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Biomedical subjects

S He

Publications and source records attributed to S He.

At least 55 records · Page 3Linked to original sources
PubMed2001

Effects of window and threshold levels on the accuracy of three-dimensional rendering techniques in coronary artery electron-beam CT angiography.

RATIONALE AND OBJECTIVES: The authors performed this study to evaluate the effect of window level and gray-scale threshold on the demonstration of coronary artery lumina at three-dimensional electron-beam computed tomographic (CT) angiography. MATERIALS AND METHODS: Forty-four coronary artery branches in postmortem pigs were evaluated with electron-beam CT angiography, and the findings were compared with those from conventional angiography. Images from electron-beam CT angiography were reconstructed with maximal intensity projection (MIP), multiplanar reformation (MPR), and shaded-surface display (SSD). Four categories of window level and gray-scale threshold were evaluated. RESULTS: Three-dimensional electron-beam CT angiography accurately depicted the luminal diameters of the coronary arteries compared with conventional angiography (r = 0.83-0.90, P < .0001). The length of lumina visualized at electron-beam CT angiography was significantly shorter than that visualized with conventional angiography (P < .001). The use of MPR enabled visualization of longer segments of coronary arteries than did the use of MIP or SSD (P < .05). The higher the window level and gray-scale threshold used, the smaller the coronary luminal diameters measured (P < .05). The most accurate window level and gray-scale threshold (82.6 HU +/- 29.8 and 89.5 HU +/- 29.7, respectively) were found to correspond to the attenuation of the lumina (275.8 HU +/- 58.8). Results of simple linear regression showed a strong correlation between luminal attenuation and window level (r = 0.89, P < .0001) or gray-scale threshold (r = 0.95, P < .0001). CONCLUSION: Electron-beam CT angiography shows promise in the visualization of coronary artery lumina. For accurate display of lumina, a proper window level and gray-scale threshold for three-dimensional rendering techniques should be determined and used on the basis of the attenuation of the target vessel.

Animals↗
PubMed2001

Optimal electrocardiographically triggered phase for reducing motion artifact at electron-beam CT in the coronary artery.

RATIONALE AND OBJECTIVES: The authors performed this study to (a) investigate coronary movement with electron-beam computed tomography (CT) and (b) find the optimal electrocardiographic (ECG) triggering phase for eliminating motion artifact. MATERIALS AND METHODS: One hundred fifty-one patients without arrhythmia were examined with electron-beam CT. First, movie scans were obtained to create displacement and velocity graphs of coronary artery movement. Then, a volume scan with an exposure time of 100 msec was obtained with various ECG trigger settings. RESULTS: Movement patterns of coronary arteries varied with heart rate. Optimal triggering phase was before atrial systole (near 71% of the R-R interval) when heart rate was slower than 68 beats per minute and at ventricular end systole when heart rate was fast. Rate of severe motion artifacts decreased from 43% to 0% when triggering was altered from 80% of the R-R interval to the individual optimal value. Experimental values of the optimal phase at different heart rates were derived, and severe motion artifact was only 3.0% with these values. CONCLUSION: ECG triggering set according to the heart rate enables a great reduction in motion artifacts at electron-beam CT with a 100-msec exposure time. The results may have implications for magnetic resonance imaging of the coronary artery.

Adult↗
PubMed2001

A rapid, simple and sensitive flow cytometric system for detection of Plasmodium falciparum.

We have established a rapid, simple and sensitive flow cytometric system for the detection of Plasmodium falciparum that involves lysing erythrocytes and staining parasites at the same time using a newly developed hemolysing and staining solution containing dodecyl methyl ammonium chloride and acridine orange. In this system, freed parasites of P. falciparum could be plotted separately from erythrocyte ghosts, white blood cells and platelets on the two-dimensional scattergram of forward-angle light scatter and green fluorescence by flow cytometry with an argon laser. It took only 2-3 min per sample to obtain the scattergram and analyze the data, including the time of sample preparation for flow cytometric analysis. Sample preparation with this method does not require any difficult handling procedures. The threshold of parasite detection was almost equal to that of microscopic examination for cultured P. falciparum. The results of drug-susceptibility assays using this system were also almost identical to those obtained using microscopic examination. In this system, parasites at different erythrocytic stages could be easily distinguished. This system must prove useful and practical for basic laboratory studies of P. falciparum including those requiring the differential measurement of parasites at specific erythrocytic stages.

