Biomedical subjects

S Chen

Publications and source records attributed to S Chen.

At least 307 records · Page 17Linked to original sources

PubMed2001

[Combined gene therapy for murine liver cancer with interleukin-18 and cytosine deaminase genes].

OBJECTIVE: To investigate the synergistic antitumor effects of murine IL-18 and CD/5FC gene therapy on mice bearing liver cancer. METHODS: A retrovirus vector pGCEN/IL-18 containing murine interleukin-18 gene was constructed. The retrovirus carrying IL-18 gene was used to infect murine liver cancer cell MM45T.Li, and proved to secret biological active IL-18. In mice bearing liver cancer, (60)Co-irradiated MM45T.Li/IL-18 vaccine was inoculated subcutaneously once a week for two weeks, and/or AdCD was injected intratumorally with 5FC injected i.p. for 8 days. RESULTS: Thirty days from the treatment, the tumor volume of control group was 1580 approximately 1625 mm(3), MM45T.Li/IL-18 vaccine group was 366 +/- 159 mm(3), AdCD/5FC group was 438 +/- 65 mm(3), and combined IL-18 and AdCD/ 5FC therapy group was 15 +/- 7 mm(3) (P<0.05). The tumor volume in single gene therapy group reduced to the smallest after three-week treatment, but grew large again, while the tumor volume in combined therapy group still remained small. The median survival time in control group was 50.0 approximately 51.5 days, MM45T.Li/IL-18 group was 65 days, AdCD/5FC group was 57 days versus 75 days for combined gene therapy group (P<0.05), and with more abundant infiltration of CD4+ and CD8+ lymphocytes around the tumor in combined gene therapy group. CONCLUSIONS: Combined gene therapy with IL-18 and CD/5FC can reduce the tumor volume and elicit the antitumor immunity of the host, which is superior to the single gene therapy for murine liver cancer.

Animals↗

PubMed2001

Atrioventricular block complicating inferior acute myocardial infarction treated with thrombolytic therapy.

OBJECTIVE: To investigate the influence and mechanism of incidence of atrioventricular block (AVB) treated with thrombolytic therapy in acute inferior myocardial infarction (AIMI). METHODS: A total of 46 patients with AIMI were divided into the thrombolytic group (n = 23) and the non-thrombolytic group (n = 23). Intravenous or intracoronary urokinase was given to the former group. We observed the advancing courses of AVB, and further assessed the relationship between occurrence of AVB and stenosis of infarct-related artery (IRA) with coronary angiography. RESULTS: Two cases died of III degree AVB in the non-thrombolytic group, but none was found in the thrombolytic group. The occurrence rate of AVB was similar in both groups; but that of III degree AVB was much lower in the thrombolytic group (4 cases) than that in the non-thrombolytic group (11 cases, P < 0.05), and the duration of AVB decreased from 201 +/- 113 hours to 102 +/- 60 hours after thrombolytic therapy (P < 0.01), which was mainly due to the decrease of AVB in the vanishing interval, but not in the developing interval. The coronary angiography demonstrated that there were an increasing reperfusion flow and a decreasing coronary stenosis of the infarct-related artery after thrombolytic therapy. CONCLUSION: Thrombolytic therapy can reduce the incidence of severe AVB, shorten its duration and decrease the mortality by increasing the coronary reperfusion flow in the patients with AIMI.

Adult↗

PubMed2001

Experiences from a collaborative project on the prevention of disability in leprosy patients in Shandong Province, the People's Republic of China.

Shandong Province (present population 89 million) in the People's Republic of China established a leprosy control programme in 1955. Between that year and the end of 1999, allowing for death and migration, the cumulative number of cases registered was 53,618, including 120 cases on multiple drug therapy (MDT) and 18,248 who had completed satisfactory courses of dapsone monotherapy and/or MDT. Of this latter group, 9500 cases (52%) suffered from visible disabilities (grade 2 of the WHO classification). Prevalence and incidence rates of leprosy have decreased dramatically since 1955 and, on average, only 50-70 new cases are now being detected annually in the entire province. Leprosy is thus no longer a public health problem, but the existence of such a large number of patients with grade 2 disabilities is clearly a matter of serious concern. This paper describes a pilot project to investigate the potential of health personnel in the leprosy programme and the dermatology and sexually transmitted diseases services to (a) prevent deterioration of existing disabilities in ex-patients through self-care and (b) prevent new neuritis in patients on MDT through early detection and the use of steroids.

Adult↗

PubMed2001

Use of the bead beater for preparation of Mycobacterium paratuberculosis template DNA in milk.

