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Biomedical subjects

H Qiu

Publications and source records attributed to H Qiu.

125 records · Page 7Linked to original sources
PubMed1992

[Molecular cytogenetic study of an extra small chromosome].

An extra small chromosome was observed in a three-generation family. Eight members of this family were involved, but their phenotypes were normal. Molecular cytogenetic study was carried out, using cytogenetic methods and chromosome in situ hybridization with 3H-labelled rDNA probe. The results showed that this chromosome was from the short arm of chromosome of D/G group. The origin and genetic effects of this chromosome and fertility of the carriers were also discussed were also discussed briefly.

Adult↗
PubMed1992

[Interphase cytogenetic studies of human X chromosome].

The chromosome in situ hybridization with human X chromosome alpha satellite DNA probe (pBamX7) on human lymphocyte metaphases and interphase nuclei was performed for interphase cytogenetic studies. The individuals with numerical or structural abnormalities of X chromosome were studied. The results showed that the probe hybridized specifically to the centromeric region (p11----q11) of X chromosome. The number of silver grain clusters in interphase nuclei was correlated with that of X chromosome. Most of the clusters located near the nuclear membrane where inactive X chromatins (Barr-bodies) were usually found. The method of ascertaining the number of X chromosomes by in situ hybridization was much more reliable than that by counting the number of Barr-bodies. The modified R-banding technique was introduced and the significance of this work was also discussed.

Chromosome Aberrations↗
PubMed1991

Cloning and expression of a yeast protein tyrosine phosphatase.

To study the regulation of tyrosine phosphorylation/dephosphorylation in Saccharomyces cerevisiae, a protein tyrosine phosphatase (PTPase) was cloned by the polymerase chain reaction (PCR). Conserved amino acid sequences within the mammalian PTPases were used to design primers which generated a yeast PCR fragment. The sequence of the PCR fragment encoded a protein with homology to the mammalian PTPases. The PCR fragment was used to identify the yeast PTP1 gene which has an open reading frame encoding a 335-amino acid residue protein. This yeast PTPase shows 26% sequence identity to the rat PTPase, although highly conserved residues within the mammalian enzymes are invariant in the yeast protein. The yeast PTP1 is physicallt linked to the 5'-end of a heat shock gene SSB1. This yeast PTP1 gene was expressed in Escherichia coli and obtained in a highly purified form by a single affinity chromatography step. The recombinant yeast PTPase hydrolyzed phosphotyrosine containing substrates approximately 1000 times faster than a phosphoserine containing substrate. Gene disruption of yeast PTP1 has no visible effect on vegetative growth.

Amino Acid Sequence↗
PubMed1991

Preclinical assessments of 90Y-labeled C110 anti-carcinoembryonic antigen immunotoxin: a therapeutic immunoconjugate for human colon cancer.

We have synthesized 90Y-labeled immunotoxin (IT) containing ricin A chain and C110 anti-carcinoembryonic antigen monoclonal antibody (MAb) to produce a therapeutic immunoconjugate for human colon cancer. The C110 IT was labeled with 90Y via a benzylisothiocyanate derivative of diethylenetriaminepentaacetic acid. The efficiency of 90Y labeling was consistently 90 to 98%, with a specific activity of about 1 microCi/microgram. In in vitro stability studies, more than 80% of 90Y remained bound to the C110 IT for up to 5 days after incubation. The percentage of binding of 90Y-labeled C110 IT to carcinoembryonic antigen-coated microbeads was 86%, indicating good retention of the initial immunoreactivity of the C110 MAb. In in vitro protein synthesis inhibition assays, 90Y-labeled C110 IT was approximately 3.7-fold more toxic to the LS174T human colon carcinoma cell line than unmodified C110 IT and 1380-fold more toxic than 90Y-labeled C110 MAb. Biodistribution studies of 90Y-labeled C110 IT in LS174T tumor-bearing mice showed that, at 24 h following i.p. injection, high accumulation of radioactivity was seen in the i.p. tumor and liver and, thereafter, high accumulation in these tissues remained almost unchanged until up to 168 h, with percentage of injected dose/g ranging from 15 to 18% in the tumor and 10 to 15% in the liver. The radioactivity in the spleen and bone gradually increased with time and reached their highest levels (approximately 8% of injected dose/g) at 168 h. Estimation of absorbed radiation doses to the tissues showed that i.p. tumor would have received an approximately 1.5 to 7 times higher radiation dose than normal organs. In in vivo therapeutic trials, 90Y-labeled C110 IT provided survival prolongation of LS174T tumor-bearing mice superior to that with either unmodified C110 IT or 90Y-labeled C110 MAb (4 less than 0.01; Mann-Whitney U test). These results indicate that 90Y-labeled C110 anti-carcinoembryonic antigen IT may be a potent therapeutic immunoconjugate for human colon cancer and that it may have direct relevance for i.p. treatment of peritoneal carcinomatosis from colon cancers.