Acridine Orange↗
PubMed2001

Hypercoagulation in surgical postmenopausal women having hormone replacement with overdose estradiol.

A benefit of estradiol replacement preventing coronary heart disease (CHD) after menopause has been suggested by clinical investigations. In the department of gynecology at our hospital, we met by chance eight senior women who were hysterectomized due to different benign gynecological disorders. Acting on their own, they took a daily dose of estradiol valerate as high as 8-50 mg for 3 years, in comparison with 1-2 mg used in routine hormonal replacement therapy. We were interested to assess whether the overdose estrogen disturbs the hemostatic function, thus losing the favorable effect on CHD occurrence. Plasma levels of some procoagulants/anticoagulants were assayed in the eight women with replacement therapy and the results were compared with those of seven age-matched senior women and of 14 young healthy women with normal menstrual cycles. Using a new laboratory method recently developed by us, the overall hemostatic potential, shown as a single parameter (Abs-sum), was also determined. Results showed that high-dose estradiol activated coagulation and depressed fibrinolysis, leading to the net effect of elevated overall hemostatic potential. Thus, the overdose estradiol replacement may not be beneficial in preventing CHD after menopause, or it may even increase the risk due to the hypercoagulable state induced therefrom.

Adult↗
PubMed2001

Evaluation of cardiovascular parameters of a selenium-based antihypertensive using pulsed Doppler ultrasound.

The pharmacology of selenium is of much interest because selenium deficiency has been linked to cardiovascular diseases, cancer, and arthritis, and selenoenzymes are critical cellular antioxidants. We have previously reported that phenyl-2-aminoethylselenide (PAESe) and its derivatives represent a novel class of selenium-based antihypertensive agents that exhibit unique biochemical and pharmacologic properties. We now report on experiments designed to probe the hemodynamic mechanism of action of these compounds in spontaneously hypertensive rats (SHR). A noninvasive pulsed Doppler ultrasound probe was used to measure peak blood flow velocity in the aortic arch from the right second intercostal space. PAESe was found to increase peak aortic blood flow velocity (+44%), heart rate (+16%), and blood flow acceleration (+105%), while decreasing left ventricular ejection time (LVET) (-37%) concomitant with a decrease in mean arterial pressure (-54%). These results were compared with the known vasodilator hydralazine, which had similar effects on mean arterial pressure (MAP) and peak velocity but caused an increase in LVET (+42%) and a decrease in heart rate (-18%). Taken together, our results suggest that PAESe decreases blood pressure via a decrease in peripheral resistance, which overcomes the initial increase in heart rate and acceleration to give a net decrease in MAP.

Animals↗
PubMed2001

Modified clotting properties of fibrinogen in the presence of acetylsalicylic acid in a purified system.

To assess how treatment with acetylsalicylic acid (ASA) alters the fibrin network structure, clotting was initiated in purified fibrinogen incubated with ASA by adding thrombin. Clotting time and maximum absorbance of the fibrin aggregation curve were used to demonstrate the potential of fibrin generation. The results showed that the clotting properties of fibrinogen decreased and that the affinity of plasminogen to fibrin or thrombin inhibition by antithrombin increased if plasminogen or antithrombin, respectively, were present in the reaction system. The effect of ASA varied in a dose dependent manner. It was concluded that ASA may directly or indirectly confer positive or negative effects on the stability of the fibrin clot and that the balance between these effects may be regulated by the ASA dose.

Aspirin↗
PubMed2001

Persistence of human immunodeficiency virus type 1-specific cytotoxic T-lymphocyte clones in a subject with rapid disease progression.

