Biomedical subjects

S Liu

Publications and source records attributed to S Liu.

At least 199 records · Page 11Linked to original sources

PubMed2001

[Chlamydia pneumoniae infection in patients with chronic obstructive pulmonary disease].

OBJECTIVE: To investigate the association of chlamydia pneumoniae infection with chronic obstructive pulmonary disease (COPD). METHODS: 61 patients with acute exacerbations of COPD, 35 patients with stable COPD and 26 healthy subjects were selected. Chlamydia pneumoniae-specific serum IgG, IgA, IgM antibodies were measured by microimmunofluorescence method. Chlamydia pneumoniae DNA in sputum were detected by nested polymerase chain reaction. RESULTS: The prevalence of acute chlamydia pneumoniae infection in COPD patients with acute exacerbation was significantly higher (31.1%) than that in patients with stable COPD (P < 0.05) and in healthy subjects (P < 0.01). The prevalences of chronic chlamydia pneumoniae infection in COPD patients with acute exacerbations (21.3%) and stable COPD patients (31.4%) were higher than that in healthy subjects (P < 0.05) The level of geometric mean titer of the serum IgA antibodies was the highest in COPD patients with acute exacerbations (20.5), intermediately elevated in stable COPD patients (10.8) and lowest in healthy subjects (3.6). CONCLUSION: Acute chlamydia pneumoniae infection is a rather frequent event in acute exacerbation of COPD, and chronic chlamydia pneumoniae infection may be involved in pathogenesis of COPD.

Acute Disease↗

PubMed2001

The biology of Diadromus collaris (Hymenoptera: Ichneumonidae), a pupal parasitoid of Plutella xylostella (Lepidoptera: Plutellidae), and its interactions with Oomyzus sokolowskii (Hymenoptera: Eulophidae).

The ichneumonid Diadromus collaris (Gravenhorst) has been recorded in many parts of the world as an important parasitoid of the diamondback moth, Plutella xylostella (Linnaeus), a serious pest of brassica vegetable crops worldwide. Some aspects of its biology and its interactions with Oomyzus sokolowskii (Kurdjumov), another major parasitoid of the same pest, were studied in the laboratory. At 25 degrees C, female wasps did not have mature eggs in their ovaries until about 12 h after emergence. Both males and females mated successfully 24-48 h after emergence, and females started to oviposit one to two days after emergence. Unmated females produced male progeny only; mated females produced progeny of both sexes. The development rate of the parasitoid increased linearly with temperature from 15 to 30 degrees C, with an estimated low temperature threshold of 7.4 degrees C and a thermal constant of 225.1 day-degrees for development from egg to adulthood. Rates of survival from larva to adulthood were about 90% between 20 and 28 degrees C and decreased as temperature decreased or increased. No immatures survived to adulthood at 35 degrees C. When provided with honey solution, the females lived on average 8.3, 11.5 and 7.0 days, and parasitized 26, 44 and 46 host pupae at 20, 25 and 30 degrees C, respectively. Female wasps could be stored at 15 degrees C for up to four weeks without detrimental effects on reproduction. Females of D. collaris attacked host pupae already parasitized by O. sokolowskii, inserting their ovipositor into the hosts at a similar frequency as into unparasitized host pupae, but they did not lay eggs inside the hosts.

Animals↗

PubMed2001

Retinochoroidal changes after severe brain impact injury in rabbits.

OBJECTIVE: To investigate retinochoroidal changes and establish eye damage model after brain impact injury. METHODS: An eye damage model after brain impact injury was established by striking the frontoparietal zone in rabbits with BIM-II bioimpact machine. Seventeen rabbits were killed at 4 different intervals after injury. The pathological characteristics of the retinal and choroid damages were observed. RESULTS: All the rabbits had severe brain injury with subarachnoid hemorrhage and brain contusion. The eye damage occurred in all of the 17 rabbits. Hemorrhage in optic nerve sheaths was observed and retinal edema and bleeding was discovered with ophthalmoscope. Histopathologic study displayed subarachnoid hemorrhage in the retrobulbar portion of the retinal nerve, general choroid blood vessel dilatation, retinal nerve fibre swelling within 6 hours after injury, and flat retinal detachment with subretinal proteinoid exudation, and degeneration and disappearance of the outer segment of the optic cell over 6 hours after injury. CONCLUSIONS: The pathological characteristic of the eye damage at early stage following brain impact injury is local circulation disturbance. At late stage, it features in retinal detachment, and optic cellular degeneration and necrosis.

