Biomedical subjects

Q Fang

Publications and source records attributed to Q Fang.

At least 37 records · Page 2Linked to original sources

PubMed2001

Preparation and characterization of biodegradable copolyester-starch based foams.

Regular (25% amylose) and waxy corn starches blended to various ratios with Eastar Bio Copolyester 14766 (EBC) were extruded into loose-fill foams using a twin screw extruder. Included in this study were two types of corn starch, three levels of EBC content, and three levels of starch moisture content. Waxy starch produced foams with greater radial expansions and lower unit and bulk densities than regular starch. Regular starch foams had lower water solubility indices (WSIs) than waxy starch foams. Foams made of both types of starch possessed similar mechanical properties. No differences were observed in compressibilities and spring indices of either waxy or regular starch foams. Higher levels of EBC addition resulted in less radial expansion and higher unit and bulk densities. Foams made with 10% EBC had higher compressibility than foams containing 25% EBC. Spring indices of single-piece samples and compressibilities and spring indices of bulk samples were not affected by the differences in the level of EBC addition. At 19% and 22% of moisture contents, foams had greater radial expansion than at 25% moisture content. Unit and bulk densities were not affected by variations in moisture content. At 22% moisture content, a lower WSI of 18.5% was obtained. At 22% moisture content, softer foams were produced. At all three levels of moisture content, no differences were detected in the spring indices.

Biocompatible Materials↗

PubMed2001

A histone fold TAF octamer within the yeast TFIID transcriptional coactivator.

Gene activity in a eukaryotic cell is regulated by accessory factors to RNA polymerase II, which include the general transcription factor complex TFIID, composed of TBP and TBP-associated factors (TAFs). Three TAFs that contain histone fold motifs (yTAF17, yTAF60 and yTAF61) are critical for transcriptional regulation in the yeast Saccharomyces cerevisiae and are found in both TFIID and SAGA, a multicomponent histone acetyltransferase transcriptional coactivator. Although these three TAFs were proposed to assemble into a pseudooctamer complex, we find instead that yTAF17, yTAF60 and yTAF61 form a specific TAF octamer complex with a fourth TAF found in TFIID, yTAF48. We have reconstituted this complex in vitro and established that it is an octamer containing two copies each of the four components. Point mutations within the histone folds disrupt the octamer in vitro, and temperature-sensitive mutations in the histone folds can be specifically suppressed by overexpressing the other TAF octamer components in vivo. Our results indicate that the TAF octamer is similar both in stoichiometry and histone fold interactions to the histone octamer component of chromatin.

Alleles↗

PubMed2001

Genetic modification of hematopoietic progenitor cells for combined resistance to 4-hydroperoxycyclophosphamide, vincristine, and daunorubicin.

AIM: To investigate whether human peripheral blood hematopoietic progenitor cells (PBPC) modified with human aldehyde dehydrogenase class-3 gene (ALDH-3) and multidrug resistance gene 1 (MDR1) would increase chemotherapy resistance to 4-hydroperoxycyclophosphamide (4-HC) and -glycoprotein effluxed drugs. METHODS: A bicistronic retroviral vector G1Na-ALDH3-IRES-MDR1 cDNA was constructed and used to transfect the packaging cell lines PA317 by electroporation. CD34+ PBPC were isolated with a high-gradient magnetic cell sorting system (MACS), and then were transfected with supernatant of retrovirus containing human ALDH-3 and MDR1 cDNA. PCR, RT-PCR, Southern blot, Northern blot, FACS, and MTT assay were used to evaluate the transfection and expression of the transgene in target cells. RESULTS: The bicistronic retroviral vector construction was verified by PCR and restriction endonuclease analysis. Dual drug resistance genes were integrated into the genomic DNA of CD34+ PBPC and expressed efficiently. The efficiency of gene transfection in CD34+ PBPC was tested to be 18 % on colonies. Nested PCR and Neor rescue assay indicated that no helper virus was present in this system. Compared with the untransduced cells, transgene recipient cells conferred 4.5-fold resistance to 4-HC, 6.6-fold and 7.8-fold resistance to P-glycoprotein effluxed drug, vincristine and daunorubicin, respectively. CONCLUSION: Efficient transduction of two different types of drug resistance genes into human peripheral blood hematopoietic progenitor cells and the co-expression may decrease cumulative myelosuppression of combination chemotherapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2001

[A study of Humphrey three zone screening to detect visual field of the patients with pituitary macroadenomas].