Mycobacterium paratuberculosis is a recognized chronic enteric pathogen that can affect many different species of animals, including primates. It has been suggested that this organism is associated with Crohn's disease in humans, and that milk is a potential source of human exposure to this organism. The limit of the detection of M. paratuberculosis in milk samples by direct PCR was 10(5) cfu/mL if the traditional boiling method was used for template DNA preparation. In this study, an improved method for template DNA preparation was examined. The method involves the use of a bead beater, which breaks up bacterial cell wall mechanically by vibrating bacteria with microbeads at high speed. The effectiveness of this method for lysing M. paratuberculosis cells was compared to that of the freeze-thaw method, and use of commercial kits such as the InstaGene Matrix and the QIAamp Tissue Kit. The bead beater procedure was tested in combination with various cell lysis and template DNA preparation procedures to determine which of these steps improved the limit of detection of PCR assay that amplifies a 413 bp fragment of the IS900 gene. Results showed that the use of the bead beater, in combination with the use of lysis buffer, boiling, and isopropanol precipitation, decreased the limit of detection of M. paratuberculosis in milk by the PCR to 10(2) cfu/mL. The limit of detection was further decreased to 10 cfu/mL when 0.0037% bovine serum albumin was included in the PCR reaction mixtures. The improved assay was 10- to 10(4)-fold more sensitive than the PCR assays using template DNA prepared by other lysis procedures including boiling alone, freeze-thaw plus boiling, or use of commercial kits for lysis.

Animals↗

PubMed2001

[Repetitious sorption of phenol to organobentonites from water].

The properties and mechanisms for repetitious sorption of phenol to organobentonites from water were studied. Results showed that organobentonites could be used to sorb phenol from water many times with high removal rates. The sorption capacities of three single-cation organobentonites were 120 CTMAB-bentonites > 120 CPC-bentonites > 120 DTMAB-bentonites, when the original concentration of phenol was 1000 mg/L. The sorption mechanisms changed from adsorption to partition in the process of repetitious sorption. Sorption of phenol to CPC-bentonites could bring synergic sorption. The distribution coefficience (Kp) were related to the quantities of phenol on CPC-bentonites, while the distribution coefficience of phenol on CTMAB-bentonites and DTMAB-bentonite were constant.

Adsorption↗

PubMed2001

[The application of air-lift loop column filling with porous carrier in wastewater treatment].

An air lift loop reactor filling with porous carrier particles was utilized as aeration column. Experiments were carried out in wide operating conditions. The experimental results showed that in the range of gas flow rate from 0.117 to 0.156 m3/(min.m3), a higher efficiency of removal of ammonium-N was achieved, and when the gas flow rate was above 0.039 m3/(min.m3), the COD was completely degraded in about 1 h. The filling ratio of the porous carriers in the column was an important factor for the removal of C and N compounds, and a filling ratio of 15% was proved to be most suitable in the operation ranges. The experimental results also indicated that the effect of aeration temperature on the removal efficiency was significant and the highest efficiency was obtained at around 25 degrees C.

Nitrogen↗

PubMed2001

[The experiment of pegylated liposomal doxorubicin to therapy tongue cancer and metastases lymph nodes].

OBJECTIVE: To investigate the effects of pegylated liposmal doxorubicin (PLD) in treating animal model of tongue cancer. METHODS: The tongue cancer model was established in 70 goldn hamsters, and PLD was injected. The free doxorubicin and its concentration in circulating blood and lymph nodes, the weight of animals, volume of tumor, were defected. RESULTS: Tumor inhibition effect of the PLD group was higher than controls. CONCLUSIONS: PLD can be regarded as a valuable drug system to treat oral cancer.

Animals↗

PubMed2001

[Relationship between ocular axial length and central retinal vein occlusion].

OBJECTIVE: To evaluate the relationship between ocular axial length and central retinal vein occlusion (CRVO). METHODS: A-scan ultrasonography was used to measure the ocular axial length in 30 patients with CRVO (the CRVO group) and 30 normal persons and 90 patients with cataract matched in sex and age with the former group (the control group). RESULTS: The mean axial length of the affected eyes in CRVO group was (22.54 +/- 0.74) mm, and that of the follow eyes, (22.95 +/- 0.92) mm. The mean axial length of the affected and the fellow eyes in CRVO group did not differ statistically (t = 2.94, P > 0.05). The mean axial length in the right eyes of the control group was (23.45 +/- 0.66) mm and that of the left eyes, (23.56 +/- 0.95) mm, the difference being not significant statistically (t = 1.96, P > 0.05). The difference in axial length between the eyes with CRVO and the eyes in the control group was statistically significant (t = 4.09, P < 0.01). CONCLUSION: Short axial length is one of the risk factor for central retinal vein occlusion.

