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Biomedical subjects

M Liao

Publications and source records attributed to M Liao.

45 records · Page 3Linked to original sources
PubMed1993

Some features of lung cancer in China.

In recent years, the high incidence of lung cancer has made the disease one of the principal causes of death in human beings. The significance of cancer morbidity in China, which holds 1/4 of the population on the globe, is naturally an issue of concern to the health organizations all over the world. As the incidence of cancer tends to rise with every passing day, China is likely to follow the track of the industrialized countries, and lung cancer will top the list of incidence and cause of death of all cancers in urban areas. Presented in this paper are the epidemiology, pathogenesis, diagnosis and treatment of lung cancer in China, which is intended to promote mutual understanding and to facilitate cooperation and research, so as to upgrade the effective control of lung cancer.

China↗
PubMed1992

Mutational analysis of carbamyl phosphate synthetase. Substitution of Glu841 leads to loss of functional coupling between the two catalytic domains of the synthetase subunit.

The synthetase subunit of Escherichia coli carbamyl phosphate synthetase has two catalytic nucleotide-binding domains, one involved in the activation of HCO3- and the second in phosphorylation of carbamate. Here we show that a Glu841----Lys841 substitution in a putative ATP-binding domain located in the carboxyl half of the synthetase abolishes overall synthesis of carbamyl phosphate with either glutamine or NH3 as the nitrogen source. Measurements of partial activities indicate that while HCO3(-)-dependent ATP hydrolysis at saturating concentrations of substrate proceeds at higher than normal rates, ATP synthesis from ADP and carbamyl phosphate is nearly completely suppressed by the mutation. These results indicate Glu841 to be an essential residue for the phosphorylation of carbamate in the terminal step of the catalytic mechanism. The Lys841 substitution also affects the kinetic properties of the HCO3- activation site. Both kcat and Km for ATP increase 10-fold, while Km for HCO3- is increased 100-fold. Significantly, NH3 decreases rather than stimulates Pi release from ATP in the HCO3(-)-dependent ATPase reaction. The increase in kcat of the HCO3(-)-dependent ATPase reaction, and an impaired ability of the Lys841 enzyme to catalyze the reaction of NH3 with carboxy phosphate, strongly argues for interactions between the two catalytic ATP sites that couple the formation of enzyme-bound carbamate with its phosphorylation.

Adenosine Diphosphate↗
PubMed1992

Isolation of a yeast artificial chromosome clone that spans the (12;16) translocation breakpoint characteristic of myxoid liposarcoma.

Cytogenetic analysis of liposarcomas has demonstrated that translocation (12;16) (q13.3;p11.2) is characteristic of the myxoid subtype of this adipose tissue tumor. Our previous results suggested that the GLI gene is close to the translocation breakpoint on chromosome 12. We now describe a yeast artificial chromosome (YAC) that contains GLI and spans the chromosome 12 region involved in the t(12;16) breakpoint. This clone will permit rapid definition of the genetic region surrounding the breakpoint and allow isolation of the gene presumably affected by the translocation.

Chromosomes, Fungal↗
PubMed1992

Localization of brain nitric oxide synthase (NOS) to human chromosome 12.

Recent research has shown that nitric oxide is a novel neuronal second messenger and transmitter that may be involved in neuronal cell death and damage in neurological illness. To map the chromosomal localization of this important brain enzyme, a rat cDNA probe was prepared by RNA PCR from rat cerebellum RNA. This rat cDNA was used to isolate a human nitric oxide synthase (NOS) cDNA from a human cerebellum cDNA library. The human cDNA clone containing 1.2 kb of brain NOS cDNA was hybridized to Southern blots containing DNAs obtained from human-rodent hybrid cell line panels using EcoRI and HindIII digestion to ascertain the location of the human NOS gene. These data showed that the human brain nitric oxide synthase mapped within 12q14-qter on human chromosome 12.

Amino Acid Oxidoreductases↗
PubMed1991

Stem cell factor (SCF), a novel hematopoietic growth factor and ligand for c-kit tyrosine kinase receptor, maps on human chromosome 12 between 12q14.3 and 12qter.

Recently a novel hematopoietic growth factor, stem cell factor (SCF), was cloned and demonstrated to be the ligand for the c-kit tyrosine kinase receptor. In the mouse, SCF is encoded by Sl (steel), a gene critical to the development of several distinct cell lineages during embryonic life and which has important effects on hematopoiesis in the adult animal. The Sl/SCF locus maps to the distal region of mouse chromosome 10, in the vicinity of genes that have been mapped to human chromosome 12. Here we report the use of somatic cell hybrid lines to localize SCF to the long arm of human chromosome 12, between 12q14.3 and 12qter. In addition to localizing the Sl homolog in man, these data provide further evidence for the conservation of synteny between the long arm of human chromosome 12 and the distal end of mouse chromosome 10.

Animals↗
PubMed1991

Assignment of the human gene for the alpha 1 subunit of the cardiac DHP-sensitive Ca2+ channel (CCHL1A1) to chromosome 12p12-pter.

A human clone corresponding to the gene encoding the alpha 1 subunit of the cardiac dihydropyridine-sensitive calcium channel (CCHL1A1) has been isolated and partially sequenced. Oligonucleotides based on the human sequence were constructed and used in the polymerase chain reaction to amplify specifically this human gene in human-rodent somatic cell hybrids. Using somatic cell hybrids that contained defined regions of human chromosome 12, the human alpha 1 subunit of the cardiac dihydropyridine-sensitive calcium channel has been assigned to the short arm of chromosome 12 in the interval 12p12-pter.

Amino Acid Sequence↗
PubMedDate not supplied

Vascular endothelial growth factor and other biological predictors related to the postoperative survival rate on non-small cell lung cancer.

OBJECTIVE: An analysis of postoperative 1-5 year-survival rates related to vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor (VEGF-r), microvascular density (MVD), P53, H-ras, CerbB2, proliferative index (PI), divisional index (DI) were carried out on 127 cases of non-small cell lung cancer (NSCLC) treated with curative resection and aim to find out more sensitive molecular prognostic predictors for the reference of medicine and molecular pathology. METHODS: All the cases were staged strictly using the UICC criteria of 1997 and regional lymphonodes seen by the naked eye should be dissected and sent to pathology with lung specimens. Immunohistochemical analyses were used for those biological predictors. Kaplan-Meier curve, Cox univariance and multivariance analysis were used for the survival and prognostic predictors. RESULTS: 52 cases (40.9%) with high expression of VEGF showed a worse postoperative year-survival rate than cases with low expression, but no statistical difference. The difference of survival on stage I case with high and low expression were closed to be significant value (P=0.0643). P53, PI and DI were related to postoperative survival, P=0.0341, 0.0005 and 0.0162, respectively. Co-expression of VEGF combined with P53, PI and DI was calculated for the difference of year-survival rate by Cox multivariance analysis. The survival rates of cases with both negative VEGF +P53 or VEGF+PI co-expression rate were better than those with both positive or either positive, P values were 0.0159 and 0.0154, respectively. CONCLUSION: The post-operative year-survival of NSCLC was of no statistical difference between with high expression and low expression of VEGF, but in stage I case it was closed to be significant difference, it speculated that the neoangiogenesis is more obviously in early stage NSCLC, but in the later stage of NSCLC, it may be covered by more complicated molecular-biological factors such as P53 and other oncogens. Co-expression of VEGF combined with p53 or PI was more meaningful than a single biological predicator on survival rate of NSCLC, it is worth to do further studies.

Biomarkers, Tumor↗