OBJECTIVE: To evaluate the clinical application of Humphrey three zone screening in detecting the visual field of the patients with pituitary macroadenomas (PMA). METHODS: There were two groups in the study. The PMA group: 128 PMA cases were selected who had symptoms of visual problem and been diagnosed with computer tomography (CT) or magnetic resonance (MR) and without apparent opacity of refractive medium. The low myopia group: thirty cases with low myopia and without other eye diseases were included. Humphrey three zone screening method was used to detect the 76-points in the central 30 degree visual fields of the patients of the two groups. RESULTS: In PMA group, 99.2% of the 128 patients and 87.1% of their eyes had visual field defect. 86.7% of the patients had the visual field defect mainly located at the temporal side and showed or tended to have a medial vertical limit. In detecting abnormality of the patients, three zone screening test had a sensitivity of 99.2% (percent of cases with true visual field defect identified by the field test). The mean test duration of each eye is (5.8 +/- 2.2) minutes. In low myopia group, two eyes of two patients had visual field defect. In testing the normal group, three zone screening test had a specificity of 93.3% (percent of cases without true visual field defect appropriately identified by the field test). CONCLUSION: Humphrey three zone screening has very high sensitivity and specificity in detecting visual field, and it is simple, fast and practical for detecting the visual field of the patients with PMA. It plays an important role in implying diagnosis and avoiding misdiagnosis of PMA.

Adenoma↗

PubMed2001

[The impact of calpain-10 gene combined-SNP variation on type 2 diabetes mellitus and its related metabolic traits].

OBJECTIVE: To investigate the impact of calpain-10 gene (CAPN-10) combined single nucleotide polymorphism (SNP) variation on type 2 diabetes mellitus (T2DM) and its related clinical metabolic traits in Chinese. METHODS: The study population consisted of 268 Chinese residents in Shanghai. Among them, 144 were subjects with normal glucose tolerance (NGT) and 124, with T2DM. Plasma glucose (PG), insulin (INS), c-peptide (CP) and free fatty acids (FFA) levels were measured at fasting and 30, 60, 120, and 180 minutes after oral 75 g glucose challenge. The islet beta-cell insulin secretion and tissue insulin sensitivity were assessed. CAPN-10 UCSNP44,-43,-19 and -63 were genotyped. RESULTS: (1) In Chinese NGT subjects, the major allele of UCSNP-44 was allele T (frequency=91%), of UCSNP43 was G(89%), of UCSNP-19 was I (3 repeats of a 32 bp sequence) (67%) and of UCSNP-63 was C allele (79%). Significant differences were observed in comparison of these allele frequencies in Chinese to those in other ethnic groups reported in the literature. (2) 14 genotype combinations of these four SNPs were observed in Chinese NGT subjects. 69% of the NGT population was composed of four genotype combinations, in the order of UCSNP44,-43,-19 and -63, i.e., combination A:TT-GG-DI-CC(haplotype combination was 1121/1111) (frequency=10%), combination B:TT-GA-II-CC(1121/1221)(10%), combination C:TT-GG-II-CC(1121/1121)(26%) and combination D:TT-GG-DI-CT(1121/1112)(22%).(3) The frequencies of the above mentioned SNP in single or in combinations were not different significantly between NGT and T2DM groups. (4) The variation of clinical metabolic parameter levels shifted from completely normal towards abnormal glucose intolerance among genotype combination subgroups. In comparison between combination A and combination D, subjects in the former subgroups had: higher PG levels with delayed peak after glucose challenge; less and lower decrement of FFA levels after challenge with no rising in late stage; higher insulin levels with delayed peak after challenge; and the tendency of decreased insulin sensitivity. More than half of the comparisons remained statistically significant after adjusted with age, gender, body mass index and waist circumference. CONCLUSION: The variation of calpain-10 gene has impact on the variation of clinical metabolic parameter levels related to type 2 diabetes mellitus. Such impact depends upon the haplotypes as well as the haplotype combination of calpain-10 gene variations.