Animals↗
PubMed1991

A morphological study of primary pulmonary hypertension--an analysis of six autopsy cases.

Six typical autopsy cases of primary pulmonary hypertension are reported. The histopathological features were as follows: medial hypertrophy of the muscular pulmonary arteries, muscularization of arterioles, internal fibrosis and fibroelastosis of muscular pulmonary arteries with typical "onion-skin" configuration, fibrinoid necrosis of the media or necrotizing arteries of muscular pulmonary arteries, and formation of highly characteristic plexiform lesions and dilatation lesions. It is thought that the plexiform lesions seen in all six cases represent morphological changes resulting from pulmonary hypertension rather than congenital abnormalities or thromboembolism.

Adult↗
PubMed1991

[Chromosomal localization of human X chromosome alphoid satellite DNA by in situ hybridization and its preliminary application].

In situ hybridization of human X chromosome-specific alphoid satellite DNA to human lymphocyte metaphase and interphase nuclei was carried out. The results showed that the probe hybridized with high specificity to the centromeric region at p11----q11 of the X chromosome. The number of silver grain clusters in the interphase nuclei was correlated with that of X chromosomes in the cells. 44% of the clusters were located near the nuclear membrane, the usual location of X chromatin (Barr body). The hybridized chromosomes were also R-banded with BrdU treatment, and the significance of this work was briefly discussed.

Centromere↗
PubMed1990

De novo purine nucleotide biosynthesis: cloning of human and avian cDNAs encoding the trifunctional glycinamide ribonucleotide synthetase-aminoimidazole ribonucleotide synthetase-glycinamide ribonucleotide transformylase by functional complementation in E. coli.

The trifunctional enzyme encoding glycinamide ribonucleotide synthetase (GARS)-aminoimidazole ribonucleotide synthetase (AIRS)-glycinamide ribonucleotide transformylase (GART) was cloned by functional complementation of an E. coli mutant using an avian liver cDNA expression library. In E. coli, genes encoding these separate activities (purD, purM, and purN, respectively) produce three proteins. The avian cDNA, in contrast, encodes a single polypeptide with all three enzyme activities. Using the avian DNA as a probe, a cDNA encoding the complete coding sequence of the trifunctional human enzyme was also isolated and sequenced. The deduced amino acid sequence of the human and avian polyproteins show extensive sequence homologies to the bacterial purD, purM, and purN encoded proteins. Avian and human liver RNAs appear to encode both a trifunctional enzyme (G-ARS-AIRS-GART) as well as an RNA which encodes only GARS. The trifunctional protein has been implicated in the pathology of Downs Syndrome and molecular tools are now available to explore this hypothesis. Initial efforts to compare the expression of GARS-AIRS-GART between a normal fibroblast cell line and a Downs Syndrome cell line indicate that the levels of RNA are similar.

Acyltransferases↗
PubMed1990

[The growth pattern of atherosclerotic rabbit aortic smooth muscle cells in culture].

