PubMed Health⌕ Search

Biomedical subjects

H Deng

Publications and source records attributed to H Deng.

At least 73 records · Page 4Linked to original sources
PubMed2000

Genetic determination of Colles' fracture and differential bone mass in women with and without Colles' fracture.

Osteoporotic fractures (OFs) are a major public health problem. Direct evidence of the importance and, particularly, the magnitude of genetic determination of OF per se is essentially nonexistent. Colles' fractures (CFs) are a common type of OF. In a metropolitan white female population in the midwestern United States, we found significant genetic determination of CF. The prevalence (K) of CF is, respectively, 11.8% (+/- SE 0.7%) in 2471 proband women aged 65.55 years (0.21), 4.4% (0.3%) in 3803 sisters of the probands, and 14.6% (0.7%) in their mothers. The recurrence risk (K0), the probability that a woman will suffer CF if her mother has suffered CF is 0.155 (0.017). The recurrence risk (Ks), the probability that a sister of a proband woman will suffer CF given that her proband sister has suffered CF is 0.084 (0.012). The relative risk lambda (the ratio of the recurrence risk to K), which measures the degree of genetic determination of complex diseases such as CF, is 1.312 (0.145; lambda 0) for a woman with an affected mother and 1.885 (0.276; lambda s) for a woman with an affected sister. A lambda-value significantly greater than 1.0 indicates genetic determination of CF. The terms lambda 0 and lambda s are related to the genetic variances of CF. These parameters translate into a significant and moderately high heritability (0.254 [0.118]) for CF. These parameters were estimated by a maximum likelihood method that we developed, which provides a general tool for characterizing genetic determination of complex diseases. In addition, we found that women without CF had significantly higher bone mass (adjusted for important covariates such as age, weight, etc.) than women with CF.

Absorptiometry, Photon↗
PubMed2000

Fluidity and fatty acid components of erythrocyte membranes in diabetic retinopathy.

BACKGROUND: Recently, numerous anomalies of erythrocyte rheology and function have been reported in diabetic patients. These changes are thought to be related to the alteration of erythrocyte membrane fluidity and may play an important role in diabetic retinopathy (DR). Nonetheless, the principal factors contributing to fluidity change remain undetermined. The influence of erythrocyte membrane fatty acid components on membrane fluidity and retinopathy was evaluated in patients with type 2 diabetes. METHODS: The fatty acid components and fluidity of erythrocyte membranes in 63 patients with type 2 diabetes with and without retinopathy were examined using high-performance liquid chromatography and fluorescence polarization. RESULTS: The content and composition of erythrocyte membrane arachidonate (C20:4n-6) was significantly lower in diabetics than in controls, and diabetics had significantly increased erythrocyte membrane microviscosity compared with controls. Furthermore, membrane microviscosity was higher in diabetics with DR than those without DR. In the diabetic patients, arachidonic acid contents of erythrocyte membranes were significantly, inversely correlated with erythrocyte membrane microviscosity, fasting blood glucose, glycosylated hemoglobin, triglycerides and cholesterol, and positively correlated with the insulin sensitivity index. CONCLUSIONS: The results suggest that erythrocyte membrane fatty acid components may contribute to alterations in membrane fluidity in patients with type 2 diabetes. Alterations in membrane fluidity may play an important role in the development of diabetic microangiopathy.

Aged↗
PubMed2000

[Progress in the studies on the molecular genetics of schizophrenia].

Although population genetic studies have long confirmed the genetic vulnerability of schizophrenia,ongoing advances in molecular genetic technology and biostatistic analysis are only now making it possible to search for the susceptibility gene of the disease. This article reviewed some of the recent findings in this area: (1) The heritability of schizophrenia is estimated around 60%-80%. The phenotype differentiation is based on standard diagnostic scales and symptom rating scales. (2) The two main approaches to finding the genes that influence the disorder are now genomic scan and candidate gene detection. Affected sib-pair (ASP) method and transmission disequilibrium test(TDT) are considered promising analyses. (3) The positive candidate regions with some independent replicable reports concentrated on 6p, 22q and 8p. Positive findings of candidate gene research involved 5-HT2A receptor, DRD3, NT-3, etc. Further directions to identify the susceptibility genes include: Applying more precise instruments to define clinical phenotype of the disease. Application of proper biological markers such as electrophysiologic parameters and brain imaging will be a prospective approach. Using larger sample to increase statistic power and developing more powerful statistic analysis, and performing advanced molecular genetic technique such as DNA pooling, DNA chips, genomic mismatch scanning (GMS), representational difference analysis(RDA), comparative genomic hybridization(CGH) and two-dimensional DNA typing methods will also facilitate this research area to greater perspective.