We longitudinally measured T-cell receptor transcript frequencies of human immunodeficiency virus type 1 (HIV-1) specific cytotoxic T lymphocytes (CTL) in an individual with rapidly progressive disease and high levels of viremia. CTL clones elicited during acute HIV-1 infection were present at the time of death, despite absent functional CTL responses, arguing against clonal deletion as a mechanism for the decline of CTL responses observed during HIV-1 infection.

Chronic Disease↗
PubMed2001

The alpha(1)- and alpha(2)-isoforms of Na-K-ATPase play different roles in skeletal muscle contractility.

The Na-K-ATPase, which maintains the Na(+) and K(+) gradients across the plasma membrane, can play a major role in modulation of skeletal muscle contractility. Although both alpha(1)- and alpha(2)-isoforms of the Na-K-ATPase are expressed in skeletal muscle, the physiological significance of these isoforms in contractility is not known. Evaluation of the contractile parameters of mouse extensor digitorum longus (EDL) was carried out using gene-targeted mice lacking one copy of either the alpha(1)- or alpha(2)-isoform gene of the Na-K-ATPase. The EDL muscles from heterozygous mice contain approximately one-half of the alpha(1)- or alpha(2)-isoform, respectively, which permits differentiation of the functional roles of these isoforms. EDL from the alpha(1)(+/-) mouse shows lower force compared with wild type, whereas that from the alpha(2)(+/-) mouse shows greater force. The different functional roles of these two isoforms are further demonstrated because inhibition of the alpha(2)-isoform with ouabain increases contractility of alpha(1)(+/-) EDL. These results demonstrate that the Na-K-ATPase alpha(1)- and alpha(2)-isoforms may play different roles in skeletal muscle contraction.

Animals↗
PubMed2001

Scattering of a Hermite-Gaussian beam field by a chiral sphere.

Scattering of a Hermite-Gaussian beam field by a chiral sphere is analyzed. A Hermite-Gaussian beam field is expressed as a superposition of multipole fields at complex-source points. Electromagnetic fields are expanded in terms of the spherical vector wave functions. The unknown expansion coefficients for the scattered field and the internal field are determined by the boundary conditions. As numerical examples, the scattered near fields of the beam incidence are calculated, and the effects of the chirality and the radius of the chiral sphere on the fields are examined. The results for a Gaussian beam incidence are also compared with those of a plane-wave incidence.

Journal Article↗
PubMed2001

[Effect on manganese exposure on blood prolactin and plasma renin activity].

In order to study the adverse effects of manganese on neuro-endocrine and cardiovascular system, radioimmunoassay (RIA) was used to test the blood prolactin concentration and plasma renin activity among manganese-exposed workers. The result showed that the blood prolactin concentration and Plasma renin activity in manganese exposed workers were significantly higher than those of control group. It suggested that manganese exposure might affect the function at tubero-infundibular area and renin-angiotensin aldosterone system.

Adult↗
PubMed2001

Angiopoietin-1 upregulation by vascular endothelial growth factor in human retinal pigment epithelial cells.

PURPOSE: To determine whether vascular endothelial growth factor (VEGF) regulates angiopoietin (Ang)-1 and -2 expression in retinal pigment epithelial (RPE) cells. METHODS: Expression of VEGF, Ang1, and Ang2 in surgically removed human choroidal neovascular membranes (CNVMs) was analyzed by double-label confocal immunofluorescence microscopy. Total RNA was extracted from cultured human RPE cells treated with VEGF for mRNA analysis. Northern blot analysis was performed to examine the time course and dose response of Ang1 and Ang2 mRNA expression. mRNA stability and nuclear run-on analyses were performed. Secreted Ang1 and Ang2 protein levels in conditioned media from RPE cells were examined by Western blot analysis. RESULTS: Ang1 and Ang2 immunostaining colocalized with VEGF-positive stromal cells in human CNVMS: Ang1 and Ang2 mRNAs were expressed by cultured serum-starved RPE cells. VEGF upregulated Ang1 mRNA in a time- and dose-dependent manner without a significant change in Ang2 mRNA. Ang1 and Ang2 mRNAs in RPE cells were as stable as that of S18. VEGF stimulation further increased the half-life of Ang1 mRNA, but did not alter its transcription rate. VEGF increased the amount of Ang1, but not Ang2, protein secreted into the medium. CONCLUSIONS: The colocalization of Ang1 and Ang2 with VEGF in CNVM stromal cells and the upregulation of Ang1 expression by VEGF in cultured RPE cells suggest that VEGF may selectively modulate Ang expression during CNV.