Alleles↗

PubMed2001

Clinical retrospective and comparative study on diaphragm injuries in 46 cases.

OBJECTIVE: To explore a way of guiding diagnosis and treatment of blunt and penetrating diaphragm injuries. METHODS: According to injury violence, 46 chest trauma patients with diaphragm rupture were divided into two groups: a blunt injury group and a penetrating injury group. The injury condition and trauma scores between the two groups were compared and analyzed. RESULTS: The incidence of blunt diaphragm injuries was lower than that of penetrating injuries (1.78% vs 8.53%, P <0.05). In the blunt injury group most patients had multiple injuries. Penetrating injuries developed more quickly than blunt injuries, and resulted in hemorrhagic shock in the early period. Trauma scores showed that there was no significant difference in the Revised Trauma Score (RTS), the Injury Severity Score (ISS) and thoracic Abbreviated Injury Scale (AIS) between the two groups (P<0.05), but the blunt injury group had lower Glasgow Coma Scale (GCS) and abdominal AIS than the penetrating group (P<0.0 5). CONCLUSIONS: Blunt and penetrating diaphragm injuries have different clinical characteristics. So they should be dealt with differently to reduce the incidence of complication and improve prognosis.

Adolescent↗

PubMed2001

[Effects of angiotensin II on proliferation and expression of interleukin-6 of human kidney fibroblasts].

OBJECTIVE: To investigate the effects of Angiotensin(Ang) II on the proliferation and expression of Interleukin (IL)-6 in human kidney fibroblasts(KFB). METHODS: The human KFB were cultured and identified, the proliferation of KFB was measured by MTT, and the level of IL-6 was measured by radioimmunoassay(RIA). RESULTS: Angiotensin II could stimulate the proliferation of KFB and enhance the expression of IL-6 in protein level on KFB. CONCLUSION: Angiotensin II can stimulate KFB's proliferation and enhance the expression of IL-6 of KFB. These findings suggest that Ang II might play a part in the mechanisms for modulating tubulointerstitial changes and induceing renal fibrosis.

Angiotensin II↗

PubMed2000

Micelle-mediated extraction and preconcentration of ginsenosides from Chinese herbal medicine.

The feasibility of employing micelle-mediated extraction as an alternative and effective method for the solubilization, purification and/or preconcentration of active ingredients from herbal products is demonstrated for the first time using the root of American ginseng as a model. When compared to methanol and water, an aqueous surfactant solution containing 10% Triton X-100 yielded faster kinetics and higher recovery for the extraction of various ginsenosides. An experimental design approach (uniform design) was demonstrated as a novel and useful method for the optimization of experimental factors involved in the micelle-mediated extraction process. For the preconcentration of ginsenosides prior to chromatographic determination, a salting-out agent (sodium sulfate) was employed to make the efficient cloud point extraction of both hydrophobic and hydrophilic ginsenosides into the surfactant-rich phase possible, as well as to increase the preconcentration factor by reducing the volume of the surfactant-rich phase.

Chromatography, High Pressure Liquid↗

PubMed2000

Sequence of genome segments 1, 2, and 3 of the grass carp reovirus (Genus Aquareovirus, family Reoviridae).

The genome segments 1, 2, and 3 of the grass carp reovirus (GCRV), a tentative species assigned to genus Aquareovirus, family Reoviridae, were sequenced. The respective segments 1, 2, and 3 were 3949, 3877, and 3702 nucleotides long. Conserved motifs 5' (GUUAUUU) and 3' (UUCAUC) were found at the ends of each segment. Each segment contains a single ORF and the negative strand does not permit identification of consistent ORFs. Sequence analysis revealed that VP2 is the viral polymerase, while VP1 might represent the viral guanylyl/methyl transferase (involved in the capping process of RNA transcripts) and VP3 the NTPase/helicase (involved in the transcription and capping of viral RNAs). The highest amino acid identities (26-41%) were found with orthoreovirus proteins. Further genomic characterization should provide insight about the genetic relationships between GCRV, aquareoviruses, and orthoreoviruses. It should also permit to precise the taxonomic status of these different viruses.