Chromosome Aberrations↗
PubMed2000

[Inhibition of the expression of Epstein-Barr virus antigens in vitro by Chinese medicine compound "Dongxia wan"].

OBJECTIVE: To investigate the effect of Chinese medicine "Dongxia wan" on the expression of Epstein-Barr virus (EBV) antigens in vitro. METHODS: Cell culture and indirect immunoenzyme methods were used. RESULTS: When Raji and B95-8 cells were cultured with 20-80 microg/'ml of "Dongxia wan", the expression of EBV early antigen (EBV-EA) and EBV capsid antigen (EBV-VCA) induced by croton oil and n-butyric acid and the natural expression of EBV-VCA were all inhibited significantly. The inhibition rates were 19.3% - 49.84%, 34.63% - 45.61% and 21.67% - 47.78%, respectively. When Raji and B95-8 cells were pretreated with "Dongxia wan" the expression of EBV-EA and EBV-VCA were also inhibited obviously. CONCLUSIONS: Chinese medicine "Dongxia wan" can inhibit the expression of EBV antigens in target cells, it may be used to the prevention and treatment of EBV related diseases.

Antigens, Viral↗
PubMed2000

[Response of broadleaved Pinus koraiensis forests in Xiaoxinganling Mt. to global climate change--a dynamic modeling].

In this paper, the Forest Gap Model and four General Circulation Models (GCMs) were employed to investigate the dynamic response of broadleaved Pinus koraiensis forests in Xiaoxinganling Mountains of China to global climate change. Under CO2 doubling which was simulated by the scenarios of Oregon State University and Goddard Institute for Space Studies, the biomass of broadleaved Pinus koraiensis forest increased and the current Picea-Abies-broadleaved Pinus koraiensis forest would gradually develop to Betula costata-Tilia amurensis-Ulmus laciniata-broadleaved Pinus koraiensis forest. Under the scenarios of Geophysical Fluid Dynamics Laboratory at Princeton University and United Kingdom Meteorological Office, Pinus koraiensis and other coniferous species would be replaced by broadleaved species such as Quercus mongolica, Tilia amurensis and Ulmus laciniata, and the broadleaved Pinus koraiensis forest would change to broadleaved forest, due to the great range increasing temperature by the scenarios. The future warming rate would determine the succession of broadleaved Pinus koraiensis forest.

China↗
PubMed2000

[Primary research on interface ecology in agroforestrial ecosystems].

In this paper, the fundamental conception, major research content of interface ecology and its application in agroforestrial systems were discussed. The action mechanism between trees and crops in agroforestrial systems mainly embodied aboveground interface for competitve light, quantity of heat and water, and underground interface for competitiye nutrient and water. It was showed in the interchange and transmission of nutrient, energy and information through interface.

Biomass↗
PubMed2000

[The measurement of tracheo-bronchial mucociliary clearance by technetium-99m DTPA aerosol scintigraphy].

Mucociliary clearance of respiratory channels is one of the important mechanisms guarding against retention of foreign particles within the lungs. Thus objective assay of the system is essential to recognizing and understanding its abnormalities. In this study, 18 healthy subjects and 32 patients with chronic obstructive pulmonary diseases (COPD) were examined by technetium-99m-DTPA aerosol scintigraphy. Monitoring was performed by visual inspection (cinescintigraphy) and quantitative analysis. The mucociliary clearance rates of 18 healthy subjects and 32 COPD patients were 3.89 +/- 0.92 mm/min and 1.32 +/- 0.59 mm/min respectively. Statistical analysis indicated that the airway clearance rate and mucociliary clearance rate of COPD patients were significantly lower than those of normal subjects (P < 0.01). The method of assay reported here is simple and objective. It has not only the advantage of visual inspection and quantitative analysis, but also the potential usefulness in studying other bronchial diseases and evaluating therapeutic effectiveness of drugs.

