Search PubMed⌕ Search

Biomedical subjects

C Guo

Publications and source records attributed to C Guo.

At least 145 records · Page 8Linked to original sources
PubMed1996

[Comparisons of three simple nutritional assessments applied to patients with oral and maxillofacial malignancies].

Combined subjective and objective nutritional assessment (SNA), concise nutritional assessment (CNA), general nutritional status score (GNS), and subjective global assessment of nutritional status (SGA) were applied to assess the nutritional status of 127 patients with oral and maxillofacial malignancies. On this base SNA was used as a standard nutritional assessment to compare the validities of CNA, GNS, and SGA. The results showed: 1) the total agreement rate of CNA (88.2%) was higher than that of GNS (78.0%) and SGA (78.7%); 2) the false positive rate (9.9%) and false negative rate (15.2%) of CNA was lower than that of GNS (17.3%, 30.4%) and SGA (14.8%, 32.6%); 3) the diagnosis index of CNA (74.9%) was significantly (P < 0.05) higher than that of GNS (52.3%) and SGA (52.6%); and 4) the nutritional parameters of CNA were measured by instruments with little man-made errors. These results indicate that CNA can be regarded as the best nutritional assessment for the patients in oral and maxillofacial surgery.

Facial Neoplasms↗
PubMed1995

Fluorescence resonance energy transfer reveals interleukin (IL)-1-dependent aggregation of IL-1 type I receptors that correlates with receptor activation.

Fluorescence resonance energy transfer (FRET) was used to investigate whether interleukin-1 (IL-1) causes the aggregation of IL-1 type I receptors (IL-1 RI) at the cell surface. For these experiments, a noncompetitive anti-IL1 RI monoclonal antibody, M5, was labeled separately with a donor probe, fluorescein isothiocyanate, or with an acceptor carbocyanine probe, Cy3. Donor-labeled M5 and acceptor-labeled M5 were simultaneously bound to transfected mouse IL-1 RI on either C-127 mouse mammary carcinoma cells or on Chinese hamster ovary (CHO)-K1 cells, and the ratio of acceptor emission at 590 nm to donor emission at 525 nm (excitation at 488 and 514 nm) was monitored with flow cytometry as an indicator of FRET. Addition of a saturating concentration of human IL-1 alpha at 22 degrees C causes a time-dependent increase in FRET for both cell lines that indicates IL-1-dependent self-association of IL-1 RI. Binding of the IL-1 receptor antagonist at 22 degrees C causes little or no FRET for both cell lines, indicating a correlation between receptor aggregation and the ability of the ligand to stimulate a functional response. When donor-labeled and acceptor-labeled Fab fragments of M5 are used to monitor FRET, IL-1 alpha causes efficient energy transfer in the CHO-K1 cells at 22 degrees C, but not at 4 degrees C. In contrast, IL-1 alpha causes much less FRET at 22 degrees C in C-127 cells when the M5 Fab fragments are used instead of the intact bivalent M5. In a striking parallel, IL-1 alpha-dependent activation of prostaglandin E2 production depends on the bivalent M5 antibody in the C-127 cells, but is independent of this monoclonal antibody in the CHO-K1 cells. These results provide a strong correlation between the ability of IL-1 to cause the aggregation of IL-1 RI and the stimulation of a functional response.

Animals↗
PubMed1995

TEL gene is involved in myelodysplastic syndromes with either the typical t(5;12)(q33;p13) translocation or its variant t(10;12)(q24;p13).

A t(5;12)(q33;p13) translocation is a recurrent chromosome abnormality in a subgroup of myeloid malignancies with features of both myeloproliferative disorders and myelodysplastic syndromes (MDSs). The molecular consequence of a t(5;12) is a fusion between the platelet-derived growth factor receptor-B gene on chromosome 5 and a novel ETS-like gene, TEL, on chromosome 12. We report on three patients with a t(5;12)(q33;p13) diagnosed as chronic myelomonocytic leukemia, and one case of a t(10;12)(q24;p13) in a progressive MDS, with eosinophilia and monocytosis. Involvement of the TEL gene in these chromosome translocations was investigated by fluorescence in situ hybridization (FISH) with cosmid probes containing selectively the 5' end or 3' end of TEL. Hybridization of these cosmids to the der(5)/der(10) or a der(12), respectively, demonstrated a rearrangement of TEL in both translocations, showing that the t(10;12) is a variant translocation of the t(5;12). Cloning of the fusion cDNA of one case of t(5;12) showed that the breakpoint occurred at the RNA level at exactly the same position as reported by Golub et al (Cell 77:307, 1994). In addition, the TEL gene on chromosome 12 could be localized between two probes previously mapped to 12p13, namely PRB1 and D12S178, leading to a better definition of the position of TEL in this chromosome region. Moreover, in the case involving chromosome 10, the breakpoint occurred between cKTN206 and cKTN312/LYT-10 at 10q24. Clinicohematological data in these studies as well as the restriction mapping of chromosomal breakpoints strongly suggest that (1) common features in MDSs involving the TEL gene are monocytosis and eosinophilia, (2) chromosomes other than no. 5 may be involved and at least a t(10;12)(q24;p13) variant chromosome translocation does exist in these MDSs, and (3) both standard and variant 12p/TEL translocations may be identified by FISH with appropriate probes.

