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Hong Liu

Publications and source records attributed to Hong Liu.

At least 379 records · Page 21Linked to original sources
PubMed2002

Techniques to improve the accuracy and to reduce the variance in noise power spectrum measurement.

Several techniques to increase the accuracy and to reduce the variance of the noise power spectrum (NPS) measurement for digital X-ray imaging systems are investigated. These techniques include: 1) averaging the outputs from subblocks of the entire image; 2) averaging the two-dimensional NPS data along a circular route centered on the origin of spectral domain; and 3) masking a window function on each subblock before Fourier transforms. Techniques 1) and 2) are used mainly to reduce the variance of the NPS measurement. Technique 3) serves to improve the accuracy of the final result. Experiments with two different charge-coupled device-based X-ray imaging systems demonstrated that the precision and accuracy of the NPS measurement could be significantly improved using these techniques. The impact of the image partition for averaging is discussed and the corresponding NPS estimations are presented for the number of subblocks ranging from 4 to 64. The effect of masking on the NPS is also studied using four different window functions.

Models, Statistical↗
PubMed2002

Comparison of analog and digital Fourier transforms in medical image analysis.

The effectiveness and limitations of medical image processing using analog and digital methods are studied. Several types of errors introduced during the image processing are analyzed. For the analog optical Fourier transform, errors are introduced by the vignetting effect and lens aberration. For the digital Fourier transform, errors are introduced by the aliasing effect and the band limit. To compare the results obtained by the two techniques, a set of x-ray images was processed both optically and digitally. The former was achieved by an optical system containing a large Fourier telephoto lens and the latter by a personal computer using a Fourier transform algorithm. The veracity of both the optical and digital Fourier spectra is analyzed. Our results indicate that the optical method has high speed due to parallel processing. High veracity can be achieved in high frequency regions by using an optimal optical system. In comparison, the digital method has the advantages of high processing precision and programmability, but has low processing speed. The comparison of the two different techniques presented in this article can provide a basis for selection of the processing method in different clinical settings. Even with today's fast computers, the optical method is still suitable for many clinical applications. The best choice lies in an analog-digital combination.

Algorithms↗
PubMed2002

Maximal induction of a subset of interferon target genes requires the chromatin-remodeling activity of the BAF complex.

The mammalian SWI/SNF-like chromatin-remodeling BAF complex plays several important roles in controlling cell proliferation and differentiation. Interferons (IFNs) are key mediators of cellular antiviral and antiproliferative activities. In this report, we demonstrate that the BAF complex is required for the maximal induction of a subset of IFN target genes by alpha IFN (IFN-alpha). The BAF complex is constitutively associated with the IFITM3 promoter in vivo and facilitates the chromatin remodeling of the promoter upon IFN-alpha induction. Furthermore, we show that the ubiquitous transcription activator Sp1 interacts with the BAF complex in vivo and augments the BAF-mediated activation of the IFITM3 promoter. Sp1 binds constitutively to the IFITM3 promoter in the absence of the BAF complex, suggesting that it may recruit and/or stabilize the BAF complex binding to the IFITM3 promoter. Our results bring new mechanistic insights into the antiproliferative effects of the chromatin-remodeling BAF complex.

Animals↗
PubMed2002

Clinical and laboratory features of preleukemia patients.

OBJECTIVE: To explore prospective diagnostic criteria for preleukemia. METHODS: A case control study was done comparing the discrepancies on clinical and laboratory features between patients with preleukemia and those with chronic aplastic anemia (CAA) or atypical paroxysmal nocturnal hemoglubinuria (a-PNH). RESULTS: There were eight variables of significance: (1) lymphocytoid micromegakaryocytes in the bone marrow; (2) immature granulocytes in the peripheral blood; (3) > or = 2.0% myeloblasts in the bone marrow; (4) positive periodic acid schiff (PAS) stained nucleated erythrocytes; (5) myeloid differentiation index > or = 1.8; (6) typical colonal karyotypic abnormalities; (7) negative sister chromatid differentiation; (8) cluster/colony ratio of granulocyte-macrophage colony-forming units (CFU-GM) > 4.0. The following criteria were assigned: A: to meet variable one and at least two of the other seven variables and B: to meet at least four of the eight variables. All of the patients with preleukemia met either A or B and none of the patients with CAA or a-PNH did. CONCLUSIONS: Preleukemia is different from CAA or a-PNH. It has its own clinical and laboratory features, which may be useful for its prospective diagnosis.