Adult↗
PubMed1999

The neural cell adhesion molecules L1 and NCAM-180 act in different steps of neurite outgrowth.

The formation of neurocircuitry depends on the control of neurite outgrowth that, in turn, can be divided into two processes: nerve growth cone protrusion and neurite extension. It has long been known that the neural cell adhesion molecules L1 and NCAM-180 promote neurite outgrowth, but how they function in growth cones is unclear. We addressed the roles of L1 and NCAM-180 in neurite outgrowth by using microscale chromophore-assisted laser inactivation (micro-CALI) of these proteins to perturb their functions at precise times in single growth cones of embryonic chick dorsal root ganglion neurons grown in culture. Micro-CALI of L1 causes neurite retraction after a 10 min lag period but does not affect growth cone protrusion. In contrast, micro-CALI of NCAM-180 causes rapid growth cone retraction but does not affect neurite extension. The simultaneous inactivation of both these molecules resulted in both distinct effects that were segregated in time. The behavior of growth cones after these micro-CALI treatments resemble the drug-induced perturbation of microtubules for L1 and F-actin for NCAM-180. These findings suggest distinct roles in the growth cone for L1 and NCAM-180 in different steps of neurite outgrowth: L1 functions in neurite extension,whereas NCAM-180 functions in growth cone protrusion.

Animals↗
PubMed1999

Association analysis between dopamine receptor genes and bipolar affective disorder.

We have performed a case-control analysis of dopamine D2-like receptor (DRD2, DRD3 and DRD4) gene polymorphisms in 118 Han Chinese cases with bipolar affective disorder and 196 control subjects, and replication analysis in 157 English cases and 143 control subjects. We found association between a functional DRD2 promoter variant (P = 0.03 by allele) and the DRD2 taq1A polymorphism (P = 0.001 by allele) in Chinese bipolar disorder patients. However, this finding was not replicated in the Caucasian subjects, indicating that the significant association we observed in the Chinese population is a false positive finding. An alternative explanation is that these polymorphisms are risk factors in Chinese but not Caucasian populations, a hypothesis which seems unlikely in view of the similarity of the clinical characteristics of bipolar disorder in the two populations. We also report a novel, rare one-repeat variant of the DRD4 exon 3 VNTR repeat in Chinese populations, which appears to be absent in Caucasians and is not associated with disease.

Adult↗
PubMed1999

Telomerase reverse transcriptase gene is a direct target of c-Myc but is not functionally equivalent in cellular transformation.

The telomerase reverse transcriptase component (TERT) is not expressed in most primary somatic human cells and tissues, but is upregulated in the majority of immortalized cell lines and tumors. Here, we identify the c-Myc transcription factor as a direct mediator of telomerase activation in primary human fibroblasts through its ability to specifically induce TERT gene expression. Through the use of a hormone inducible form of c-Myc (c-Myc-ER), we demonstrate that Myc-induced activation of the hTERT promoter requires an evolutionarily conserved E-box and that c-Myc-ER-induced accumulation of hTERT mRNA takes place in the absence of de novo protein synthesis. These findings demonstrate that the TERT gene is a direct transcriptional target of c-Myc. Since telomerase activation frequently correlates with immortalization and telomerase functions to stabilize telomers in cycling cells, we tested whether Myc-induced activation of TERT gene expression represents an important mechanism through which c-Myc acts to immortalize cells. Employing the rat embryo fibroblast cooperation assay, we show that TERT is unable to substitute for c-Myc in the transformation of primary rodent fibroblasts, suggesting that the transforming activities of Myc extend beyond its ability to activate TERT gene expression and hence telomerase activity.

Animals↗
PubMed1999

Dependence of the Raman signature of genomic B-DNA on nucleotide base sequence.

