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Biomedical subjects

X F Qiu

Publications and source records attributed to X F Qiu.

18 recordsLinked to original sources
PubMed2005

Aclarubicin and low-dose Cytosine arabinoside in combination with granulocyte colony-stimulating factor in treating acute myeloid leukemia patients with relapsed or refractory disease and myelodysplastic syndrome: a multicenter study of 112 Chinese patients.

One hundred twelve patients with geriatric acute myeloid leukemia (AML), refractory or relapsed AML, or myelodysplastic syndrome and refractory anemia with excess of blasts in transformation (MDS-RAEBt) were entered into this study to receive CAG (aclarubicin and low-dose cytosine arabinoside [Ara-C]in combination with granulocyte colony-stimulating factor [G-CSF]) with the objective of evaluating the efficacy and tolerance of this regimen. Low-dose Ara-C was given subcutaneously at a dosage of 10 mg/m2 every 12 hours on days 1 to 14. Aclarubicin was administered intravenously at a dosage of 14 mg/m2 per day on days 1 to 4 (CAG regimen A) or 7 mg/m2 on days 1 to 8 (CAG regimen B). Recombinant G-CSF was given subcutaneously at a dosage of 200 3g/m2 per day on days 1 to 14. We demonstrated comparable overall complete remission rates for the 4 groups of patients: 30.8% (8/26) in the elderly patients, 48.4% (30/62) in the refractory AML patients, 44.4% (8/18) in the relapsed AML patients, and 38.5% (5/13) in the MDS-RAEBt patients. Of the 52 patients followed up, the 12-month progression-free survival (PFS) and overall survival (OS) rates estimated by the Kaplan-Meier method were 40.73% 3 8.15% and 42.85% 3 8.23%, respectively. The median PFS and OS times were 9.0 3 2.2 months and 11.0 3 1.6 months, respectively. Toxic effects were very rare and mainly consisted of neutropenia and thrombocytopenia due to myelosuppression; approximately 70% to 80% of patients had neutropenia or thrombocytopenia that exceeded National Cancer Institute grade II. Nonhematologic toxicities were not observed in this study. The CAG regimen seems promising, with acceptable toxicity, for the treatment of various categories of poor-prognosis AML and MDS-RAEBt.

Aclarubicin↗
PubMed1998

[Splicing and stability of intron in the expression retroviral vector with human clotting factor IX].

To study the role of intron in the expression of hFIX, retroviral vectors with intron containing hFIX were constructed. It is fundamental for the intron study whether the intron constructed in retroviral vector can be steadily transferred into target cell. First, we constructed two forward-orientation retroviral vectors: G1NaC-i-IX contains the exogenous intron from IL-2, and G1NaC-i'-IX contains the truncated intron I from hFIX gene, covering the splicing donor and acceptor sequences. RT-PCR result indicated that intron in the forward-orientation retroviral vector was spliced after packaging in PA317. Then, reverse-orientation retroviral vectors G1NaC-i'-IXR and G1NaPAIXi' BAM were constructed, in which the reverse and complimentary sequences of hFIX gene with intron appeared in retroviral RNA. RT-PCR assay combined with ELISA test indicated that intron was retained after packaging and hFIX gene with intron constructed in the reverse-orientation retroviral vector can be transduced intact and expressed hFIX at a high level in vitro.

Factor IX↗
PubMed1997

Increment of hFIX expression with endogenous intron 1 in vitro.