Adult↗
PubMed1995

Identification of a splice variant of the rat and human mineralocorticoid receptor genes.

The sequence of a splice variant of the rat mineralocorticoid receptor (MR) gene is presented. A cDNA clone corresponding to rat MR was isolated from a rat brain cDNA library. Sequence analysis of the region corresponding to the DNA binding domain revealed the presence of a 12 base pair (bp) insertion. Analysis of mRNA from several rat tissues suggests that the variant is less abundant than the wild type in most tissues. The insertion variant is also a product of the human MR gene, the identical splice variant was also observed in human white blood cell mRNA. Unlike other splice variants reported for the MR, this variant alters the encoded protein by the addition of four amino acid residues in the DNA binding domain. The altered protein may influence the affinity of the MR for mineralocorticoid or glucocorticoid response elements.

Alternative Splicing↗
PubMed1995

A physical map of the region spanning the chromosome 12 translocation breakpoint in a mesothelioma with a t(X;12)(q22;p13).

We have constructed a physical map of a 4.6-cM region of human chromosome band 12p13.3 that contains a translocation breakpoint from a mesothelioma with a t(X;12)(q22;p13). The map contains a contig of 22 yeast artificial chromosomes (YACs), onto which we have placed 18 sequence tagged site (STS) markers, including seven genes: D12S370, FGF6, KCAN1, KCNA5, KCNA6, NTF3, and VWF. A second YAC contig, comprised of 22 YAC clones, was located distal to the mesothelioma breakpoint and contained 12 STS markers, including four genes (CACNL1A1, D12S380E, D12S381E, and D12S382E). Based on STS content and fluorescence in situ hybridization experiments, two stable, nonchimeric YAC clones were found that span the mesothelioma breakpoint. A long-range restriction map of an 800-kb region was constructed and used to refine the mesothelioma breakpoint to a region of approximately 100 kb, flanked by the potassium channel genes KCNA1 and KCNA5. The latter was confirmed by direct visual hybridization (DIRVISH) experiments, using cosmids isolated for markers flanking the breakpoint as probes.

Animals↗
PubMed1995

Severe alport phenotype in a woman with two missense mutations in the same COL4A5 gene and preponderant inactivation of the X chromosome carrying the normal allele.

The X-linked form of Alport disease, caused by mutations in the COL4A5 or the COL4A6 gene, usually leads to terminal renal failure in males, while affected females have a more variable and moderate phenotype. We detected in a female patient, with a severe Alport phenotype, two new missense mutations. One mutation (G289V) occurred in exon 15 and converted a glycine in a collagenous domain of COL4A5 to a valine. The second mutation, located in exon 46, substituted a cysteine proximal to the NC1 domain of COL4A5 for an arginine. In white blood cells and kidney both mutations were present on > 90% of the mRNA, while at the genomic level the patient was heterozygous for both mutations. The two mutations therefore occurred in the same COL4A5 allele. No mutation was found in the COL4A5 promoter region by sequencing nor was a major rearrangement of the normal allele detected. A skewed pattern of X inactivation was demonstrated in DNA isolated from the patient's kidney and white blood cells: > 90% of the X chromosomes with the normal COL4A5 allele was inactivated. It is suggested that this skewed inactivation pattern is responsible for the absence of detectable normal COL4A5 mRNA and hence the severe phenotype in this woman.

Adult↗
PubMed1995

Lack of association between HLA class II polymorphisms and essential hypertension in a Belgian population.

The aim of the present study was to investigate whether the HLA class II polymorphisms contributes to the susceptibility to essential hypertension in the Belgian population. For this purpose we studied 120 hypertensive patients and 168 normotensive controls by means of a PCR-SSO assay. No significant difference in allele and genotype frequencies of the DRB and DPB1 loci could be found between the two groups. We concluded that essential hypertension as a multifactorial and heterogeneous disease cannot be associated with one of the HLA class II DRB and DPB1 alleles in Belgian patients.