Rabbit aortic smooth muscle cells (SMCs) both from normal and atherosclerotic (AS) animals were cultured for study on their growth activities and the relation to the cell cycle kinetics. The growth activities of different cell populations were compared by measuring cell doubling time, labelling index and mitosis index. For cell cycle analysis, 3H-TdR flash labelling method was employed. The results showed that SMCs derived from atherosclerotic rabbits grew more rapidly in culture than those from normal animals, the cell doubling time in the AS group was shorter than normal, 28.8 hrs versus 40.8 hrs, while the labelling and mitosis index in the AS group were higher. SMC cell cycle analysis showed that their generation time was 9.6-9.9 hrs and there was no significant difference of the distribution of cell cycle phases and their generation time between SMCs from AS and control group. The results indicate that the increased proliferative activities of atherosclerotic SMCs are not due to the change of their cell cycle kinetics, but having more cells emerging from G0/G1 phase into S phase.

Animals↗
PubMed1990

[Analysis of 26 cases of internal biliary fistula].

One of the more difficult problems in cholelithiasis surgery is posed by the internal biliary fistula. This lesion is defined as an abnormal communication between the accessory biliary tract (gall bladder or cystic duct) and the gastrointestinal tract or main bile duct. Twenty-six patients with internal biliary fistula were operated on over a 12-year period in the Abdominal Surgery Department of Peking Union Medical Hospital. Right upper quadrant abdominal pain was present in all, but variable in degree and persistence. Most of the patients had jaundice, fever and chills. No particular clinical picture is associated with cholelithiasis, and preoperative diagnosis is rare. When internal biliary fistula is diagnosed, the patient should be advised to accept the operation. At operation, adhesions were strikingly dense. In order to protect the main bile duct from injury, it is sometimes necessary to open the gall bladder, then extract stones and perform cholangiography to assess the situation.

Adult↗
PubMed1989

Two precursors of melanin-concentrating hormone: DNA sequence analysis and in situ immunochemical localization.

Two precursors to Chinook salmon (Oncorhynchus tshawytscha) melanin-concentrating hormone, an important factor in teleosts involved in the control of skin pigmentation and stress responsiveness, have been identified from DNA sequence analysis. Both precursors encode proteins of 132 amino acids and they share 107/132 amino acid identities. The biologically active 17-residue peptide is located at the C terminus of both precursors and can be liberated by proteolytic cleavage following two adjacent arginine residues. Additional putative proteolytic processing sites are located within the two precursors. Northern analysis demonstrated an intense hybridization signal of 750 nucleotides in the hypothalamus. Immunocytochemical studies as well as in situ hybridization analyses identify intensely staining cell bodies in the hypothalamus in the area of the lateral tuberal nucleus.

Amino Acid Sequence↗
PubMed1988

Cloning, characterization, and sequence of a porcine cDNA encoding a secreted neuronal and endocrine protein.

This report describes the cloning, sequence, and characterization of a cDNA which encodes a protein synthesized in the brain and endocrine tissue, including pituitary, adrenal medulla, and ovary. The deduced 207-amino-acid sequence of the 23-kD protein contains a hydrophobic signal peptide suggesting that it is secreted. Northern blot analysis utilizing the cDNA clone identifies a single RNA of approximately 1400 nucleotides in porcine brain, adrenal medulla, pituitary, and ovary, as well as in human endocrine tumors. Very high levels of RNA were observed in one human pancreatic tumor. Southern blot analysis suggests that sequences homologous to the porcine cDNA are present in human, cow, rat, and salmon DNA, indicating that the gene(s) have been highly conserved during evolution.

Amino Acid Sequence↗
PubMedDate not supplied

Progression of a focal ischemic lesion in rat brain during treatment with a novel glycine/NMDA antagonist: an in vivo three-dimensional diffusion-weighted MR microscopy study.