Animals↗

PubMed2001

[Clinical and cytogenetic analysis of patients with lymphoid malignancies carrying 14q32 abnormality].

OBJECTIVE: To investigate the clinical and cytogenetic characteristics of patients with lymphoid malignancies (LM) harboring 14q32 abnormalities. METHODS: The cases with 14q32 aberrations in 225 patients with various LM were analyzed by clinical data. RESULTS: Fifteen (6.67%) patients with abnormalities involving 14q32 were found and the pattern of 14q32 aberration was associated with different types of LM. t(8;14)(q24;q32) was the commonest karyotypic aberration and predominant in acute leukemias. There was no consistent profile morphologically and immunophenotypically in the involving leukemias, however there were common clinical and prognostic features and often with an additional characteristic abnormality of ins(1;6)(q11;q23q27). One case of myelodysplasia (MDS) secondary to multiple myeloma displayed t(7;14)(q34;q32) in primary clone and additional 7q- and 20q- in derivative clone that was frequently involved in MDS. CONCLUSIONS: 14q32 abnormalities and additional chromosomal alterations can facilitate the diagnosis and prognostic assessment for the involving LMs.

Adolescent↗

PubMed2001

[A novel Fe/AC desulphurizer at low temperature].

Activated coke was used to support Fe2O3(Fe/AC) for flue gas SO2 removal. Reaction conditions on DeSOx activity were investigated. The results show that Fe/AC had higher activity than AC or Fe2O3 at temperature of 120 degrees C-250 degrees C. H2SO4 and Fe2(SO4)3 were formed after Fe/AC sorbed SO2, H2O and O2 increased the amount of SO2 adsorption. Fe/AC derived from AC of higher BET surface area had higher DeSOx activity. Fe/AC was suitable to be used at GHSV below 800 L/(kg.h).

Air Movements↗

PubMed2001

[Autotrophic denitrification of groundwater by electrochemical process].

An autotrophic denitrification process and its reactor for removing nitrate from groundwater was investigated in this paper. Using activated carbon fiber(ACF) as electrodes, the electrochemical reactions could produce hydrogen as the donor for autotrophic denitrification. In the process, nitrate was removed effectively and no accumulation of nitrite in the effluent. The results in this study proved that some key factors, such as the applied current density, flow rate of water, oxidation-reduction potential and the nitrate concentration in raw water, influenced the electrochemically denitrifying effect. When the concentration of NO3(-)-N was 28.8 mg/L in inlet water, the optimum applied density was 9 mA, the highest hydraulic load of the reactor was 35 ml/h, and the reactor performed a practical buffering capacity to pH. After applying electricity to the reactor for 1 h, the oxidation-reduction potential decreased to below--200 mA, so an adaptable reductive environment could be provided in the reactor for denitrification.

Carbon↗

PubMed2001

[Preparation of genetically engineered retinal pigment epithelial cells capable of secreting nerve growth factor].

OBJECTIVE: To develop genetically engineered retinal pigment epithelial (RPE) cells which are able to express bioactive nerve growth factor (NGF) steadily and efficiently and to combine gene therapy with retinal transplantation techniques to treat retinal degeneration. METHODS: Replication-deficient retrovirus-plasmid recombinant pLXSN-NGF was constructed via subclone and clone, and then packaged into pT67 cells to obtain virion containing a secretable form of NGF gene. We evaluated titer of the retroviral recombinant with NIH 3T3 cells and then transduced NGF gene into cultured RPE cells by the retroviral recombinant. We also analyzed the expression of NGF gene in transduced and untransduced RPE cells via reverse transcription (RT)-PCR and Western blot. The bioactivity of expressed NGF were evaluated by stimulating PC 12 cells with conditioned medium from transduced and untransduced RPE cells. RESULTS: The titer of replication-deficient retroviral recombinant reached 1.2 x 10(7) cfu/ml. NGF protein and mRNA were detected in the conditioned medium from transduced RPE cells, but not from the normal RPE cells. Marked neurite process outgrowth from PC 12 cells was observed after being stimulated with the conditioned medium from transduced RPE cells. CONCLUSIONS: RPE cells are able to be transduced by replication-deficient retrovirus with high efficiency, and secret bioactive NGF at a high level, which might be an ideal candidate for engineered cells.