Angiopoietin-1↗
PubMed2001

The role of factor XI in a dilute thromboplastin assay of extrinsic coagulation pathway.

Blood coagulation has been thought to be composed of both intrinsic and extrinsic pathways. Recent evidence strongly supports the critical role of the extrinsic pathway in the initiation of blood coagulation. This investigation established an assay that examines the role of FXI in the thromboplastin-initiated (extrinsic) coagulation based on this new concept. Plasma clotting times were measured at different concentrations of thromboplastin with activated FXII inhibited (FXIIa-inhibited Diluted Thromboplastin Time, FXIIaiDTT). Only at low concentrations of thromboplastin was FXIIaiDTT of FXI-deficient plasma significantly prolonged than that of normal plasma. Depletion of FXI from normal plasma prolonged its FXIIaiDTT and replenishment of FXI shortened it. FXIIaiDTTs of both FVIII-deficient and FIX-deficient plasma were remarkably prolonged, and addition of normal plasma dose-dependently shortened it. Furthermore, earlier alpha-thrombin inhibition was directly correlated with decreasing FXa generation. The amount of FXa production was: platelet-rich plasma > platelet-poor plasma > FXI-deficient plasma. Therefore, our findings from the FXIIaiDTT assays not only support the critical role of extrinsic pathway in blood coagulation initiation, but also demonstrate the importance of FXI as an amplifier of thrombin generation in thromboplastin-initiated coagulation.

Blood Coagulation↗
PubMed2001

[Effect of EGTA and La2+ on induction of sesquiterpene cyclase gene expression in leaves of Capsicum annuum by several abiotic elicitors].

To destroy Ca2+ signal system, the detached leaves of Capsicum annuum were pretreated with EGTA, a commonly used Ca2+ chelator, or La3+, an ion which competitively inhibits Ca2+ movement through plasma membrane channels. The induction of sesquiterpene cyclase gene expression in the pretreated pepper leaves under the treatments of CuCl2, HgCl2 and UV was conducted in this paper. The result showed that no hindrance of sesquiterpene cyclase enzyme activity was detected in the EGTA or LaCl3 pretreated leaves, compared to the controls treated with CuCl2, HgCl2, and UV without the pretreatment, while the pretreatment with EGTA enhanced the inductivity of the above exogenous abiotic elicitors on the enzyme activity. The sesquiterpene cyclase activity was also detected in leaves treated with EGTA only, and the result of Northern Blot analysis indicated that the enhancement of EGTA on the enzyme activity was due to the induction of EGTA on the gene transcription. It is suggested that there might exist other signal pipelines, in addition to the Ca2+ signal system in sesquiterpene cyclase gene expression in pepper leaves, and the mechanism of induction of abiotic elicitors on sesquiterpene cyclase in C. annuum differed from that of biotic elicitors.

Calcium Signaling↗
PubMed2001

[Phenolic acid degradation fungi screened from successive plantation site of Chinese fir].

Successive plantation of Chinese fir (Cunninghamia lanceolata) leads an obvious decline of soil fertility. To solve the urgent problem, five fungal species (F2, F3, F4, F7, F15) which can effectively degrade phenolic acid were screened to degrade the toxic material in successive plantation site and to improve the soil bioactivity. Pot experiment showed that all test fungus, except F4, could improve plant growth individually, but not counteract the effect of phenolic acid. Inoculating five inoculated fungi mixed with equal proportion not only counteracted the inhibitory effect of phenolic acid but also improved the growth of Chinese fir uninoculated with VAM fungi but inoculated with G. mosseae.

Abies↗
PubMed2001

[Value of 18F-fluorodeoxyglucose positron emission tomography imaging in staging of non-small cell lung cancer].