Adult↗

PubMed2001

Arsenic trioxide induces multiple myeloma cell apoptosis via disruption of mitochondrial transmembrane potentials and activation of caspase-3.

OBJECTIVE: To investigate the response of multiple myeloma (MM) cells to arsenic trioxide (As2O3) and their possible mechanisms. METHODS: Two MM-derived cell lines RPMI8226 and U266 cells were used as in vitro models. Cell apoptosis was assessed by morphology, flow cytometry, and DNA gel electrophoresis. Mitochondrial transmembrane potentials (delta psi m) were evaluated by measuring cellular Rhodamine 123 staining intensity. Protein expression was analyzed using Western blot. RESULTS: Zero point one to 0.5 mumol/L As2O3 inhibited cell proliferation and 2.0 mumol/L As2O3 induced cell apoptosis, while 1.0 mumol/L As2O3 inhibited proliferation with a weak degree of apoptosis induction in RPMI8226 and U266 cell lines. As2O3-induced apoptosis was accompanied by mitochondrial transmembrane potentials (delta psi m) collapse and caspase-3 activation in the presence of intact membrane. Glutathione depleter buthionine sulfoximine enhanced, while disulfide bond-reducing agent dithiothreitol partially antagonized As2O3-induced delta psi m collapse and apoptosis in MM cells. All-trans retinoic acid (ATRA) could also induce apoptosis in RPMI8226 cells, but it did not show any cooperative effects with As2O3. CONCLUSION: As2O3 exerts apoptosis-inducing and growth-inhibiting effects on MM cells, and mitochondrium is a pivotal and common target of As2O3 for apoptosis induction.

Antineoplastic Agents↗

PubMed2001

Eldepryl prevents 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced nigral neuronal apoptosis in mice.

OBJECTIVE: To study the apoptotic effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on the nigral dopaminergic neurons of mice and 1-methyl-4-phenylpyridium ion (MPP+) on pheochromocytoma (PC12) cells, as well as the antagonism of Eldepryl against MPTP's apoptotic effect. METHODS: Three groups of C57BL mice were treated with MPTP, Eldepryl plus MPTP and normal saline, respectively, for 7 days before performing TUNEL (terminal deoxyneucleotidyl transferase-mediated dUTP-x nick end labeling) and FACS (fluorescence activated cell sorting) analyses of neuronal apoptosis in the substantia nigra. The same tests were employed in cell culture to examine apoptosis in PC12 cells treated with MPP+, MPTP or PBS. RESULTS: Intraperitoneal administration of MPTP 30 mg/kg could induce nigral apoptosis, and oral use of Eldepryl prior to MPTP treatment could completely prevent the nigral apoptosis caused by MPTP. MPP+, an intermediate metabolite of MPTP, could lead to the apoptosis of PC12 cells, whereas MPTP itself had no such effect on PC12 cells. CONCLUSIONS: The experiment indicated that the neurotoxin, MPTP, might cause the death of nigral neurons through a mechanism of apoptosis and this effect might be mediated by its bioactive intermediate metabolite MPP+. Eldepryl could protect the neurotoxicity from MPTP.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

PubMed2001

Analysis of hypermutation of the 5' noncoding region in the BCL-6 gene.

OBJECTIVE: To investigate BCL-6 gene mutations in Chinese populations with B-cell non-Hodgkin's lymphoma. METHODS: Polymerase chain reaction (PCR), denaturing gradient gel electrophoresis (DGGE) and direct DNA sequencing were used to identify mutations in the 5' noncoding region of the BCL-6 gene in a total of 40 cases of diffuse large-cell lymphoma (DLCL) and follicular lymphoma (FL). RESULTS: Nine cases were found to have base substitutions. The incidence of BCL-6 gene mutation and the frequency of single-base changes were approximately 25.7% and (0.56-1.10) x 10(-2)/bp, respectively. CONCLUSIONS: The 5' regulatory region of the BCL-6 gene undergoes frequent somatic hypermutation during lymphomagenesis and the identification of BCL-6 gene hypermutations provides a molecular marker for confirmatory diagnosis of B-NHL.

5' Flanking Region↗

PubMed2001

Stable clonal expansion of the T-cell receptor V beta 6, V beta 17 and V beta 19 T cells in a cGVHD case using genescan analysis.

