Biomedical subjects

L Zhou

Publications and source records attributed to L Zhou.

At least 199 records · Page 11Linked to original sources

PubMed2000

[Effect of electrical lesion of the area postrema on gastrointestinal interdigestive migrating motor complex in conscious dogs].

OBJECTIVE: To investigate the effect of area postrema (AP) of medulla oblongata on gastrointestinal interdigestive migrating motor complex (MMC). METHODS: Interdigestive MMC activity of antrum and duodenum was recorded by strain gauge implanted on the serosa in 8 conscious dogs. Cannula was intubated in the femoral vein for motilin injection. Plasma motilin concentration was measured by RIA. We observed (1) normal interdigestive MMC activity and fluctuation of plasma motilin concentration; (2) the effect of electrically destroying AP on MMC activity and plasma motilin level and (3) whether or not intravenous injection of motilin could induce phase III contractions after AP was destroyed. RESULTS: (1) Typical interdigestive MMC with phases I, II, III and IV was recorded in normal dogs. Phase III was concurrent with the peak of plasma motilin level. (2) In dogs electrically destroyed AP with antroduodenal interdigestive MMC contractions were suppressed; cyclic, phasic and migratory pattern of MMC was disrupted. Plasma motilin concentration was decreased. Intravenous injection of motilin could not induce phase III contractions. CONCLUSION: Area postrema plays an important role, which is mediated by motilin, on the regulation of interdigestive MMC.

Animals↗

PubMed2000

[Expression of Epstein-Barr virus latent membrane protein 2 in murine fibroblasts by retroviral-mediated gene transfer].

OBJECTIVE: This study is to find an efficient way to express EB virus latent membrane protein 2 in mammalian cells, and provide for further investigate on the function of LMP2 protein and its role in cellular immunity. METHODS: The LMP2 gene was cloned into the EcoR I site of a retroviral vector LXSN and the recombinant LXSN-LMP2 was transfected into PT67 by lipofect TAMINE. After screened by G418, the supernatant of G418-resistant cells was used to infect murine fibroblasts NIH 3T3 to determine the virus titer. DNA was extracted from transfected cells and tested by PCR. Indirect immunofluorescence assay was used to detect the expression of the inserted gene. RESULTS: The virus titer was 5.8 x 10(5) PFU/ml. The result of PCR showed that the LMP2 gene had been integrated into the DNA of transfected cells. Indirect immunofluorescence showed that the LMP2 gene had been expressed in the murine fibroblasts. CONCLUSIONS: EB virus LMP2 gene had been integrated into the genome of cells by retroviral-mediated transfer and the target gene had been expressed.

3T3 Cells↗

PubMed2000

[Numerical simulation on maize growth in a regular windbreak system in Huanghuaihai Plain].

The modified production ecological model SUCROS was used to simulate the growth process of summer corn with the protection of windbreaks in Huanghuaihai Plain, and the simulated result was compared with the field monitoring data. The effects of various physiological and ecological factors that affect the growth of the summer corn were analyzed. The modified SUCROS could simulate the growth process successfully. The leaf area index and organ biomass simulated by the model could be fairly consistent with the monitoring data when the effects of insect and disease pests and weeds were considered simultaneously. As compared with the simulated data in the monoculture field, the corn yield in the windbreak system was about 6.8% higher due to the improved microclimate. Based on the simulation of the relationships between sowing density, sowing date and seed production, the density standard for high yield in the region was 6.75-7.50 plants.m-2, even high as 9.00 plants.m-2 in the fields with sufficient soil nutrients and water supply. It is suggested that the optimal sowing period is from May 21 to June 5. Through simulating the influence of "cool summer" on the growth of summer corn in southern Huanghuaihai Plain, it was found that the growth period of corn would extend 3 to 4 days if the average air temperature during the growing period lowered by one degree. The "less radiation" and correspondent "lower temperature" were the direct reasons of yield reduction in "cool summer".

Biomass↗

PubMed2000

[Mechanism of nutrient preservation and supply by soil and its regulation. IV. Fertility regulation and improvement of brown earth type vegetable garden soil and their essence].