Adolescent↗
PubMed2002

Clinical analysis of 78 cases of paroxysmal nocturnal hemoglobinuria diagnosed in the past ten years.

OBJECTIVE: To learn more about the clinical and laboratory features of patients with paroxysmal nocturnal hemoglobinuria (PNH) diagnosed in the past ten years. METHODS: Clinical and laboratory data for 78 cases of PNH diagnosed from January 1990 to November 1999 in our hospital were analyzed retrospectively. RESULTS: In comparison with PNH cases reported in the 1980s, the newly diagnosed PNH cases showed the following features: (1) older age of disease onset (from 27 to 34 years); more female cases (from 18.5% to 38.5%); more cases without hemoglobinuria (from 24.2% to 38.5%). (2) No positive family hereditary history. (3) Bone marrow dysplasia, abnormal karyotype and negative sister chromatid differentiation were found in 19.2%, 12.2% and 8.9% of the PNH patients, respectively. 12.3% of the patients had bone marrow hypoplasia, and most of them had no hemoglobinuria. Ham's tests were negative in about 34.2% of the cases. CD55 and CD59 on peripheral blood cells were deficient in 100.0% of the cases, suggesting that CD55 and CD59 tests can improve the diagnosis of PNH. (4) Adrenocortical hormone was effective in 83.8% of the patients, 54.2% of whom relapsed within one year. Eight refractory and relapsed patients were treated with low dose chemotherapy (MP therapy: Melphalan 2 - 6 mg x d(-1); Prednisone 0.5 mg x kg(-1) x d(-1)). Five (62.5%) of them showed positive responses. Bone marrow failure and other side effects were not serious in this group of patients. CONCLUSIONS: PNH, an acquired blood disease seen more often among adult males, can be diagnosed more sensitively by hemocyte member CD55 and CD59 tests and treated more effectively with adrenocortical hormone or low dose chemotherapy.

Adolescent↗
PubMed2002

[In vitro effects of low-molecular weight heparin and dexamethasone on the hemolysis of red blood cells from paroxysmal nocturnal hemoglobinuria patients].

OBJECTIVE: To study the in vitro effects of low-molecular weight heparin (LMWH) and dexamethasone on the hemolysis of red blood cells from paroxysmal nocturnal hemoglobinuria (PNH) patients. METHODS: By Ham's test and micro-complement lysis sensitive test (mCLST), the changes of hemolysis of red blood cells from 6 PNH patients were tested by adding different doses of LMWH and dexamethasone into the test mixture. The effects of LMWH and dexamethasone on the coagulation of the tested blood samples were also studied by activated partial thromboplastin time (APTT). RESULTS: (1) Either LMWH or dexamethasone could dose-dependently inhibit the hemolysis of PNH red blood cells, and the effects were synergistic when added together. The same dose of LMWH induced a less than 100% prolongation of APTT. (2) Dexamethasone could inhibit the hemolysis in Ham's test and had different effects on the hemolysis by different adding methods in mCLST. LMWH could inhibit the hemolysis in both Ham's test and mCLST. CONCLUSION: Both LMWH and dexamethasone could inhibit the hemolysis of PNH red cells and showed a synergistic effect. The mechanisms of the inhibition of hemolysis were different. Furthermore, a tolerable dose of LMWH induced only a limited prolongation of APTT, which might be useful for controlling acute hemolysis and reducing the dose of dexamethasone.

Anti-Inflammatory Agents↗
PubMed2002

[A long-term follow-up study of 50 patients with severe aplastic anemia who have survived more than 3 years after immunosuppressive therapy].

OBJECTIVE: To evaluate the long-term outcome of immunosuppressive therapy (IST) in patients with severe aplastic anemia (SAA). METHODS: Hematopoietic recovery (peripheral blood cell counts, bone marrow aspirates, bone marrow biopsy, in vitro culture of hematopoietic progenitors), immunity of T lymphocyte, quality of life and side-effects of the therapy were assessed in 50 SAA patients who have survived more than 3 years after IST. RESULTS: At 3 years, 4 years and 5 years follow-up, 81.5% (13 cases), 86.7% (13 cases) and 89.5% (17 cases) of the SAA patients reached and maintained normal peripheral blood cell counts, 93.4% (15 cases), 93.3% (14 cases) and 94.7% (18 cases) showed normal bone marrow pictures, and 37.5% (6 cases), 40.0% (6 cases) and 73.7% (14 cases) had normal yields of bone marrow cell culture, respectively. Overall, 86.0% (43 cases), 94.0% (47 cases) and 52.0% (26 cases) of the total SAA patients were normalized in peripheral blood counts, bone marrow picture and culture of hematopoietic progenitor yields, respectively. During the follow-up, 88.0% (44 cases) of the patients achieved 100 of Karnofsky scores; 26 of the 31 patients (83.9%) who received bone marrow biopsy showed normal histological pictures, and 29 of 37 patients (78.4%) tested had normal subsets of T lymphocytes. No clonal disease was found. The late side-effects of IST were mild. All of the parameters tested were normal in 24 patients. CONCLUSION: After IST, the hematopoietic function of bone marrow, the immunity of the T lymphocyte and the life quality were normalized with few side-effects in patients with SAA. These patients would probably be cured.