The vibrational spectra of four genomic and two synthetic DNAs, encompassing a wide range in base composition [poly(dA-dT). poly(dA-dT), 0% G + C; Clostridium perfringens DNA, 27% G + C; calf thymus DNA, 42% G + C; Escherichia coli DNA, 50% G + C; Micrococcus luteus DNA, 72% G + C; poly(dG-dC).poly(dG-dC), 100% G + C] (dA: deoxyadenosine; dG: deoxyguanosine; dC: deoxycytidine; dT: thymidine), have been analyzed using Raman difference methods of high sensitivity. The results show that the Raman signature of B DNA depends in detail upon both genomic base composition and sequence. Raman bands assigned to vibrational modes of the deoxyribose-phosphate backbone are among the most sensitive to base sequence, indicating that within the B family of conformations major differences occur in the backbone geometry of AT- and GC-rich domains. Raman bands assigned to in-plane vibrations of the purine and pyrimidine bases-particularly of A and T-exhibit large deviations from the patterns expected for random base distributions, establishing that Raman hypochromic effects in genomic DNA are also highly sequence dependent. The present study provides a basis for future use of Raman spectroscopy to analyze sequence-specific DNA-ligand interactions. The demonstration of sequence dependency in the Raman spectrum of genomic B DNA also implies the capability to distinguish genomic DNAs by means of their characteristic Raman signatures.

Animals↗
PubMed1999

Structural effects of cobalt-amine compounds on DNA condensation.

Light scattering and electron microscopy have been used to investigate the structural effects of the trivalent complexes hexaammine cobalt (III) chloride (Cohex), tris(ethylenediamine) cobalt(III) chloride (Coen), and cobalt(III) sepulchrate chloride (Cosep) on DNA condensation. These cobalt-amine compounds have similar ligand coordination geometries but differ slightly in size. Their hydrophobicity is in the order Cosep > Coen > Cohex, according to the numbers of methylene groups in these ligands. All of these compounds effectively precipitate DNA at high concentrations; but despite a lower surface charge density, Cosep condenses DNA twice as effectively as Coen or Cohex. UV and CD measurements of the supernatants of cobalt-amine/DNA solutions reveal a preferential binding of Delta-Coen over Lambda-Coen to the precipitated DNA, but there is no chiral selectivity for Cosep. Competition experiments show that the binding strengths of these three cobalt-amine compounds to aggregated DNA are comparable. A charge neutralization of 88-90% is required for DNA condensation. Our data indicate that 1) electrostatic interaction is the main driving force for binding of multivalent cations to DNA; 2) DNA condensation is dependent on the structure of the condensing agent; and 3) the hydration pattern or polarization of water molecules on the surface of condensing agents plays an important role in DNA condensation and chiral recognition.

Amines↗
PubMed1999

The effect of CpG sequences on the B cell response to a viral glycoprotein encoded by a plasmid vector.

The effect of palindromic CpG sequences on the B cell response to plasmid vectors expressing a highly immunogenic viral glycoprotein was investigated. Methylation of the CpG sequences of bacterial expression vectors abolished their ability to induce an antibody response to the transgene product in mice. The antibody response could be rescued by concomitant injection of oligonucleotides carrying immunostimulatory sequences. The B cell response to two plasmid vectors, both expressing the same viral glycoprotein but containing a different content of the highly stimulatory AACGTT motif, was compared. Comparable B cell responses were induced to the two constructs given at an optimal vaccine dose while the vector containing additional palindromic sequences resulted in higher antibody titers at a suboptimal dose. These data indicate that deletion of CpG motifs or methylation of such sequences in plasmid DNA can abrogate the immune response to the vector encoded antigen and might thus enhance their usefulness as gene therapy vehicles.

Animals↗
PubMed1999

Brief 95% O2 exposure effects on surfactant protein and mRNA in rat alveolar and bronchiolar epithelium.

In acute lung injury, a disturbed surfactant system may impair gas exchange. Previous evaluations of hyperoxia effects on surfactant proteins (SPs) followed exposures >1-2 days. To evaluate the effects of brief exposure to hyperoxia on the SP system, we exposed adult male rats to 95% O2 or air for 12, 36, and 60 h. SP-A, -B, and -C mRNAs were analyzed by Northern blot and semiquantitative in situ hybridization (ISH). SP-A and -B were analyzed in whole lung homogenates, lung lavage fluid, and fixed tissue by semiquantitative immunohistochemistry (IHC). All SP mRNAs were diminished at 12 h and rose to or exceeded control by 60 h as determined by Northern blot and ISH. These effects were seen mainly in the intensity of ISH signal per cell in both type II and bronchiolar epithelial (Clara) cells and to a lesser extent on numbers of positively labeled cells. SP-B declined to 50% of control in lavage at 12 h, but no changes in total lung SP-A and -B were seen. The number of SP-A positively labeled cells did not change, but SP-A label intensity measured by IHC in type II cells showed parallel results to Northern blots and ISH. The response of SP-A in Clara cells was similar. SP-B immunolabeling intensity rose in both type II and Clara cells throughout the exposure. SP-C ISH intensity fell at 12 h and was increased to two times control by 60 h of hyperoxia. Sharp declines in SP expression occurred by 12 h of 95% O2 and may affect local alveolar stability.