Pot experiment studies on the fertility regulation and improvement of fertile and infertile brown earth type vegetable garden soils and their functionary essence show that under conditions of taking different soil fertility improvement measures, the nutrient contents in fertile and infertile soils were not always higher than the controls, but the aggregation densities of soil microaggregates were increased, and the proportion of different microaggregates was more rational. There was no significant relationship between soil productivity and soil microaggregates proportion. It is proved that the essence of soil fertility improvement consists in the ultimate change of the preservation and supply capacities of soil nutrients, and the proportion of soil microaggregates could be an integrative index to evaluate the level of soil fertility and the efficiency of soil improvement.

Particle Size↗

PubMed2000

Temporary and permanent focal cerebral ischemia in the mouse: assessment of cerebral blood flow, brain damage and blood-brain barrier permeability.

OBJECTIVE: To establish a mouse model of middle cerebral artery occlusion, which mimics focal ischemia in humans and to demonstrate the advantages and disadvantages of the model. METHODS: CD-1 mice (n = 126) had permanent middle cerebral artery occlusion for 24 h, or temporary occlusion for either one hour followed by 23 h of reperfusion or 2 h of occlusion with 22 h of reperfusion. The middle cerebral artery was occluded by insertion of a suture through the internal carotid artery. Reperfusion was established by suture withdrawal. The degree of occlusion and the extent of reperfusion were determined using laser Doppler. Infarct volume was measured with 2, 3, 5-triphenyl tetrazolium chloride staining, and the blood-brain barrier disruption was demonstrated using albumin immunohistochemistry. RESULTS: Blood flow decreased to 14%-19% of baseline in both the permanent and temporary occlusion groups and was restored to 51%-75% of baseline after reperfusion. The infarct volume was smaller in the 1 h/23 h temporary occlusion group (P < 0.05) than in either the 24 h permanent occlusion group or the 2 h/22 h temporary occlusion group. Blood-brain barrier disruption was also smaller in the 1 h/23 h temporary occlusion group than in either the 24 h permanent occlusion or the 2 h/22 h temporary occlusion group (P < 0.05). CONCLUSION: Permanent or temporary middle cerebral artery occlusion causes reproducible brain injury in the mouse. Blood-brain barrier disruption and infarct volume remain important markers of focal cerebral ischemia.

Animals↗

PubMed2000

Vasoactive effects of adrenotensin and its interactions with adrenomedullin.

OBJECTIVE: To investigate the vasoactive effects of adrenotensin and the interactions between adrenotensin and adrenomedullin (ADM). METHODS: Isolated rat aortic tension, rat mean arterial pressure and 3H-TdR incorporation of rat vascular smooth muscle cells were measured. Isolated rat aortas were incubated in K-H solution containing adrenomedullin or adrenotensin. The released adrenotensin or adrenomedullin (in incubation medium) from rat aortas was measured by radioimmunoassay. RESULTS: 1 x 10(-8) and 1 x 10(-7) mol/L adrenotensin augmented rat aortic tension in a dose-dependent manner (P < 0.01). An intravenous bolus injection of adrenotensin (2.5 nmol/kg, i.v.) increased the mean arterial pressure by 28% in anesthetized rats (P < 0.01). 1 x 10(-7) mol/L adrenotensin increased 3H-TdR incorporation in cultured rat vascular smooth muscle cells by 55% (P < 0.01). Adrenomedullin inhibited these activities of adrenotensin to different extents. 1 x 10(-9), 1 x 10(-8) and 1 x 10(-7) mol/L adrenotensin decreased adrenomedullin release rates by 19%, 35% and 46%, respectively (P < 0.05 or P < 0.01) and 1 x 10(-8) mol/L adrenomedullin also inhibited adrenotensin release by 45% from rat aorta (P < 0.01). CONCLUSION: Adrenotensin is a novel peptide that elicits the activities of vasoconstriction, pressor effects and induces the proliferation of vascular smooth muscle cells. There is antagonism in vascular activities and reciprocal inhibition in the release between adrenotensin and adrenomedullin. These interactions are manifestations of intramolecular regulation of proadrenomedullin (Pro-ADM).

Adrenomedullin↗

PubMed2000

Diagnosis and surgical treatment of posterior fossa solid hemangioblastomas.