This paper probes into the feasibility of increasing expression level of hFIX gene with endogenous intron 1 sequence. hFIX minigene was obtained with middle sequence truncated intron 1 inserted into the relative site of hFIX cDNA, and plasmid vector pKG5i'IX, retroviral vector GINaCi'IX were constructed. These vectors were transduced into target cells of PA317, C2C12, primary rabbit skin fibroblasts (RSF) and primary human skin fibroblasts (HSF). The expression level of mixed colonies are PA317/pKGoi'IX, 151 ng/10(6) cells/24h; PA317/G1NaCi'IX, 308 ng/10(6) cells/24 h; C2C12/G1 NaCi'IX, 188 ng/10(5) cells/24 h; RSF/G1NaCi'IX, 1929 ng/10(5) cells/24 h; HSF/G1NaCi'IX, 1646 ng/10(6) cells/24 h. These results indicated that hFIX minigene with intron 1 is able to increase the expression level to about 3 times of that of hFIX cDNA. Meanwhile, in order to study the application of hFIX minigene in the retroviral-mediated gene transfer system and refrain from intron splicing during viral production, a retroviral vector G1NaCi'IXR with reversely inserted hFIX minigene expression cassette was constructed. The expression level of reverse constructor in PA317 cells was 390 ng/10(6) cells/24 h with 79% of bioactivity. PCR detection of HT/G1NaCi'IXR cells infected with PA317/G1NaCi'IXR supernatant confirmed the existence of intron 1 sequence. These results suggested that expression vector with forward-inserted intron1-carrying hFIX expression cassette can be used in directed gene transfer, but when using the retroviral-mediated gene transfer system, reversely-inserted intronl-carrying hFIX expression cassette should be considered.

Animals↗
PubMed1994

Isolation, mapping, DNA sequence and RFLPs studies of random single-copy DNA segments on human X chromosome.

Using the total human/mouse DNA as the probe, screening has been carried out three times with in situ plaque hybridization to obtain the single-copy DNA sequence from the human X chromosome genomic library. The effective rate of screening is 1.45%. DNAs from clones containing single-copy inserts have been analyzed by a panel of hybrid cells with or without human X chromosome. Three segments, designated by DXFD52,73,75, are mapped to the X chromosome. DXFD52 has been precisely localized on Xq12-q13 with in situ chromosomal hybridization. DXFD52 has been partially sequenced. The results indicate that DXFD52 is a new isolated single-copy segment on the X chromosome. Great progress in the RFLPs study with DXFD52 has been achieved in the population of Chongqing, Sichuan Province. The results show that the DXFD52 can be used to detect the RFLP with Hind III, Bgl II, and Hinf I. DXFD52 will be a potential "landmark" for the construction of the complete linkage map of human genome and the analysis of genomic sequence. And also, the results provide the experience in the development of a useful DNA probe to be applied to diagnosing X-linked disorders.

Base Sequence↗
PubMed1994

[Changes in neuroendocrine cells and immunocompetent cells in bronchiectasis].

Pulmonary endocrine cells and immunocompetent cells from the lungs of 35 subjects with bronchiectasis and in 10 normal controls were investigated by using immunohistochemical technique. The morphological and immunohistochemical characteristics of bronchus associated lymphoid tissue (BALT) of the lung were also studied. The number of calcitonin and serotonin immunoreactive pulmonary endocrine cells increased significantly in bronchiectasis as compared with those from control subjects. The number of IgA, IgG and IgM positive cells and UCHL1 positive cells were higher in the bronchial lamina propria in bronchiectasis than those in controls. These changes were most marked in hyperplastic BALT areas, which suggest that neuroendocrine and immune mechanisms may be involved in the pathogenesis of bronchiectasis.

Adult↗
PubMed1994

[The treatment of borderline ovarian tumors and its prognosis].

Twenty patients with ovarian borderline epithelial tumors were analysed. The tumor in 9 patients were serous and in 11 patients mucinous in nature type. 15 cases were classified as of stage I, 3 cases of stage II and 2 cases of stage III, according to the FIGO staging. All pathologic slides were re-reviewed to confirm the diagnosis and no patients were lost to follow-up. Total hysterectomy and unilateral or bilateral salpingo-oophorectomy were done in 12 patients, among whom, 2 died of tumor recurrences. Unilateral adnexectomy was done in 8 patients, and none died of tumor recurrence. Fourteen patients received post operative chemotherapy 1-8 courses with PAC regimen, 12 patients were alive up to the present. Six patients did not receive chemotherapy and among these 3 with stage Ia were alive and 1 with stage Ib died of tumor recurrences. The survival rate of stage I was 92.3%. Our results indicated that the prognosis was closely related to clinical staging. We suggested that patients of stage I who wish to preserve childbearing function may be treated with unilateral salpingo-oophorectomy, and chemotherapy should be given to the patients with high risk factors. Because of the indolent nature of these tumors, long-term follow-up at least 10 years is necessary.