Adolescent↗
PubMed2002

[Quantity and apoptosis-related protein level of B lymphocyte in patients with immunorelated pancytopenia].

OBJECTIVE: To examine the quantity and apoptosis-related protein level of B lymphocyte in the patients with immunorelated pancytopenia (IRP) and explore the role of B lymphocyte in the pathogenetic mechanism of IRP. METHODS: Quantities of all B lymphocytes and CD(5)(+) B lymphocytes and the expressions of Fas and bcl-2 on B lymphocytes in 25 patients with untreated IRP, 15 IRP patients in complete remission (CR) and 10 normal controls were assayed by FACS. RESULTS: The percentages of B lymphocyte and CD(5)(+) B lymphocytes were significantly higher in untreated IRP patients than in CR IRP patients and normal controls (P < 0.05); there was no significant difference between the latter two groups (P > 0.05). There was no significant difference of Fas expression in B lymphocytes among the three groups (P > 0.05). The expression of bcl-2 on B lymphocytes was significantly higher in untreated patients than in CR patients or normal controls (P < 0.05), and so did in CR patients than in normal controls (P < 0.01). The apoptosis-related index was significantly lower in untreated patients than in CR patients or normal controls (P < 0.01), and was lower in CR patients than in normal controls (P < 0.05). The percentage of B lymphocyte was positively correlated with the duration from the beginning of treatment to response. CONCLUSION: The production of auto-antibodies in IRP patients probably has some relationships with the abnormal quantities of B lymphocyte and its subsets, and with the inhibition of B lymphocyte apoptosis.

Adolescent↗
PubMed2002

[A study on examination of color vision with pattern-visual evoked potential].

OBJECTIVE: To understand the specific nature of the color and brightness components of the human visual evoked potential and explore the possibility of an objective method for examining the color vision. METHOD: The transient VEP was measured in normal subjects and persons with deficient color vision by multichannel electro-physiological apparatus. In the experiment, four kinds of reversal checkerboard patterns are simulated by the computer software technology as stimuli. The patterns included black-white (95% contrast), isoluminance chromatic checkerboards red-white, green-white, red-green (100% saturation), which were 25 ' in visual angle and alternated at a rate of 0.8 Hz. The main component, P (1) wave, was analyzed. RESULTS: (1) The normal subject group: The P (1) latencies in four conditions were obtained in terms of the length of latencies, the ordinal of P (1) latencies (from short to long) was as follows: red-white < black-white < red-green < green-white. There were very significant differences among the four latencies (P < 0.01). The P (1) amplitudes elicited with the black-white were higher than those with chromatic ones. But among the P(1) amplitudes elicited with chromatic checkerboards there were no difference. (2) The group with deficient color vision: There were no significant differences in the P(1) latencies and amplitudes elicited with the four stimuli. The length of latencies with black- white stimulus was the shortest. Red-green blindness as well as deuteranopia had no response to green stimulus but did to red or red-green stimulus. (3) Between the two groups, there were no differences in the P (1) latencies, but the P (1) amplitudes of persons with deficient color vision elicited with the chromatic stimuli were obviously lower. CONCLUSION: The results show that it is feasible to use chromatic VEP for examining congenital color vision deficiency, especially for red-green blindness and deuteranopia. At present, there is lack of quantitative and qualitative results of color VEP examination.

Adolescent↗
PubMed2002

[Characteristics of polymorphism of 129th amino acid in PRNP among Han and Uighur Chinese].