OBJECTIVE: To elucidate the diagnosis and surgical treatment of the posterior fossa solid hemangioblastomas (PFSHs). METHODS: The data from 22 patients with PFSHs verified by surgery and pathology were analyzed retrospectively and a review of relevant literature was conducted. RESULTS: The preoperative definitive diagnosis rate was 13/22. Total tumor removal was achieved in 20 patients. Two of the 22 patients died after surgery, one of brain-stem injury and the other from an intracranial hemorrhage. Twenty patients were followed up for 2 months to 8 years (average, 2 years). Kamofsky scale was > or = 80 in 15 patients, 60-70 in 1 patient and not measured in 4 patients who died during follow-up. The causes of death were pneumonia (2 patients) and purulent meningitis (2). CONCLUSION: MRI and DSA (digital subtraction angiography) are major preoperative diagnostic modalities for PFSH, but PFSH remains a challenging benign neoplasm. Special microsurgical techniques and improved operative manipulation can improve surgical efficacy.

Adult↗

PubMed2000

[The effect of plasma from women with preeclampsia on endothelial cells activators in vitro].

OBJECTIVE: To study the effect of plasma from women with preeclampsia on endothelial cell activators in vitro and determine whether factor(s) in the plasma of women with preeclampsia induces activation of vascular endothelial cells. METHODS: Twenty women with preeclampsia and 15 normal ones at late trimester of pregnancy were studied, from whom maternal venous blood samples were collected. Plasma 6-keto-PGF1 alpha, the end products of prostacyclin (PGI2) and TXB2, the end products of thromboxane A2(TXA2), were measured by radioimmunoassay. Plasma from women with preeclampsia or from normal women at late trimester was added to the bovine pulmonary microvessel endothelial cells in vitro. Twenty-four hours later, levels of 6-keto-PGF1 alpha produced by cultured endothelial cells were measured. RESULTS: The mean values of 6-keto-PGF1 alpha in matrnal venous plasma were (94.49 +/- 25.23) ng/L in preeclamptic group and (248.81 +/- 51.99) ng/L in normal pregnant group. Plasma TXB2 values were (104.61 +/- 13.12) ng/L in preeclamptic group and (66.26 +/- 38.80) ng/L in normal pregnant group. TXB2/6-keto-PGF1 alpha ratios were (1.11 +/- 0.03) in preeclamptic group and (0.28 +/- 0.02) in normal pregnant group. Maternal plasma values of 6-keto-PGF1 alpha were lower in peeclamptic group than those of normal pregnant group (P < 0.01). On the other hand, plasma TXB2 values were higher in preeclamptic group than in normal pregnant group (P < 0.01). TXB2/6-keto-PGF1 alpha ratios, however, were significantly different between the two groups (P < 0.01). The values of 6-keto-PGF1 alpha produced by cultured endothelial cells exposed to 2% plasma were (1,363.00 +/- 99.16) ng/L in preeclamptic group and (819.49 +/- 96.62) ng/L in normal pregnant group (P < 0.01). CONCLUSIONS: PGI2 and TXA2 may play an important role in preeclampsia. Plasma from women with preeclampsia could stimulate the production of prostacyclin in cultured endothelial cells in vitro.

6-Ketoprostaglandin F1 alpha↗

PubMed2000

[Treatment of advanced Hodgkin's disease: an analysis of 128 cases].

OBJECTIVE: To explore the rational treatment for advanced Hodgkin's disease. METHODS: A total of 128 patients with advanced Hodgkin's disease was included in this study. They could be divided into 3 groups according to the treatment they received. Patients in group 1 (n = 99) were treated by combination chemotherapy plus radiotherapy. Patients in group 2 (n = 24) were treated by chemotherapy alone. The remaining 5 patients in group 3 were treated by radiotherapy alone. The chemotherapeutic regimens used were MOPP, MOPP alternating with CHOP, or with ABVD. RESULTS: The overall response rate of 127 evaluable patients was 96.1%. The overall 1-, 3-, 5, and 10-year survival rate was 91.4%, 70.3%, 56.8% and 52.4%, respectively. The complete response (CR) rate in the 3 groups of patients was 69.7%, 58.3% and 100%, respectively. Patients in clinical stage III with no bulky mass, no systemic symptoms, and their tumor was predominantly of lymphocytic or nodular sclerotic type had better long term survival than those in clinical stage IV with bulky mass, systemic symptoms, and with lymphocyte depleting, mixed cellular tumor. Better long term survival was seen in patients who showed complete response to combined chemotherapy and radiotherapy. At least 6 cycles of chemotherapy were needed. CONCLUSION: Combination chemotherapy plus radiotherapy is effective in the treatment of advanced Hodgkin's disease.