Animals↗

PubMed2000

The resonant recognition model (RRM) predicts amino acid residues in highly conserved regions of the hormone prolactin (PRL).

The resonant recognition model (RRM) is a model which treats the protein sequence as a discrete signal. It has been shown previously that certain periodicities (frequencies) in this signal characterise protein biological function. The RRM was employed to determine the characteristic frequencies of the hormone prolactin (PRL), and to identify amino acids ('hot spots') mostly contributing to these frequencies and thus proposed to mostly contribute to the biological function. The predicted 'hot spot' amino acids, Phe-19, Ser-26, Ser-33, Phe-37, Phe-40, Gly-47, Gly-49, Phe-50, Ser-61, Gly-129, Arg-176, Arg-177, Cys-191 and Arg-192 are found in the highly conserved amino-terminal and C-terminus regions of PRL. Our predictions agree with previous experimentally tested residues by site-direct mutagenesis and photoaffinity labelling.

Algorithms↗

PubMed2000

Cartilage-reactive T cells in rheumatoid synovium.

Rheumatoid arthritis (RA) is an inflammatory polyarthritis genetically linked to HLA-DR4 and related haplotypes. RA synovial tissue is characterized by T cell infiltration and activation of macrophage-like cells, strongly implicating a T cell-antigen-presenting cell (APC) interaction in RA pathogenesis. To investigate the nature of the antigens driving the T cell response, synovial tissue was obtained from a patient with chronic RA and T cells were enriched. These T cells were stimulated by endogenous APC from the same synovial tissue. The T cell lines were subsequently evaluated for responsiveness to autologous APC and cartilage antigens. Specific proliferative responses to autologous APC which were enhanced by cartilage extract were seen. Immunomagnetic bead selection and RT-PCR was used to identify TCR alphabeta pairs which appeared to respond to antigen(s) in the cartilage extract. T cell clones derived from the same joint were shown to release IL-2 in response to the cartilage extract and expressed a related TCR. With these experiments we have shown direct evidence that autoreactive T cells are found within the inflamed rheumatoid synovium and, further, that the antigens driving these T cells are cartilage derived. Since the antigens recognized by these populations of T cells are found within cartilage our data provides evidence that RA pathology could be related to a self-driven autoimmune response to cartilage proteins.

Adult↗

PubMed2000

Targeted deletion of the tub mouse obesity gene reveals that tubby is a loss-of-function mutation.

The mouse tubby phenotype is characterized by maturity-onset obesity accompanied by retinal and cochlear degeneration. A positional cloning effort to find the gene responsible for this phenotype led to the identification of tub, a member of a novel gene family of unknown function. A splice defect mutation in the 3' end of the tub gene, predicted to disrupt the C terminus of the Tub protein, has been implicated in the genesis of the tubby phenotype. It is not clear, however, whether the Tub mutant protein retains any biological activity, or perhaps has some dominant function, nor is it established that the tubby mutation is itself responsible for all of the observed tubby phenotypes. To address these questions, we generated tub-deficient mice and compared their phenotype to that of tubby mice. Our results demonstrate that tubby is a loss-of-function mutation of the tub gene and that loss of the tub gene is sufficient to give rise to the full spectrum of tubby phenotypes. We also demonstrate that loss of photoreceptors in the retina of tubby and tub-deficient mice occurs by apoptosis. In addition, we show that Tub protein expression is not significantly altered in the ob, db, or melanocortin 4 receptor-deficient mouse model of obesity.

Adaptor Proteins, Signal Transducing↗

PubMed2000

Establishment and chimera analysis of 129/SvEv- and C57BL/6-derived mouse embryonic stem cell lines.