Adolescent↗
PubMed1993

Long-term expression of human factor IX cDNA in rabbits.

In this study, rabbits were used as a model for gene therapy for hemophilia B. Human factor IX cDNA was transferred to cultured normal rabbit skin fibroblasts (RSF) by a recombinant plasmid (pCMVIX) or retrovirus (XL-IX or N2CMVIX) constructed in our laboratory. Infected fibroblasts capable of synthesizing and secreting high levels of biologically active human factor IX protein were selected and embedded in a collagen matrix. The latter was surgically implanted into rabbits as autografts or allografts. Human factor IX protein was detected in the plasma of all the grafted rabbits, and its expression has been maintained for more than 10 months at the time of writing. In addition, we have improved and simplified the method of implantation from surgically grafting the tissue-like matrix to the injection of the infected cell-collagen mixture subcutaneously. Using the latter method, human factor IX in rabbits injected with RSF-N2CMVIX reached a peak of 480 ng/ml plasma, and its expression has continued for more than 3 months at the time of writing. We suggest that the simplified method of transplantation by subcutaneous injection would offer an effective and acceptable approach to somatic cell gene therapy and may be practical for human trials.

Animals↗
PubMed1993

Stage I clinical trial of gene therapy for hemophilia B.

This paper describes the first human gene therapy trial for hemophilia B. Retroviruses were used to introduce human factor IX into autologous, primary human skin fibroblasts from the patients. Recombinant retroviral vector containing human FIX cDNA driven by viral LTR promoter (XL-IX) and double-copy retroviral vector driven by human cytomegalovirus enhancer-promoter (N2CMV-IX) were constructed. After the safety assessment, including soft-agar test, cell morphology observation, analysis of endotoxin, chromosome karyotype, allergic reaction test, nude mice test, routine pathological test, electromicroscopic analysis, and virus detection by PCR, etc., the engineered cells were pooled and embedded in collagen mixture, autologously injected into the patients respectively. The concentration of human FIX protein of Patient 1 increased from 71 ng/ml to 220 ng/ml, with a maximum level of 245 ng/ml. The expression of FIX has lasted for 6 months at the time of writing. The clotting activity also increased from 2.9% to 6.3%, his clinical symptoms have been alleviated obviously. The secretion rate of FIX for Patient 2 increased from 130 to 250 ng/ml, maintained at the level of 220 ng/ml for 5.5 months at the time of writing, but the clotting activity has not been increased steadily. There is no deleterious effect to be found in the two patients since the ex-vivo cells were implanted. The two patients are now under follow-up investigation. We suggested that retrovirus-mediated transfer of genes into skin fibroblasts, to be embedded in collagen and subcutaneously injected into patients, is a simple and effective approach for the gene therapy for hemophilia B.

Adolescent↗
PubMed1993

Expression of human factor IX cDNA in mice by implants of genetically modified skin fibroblasts from a hemophilia B patient.

Double-copy retroviral vector containing human factor IX cDNA driven by human cytomegalovirus enhancer-promoter was constructed. The vector was introduced into the amphotropic packaging cell line PA317. The recombinant virus produced in PA317 was used to transduce skin fibroblasts from a hemophilia B patient. The infected cells produced high levels of biologically active human factor IX at a rate of 3420 ng/10(6) cells/24 h. These cells were embedded in a collagen matrix and implanted into the peritoneal cavity or subcutaneous space of mice. It was demonstrated that human factor IX was produced by the implants for at least 12 days in vivo, reaching a peak of 105 ng/ml plasma. Over 90% of the protein was functionally active. This technique has the potential to be developed into a new approach for gene therapy for hemophilia B.