Adolescent↗

PubMed2000

[Development of a video system for three-dimensional cephalometry and dental cast analysis].

OBJECTIVE: The purpose of this article is to introduce the outline of our newly developed video system for three-dimensional cephalometry and dental cast analysis. METHODS: The video measuring technique was utilized in the field of dentistry in our study. Two CCD cameras were used to capture the images both of the dental cast and headfilms. The dental cast analysis and three-dimensional cephalometry shared a set of operating system. The three-dimensional reconstruction was based on the LAT and PA films. RESULTS: The measurement error of dental cast analysis is less than 0.09 mm, and the error of three-dimensional cephalometry is less than 0.45 mm. CONCLUSIONS: The clinical application suggests that the use of our system is feasible not only for clinical evaluation of malocclusion but also for saving time necessary for treatment planing and diagnosis.

Cephalometry↗

PubMed2000

[Protective effect of extract of folium ginkgo on repeated cerebral ischemia-reperfusion injury].

OBJECTIVE: To study the protective effect of extract of Folium Ginkgo (FGE) on repeated cerebral ischemia-reperfusion injury. METHODS: The model in waking mice induced by repeated cerebral ischemia-reperfusion were used in the experiment to observe the effect of FGE on behavior, oxygen free radical metabolism and prostaglandin E2 (PGE2) content by step-through experiment, diving stand and colorimetric method. RESULTS: FGE could obviously improve the learning ability and memory of model animals, and could lower obviously the content of malonyldialdehyde, nitric oxide and PGE2, restore the lowered activity of superoxide dismutase and catalase in cerebral tissue. CONCLUSION: FGE has highly protective effect against repeated ischemia-reperfusion injury, the mechanism might be related with its action on anti-lipid oxidatin, improve the activity of antioxidase and inhibit the producing of PGE2.

Animals↗

PubMed2000

[Effects of arsenic trioxide on K562 cells stably expressing two promyelocytic leukemia-specific fusion proteins].

OBJECTIVE: To illustrate the possible roles of acute promyelocytic leukemia-specific chimeric proteins PML-RARalpha and PLZF-RARalpha in the effects of arsenic trioxide (As(2)O(3)). METHODS: K562 sublines stably expressing PML-RARalpha (K(PML() and PLZF-RARalpha (K(PLZF)) were established by retrovirus transfection with K(V) transfected empty vectors as controls. Effects of As(2)O(3) and all-trans retinoic acid (ATRA) on these sublines were analyzed through cell count, morphology, measurement of cellular DNA contents and differentiation antigens on flow cytometry. Subcellular distributions of PML-RARalpha proteins were observed with immunofluorescence. RESULTS: 1.0 micromol/L of As(2)O(3) did not induce cell apoptosis and differentiation, but it significantly inhibited the growth of K(V) sublines. As(2)O(3) showed the similar but more potent effects in K(PML) and K(PLZF) sublines. 1.0 micromol/L As(2)O(3) treatment for 3 days induced growth inhibition by 32% +/- 3%, 57% +/- 4% and 54% +/- 6%, respectively in K(V), K(PML) and K(PLZF) sublines. 1.0 micromol/L ATRA also exerted, to a less extent than As(2)O(3), growth-inhibitory effects in K(V) sublines, which became more obvious in K(PML) but not in K(PLZF) sublines. In addition, PML/PML-RARalpha proteins were decreased and even disappeared in K(V) and K(PML) sublines with the treatment of 1.0 micromol/L As(2)O(3) for 48 hours. CONCLUSION: PML-RARalpha and PLZF-RARalpha markedly enhance growth-inhibitory effects of As2)O3) on K562 cells.

Antineoplastic Agents↗

PubMed2000

[Attenuation of reperfusion injury in the mouse transfected interleukin-1 receptor antagonist].