3T3 Cells↗

PubMed2001

[A pathological study of lens subcapsular epithelial proliferation].

OBJECTIVE: To observe the histopathological changes of lens subcapsular epithelial proliferation and analyze their etiology. METHODS: Sixty-four enucleated eyes with lens subcapsular epithelial proliferation were observed with light microscopy and analyzed retrospectively. Among all the cases of lens subcapsular epithelial proliferation, there were 36 ones enucleated because of trauma, 10 absolute glaucoma, 6 corneoscleral staphyloma, 5 intraocular tumor, 2 after cataract extraction, 4 endophthalmitis, 1 cataract combined with ocular atrophy (diabetes type II). RESULTS: Proliferated lens subcapsular epithelial cells were atypical, irregularly arranged, and extended to the posterior subcapsule. In cases with lens capsular rupture or partial absence, there were subcapsular fibro-connective tissue metaplasia, scar tissue formation, cortical collapse, local liquefaction and calcification. CONCLUSION: Lens subcapsular epithelial proliferation is caused by some intraocular pathological conditions. In cases with endophthalmitis and ocular trauma, its severity is the most serious.

Adolescent↗

PubMed2001

[Regulation of c-myc expression in leukemic cell line Meg-01 by the death domain of Fas gene].

OBJECTIVE: To investigate the mechanism of disordered proliferation of leukemic cells and the proliferation inhibition by the Fas death domain (FASDD) in human leukemia cell line Meg-01. METHODS: The chimerical receptors (Fas/190, Fas/130) were constructed by Fas cytoplasmic domain with the leukemic inhibitory factor (LIF) receptor subunits gp190 and gp130, another chimerical receptor was constructed by replacing the gp130 in Fas/130 with Fas death domain (FAS/130f). The chimerical receptors were separately expressed on the membrane of Meg-01, and activated with anti-Fas antibodies to induce the oligomerics of the cytoplasmic regions (190cyt-190cyt-190cyt, 130cyt-130cyt-130cyt or FASDD-FASDD-FASDD) for initiating the intracellular signal transduction. c-myc expression level was assayed by means of immunoblotting and immunobiochemistry. RESULTS: Increased c-myc expression and cell proliferation were observed in the group of Fas/130 as compared with the other two groups. CONCLUSION: The cytoplasmic domain of gp130 might involve the induction of c-myc expression and the cell proliferation of Meg-01 cell. The Fas death domain may be a medium in the apoptosis induction against the effect of gp130.

Cell Line, Tumor↗

PubMed2001

[Dynamic monitoring of Ph positive cells during early post-transplant period in chronic granulocytic leukemia by interphase FISH].

OBJECTIVE: To assess the effectiveness of transplantation and observe the kinetics of residual leukemic cells during early post-transplantation period in chronic granulocytic leukemia (CGL). METHODS: Ten normal controls, seven untreated CGL patients and eleven CGL patients after allogeneic bone marrow transplantation (allo-BMT) or peripheral blood stem cell transplantation (PBSCT) were studied by interphase fluorescence in situ hybridization (I-FISH) with the FITC fluorescein labeled BCR probe. Conventional cytogenetic analysis (CCA) and reverse transcriptase-polymerase chain reaction (RT-PCR) were also employed. RESULTS: The normal cutoff was defined as less than 6.68% (x +/- 3s) from the analysis of normal controls. The reproduciblity of FISH method was confirmed by serial dilutions by mixing Ph positive cells and normal cells. Forty specimens from 11 CGL patients at 1 week to 6 years post-BMT were investigated after PBSCT and the results showed that (1) FISH and RT-PCR could accurately evaluate Ph (+) cells during early transplantation period (within one month), but RT-PCR was more sensitive in six months after BMT. (2) Residual Ph (+) cells tended to be linear decreasing with the time after transplantation and fell in normal range in most samples three months later. The mean time of normaligation was 57 days (20 to 170 days). (3) One case relapsed and received a second transplantation. FISH presented more precise data for predicting relapse as compared to CCA and RT-PCR. CONCLUSIONS: I-FISH as a useful tool can not only offer more precise assessment of residual leukemic cells compared with CCA and RT-PCR, but also provide dynamic monitoring during early post-BMT period to evaluate the transplantation outcome and predict relapse.