Animals↗
PubMed1992

[Cisplatin nephrotoxicity: clinical observation and animal experiment].

Animal experiment and clinical observation were carried out to study the nephrotoxicity of cisplatin in order to give protective measures. In animal experiment it had been demonstrated that the nephrotoxicity induced by cisplatin was mainly related to the intraperitoneal concentration of cisplatin. The nephrotoxicity was permanent in rats treated with cumulative cisplatin. The main pathologic lesions were characterized by interstitial hyperemia, degeneration of the tubular cells and formation of tubular casts. In a Clinical study to compare two preventive methods (sodium thiosulfate and hydration) from cisplatin induced nephrotoxicity, the BUN and serum Cr were measured in 28 patients. The results revealed that there was no significant difference between the two groups (P greater than 0.05). The two protective measures had similar effect in reducing the nephrotoxicity of cisplatin. Five of 6 patients treated with cisplatin developed hypo-magnesemia but only one had symptoms.

Adolescent↗
PubMed1992

High efficient transfer and expression of human clotting factor IX cDNA in cultured human primary skin fibroblasts from hemophilia B patient by retroviral vectors.

To study the possibility of somatic gene therapy for hemophilia B via gene transfer to primary factor IX-deficient skin fibroblasts, we constructed four retroviral vectors containing factor IX cDNA driven by retroviral LTR promoter, SV40 early promoter and mouse MT-I promoter, respectively. These retroviral vectors were transfected into an amphotropic packaging cell line, PA317 cells, by electroporation, and a human fibrosarcoma cell line, HT1080 cells, was used to assay the factor IX-virus titers of these four virus-producing PA317 cells, which ranged from 2 x 10(4) to 5 x 10(5) cfu/ml. The factor IX proteins produced by bulk population of four virus-producing PA317 cells were determined by ELISA. Results showed that LTR promoter directed the highest production of factor IX at the rate of 584 ng/10(6) cells/24 h, while SV40 early promoter and MT promoter directed about 10 and 20 times less production of factor IX than LTR promoter. The highest expressed retroviral vector XL-IX was used to infect a line of factor IX-deficient human primary skin fibroblasts, FDIX cells. The factor IX secretion rate of the infected FDIX cells was about 549 ng/10(6) cells/24 h and over 75% of secreted factor IX was biologically active. We are convinced that this factor IX-deficient human primary skin fibroblast had been cured, or genetically corrected, by retroviral-mediated gene therapy in vitro.

Adult↗
PubMed1991

[The RFLP of LDR152/PstI in the Chinese and its application to linkage analysis in a myotonic dystrophy family].

Myotonic dystrophy (DM) is inherited as an autosomal dominant trait and is characterized by variable expressivity and late age-of-onset. In the present paper, the DNA from 61 normal individuals and a DM family with 15 members of 4 generations were collected and digested with PstI, then hybridized with the LDR152 (D19S19). The results showed that the alleles for the PstI polymorphism were 19 and 11kb in size (gene frequencies were 0.4344 and 0.5656 respectively, which are obviously different from the previous data reported). In this DM family, the carriers who had lived most of their life without knowing that they had been infected with the disease were detected by the LDR152 and the estimation of DM risk on at-risk-individuals was also calculated.

Chromosomes, Human, Pair 19↗
PubMed1990

[Preparation of human minisatellite DNA probes].

A 23-mer oligonucleotide based on the core sequence was chemically synthesized and used to screen the human genomic library. Fifteen positive recombinants containing the minisatellite sequences were identified, and one of them, C35.9, was used to perform Southern hybridization with the DNAs from unrelated Chinese individuals. Each sample has 3-11 hybridizing bands, and some of which are polymorphic. The band patterns detected under controlled condition are individual-specific in a limited population. This indicates that the minisatellites obtained by screening the library can be used to detect the polymorphisms of the minisatellites.