OBJECTIVE: To investigate the therapeutic effects of overexpression of interleukin-1 receptor antagonist (IL-1ra), administered by gene transfer, on the transient cerebral ischemic injury in an experimental mice suture model. METHODS: Adenovirus vector encoding human IL-1ra gene (Ad.RSVIL-1ra) or LacZ gene (Ad.RSVLacZ) or normal saline was administered by injection into the right lateral ventricle in adult CD-1 mice. Five days after the virus injection, the mice received 1 h transient middle cerebral artery occlusion with 23 h reperfusion. Surface cerebral blood flow was measured using laser Doppler flowmetry. Brain infarct volume was evaluated on the sections with hematoxylin-eosin staining. Blood-brain barrier (BBB) permeability was determined using immunostaining of extravasated endogenous albumin. The number of intracellular adhesion molecular-1-positive vessels was determined by immunohistochemistry. RESULTS: The infarct volume in the Ad. RSVIL-1ra transfected mice was markedly reduced compared with the Ad. RSVLacZ transfected or saline mice (36.0 +/- 5.3 mm(3) vs 60.0 +/- 6.2 mm(3), 69.5 +/- 6.3 mm(3), P < 0.05). BBB disruption area was also smaller in the Ad. RSVIL-1ra transfected mice than in the Ad. RSVLacZ transfected and saline mice (P < 0.05). The expression of intracellular adhesion molecular-1 (ICAM-1) positive vessels in the ischemic cortex and basal ganglia was greatly attenuated in the Ad. RSVIL-1ra transfected mice (cortex: 135 +/- 23, vs 311 +/- 40 and 357 +/- 51 pound sterling basal ganglia: 90 +/- 21, vs 207 +/- 43 and 259 +/- 43, P < 0.05. CONCLUSION: IL-1ra has neuroprotective property during ischemia/reperfusion injury. Overexpression of IL-1ra via gene transfer can attenuate the expression of ICAM-1 in the ischemic area.

Adenoviridae↗

PubMed2000

[Effects of serum and decidual tissue fluid in early pregnant women on natural killer cells activity and lymphocyte proliferation].

OBJECTIVE: To study the effects of serum and decidual tissue fluid in early pregnant women on natural killer cells (NK cells) activity and lymphocyte proliferation. METHOD: The effects of the serum and decidual tissue fluid obtained from 32 normal early pregnant women on NK cells activity and lymphocyte proliferation were tested by isotope incorporation methods. Sera of 25 nonpregnant women were chosen as controls. RESULTS: The NK cells activity and lymphocyte proliferation of sera and decidual tissue fluids from early pregnant women were lower than those of sera from nonpregnant women (P < 0.01). So were those of decidual tissue fluid as compared with sera during early pregnancy (P < 0.005). CONCLUSIONS: Serum and decidual tissue fluid from early pregnant women expressed immunosuppressive effects. It is possible that these effects of decidual tissue fluid play an important role in regulating local immune status of pregnant uterus.

Adult↗

PubMed2000

[An epidemiological study on the incidence rates of colorectal cancer through different drinking water sources].

OBJECTIVE: In order to identify the association of incidence rates of colorectal cancer and different drinking water sources. METHODS: With the retrospective cohort method, 8 villages or townships in Haining city were randomly selected as the study area where a total 408 cases were collected during 1977 to 1996. The incidence rates according to the drinking water sources were calculated by sex and sites of the cancer. The RR estimates were given to each sex and site by comparing to that in well water source. RESULTS: The incidence rates of colorectal cancer by sequence of the sources were shown as follows drinking water: (male: pool water 126.04/10(5); female: 81.76/10(5)), river water (male: 45.06/10(5); female: 63.43/10(5)), tap water (male: 7.99/10(5); female: 5.17/10(5)) and well water (male: 3.19/10(5); female: 3.06/10(5)). All of them were statistically significance through chi(2) trend tests. Poisson test was used to have found the differences of incidences of colorectal cancer between different drinking water sources (P < 0.01). RR estimates showed that the risk of colorectal cancer with pool or river water sources were 7 times higher than that with well water. CONCLUSION: Study of this kind might uncover the differences which accounted for the associations between the drinking water sources and colorectal cancer.

China↗

PubMed2000

[Randomized controlled trial of sequence mass screening program for colorectal cancer].