BACKGROUND: An amino acid polymorphism for Met to Val has been identified at PrP codon 129 from different human races. In this study,the characteristics of polymorphism of PRNP 129th amino acid in Han and Uighur Chinese have been investigated. METHODS: Human DNAs were extracted from peripheral lymphocytes and PrP gene fragments were amplified with a specific PCR protocol. The distribution of 129th amino acid in PRNP was determined by a PCR-RFLP and the results were analyzed with software SAS for Windows 6.12. RESULTS: The frequencies of the allele 129 Met and 129 Val were 97.0% and 3.0% in Han Chinese, whereas 91.4% and 8.6% in Uighur Chinese. The frequency of 129 M/M phenotypes in Han Chinese was significantly higher than that in Uighur Chinese (P=0.0490). Comparing the phenotype distributions of codon 129 of Han Chinese with that of Japanese and Caucasian, there was significant difference with Caucasian (P=0.0005),but there was no difference with Japanese (P=0.5040). CONCLUSIONS: The polymorphism of 129th amino acid in PRNP of Han Chinese is similar to Japanese, but different from Uighur Chinese.

Asian People↗
PubMed2002

[Role of Th1 cell in the pathogenesis of aplastic anemia].

OBJECTIVE: To detect the quantity, proportion and function of producing cytokines of Th1 and Th2 cells in aplastic anemia (AA) patients and their contribution to the hematopoietic failure. METHODS: (1) Eleven patients with severe aplastic anemia (SAA) at diagnosis were observed by Marsh's method for the CFU-E, BFU-E and CFU-GM before and after depletion of CD(4)(+) T lymphocytes from bone marrow mononuclear cells (BMMNC); (2) Th1 (CD(4)(+) IFN-gamma(+)) and Th2 (CD(4)(+) IL-4(+)) cells in peripheral blood mononuclear cells (PBMNC) of 21 SAA patients and 17 normal controls were counted by FACS. (3) mRNA expression of IFN-gamma and IL-4 gene in unstimulated BMMNC from 16 SAA patients, 11 chronic aplastic anemia (CAA) patients, 26 other hematological diseases patients and 11 normal controls were measured by reverse transcriptase polymerase chain reaction (RT-PCR). RESULT: (1) CFU-E, CFU-GM and BFU-E increased significantly after depletion of CD(4)(+) T lymphocytes from BMMNC of SAA patients. (2) The percentage of IFN-gamma producing CD(4)(+) T cell (Th1) of SAA patients was significantly higher than that of controls, the percentages of IL-4 producing CD(4)(+) T cells (Th2) had no difference between SAA patients and normal controls. (3) IFN-gamma mRNA was detected in unstimulated BMMNC in 13 of 16 SAA patients, 6 of 11 CAA patients and one of 6 paroxysmal nocturnal hemoglobinuria (PNH) patients. The IFN-gamma mRNA was not detected in unstimulated BMMNC of 11 normal controls and other hematological diseases patients. CONCLUSIONS: Disbalance of CD(4)(+) T lymphocytes subsets and increases in quantity and IFN-gamma producing function of Th1 cells might be important for the development of bone marrow failure in AA and in distinguishing AA from other kinds of pancytopenic diseases.

Adolescent↗
PubMed2002

[Clinical analysis of 185 patients with polycythemia vera].

OBJECTIVE: To understand the clinical feature and natural course of polycythemia vera (PV). METHODS: The clinical symptoms, signs, laboratory examination and prognosis of 185 patients with PV were analysed. RESULTS: There are 122 males and 63 females. The mean age was (52.7 +/- 14.1) years. The mean hemoglobin level was (208.3 +/- 21.2) g/L. Pancytosis was displayed in 74 (40%) cases, excess of red blood cells in 33 (17.8%), excess of red blood cells and granulocytes in 67 (36.2%) and excess of red blood cell and platelets in 11 (5.9%). Splenomegaly was found in 123 (66.5%) patients and hepatomegaly in 30 (16.2%). Quantitative assess of serum Epo was done in 25 patients. The level was low in 16 (64.2%) and normal in 9 (36.0%). Hematopoietic progenitor culture yields was elevated in 11 patients, endogenous erythroid colonies (EEC) formation was found in 10 cases (90.9%). Eighty two patients (44.3%) had 101 attacks of vascular thrombotic incidents, 7 patients developed myelofibrosis (MF). Secondary cancer occurred in 1 patient. Two patients died of thrombosis. CONCLUSION: PV is an elderly adult myeloproliferative disease with a high frequency of thrombosis. EEC can be found out in PV patients. The serum Epo level is not increased in PV patients. The main sequelae of PV is MF.