Adult↗

PubMed2001

Analysis of the 1991-2000 influenza epidemic in Guangdong Province, China.

Influenza surveillance networks in Guangdong were established to investigate the epidemiological characteristics of influenza and influenza epidemics. Influenza activity peaked annually from March to July in Guangdong in 1991-2000; influenza H3N2 predominated in the epidemic (7 years of 10); the outbreak of influenza in 1996 was the remarkable result of antigenic drift of H3N2 strain. Ten isolates of H9N2 strains were discovered from human subjects in 1998 and 1999: chicken strains isolated after the Hong Kong fowl influenza outbreak. It was found that there was just one influenza activity season per annum in Guangdong and that the influenza H3N2 subtype still predominates in Guangdong. Further research into the pathogenicity of influenza H9N2 in humans warranted.

Animals↗

PubMed2001

[Ultrasonic multiple measurement estimation of fetal weight in parturient].

OBJECTIVE: To evaluate the ultrasonic measurements of parturient fetal cerebellar diameter (CD), liver length(LL), kidney length (KL) and femur thigh soft tissue thickness(FSTT) for the estimation of fetal weight. METHODS: Ultrasonic measurements of the parturient fetal cerebellar diameter, liver length, kidney length and femur thigh soft tissue thickness were made in 115 cases. The data on these parameters were analyzed with statistical methods, and a multiple linear regressional equation for predicting the fetal body weight was derived. The calculated value of fetal body weight and the estimated parameters of the fetal body were compared with the actually measured values immediately after birth. The error of estimation was analyzed. RESULTS: CD, LL, KL and FSTT were significantly correlated with neonatal birth weight, the coefficient of multiple correlation R = 0.9425 (P < 0.001); among the 115 cases, 101 had absolute error less than +/- 200 g, with an agreement rate of 88%. The sensitivity and accuracy for detection of normal fetus were 98.13% and 94.78% respectively. The multiple linear regression equation derived was BW = -1009.914 + 356.1303FSTT + 354.0682KL + 236.8484 LL + 179.7384 CD. CONCLUSION: The equation is a simple, accurate and valuable equation for the estimation of fetal weight and can be used in clinical practice.

Birth Weight↗

PubMed2001

[Quantitative detection of flow indices in tubal flow via pulsed Doppler ultrasound, in vitro].

OBJECTIVE: This paper deals with the method and feasibility of quantitative detection of flow indices via commercially available Pulsed Doppler Ultrasound. METHODS: The indices, such as Reynolds number, relative spectral broadening (RSB), laminar shear stress and Reynolds normal stress (RNS) were selected and evaluated. Detection was done temporally and spatially, upstream and downstream of the stenosis. The data were evaluated qualitatively and quantitatively. RESULTS: The roughest turbulence was met at 1/2R sample volume, 1.0 cm downstream of the stenosis. CONCLUSION: The methodology in this study is proved to be feasible and may have good prospects in clinical use.

Biomechanical Phenomena↗

PubMed2001

[IL-2 gene and cisplatin combined therapy for head and neck squamous cell carcinoma].

OBJECTIVE: The objective of this study is to assess the efficacy of IL-2 gene and cisplatin combined therapy on murine HNSCC models. METHODS: HNSCC tumors were established in murine models. The sizes of tumors were measured before and after combined IL-2 and cisplatin treatment, and the results were evaluated by comparing different single treatment groups and the control IL-2 expression was measured after IL-2 gene transfer. Cytotoxic T-lymphocyte (CTL) and natural killer (NK) assays were also performed. RESULTS: HNSCC tumor growth was significantly inhibited following combined IL-2 gene and cisplatin therapy, when compared with that of the control. The levels of IL-2 protein expressions were increased in combined and single IL-2 treated groups. The activities of cytotoxic T-lymphocytes and natural killers in both the combined treatment group and the IL-2 treated group are higher than those of the controlled group. CONCLUSION: Combined IL-2 gene and cisplatin therapy can significantly inhibit HNSCC tumor growth in the murine models, and efficiently induces anti-tumor immune reaction of hosts.

Animals↗

PubMed2001

[A study on mRNA expression levels of integrin beta 1 during the healing process of mandibular fractures].