Hundreds of new mutant mouse lines are being produced annually using gene targeting and gene trap approaches in embryonic stem (ES) cells, and the number is expected to continue to grow as the human and mouse genome projects progress. The availability of robust ES cell lines and a simple technology for making chimeras is more attractive now than ever before. We established several new ES cell lines from 129/SvEv and C57BL/6 mice and tested their ability to contribute to the germline following blastocyst injections and/or the less expensive and easier method of morula-ES cell aggregation. Using morula aggregation to produce chimeras, five newly derived 129/SvEv and two C57BL/6 ES cell lines tested at early passages were found to contribute extensively to chimeras and produce germline-transmitting male chimeras. Furthermore, the two 129S/vEv ES cell lines that were tested and one of the C57BL/6 ES cell lines were able to maintain these characteristics after many passages in vitro. Our results indicate that the ability of ES cells to contribute strongly to chimeras following aggregation with outbred embryos is a general property of early passage ES cells and can be maintained for many passages. C56BL/6-derived ES cell lines, however, have a greater tendency than 129-derived ES cell lines to lose their ability to colonize the germline.

Animals↗

PubMed2000

[Analysis of chromosomal karyotypes in 300 fetal blood samples during the second and third trimesters of gestation].

OBJECTIVE: To analyze the fetal chromosomal karyotypes from the blood samples obtained by cordocenteses during the second and third trimesters, and to investigate the types of chromosomal abnormalities, as well as the relationship between the abnormal karyotypes and the indications of prenatal diagnosis. METHODS: Cordocenteses were performed in 300 pregnant women with different indications for prenatal diagnosis during the 18 to 38 gestational weeks, and fetal chromosomal karyotypes were examined. RESULTS: Twenty three chromosomal abnormalities(7.7%) were checked out. In the second trimester, there were 15 abnormalities in 174 samples(8. 6%); whereas in the third trimester, it was 8 out of 126(6.3%), P=0. 77. Trisomy, the leading abnormality, consisted of 60.9%(14/23) of all abnormalities and 9 out of 14 were trisomy 21, which was 39. 1%(9/23). In those aged over 35 years, trisomy 21 was detected in 5 of 92(5.4%), and in the age under 35 years, it was 4 out of 208(1. 9%), P=0.26. Thirty three women had the history of giving a birth of trisomy 21 previously, this time, however, no one was recurrent. Highest chromosomal aberration rate, 26.3%(5/19), was detected in the fetuses with intrauterine growth retardation(IUGR), and all were trisomy. Balanced translocation was found in 5 fetuses (1 associated with Robertsonian translocation), which was 21.7%(5/23). CONCLUSION: During the second and third trimesters, the rate of chromosomal abnormality is 7.7% in those fetuses who have maternal indications for prenatal diagnosis. trisomy, especially trisomy 21, is the most common abnormal karyotype found in these periods and in advanced maternal age, as well as in severe IUGR.

Adult↗

PubMed2000

[Differentiation of achondroplasia and other similar genetic dwarfism by FGFR3 gene analysis].

OBJECTIVE: To study the gene mutation of Chinese patients with achondroplasia(ACH) and to set up a simple and rapid molecular diagnostic method to differentiate ACH from other similar genetic dwarfism. METHODS: The specific fragment of fibroblast growth factor receptor 3(FGFR3) transmembrane domain was amplified from dried blood spots of 21 patients with ACH and 6 suspicious patients with ACH by polymerase chain reaction, then mutation was screened and detected by restrictive enzyme analysis, single strand conformation polymorphism(SSCP) and denaturing gradient gel electrophoresis(DGGE). RESULTS: One out of 6 suspicious cases was ACH and 5 were pseudoachondroplasia(PSACH). Twenty-one out of 22 patients with ACH bore a G to A transition at nucleotide 1138 and 1 bore a G to C transversion at this same position. CONCLUSION: The nucleotide 1138 of FGFR3 gene is also the hotspot of mutation in Chinese patients with ACH. A simple and rapid molecular diagnostic method has been set up to differentiate ACH from other similar genetic dwarfism.

Achondroplasia↗

PubMed2000

[Difluoromethylornithine synergizes with antisense bcl-2 RNA in the induction of apoptosis of HL60 cells].