OBJECTIVE: To investigate the distribution and clonality of the T-cell receptor (TCR) V beta repertoire in chronic graft versus host disease (cGVHD). METHODS: The complementarity determining region 3 (CDR3) of the TCR beta gene with 24 variable regions was amplified in peripheral blood mononuclear cells drawn from one cGVHD patient after allogenic bone marrow transplantation (allo-BMT) 35, 39, 43 or 45 months respectively, using RT-PCR, to observe the expression of TCR V beta repertoire T cells. The PCR products were further analyzed by genescan to evaluate clonality of T cells. RESULTS: Fourteen or 16 TCR V beta subfamily T cells were detected in each sample of cGVHD case. Oligoclonal T cells were identified in TCR V beta 6, 16, 17, 19 and 21 subfamilies. The stable clonal T cells in all samples were identified in V beta 6, V beta 17 and V beta 21 subfamilies. CONCLUSION: Skewing distribution and stable clonal expansion of T cells can be found in cGVHD cases and it may be related to the initiation of cGVHD.

Adult↗

PubMed2001

The preparation of rat heme oxygenase-1 mutant to reduce the level of bilirubin.

OBJECTIVE: To prepare rat heme oxygenase-1 (HO-1) mutants and to determine the activity and inhibition of this mutated enzyme. METHODS: pcDNA3HO1 containing truncated native rat HO-1 cDNA and pcDNA3HO1 delta 25 carrying mutated rat HO-1 cDNA (His25Ala) were constructed, respectively. COS-1 cells transfected with pcDNA3HO1 and pcDNA3HO1 delta 25 were collected and their activities were analyzed. RESULTS: Native rat HO-1 was highly expressed in transfected cells and its activity was 13,688-15,600 U/mg protein per hour. However, the enzyme activity of mutated HO-1 declined and the value was 1948-2160 U/mg protein per hour. When an equal amount of mutant was added to the enzyme reaction system, the level of bilirubin decreased by 42%. CONCLUSION: The His25Ala mutant reduced the formation of bilirubin, suggesting that the mutant could completely bind the heme with native enzyme.

Animals↗

PubMed2001

[Effects of leptin on estradiol and progesterone production by human luteinized granulosa cells in vitro].

OBJECTIVE: To investigate the effects of leptin on steroidogenesis of human luteinized granulosa cell in vitro. METHODS: Human luteinized granulosa cells were isolated from follicular fluid obtained during oocyte retrieval of in vitro fertilization-embryo transfer program and were cultured with M199 medium plus various concentration of leptin (0, 10, 30, 100, 300 ng/ml), human menopausal gonadotropin (hMG, 0, 0.1, 0.2, 0.5, 1, 2, 5, 10 IU/ml) and testosterone 100 micrograms/ml. For 2 days the media were collected for estradiol and progesterone measurements. RESULTS: Addition of leptin alone did not alter estradiol and progesterone production (P > 0.05) by human luteinized granulosa cells. Leptin of 10-30 ng/ml concentrations caused a dose-dependent inhibition of estradiol production (P < 0.05) while greater than 0.5 IU/ml of hMG were added. There was no effect of leptin on hMG-stimulated progesterone production (P > 0.05). CONCLUSION: Leptin can directly inhibit hMG-stimulated estradiol production by human luteinized granulosa cells in vitro, but has no effect on progesterone production. Leptin may play an important role in follicle development and luteinization.

Cells, Cultured↗

PubMed2001

Neutralization/enhancement of macrophage-tropic SIVmac infection by plasma from macaques infected with macrophage-tropic or lymphocyte-tropic SIVmac.

Plasma from macaques inoculated with macrophage-tropic SIVmac were tested for neutralization/enhancement of macrophage-tropic SIVmac239-17EBR in normal rhesus macrophages. The plasma of a macaque (R71) that developed a highly virulent neuro-tropic (macrophage-tropic) strain of SIVmac in neuro-adaptation studies significantly enhanced infection of SIVmac239-17EBR as well as infection of dual-tropic SIVmac251. Plasma from other macaques that were inoculated with macrophage-tropic virus, neutralized SIVmac239-17EBR. Also, plasma from macaques infected with lymphocyte-tropic SIVmac239 or dual-tropic SIVmac251 neutralized SIVmac251 infection. When the effect of R71 plasma on the early stages of the SIV life cycle was investigated, this plasma significantly increased binding of 35S-methionine labeled SIVmac239-17EBR and increased binding of 35S-SIVmac251 to primary macrophages, unlike plasma from other macaques infected with either macrophage-tropic or lymphocyte-tropic SIV. A single-cycle infection assay showed higher percentages of positive cells and more intense fluorescence in cultures treated with R71 plasma compared with control plasma. By in situ hybridization, SIV RNA transcripts were detected earlier (12 hr post-infection) and in higher percentages, in cultures treated with R71 plasma than in cultures treated with control plasma (18 hr post-infection). These results indicate that enhancing activity in infected macaque plasma may be associated with severe infection by highly virulent macrophage-tropic (neuro-tropic) SIV. The enhancing effect occurs early in infection and results in increased transcription of SIV RNA.

