iclR::lacZ operon fusion. Although aceBAK and iclR are both regulated by IclR, aceBAK expression responds to the carbon source, while expression of iclR does not.

Bacterial Proteins↗
PubMed1996

Regulated expression of a repressor protein: FadR activates iclR.

The control of the glyoxylate bypass operon (aceBAK) of Escherichia coli is mediated by two regulatory proteins, IclMR and FadR. IclMR is a repressor protein which has previously been shown to bind to a site which overlaps the aceBAK promoter. FAR is a repressor/activator protein which participates in control of the genes of fatty acid metabolism. A sequence just upstream of the iclR promoter bears a striking resemblance to FadR binding sites found in the fatty acid metabolic genes. The in vitro binding specificity of FadR, determined by oligonucleotide selection, was in good agreement with the sequences of these sites. The ability of FadR to bind to the site associated with iclR was demonstrated by gel shift and DNase I footprint analyses. Disruption of FadR or inactivation of the FadR binding site of iclR decreased the expression of an iclR::lacZ operon fusion, indicating that FadR activates the expression of iclR. It has been reported that disruption of fadR increases the expression of aceBAK. We observed a similar increase when we inactivated the FadR binding site of an iclR+ allele. This result suggests that FadR regulates aceBAK indirectly by altering the expression of IclR.

Bacterial Proteins↗
PubMed1996

Effects of Coriolus versicolor polysaccharides on superoxide dismutase activities in mice.

AIM: To study if Coriolus versicolor polysaccharides (CVP) influence the superoxide dismutase (SOD) activities in mice. METHODS: Normal, tumor-bearing, and radiated ICR mice were injected ip with CVP daily for 3-15 d. The SOD activity was assayed by epinephrine autoxidation test. RESULTS: The SOD activities in lymphocytes and thymus were increased by CVP in both the normal mice with or without delayed hypersensitivity (DH). In tumor-bearing mice, CVP exerted not only inhibitory effects on tumor, growth and SOD activity in tumor tissue but also complete or partial restorative effects on the suppressed DH and on the declined SOD activities in lymphocytes, spleen, and thymus. The total SOD and manganese-containing SOD (MnSOD) activities in lymphocytes and thymus were dose-dependently enhanced by CVP (5-20 mg.kg-1) on d 3 after the tumor transplantation. In the mice exposed to 60Co (3 or 6 Gy), DH and SOD activities were dose-dependently decreased. These changes were completely or partly prevented by CVP. CONCLUSION: CVP exerted the favorable effects on SOD activities in mice. Coriolus versicolor polysaccharides (CVP) exert inhibitory effects on experimental and clinical tumors. These effects are presumed to be mediated mainly by host-defence mechanism, especially immunological responeses. Superoxide dismutase (SOD) plays an important role in protecting cells against superoxide radical (O2-.) damages and over-production of O2-. or SOD abnormities exist in many diseases. The present study was to investigate if the CVP could exert some favorable effects on SOD activities in vivo.

Animals↗
PubMed1995

Differences in colorectal cancer between China and Japan: a clinical and histological study of two groups of cases.

It is well known that most tumours are attributed to life style, especially the tumours of the digestive system. Clinical and histopathological investigation of tumours in different human groups and societies, and analysis of the variations will provide evidence for this, and is one of the approaches to study carcinogens. Clinical data obtained from 391 patients with colorectal cancer at the Sakai Municipal Hospital, Japan, and Shanghai Jinshan Hospital and Cancer Hospital, China, from 1987 to 1992, included the sex, age and tumour subsite. Sections of histological specimens were also retrieved. The results were compared between two countries. The average age of patients with colorectal cancer in Shanghai was 8.5 years less than in the Sakai group. The age peak of the former was 51-60, and in the latter, 61-70 years. The most frequent site of the cancer in the Shanghai group was the rectum, contrasting with the higher percentage of sigmoid colon cancer in Sakai group. There was also a significant difference in histological subtype of the cancer between the two groups. Mucinous adenocarcinoma was notably more common in the Shanghai group than in the Sakai group, and the high frequency was mainly in the colon. All of the variations were suggested to be attributable to differing socioeconomic circumstances and lifestyle, especially the dietary habits of the countries.

Adult↗