Animals↗
PubMed1999

[Identification of mutations in the human EXT1 and EXT2 genes].

OBJECTIVE: To investigate further the genetic basis of hereditary multiple exostoses (EXT) and provide useful information for gene diagnosis of the disease. METHODS: Polymerase chain reaction-single strand conformation polymorphism was used to examine the entire coding regions of EXT(1) gene on chromosome 8 and EXT(2) gene on chromosome 11 for mutation in thirty EXT families. Mutations were further identified by sequencing. RESULTS: Two frameshift mutations were identified in two unrelated EXT families. One was the deletion of one base(T) in exon 6 of the EXT(1) gene, and the other was the deletion of four bases (tgtt) in exon 2 of the EXT(2) gene. Both of the mutations resulted in a frameshift and premature termination of translation. CONCLUSION: EXT is a genetically heterogeneous bone disorder caused by the mutation of EXT tumor suppressor gene. These results could be directly applied in the genetic counseling and prenatal genetic diagnosis of EXT.

Chromosome Deletion↗
PubMed1999

[Mitochondrial DNA length variation and heteroplasmy in Chinese sturgeon (Acipenser sinensis)].

The D-loop of mitochondrial DNA from Chinese sturgeon (Acipenser sinensis) was amplified using PCR. The length variations among individuals and within individual (heteroplasmy) were detected. DNA sequence analysis revealed that interindivadual and intraindividual length variation occurred within D-loop near tRNA(pro), and caused by tandam repeat with 82 bp in length. Out of 47 individuals, 27(57.4%) individuals were heteroplasmy whereas 20 individual (42.6%) were homoplasmic. The length variation was also found among homoplasmic individuals. In homoplasmic individual four different size classes (number of tandem repeats) e.g. 2, 3, 4 or 5 repeats were noted. The frequencies of size classes from the highest to the lowest were 3-->2-->4-->5. In heteroplasmy two molecular size classes coexisted in an individual was most common (77.78%). The second type of heteroplasmy was three size classes coexisted (18.52%) and the lowest one was four size classes together in an individual (3.70%). No five different size classes coexisted in an individual was found. Through densitometry of DNA bands the frequencies of mtDNA size classes were determined for the sample of individuals, and the frequency distribution of repeats from the highest to the lowest was similar to that in homoplasmy (3-->2-->4-->5-->1). The diversity within each heteroplasmic individual was carried out and genetic diversity at hierarchical level was analyzed. 65.3% of genetic diversities were from among individuals in population and 34.7% of genetic diversities were from within individual. The mtDNA length variation within individual (heteroplasmy) is another genetic diversity resource for Chinese sturgeon.

Animals↗
PubMed1999

Identification of mutation in a candidate gene for hereditary multiple exostoses type II.

OBJECTIVES: To identify possible mutations in our previously cloned candidate gene for hereditary multiple exostoses type II (EXT2) in affected members of EXT families so as to confirm that it is the disease-causing gene. METHODS: The mutation was detected first by single strand conformational polymorphism (SSCP) of all coding exons of the candidate gene and then by sequencing analysis. RESULTS: After analyzing 37 patients from 20 Chinese EXT families by SSCP and DNA sequencing analysis, one 2-bp insertion mutation was identified in this candidate gene in affected members of an EXT family. This mutation resulted in the frameshift and generated a truncated gene product consisting of 105 amino acids. CONCLUSIONS: The identification of the mutation in the candidate gene indicates that this novel gene is responsible for EXT2 (one of the disease-causing gene of EXT).

Amino Acid Sequence↗