Animals↗

PubMed2001

Transforming growth factor-alpha promotes mouse blastocyst outgrowth and secretion of matrix metalloproteinases.

OBJECTIVE: To study the effect of transforming growth factor-alpha (TGF-alpha) on early stage of embryo implantation. METHODS: Mouse blastocysts were cultured in vitro in medium containing various concentrations of TGF-alpha. Blastocyst implantation capacity was evaluated by calculating the percentage of embryos with attachment or outgrowth. Matrix metalloproteinases (MMPs) secretion of blastocysts was observed using gelatin zymography. RESULTS: There was no significant difference in the percentage of attachment between control and TGF-alpha treated groups, but the percentage of outgrowth of TGF-alpha treated groups was significantly higher than that of the control group after 24 h culturing. Gelatin zymography showed that blastocysts cultured in TGF-alpha treated groups started secreting MMPs earlier than those in the control group. CONCLUSION: TGF-alpha is involved in regulating the mouse embryo implantation process by promoting blastocyst outgrowth and secreting matrix matalloproteinases.

Animals↗

PubMed2001

[A clinical analysis of 798 cases of M protein positive patients].

OBJECTIVE: To improve the understanding of the diseases with positive M protein by analyzing 798 cases, so as to reduce the failure and error of diagnosis. METHODS: The relations of diseases with the types of the disease and age and sex of the patients were analyzed. The presenting symptoms of multiple myeloma(MM) and non-MM were compared. The difference of Ig content among each type of MM and the characteristics of M protein in non-MM were also studied. RESULTS: In 798 cases with positive M protein, there were 648 cases of MM (81.2%) and 34 cases of Waldenstrom's macroglobulinemia (WM) (4.3%). The remaining 116 cases (14.5%) were benign or secondary monoclonal gammopathies. The average age of the patients was 58.3 years, and there was no difference of disease incidence between men and women. There was a marked difference between MM and non-MM in the presenting symptoms which were mainly lumbago and bone pain in MM but fever, weight loss and fatigue in non-MM. 648 cases of MM included 290 cases of IgG type (44.8%), 143 of IgA type (22.1%), 138 of light chain type (21.3%), 45 of IgD type (6.9%), 30 of non-secretion type (4.6%) and 2 of double-clonal type (0.3%). There was no marked distinction between kappa and lambda chain except in IgD type. The average M protein content of 116 cases of benign or secondary monoclonal gammopathies was (11.3 +/- 6.5) g/L. 55 of the 116 cases were monoclonal gammopathy of undetermined significance (MGUS), which accounted for 6.9% of all the cases. 35 cases were non-Hodgkin's lymphoma (NHL) (4.4%). CONCLUSION: M protein was mainly discovered in MM; it may also be discovered in MGUS, NHL, WM and other diseases. It is essential to have a better understanding of these diseases.

Adult↗

PubMed2001

[Expression of surviving gene and its relationship with expression of P53, c-myc, k-ras proteins in non-small-cell lung cancer].

OBJECTIVE: To study the expression of surviving and its relationship with expression of P53, c-myc, k-ras in non-small-cell lung cancer (NSCLC). METHODS: Expression of the surviving mRNA was evaluated by reverse transcriptase polymerase chain reaction (RT-PCR) in 76 NSCLC tumor samples, 20 benign phymatoid lesion and 21 adjacent normal lung tissue samples. Immunohistochemical assay was to detect the expression of P53, c-myc, k-ras proteins. RESULTS: Expression of surviving gene was detected in a significantly greater proportion of NSCLC (61%) than phymatoid lesion (30%) and adjacent normal lung tissue (19%) (P < 0.001). There was no relationship between surviving gene expression and histologic subtype, differentiation, TNM stages, or lymph node metastases. The expression of surviving gene correlated with P53 or c-myc expression, but not k-ras expression. CONCLUSION: (1) The up-regulation expression of surviving gene in NSCLC suggested that surviving may play a role in the pathway of carcinogenesis and surviving may be identified as a potential therapeutic target in NSCLC. (2) surviving, de-activation of antioncogene P53 and up-regulation of oncogene c-myc might play synergetic roles in the process of carcinogenesis of NSCLC. But surviving and k-ras may be independently involved in the pathogenesis of lung cancer.

Adult↗