Stroke was induced in two groups of anesthetized rats by occlusion of the middle cerebral artery (MCA) and ipsilateral common carotid artery. Group 1 (control) received vehicle and group 2 received the glycine N-methyl-D-aspartate (NMDA) antagonist ZD9379. Stroke volume was assessed by three-dimensional diffusion-weighted MR microscopy at 2.5 and 6 hours of MCA occlusion. At 2.5 hours, stroke volumes were identical in the two groups. At 6 hours, stroke volumes had increased by 15% in the control group; in contrast, the treated group showed a 40% reduced stroke volume. Conclusions from this in vivo study were as follows: (a) our technique allows more efficient and accurate measurement of stroke volume with an improvement in resolution over a previous method; (b) the ability to measure stroke volume at multiple time points shows volume change and assessment of time dependency of drug treatment; (c) at 6 hours, the glycine antagonist ZD9379 reduced stroke volume by 40%.

Animals↗
PubMedDate not supplied

Studies on vitrectomy cases associated with complicated branch retinal vein occlusion.

PURPOSE: To study the preoperative factors leading to vitrectomy, and to demonstrate the postoperative conditions causing the decreased visual acuity that results from branch retinal vein occlusion (BRVO). METHODS: In 113 patients (114 eyes) with BRVO, the following data were analyzed: age, general complications, distribution of occluding vessels, location of retinal breaks, classification of vitreoretinal pathology, and the number of cases, period from onset of BRVO to vitreous hemorrhage and from vitreous hemorrhage to vitrectomy, number of operations, relationship between posterior vitreous detachment (PVD) and number of operations, preoperative photocoagulations, pre- and postoperative visual acuity, and cases with poor visual outcome. RESULTS: The visual prognosis was much better in cases with vitreous hemorrhage only than in those with proliferative membrane and retinal detachment (P =.0023). Repeated surgeries were needed in the cases where there was only partial PVD (P =.0029). Macular disorders and optic nerve atrophy were the main causes of postoperative visual acuity < 0.1. CONCLUSIONS: Early vitrectomy before development of vitreo retinal proliferation and retinal detachment, especially in cases where there is only partial PVD, seems to be essential for case management and treatment to attain better visual acuity for the patient.

Aged↗
PubMedDate not supplied

Physical and cDNA mapping in the DBH region of human chromosome 9q34.

Chromosome 9q34 has been extensively studied and mapped due to the presence of known disease genes, principally tuberous sclerosis 1 (TSC1), in this region. During the course of our mapping of this region we constructed a 555-kb contig beginning approximately 50 kb proximal to the dopamine-beta-hydroxylase (DBH) gene and extending, with one small deletion, distal to the D9S114 marker. The contig consists of 11 P1 clones, four PAC clones, one BAC clone and six cosmid clones and contains 27 new nonpolymorphic STSs. We have found the region to be unstable in P1, PAC and BAC cloning vehicles and have identified several deleted genomic clones. In addition, we have isolated and mapped the 3' portions of three putative genes located within or immediately distal to the DBH gene, including one large gene that runs on the opposite strand to DBH and utilizes portions of two DBH exons. The genomic clones of the contig, cDNAs and new STSs will be useful reagents for the further study and mapping of this region.

Base Sequence↗
PubMedDate not supplied

The encapsulation of a model protein in poly (D, L lactide-co-glycolide) microparticles of various sizes: an evaluation of process reproducibility.

Poly (D, L lactide-co-glycolide) and poly (D, L lactide) microparticles were prepared by solvent evaporation and the process reproducibility was evaluated in terms of the loading of a model protein into the microparticles, the microparticle size and the in-vitro release profiles of the protein. The results showed that the microencapsulation method allowed the preparation of microparticles with mean sizes from < 0.5 micron to 100 microns in size, with protein entrapment from 0.5 to 5% w/w. The microparticles were smooth and free from surface defects. Moreover, the reproducibility of the preparation method was demonstrated by the in-vitro release profiles obtained using different batches of microparticles prepared under similar conditions and by the reproducibility of microparticle size and protein loading. The results demonstrated that the preparation method was both robust and reproducible and allowed the preparation of microparticles with desired characteristics in terms of loading levels, particle size and release rates.

Lactic Acid↗