OBJECTIVE: In order to assess the effectiveness of mass screening program for colorectal cancer, a sequence mass screening program based on RPHA-FOBT and individual quantitative risk assessment model (attributive degree value, AD) was used and evaluated on its effectiveness in a randomized controlled trial. METHODS: The residents of Jiashan county aged 30 years and over were randomized to either screening or control groups in 1989. Participants in screening group were asked to fill in a questionnaire and to submit one paper slide with stool. Participants who tested positive underwent diagnostic evaluations including flexible sigmoidoscopy and colonoscopy. RESULTS: According to the cancer registry of Jiashan, after initial mass screening in 1989, the 8-year cumulative incidence per 1,000 of colorectal cancer in screening and control groups appeared to be 3.95 (95% CI 3.81 - 4.10) and 4.01 (95% CI 3.86 - 4.16) respectively. There was no significant statistical difference between two groups (P > 0.05). Nevertheless, the 8-year cumulative mortality for colorectal cancer in screening group (2.08 per 1,000; 95% CI 1.96 - 2.18) was reduced 14.7% comparing with the control group (2.44 per 1,000; 95% CI 2.33 - 2.55). In particular, the cumulative mortality of rectal cancer was significantly (31.7%) lower than that in control group. Log-rank test showed that survival rate of rectal cancer in screening group was higher than that in controls (log-rank = 9.01, P = 0.0027). CONCLUSIONS: The sequential mass-screening program which based on RPHA-FOBT and ADV might reduce the mortality for colorectal cancer in the Chinese population.

Adult↗

PubMed2000

[Drinking water types, microcystins and colorectal cancer].

OBJECTIVE: To assess the relationship between microcystins (a blue-green algal toxin) in drinking water and colorectal cancer. METHODS: Eight townships were randomly selected as study sites in Haining city of Zhejiang province, China. Four hundred and eight colon and rectum carcinoma cases diagnosed from 1977 to 1996 were identified from cancer registry in the study sites. A retrospective survey on types of drinking water of all 408 cases was conducted. Population data and drinking water sources data were provided by local household registration and local health institution, respectively. Water samples from different sources (well, tap-water, river and pond) were collected and microcystins concentrations were measured by an indirect competitive ELISA method. RESULTS: The incidence rates of colorectal cancer were significantly higher among people drinking river or pond water than those who drank well water or tap-water in both males and females. And comparing with other sources to well water, the relative risks (RR) were much higher for people using river water (7.94) and pond water (7.70). The positive detection rates (> 50 pg/ml) of microcystin in well, tap-water, river and pond water were 0.00%, 0.00%, 36.23% and 17.14% respectively. The highest concentrations of microcystins were 1 083.43 pg/ml (river) and 1 937.94 pg/ml (pond) in the positive samples. Microcystins concentrations in river and pond were significantly higher than the concentrations in well and tap water (P < 0.01). The Spearman rank correlation analysis showed that in the study sites, the microcystins concentrations of river and pond water were positively correlated with the incidence of colorectal cancer (r = 0.881, P < 0.01). CONCLUSION: Drinking surface water (river or pond) is one of the risk factors for colorectal cancer. Microcystins may be associated with incidence of colorectal cancer. It is suggested that further study should be carried out to clarify the relationship between colorectal cancer and microcystin in drinking water.

Bacterial Toxins↗

PubMed2000

[Signal transduction pathway for antral smooth muscle cell contraction induced by motilin and gastrin in rats].

Signal transduction pathway that mediates motilin and gastrin induced contraction of antral smooth muscle cells was investigated in rats. The results are as follows. (1) Motilin and gastrin induced contraction of isolated gastric smooth muscle cells in a dose dependent manner. (2) Motilin and gastrin induced antral smooth muscle cell contraction was inhibited by antibodies against G( i-3). Motilin and gastrin caused an increase of Guanosine 5 -(3- (35)S thio)triphosphate( (35)S GTPgammaS) binding of G( i-3). (3) Contraction of antral muscle cells induced by motilin and gastrin was inhibited by the phospholipase C (PLC) inhibitor U 73122 and the IP(3) receptor antagonist heparin. The results suggest that motilin and gastrin induced contraction of rat antral smooth muscle cells is mediated by stimulating G(I) protein coupled with PLC that produces IP(3).

Animals↗