OBJECTIVE: To evaluate the accuracy and value of fluorine desoxy-glucose Positron emission tomography (FDG PET) imaging in the staging of non-small cell lung cancer (NSCLC). METHODS: A retrospective analysis of 82 patients with NSCLC confirmed by pathological examination was made to study the staging of whole-body FDG PET scanning compared with computerized tomography (CT). RESULTS: The intake of FDG increased in the lung and metastatic foci among all 82 NSCLC patients. Whole-body PET scanning showed concentrated FDG in the 41 NSCLC patients with extrathoracic metastasis. The sensitivity and specificity of FDG PET in prediction of metastasis of mediastinal lymph nodes in patients with lung cancer were 94.4% and 100% respectively. The accuracy of PET scanning in staging of NSCLC was 95.2% in 42 patients who underwent operation after PET imaging. 37 NSCLC patients (45.1%) were restaged after the whole-body FDG PET scanning and their treatment programs were changed. CONCLUSION: PET is more advantageous in pre-operational staging of NSCLC than other conventional imaging techniques, such as CT. For accurate positioning, PET should be combined with anatomical imaging techniques.

Adult↗
PubMed2001

Evaluation of coronary artery bypass graft patency using three-dimensional reconstruction and flow study of electron beam tomography.

OBJECTIVE: To establish and evaluate two protocols for the noninvasive visualization and assessment of coronary artery bypass graft (CABG) patency on electron beam tomography (EBT). METHODS: Two hundred and fourteen consecutive patients who underwent coronary artery bypass graft surgery were scanned using both EBT angiography with 3-dimensional reconstruction and EBT flow study with time-density-curve analysis. RESULTS: There were 589 CABGs evaluated in this study (10 grafts were excluded because of artifacts). Among them, 133 (98.5%) of 135 arterial grafts were patent, and 345 (77.7%) of 444 saphenous-vein grafts were patent. Within 5 years or between 5 and 10 years after operation, arterial graft patency exceeded venous graft patency (P < 0.001). Three-dimensional EBT angiography achieved higher sensitivity, specificity and accuracy (97.7%, 94.1% and 96.7%, respectively) than did EBT flow study (88.4%, 82.4% and 85.2%, respectively) for evaluating occlusion or patency of CABG. The intra-graft flow of patent arterial and venous grafts were 4.9 +/- 2.2 ml.min-1.g-1 and 6.9 +/- 2.8 ml.min-1.g-1, respectively (P < 0.001). CONCLUSION: The combination of EBT three-dimensional reconstruction and flow study can be more effective in the assessment of CABG anatomy and quantification of patent CABG blood flow.

Adult↗
PubMed2001

[Trends of diagnosis and management of pulmonary thromboembolism in hospitalized patients in the last fifteen years].

OBJECTIVE: To assess the accuracy of diagnosis and efficacy of management of pulmonary thromboembolism (PTE) and the related risk factors in hospitalized patients. METHODS: The clinical data of 149 inpatients with PTE admitted to Anzhen hospital from Jan 1985 to Dec 1999 were reviewed. The clinical epidemiological profile including approaches of diagnosis and treatment and prognosis in three different time intervals (1985 approximately 1989, 1990 approximately 1994, 1995 approximately 1999) were compared. RESULTS: There was a four time increases of the annual admitted PTE cases in 1995 approximately 1999 period as compared with the former two periods. Mortality fell from 42.0% to 9.0%. In the first period (1985 approximately 1989) 83.3% of patients were diagnosed based on clinical symptoms only and 4.2% on ECT, as compared with 75.0% on ECT, 15% on catheterization and only 7.8% on simply clinical symptoms in the last period (1994 approximately 1999). False or misdiagnosis rate was 57.7% in those patients on admission. Male Patients < 40yrs were significantly more than female (P < 0.05). Cardiovascular intervention operation may be an important risk factor inducing PTE. CONCLUSION: There was an increasing trend of diagnosis PTE in inpatients. Owing to the improvement of diagnosis, mortality significantly decreased in the last ten years.

Adolescent↗