OBJECTIVE: The aim of this study was to investigate the spatial and temporal mRNA expression changes of integrin beta 1 during the healing process of mandibular fractures. METHODS: The in situ hybridization was performed using digoxigenin-labeled integrin beta 1 mRNA oligonucleotide probe. During the healing process of mandibular fractures, the staining pattern of beta 1 mRNA was examined both spatially and time-dependently. RESULTS: Integrin beta 1 was widely present in the cells of the fractured bone, especially in osteoblasts. The positive staining was observed in the cytoplasm and nucleolus of osteoblasts. After 7 days of fracture, the expression level of integrin beta 1 increased. The peak appeared between the 14th and the 30th day, and almost recovered to normal between the 60th and 90th day. CONCLUSION: During the healing process of mandibular fracture, the expression level of integrin beta 1 in bone, especially in osteoblasts rose. It is suggested that integrin beta 1 may play an important role in the fracture healing process.

Animals↗

PubMed2001

[Cytokine expression in effusions of secretory otitis media].

OBJECTIVE: To assess the cytokine level in effusions of secretary otitis media and it's relationship with clinical index. To further study the inflammatory mechanism of otitis media with effusion. METHOD: The concentration of TNF-alpha and TNFsolR II was quantitatively determined using enzyme-linked immunosorbent assay and it was correlated with clinical index in otitis media with effusion using stepwise regression analysis. RESULT: TNF-alpha and TNFsolR II was found in 100% effusions. Mean values of TNF-alpha were (3.42 +/- 2.25) ng/g total protein. Mean values of TNFsolR II were (405.80 +/- 216.53) ng/g total protein. Mean values of TNFsolR II index was (154.18 +/- 90.45) U. There was a significant decrease of TNFsolR II and TNFsolR II index in patients who recurred (P < 0.05). CONCLUSION: Cytokine TNF-alpha and TNFsolR II are important inflammatory medium which exist in all otitis media effusions. The decrease of the level of TNFsolR II and TNFsolR II index present significantly in middle ear effusions with recurrence, but there is no any relation of TNF-alpha in middle ear effusions with recurrence.

Adult↗

PubMed2001

[Effects of blood transfusion on cellular immuno-function in patients with laryngeal carcinoma].

OBJECTIVE: To explore the influence of blood transfusion on cellular immunofunction in patient with laryngeal carcinoma. METHOD: EPICS-XL flow cytometry was used to measure T cell subgroup, NK cell and CD28 in 36 patients with laryngeal carcinoma pre-operation and 2 weeks post-operation. Patients were divided into allotransfusion group and non-transfusion group. Comparison was conducted between the 2 groups. RESULT: 1. Comparison with normal population, decreasing of CD3, CD4, NK cell and CD28 in the 36 patients pre-operation was statistically significant (P < 0.01). 2. Decreasing of CD3, CD4, NK cell and CD28 was statistically significant post-operation (P < 0.05). 3. In the non-transfusion group change of CD3, CD4, CD8, NK cell and CD28 post-operation was statistically insignificant (P > 0.05). CONCLUSION: While cellular immunofunction is generally low in patients with laryngeal carcinoma, allotransfusion will reduce further. It makes contribution to spreading and metastasis of carcinoma easier.

Aged↗

PubMed2001

[The influence of labyrinthectomy on the expression of NMDA R1 mRNA].

OBJECTIVE: To study the effect of labyrinthectomy on the expression of NMDAR1 (N-methyl-D-aspartate receptor subunit R1). METHOD: The in situ hybridization was used to observe the expression of NMDA R1mRNA post-unilateral labyrinthectomy and investigate its effect on vestibular compensation. RESULT: 20 h post-unilateral labyrinthectomy, the NMDA R1mRNA positive neurons in the medial vestibular nucleus increased significantly compared with the unlesioned side(P < 0.01). 40 h-6 d, the positive cells decreased gradually. 6 d post lesion, the positive neuron counts of the lesioned side had no significant difference compared with those of the un-lesioned side (P > 0.05). CONCLUSION: The changing trend of the expression of NMDA R1mRNA in the medial vestibular nucleus is related to the recovery of the vestibular static symptoms after unilateral labyrinthectomy. It is suggested that the modulation of the efficacy of the NMDA R1 play an important role in the compensation of the static symptoms.

Animals↗