Adult↗
PubMed1995

[Comparison of toxic effects of brucite and aluminium-treated chrysotile on macrophage].

Toxicity of brucite and two kinds of chrysotile (Xinkang and Sichuan chrysotile) treated with aluminium chloride to alveolar macrophage from guinea pigs was compared in vitro. Results showed changes of toxicity, indicated as generation of O2-., increase in membrane lipid fluidity and leakage of intracellular potassium, etc., caused by aluminium-treated chrysotile, were significantly lower than those by bructite of same dose (P < 0.05 and P < 0.01, respectively), and changes of other toxic indicators, such as release of lactic dehydrogenase (LDH) and acid phosphatase (ACP) from macrophage and its mortality, were similar to those by brucite. It suggests aluminium chloride can be used to antagonize pathogenic bioactivity of chrysotile in practice.

Aluminum Chloride↗
PubMed1995

[Isolation and identification of enteric adenovirus in China].

Enteric adenovirus type 40/41 is considered to be the second major cause of gastroenteritis in young children. In this study fecal specimens 86-123 from diarrhea patients were isolated and examined in Grahm 293 cells. This induced cytopathic effect (CPE) at this cells. Viral particles were also found in fecal specimens and by electron microscopy. Examination of the isolate with Cambridge Biotech Adenoclone-Type 40/41 test kit indicated that it contained EAd. On the basis of the above studies, one strain of EAd was the first isolated virus in China.

Adenoviruses, Human↗
PubMed1995

[A cytogenetic study of four species of turtle from China].

The karyotypes, C-banding and Ag-NORs of four species of turtle from China have been studied. The results demonstrated that Cuora aurocapitata has 2n = 52(14M + 2SM + 4ST + 6T / 26m), NF = 72, 8 + 5 + 13(karyotypic formulae). Its secondary constrictions (SC) located on No. 1 p inter of group I; C. trifasciata has 2n = 52(12M + 4SM + 4ST + 6T + 26m), NF = 72, 8 + 5 + 13; Cistoclemmys flavomarginatus has 2n = 52(16M + 4ST + 6T + 26m), NF = 72, 8 + 5 + 13. The SC is also on No. 1 p inter of group I; C. galbinifrons has 2n = 52(16M + 2SM + 4ST + 6T + 24m), NF = 74, 9 + 5 + 12. Four pairs of SC of C. galbinifrons are on No. 1 p inter, No. 3,7 p par and No. 6(X chromosome) q per of group I. The heteromorphic chromosomes related with sexuelity were discovered in C. galbinifrons, while there is no that in other three species. All the centrometric regions of the chromosomes for the four studied species showed the various degree staining of C-positive. Only one homologous pair of Ag-NOR, is found for C. galbinifrons, which locate on No. 5 q per of group II. The Ag-NOR, of other three species lies in No. 7 q ter of group I. The mechanism of the karyotypic evolution is discussed. Individual evolutional mechanism of an heteromorphic sex pair of chromosomes.

Animals↗
PubMed1994

Cloning and sequence of the Xenopus laevis homologue of the midkine cDNA.

The Xenopus laevis (Xl) homologue of the midkine-encoding gene (MK) has been isolated and sequenced from a X. laevis cDNA library made from the head region of stage-22 embryo. The nucleotide and deduced amino-acid sequences show a high degree of conservation with the avian and mammalian MK and pleiotrophin (PTN) genes and gene products. Highly conserved domains may indicate important regions for the function of the MK and PTN proteins.

Amino Acid Sequence↗
PubMed1994

Toxic effect of the bloom-forming Trichodesmium sp. (Cyanophyta) to the copepod Acartia tonsa.

The toxicity of the marine cyanobacterium Trichodesmium sp. to the copepod Acartia tonsa was assessed in a series of experiments during a Trichodesmium bloom off the North Carolina coast in late October 1992. Healthy intact cells of Trichodesmium sp. were not toxic to A. tonsa and were ingested by A. tonsa when no other foods were available. However, homogenized Trichodesmium cells were toxic to A. tonsa, suggesting that Trichodesmium sp. contains certain type(s) of intracellular biotoxins. This hypothesis was consistent with the observed high mortality when A. tonsa was treated with aging Trichodesmium sp. cells or with filtered cell homogenate. The affected copepods showed weakness, recumbency, and reduced responsiveness. Many were observed to have distended intestines. Bioassays using aged Trichodesmium sp. cells and filtered homogenate demonstrated a dose-dependent effect on A. tonsa survival.