Adult↗
PubMed2002

[Discovery of two sub-types of Hantanvirus in Anhui mountain areas].

OBJECTIVE: To investigate the existence of hemorrhagic fever with renal syndrome (HFRS) foci in high mountains and forest areas. METHODS: A survey was conducted in the areas of 1 400 meter altitude in Dabie mountain and of 1,600 meter altitude in Wannan mountain in the mid 1990's using methods related to epidemiology, geographic-epidemiology, serum epidemiology, pathogenic and molecular epidemiology. RESULTS: Two strains of HFRS viruses were isolated from pulmonary tissues of Rattus niviventer and both of them were identified as A types. The analysis of the nuclei sequence showed that there were significant differences between both sub types and HTN 76-118. CONCLUSION: It was confirmed that there were HFRS foci in the areas with 2 strains possible new sub-types of HFRS.

Animals↗
PubMed2002

[Study on Pseudomonas sp. WBC-3 capable of complete degradation of methylparathion].

A bacterial strain was isolated from the polluted soil around Shashi Pesticides Factory, which was capable of complete degradation of methylparathion. Through chemotaxonomic characterizations and phylogenetic inference based on 16S rDNA sequence analysis, the strain was identified as a member of the genus and was named as Pseudomonas sp. WBC-3. It can tolerate high-concentration methylparathion up to 800 mg/L in basic medium and up to 2000 mg/L in 0.1% glucose medium. Using 300 mg/L methylparathion as its sole carbon and nitrogen sources, the strain was able to degrade 15 mg of parathion per liter per hour and reached its stationary phase in about 22 hours. The strain possessed broad-spectrum degradative capability to kinds of organophosphorus pesticides and aromatic compounds. Its organophosphate hydrolase was purified from the periplasm of WBC-3 to homogeneity, through a whose process consisting of ammonium sulfate precipitation, Sephadex G-75 gel filtration, Q Sepharose FF ionexchange column chromatography. The purified enzyme showed a single band on SDS-PAGE gel with an approximate molecular weight of 33.5 kD.

Biodegradation, Environmental↗
PubMed2002

[Effects of refined konjac meal on lipid metabolism and blood viscosity of rats fed by high fat forage].

Male SD rats are fed by high fat diet supplemented with refined konjac meal for 6 weeks and the effect of refined konjac meal on the serum lipid peroxides (LPO) and blood viscosity are observed. The results showed that the refined konjac meal can obviously decrease serum cholesterol, triglyceride and serum LPO of rats in comparison with those of rats fed only by high fat forage, and can elevate, at the same time, the high density lipoprotein-cholesterol and high density lipoprotein-cholesterol/triglyceride value. It is also shown that the refined konjac meal can decrease the blood viscosity, but has no effect on forage intake and weight gain of rats.

Animals↗
PubMed2002

[Study on effects of scutellarin on scavenging reactive oxygen].

OBJECTIVE: To study the antioxidative effects and its mechanism of scutellarin. METHODS: Scavenging effects of scutellarin on hydroxyl radical (OH.) produced from 0-phenathroline-ascorbic acid system, super oxide anion radical (O2-.) produced from xanthine-xanthine oxidase-luminol system and hydrogen peroxide was studied by a chemiluminescence assay. RESULTS: Scutellarin has a significant effect on scavenging hydroxyl radicals, super oxide anion radicals, hydrogen peroxide, their IC50 are 66 micrograms/ml, 1.3 micrograms/ml and 1.6 micrograms/ml respectively. CONCLUSION: Scutellarin is an efficiency antioxidant.

Apigenin↗
PubMed2002

[A study of oral epithelial cells cultured with L929 cells as seed cells in vitro].

OBJECTIVE: To purpose of study aimed at investigating the technique of culturing oral epithelia in vitro and to set up an experimental model for further reconstructing oral mucosa in vitro. METHODS: The oral mucosa was taken from young New Zealand rabbits, and the mucosa was digested with enzyme and suspended in liquid to form cellular suspension. Being seeded, the cells were cultured motionlessly. The medium was changed regularly and the cells were subcultured. RESULTS: The cultured cells were all epithelial cells without fibroblasts, and they were proved to be diploid cells. The cells were subcultured in 1-13 generations which survived for 50-60 days. CONCLUSION: The oral epithelium of young New Zealand rabbit can be cultured in vitro, maintaining the ability to proliferate in a certain period. It is a pilot study to reconstruct oral tissue in vitro.

Animals↗