DNA Probes↗
PubMed1989

Identification of partial mutational sites in human mitochondrial DNA in the Chinese and its significance.

A simple method for the identification of mutational sites in human mitochondrial DNA (mtDNA) was described. It was based on the human Cambridge sequence as a relative standard sequence and a single base pair substitution in mtDNA as a unique mutational form. The partial mutational sites can be determined using this method which was characterized by combining the restriction mapping with the analysis for the table of human mtDNA potential mutational sites with rapidity and simplicity. In the meanwhile, six mtDNA mutational sites found in Chinese population were identified by means of this method.

China↗
PubMed1988

Mitochondrial DNA polymorphism in Chinese.

Human mitochondrial DNA (mtDNA) restriction endonuclease fragment patterns were analyzed using placenta DNA isolated from 273 individuals representing four different nationalities, the Han, the Uygur, the Kazakh and the Hui populations. Thirty-eight fragment patterns (morphs) were observed with the enzyme ApaI, BamHI, EcoRI, HindIII, HinfI, HhaI, HapII, KpnI, Mbol, PstI, PvuII, SacI, ScaL and XhoI. Fourteen new morphs, including some only existing in individual racial and national populations were observed, which indicates that there is a significant difference in the distribution of mtDNA morphs among various national and racial populations. By comparison with the mtDNA sequences in primate species, some mtDNA ancestral morphs were found to be retained in Oriental population today. This result provided indirect evidence that Asia may be one of the human original sources. Genetic distances among four national populations computed and employed in construction of an average linkage tree suggested that the Uygur and the Kazakh populations combined to form a branch at first, then the Han and the Hui came together to form another one, and at last, these two branches converged into a stem. Again, it was found that the internal variation within the Uygur and the Kazakh populations was greater than that within the Han and the Hui populations. These results showed a relationship among the four different national populations in China based on the molecular level.

China↗
PubMed1987

Establishment of a human/Chinese hamster hybrid clone panel.

Combined with the chromosome G-banding, followed by Giemsa-11 techniques and chromosomal marker isozyme analysis, 6 out of 200 subclones have been analyzed in detail. A primary hybrid clone panel has been established, which can be used to map genes on chromosomes 4, 5, 8, 12, 20 and 22. Since the panel contains deleted chromosomes 4, 5, 8 and 12, genes on these chromosomes can be mapped regionally.

Animals↗
PubMed1987

Regional assignment of human alcohol dehydrogenase (ADH) gene to 4pter----4q21.

The hybrid clone FD1 constructed by fusion of Chinese hamster cell line Wg3-h with human lymphocyte was irradiated with X-ray. Fourteen survival clones were isolated and 3 of them, F5B, F52B, F61A were analyzed in detail by cytogenetic and biochemical methods. The results of chromosome G-banding followed by Giemsa-11 differential staining show that there exists a deleted human chromosome 4 in all of the three hybrids. This deletion of human chromosome 4 in F61A is 4pter----4q21. The results of isozyme analysis of phosphoglucomutase-2 (PGM2) which is located on 4p14----4q21 confirm our cytogenetic conclusion. We used polyacrylamide gel electrophoresis to study the alcohol dehydrogenase (ADH) in human lymphocyte, Wg3-h and hybrid clones. Their electrophoretic pattern showed that human ADH isozyme did express, in the peripheral blood lymphocyte, hybrids F5B, F52B, F61A and FD1. According to these results, we suggest that one of the Class I ADH structural genes is located on the human chromosome 4pter----4q21. Recently, McKusick reported that Class I ADH gene cluster had been assigned to chromosome 4q21----4qter. Considering this fact, we suggest that Class I ADH gene might be assigned to chromosome 4q21 or on its vicinity.

Alcohol Dehydrogenase↗