Animals↗
PubMed1994

Iron-Stimulated N(2) Fixation and Growth in Natural and Cultured Populations of the Planktonic Marine Cyanobacteria Trichodesmium spp.

In light of recent proposals that iron (Fe) availability may play an important role in controlling oceanic primary production and nutrient flux, its regulatory impact on N(2) fixation and production dynamics was investigated in the widespread and biogeochemically important diazotrophic, planktonic cyanobacteria Trichodesmium spp. Fe additions, as FeCl(3) and EDTA-chelated FeCl(3), enhanced N(2) fixation (nitrogenase activity), photosynthesis (CO(2) fixation), and growth (chlorophyll a production) in both naturally occurring and cultured (on unenriched oligotrophic seawater) Trichodesmium populations. Maximum enhancement of these processes occurred under FeEDTA-amended conditions. On occasions, EDTA alone led to enhancement. No evidence for previously proposed molybdenum or phosphorus limitation was found. Our findings geographically extend support for Fe limitation of N(2) fixation and primary production to tropical and subtropical oligotrophic ocean waters often characterized by Trichodesmium blooms.

Journal Article↗
PubMed1994

Genetic study of indirect inguinal hernia.

We performed a genetic analysis of 280 families with congenital indirect inguinal hernia ascertained in Shandong province. The multifactorial threshold model and segregation analysis were applied to these families to investigate the mode of inheritance of congenital indirect inguinal hernia. Our results indicate that congenital indirect inguinal hernia is not compatible with a multifactorial threshold model, and the frequent vertical transmission and high segregation ratio suggest autosomal dominant inheritance with incomplete penetrance and sex influence. Through further pedigree analysis of the multiple case families with at least two closely related affected members, we noted preferential paternal transmission of the disease gene, which might suggest the role of genomic imprinting in the aetiology of this condition.

Chi-Square Distribution↗
PubMed1994

Lack of association between the I/D polymorphism of the angiotensin-converting enzyme gene and essential hypertension in a Belgian population.

We tested the insertion/deletion (I/D) polymorphism of the ACE gene in 119 hypertensive patients and in 109 normotensive controls by means of the polymerase chain reaction (PCR). The allele and genotype frequencies of the I/D polymorphism in the ACE gene are essentially identical in both groups, regardless of age or sex. The I/D polymorphism of the ACE gene is thus not implicated in Belgian hypertensive patients.

Base Sequence↗
PubMed1993

Site-specific methylation inhibits transcriptional activity of platelet-derived growth factor A-chain promoter.

Expression of the platelet-derived growth factor (PDGF) A-chain gene is temporally and spatially restricted in development and highly regulated in selected normal and tumor cell lines. Because DNA methylation appears to be important in regulating tissue specific gene expression, we tested the influence of in vitro methylation of the human PDGF A-chain promotor on its activity in vivo in transient transfection assays. We now report that PDGF A-chain promoter activity is strongly repressed by DNA methylation in a DNA sequence-specific manner and that the repression of promoter activity by methylation requires a methyl CpG-binding protein(s). We also report that incubation of HeLa cells with 5-azacytidine sharply increases levels of endogenous PDGF A-chain gene transcripts. These results indicate that the promoter activity of the PDGF A-chain gene is sharply and selectively reduced by in vitro DNA methylation and that DNA methylation in vivo also may reduce its function in selected cell lines.

Base Sequence↗
PubMed1993

Differential splicing of COL4A5 mRNA in kidney and white blood cells: a complex mutation in the COL4A5 gene of an Alport patient deletes the NC1 domain.

PCR conditions were optimized to amplify the COL4A5 cDNA from lymphoblasts and kidney tissue. Sequencing of the COL4A5 mRNA isolated from the kidney of an Alport syndrome patient revealed two differences with the published sequence. One divergence, the insertion of an 18 bp sequence between exon 11 and 10 of the COL4A5 mRNA added two Gly-X-Y triplets to the COL4A5 sequence and was subsequently found in the mRNA of four normal kidney mRNA samples. This sequence was absent in all white blood cell RNA samples sequenced by us, indicating tissue specific splicing with the presence of an additional exon in kidney COL4A5 mRNA. This finding of differential splicing of COL4A5 mRNA in kidney and white blood cells might affect the use of white blood cell mRNA for the analysis of Alport mutations. Second, a complex mutation was detected in the mRNA from the AS patient introducing a premature stop codon in the message, deleting part of the triple helical domain and the complete NC domain. The mother of the patient was shown to be heterozygous for this mutation.

Adult↗