OBJECTIVE: To study the combined effect of difluoromethylornithine (DFMO) and bcl-2 antisense RNA in the induction of apoptosis of HL60 cells. METHODS: HL60 cells were transfected with recombinant retroviral vector expressing bcl-2 antisense RNA. The growth characteristics of transfectants were studied by morphological observation, growth curve, FCM analysis, colony formation in soft agar, DNA electrophoresis, molecular hybridization and immunocytochemical staining. RESULTS: The recombinant retroviral vectors expressing bcl-2 antisense RNA and the cell line producing recombinant virus were constructed. Although the expression of bcl-2 at mRNA and protein levels in the HL60 cells transfected with antisense bcl-2 were down-regulated, there was no change in cell growth, cell cycles and expression of ornithine decarboxylase (ODC) compared with the parental cells albeit some decrease in colony formation. In addition, transfection with antisense bcl-2 did not induce marked apoptosis whereas treatment of the transfectant with low concentration (0.2 mmol/L) of DFMO resulted in enhanced expression inhibition of bcl-2 protein, inhibition of cell growth and induction of apoptosis. CONCLUSION: DFMO synergizes with antiense bcl-2 RNA in the induction of apoptosis of HL60 cells.

Antineoplastic Agents↗

PubMed2000

[The detection of disparity evoked potentials in anisometropes].

OBJECTIVE: To investigate the affection of anisometropia on stereopsis and its mechanism. METHODS: A new set of static random-dot stereograms was utilized as a stimulus to elicit evoked potentials in 20 anisometropes and 40 normal subjects. RESULTS: Under the stimulus of different degrees of disparity in anisometropes, the P(250) waves related to stereopsis could be recorded. However, the percentage of their P(250) wave amplitude over the plane figure was significantly lower than that of normal persons (P < 0.05). The P(250) wave mean amplitude of severe anisometropes (aniseikonia >or= 5%) in fine disparity (14' and 23') was lower than that in mild anisometropes (aniseikonia < 5%, P < 0.05). CONCLUSIONS: Anisometropia may affect and disturb the stereopsis. The degree of disturbance is related to the degree of anisometropia. The higher the degree of anisometropia, the lower the amplitude of the P(250) potential, and the main defect is at the part of fine disparity.

Adolescent↗

PubMed1999

Influence of fetal to neonatal transition on nitric oxide synthase expression in the nucleus tractus solitarius in sheep.

Transition from fetal to newborn life is accompanied by a marked rise in circulating norepinephrine (NE) concentrations though arterial blood pressure does not substantively change. Nitric oxide (NO) plays an important role in the central regulation of sympathetic tone in the nucleus tractus solitarius (NTS) and neuronal NO synthase (nNOS) expression is functionally regulated in the brain. The purpose of these studies was to determine the influence of transition at birth on nNOS expression in the brainstem nuclei, particularly in the NTS, associated with changes in arterial pressure and plasma NE concentration. Experiments were performed using time-dated gestational ewes with twin fetuses. Arterial blood pressure was recorded and arterial blood NE concentrations were measured in the term fetus (gestational 147-148 days) and newborn lambs (4 h of postnatal age). The fetal and newborn animals were then perfused with 4% paraformaldehyde. Sections of the medulla were examined by using both immunolabeling with a polyclonal antibody directed against nNOS and nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) histochemistry, a marker for expression of nNOS. Micrographs were quantified using a microscope with reticule grid to measure the number of positive cells containing color staining in the brainstem nuclei. Plasma NE concentration in the newborn was more than two-fold greater compared to fetal values but mean arterial blood pressure was similar between fetus and newborn. The nNOS positive cells and NADPHd positive cells were significantly increased in the medial NTS (mNTS) of the newborn compared to fetus. nNOS immunoreactivity and NADPHd reactivity tended to increase in the rostral ventral medulla (RVM) in newborn, but were not altered in other brainstem nuclei during the transition from fetal to newborn life. The results suggest that nNOS expression in the mNTS is predominately enhanced at 4 h of neonatal age vs. the term fetus. We conclude that elevated circulating NE is associated with up-regulation of nNOS in the mNTS which may serve a protective role in central regulation of neonatal arterial blood pressure.

Animals↗