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Biomedical subjects

R Gao

Publications and source records attributed to R Gao.

At least 37 records · Page 2Linked to original sources
PubMed2001

"Hybrid" revascularization: video-thoracoscopy assisted MIDCAB combined with angioplasty.

A "hybrid" revascularization technique has been developed for cases in which a chronic total occlusion of the left anterior descending coronary artery (LAD) cannot be recanalized by percutaneous coronary intervention, but the lesions in the right coronary artery and/or left circumflex artery are very good candidates for angioplasty. This technique, which uses video-thoracoscopy assisted minimally invasive direct coronary artery bypass to recanalize the occluded LAD and angioplasty to dilate favorable lesions in other vessels, would achieve complete revascularization in selected patients with multi-vessel disease. In this preliminary study of four patients, angioplasty and stenting were successful in all patients without any complications; complete revascularization was achieved in all 4 patients. No recurrence of angina and no cardiovascular events developed during follow-up; this study therefore supports the belief that the "hybrid" revascularization technique is both feasible and safe.

Adult↗
PubMed2001

[Tracing algorithms of ECG tracks from scanned image].

This paper presents a discussion on the tracing algorithms of the extraction of Electrocardiogram (ECG) data from scanned image of hardcopy ECG. We have advanced a new algorithm integrated by seek-and-predict method and polygon model method, which can tolerate crossing of two leads, fault-line and disturbing of grid lines. Two practical situations that may be encountered while processing hardcopy ECG are discussed in detail. Furthermore, the after-treatment of extraction-filtering is considered and an SVD-based filter designed to smooth ECG signal is analyzed.

Algorithms↗
PubMed2001

Clinical outcome of patients with previous myocardial infarction and left ventricular dysfunction assessed with myocardial (99m)Tc-MIBI SPECT and (18)F-FDG PET.

UNLABELLED: Myocardial viability was assessed by (99m)Tc-methoxyisobutylisonitrile (MIBI) SPECT and (18)F-FDG PET to evaluate the prognosis and treatment strategy of patients with myocardial infarction (MI) and left ventricular (LV) dysfunction. METHODS: One hundred twenty-three consecutive patients with previous MI and LV dysfunction (LV ejection fraction [EF], 35% +/- 6% [mean +/- SD]) who underwent (99m)Tc-MIBI SPECT and FDG PET were followed-up for 26 +/- 10 mo (mean +/- SD). Distributions of the 2 radiotracers in myocardial segments were classified into 2 patterns: myocardial perfusion-metabolism mismatch (MM) and match (M). LV EF and LV end-diastolic diameter (EDD) were measured by echocardiography at baseline, 3 mo (Pos1), and 6 mo (Pos2) after revascularization. Cardiac death, acute MI, unstable angina, and late revascularization (>3 mo) experienced by the patients during follow-up were defined as cardiac events. RESULTS: Sixty-seven patients underwent revascularization and 56 patients were treated medically. Of the 72 patients with > or =2 MM segments, 42 underwent revascularization (group A1) and 30 were treated medically (group A2). Of the 51 patients with <2 MM segments, 25 underwent revascularization (group B1) and 26 were treated medically (group B2). The 4 groups had similar baseline characteristics and rest LV EF. After revascularization, EF (mean +/- SD) increased in group A1 from 36% +/- 5% to 44% +/- 8% (P < 0.0001) in Pos1 and to 51% +/- 9% (P < 0.0001) in Pos2. EDD (mean +/- SD) decreased from 62 +/- 8 mm to 56 +/- 5 mm (P < 0.001) in Pos1 and to 55 +/- 5 mm (P < 0.001) in Pos2. However, EF and EDD were unchanged in group B1 (P > 0.05). During the follow-up, 22 patients (17.9%) suffered from cardiac events, including 11 cardiac deaths, 4 acute MI, 6 late coronary artery bypass grafting, and 1 unstable angina pectoris. The cardiac event rate in group A2 (50%) was significantly higher than that of groups A1 (2.4%; chi(2) = 23.08; P < 0.0001), B1 (12%; chi(2) = 8.94; P = 0.003), and B2 (11.5%; chi(2) = 9.45; P = 0.002). CONCLUSION: Assessment of myocardial viability using hybrid (99m)Tc-MIBI SPECT and FDG PET can predict the clinical outcome and is helpful to decision making in the treatment strategy of patients with MI and LV dysfunction. Revascularization can improve the LV function and clinical outcome of patients with >2 viable myocardial segments.

Aged↗
PubMed2001

Intravascular local gene transfer mediated by protein-coated metallic stent.

OBJECTIVE: To assess the feasibility, efficiency and selectivity of adenovirus-mediated gene transfer to local arterial wall by protein-coated metallic stent. METHODS: A replication-defective recombinant adenovirus carrying the Lac Z reporter gene for nuclear-specific beta-galactosidase (Ad-beta gal) was used in this study. The coating for metallic stent was made by immersing it in a gelatin solution containing crosslinker. The coated stents were mounted on a 4.0 or 3.0 mm percutaneous transluminal coronary angioplasty (PTCA) balloon and submersed into a high-titer Ad-beta gal viral stock (2 x 10(10) pfu/ml) for 3 min, and then implanted into the carotid arteries in 4 mini-swines and into the left anterior descending branch of the coronary artery in 2 mini-swines via 8F large lumen guiding catheters. The animals were sacrificed 7 (n = 4), 14 (n = 1) and 21 (n = 1) days after implantation, respectively. The beta-galactosidase expression was assessed by X-gal staining. RESULTS: The results showed that the expression of transgene was detected in all animal. In 1 of carotid artery with an intact intima, the beta-gal expression was limited to endothelial cells. In vessels with denuded endothelium, gene expression was found in the sub-intima, media and adventitia. The transfection efficiency of medial smooth muscle cells was 38.6%. In 2 animals sacrificed 7 days after transfection, a microscopic examination of X-gal-stained samples did not show evidence of transfection in remote organs and arterial segments adjacent to the treated arterial site. CONCLUSIONS: Adenovirus-mediated arterial gene transfer to endothelial, smooth muscle cells and adventitia by protein-coated metallic stent is feasible. The transfection efficiency is higher. The coated stent may act as a good carrier of adenovirus-mediated gene transfer and have a potential to prevent restenosis following PTCA.

Adenoviridae↗
PubMed2001

[Stroke related knowledge, attitude and behavior of Chinese health professionals].

OBJECTIVE: To understand the knowledge, attitude and behavior (KAB) of Chinese health professionals and the affected factors in stroke. METHODS: 1722 anticipated participants were selected by stratified-random sampling, actual participants were 1609. Out of these participants, 1,537 were eligible for analysis. The data were gathered through self-administrated questionnaire. RESULTS: More than 70% of the health professionals selected the correct answers to some questions, but only 25.7% realized that cerebral arteriosclerosis is the most important cause of ischemic stroke. 57.8% and 48.1% of the health professionals suggested and helped patients to reduce weight and restrict salt, respectively; but only 28.0% suggested and helped patients to do physical exercise in non-acute phase. Analyses of multiple linear regression showed that health professionals' education, title, specialty and training in prevention and control of cardiovascular disease as well as the cardiovascular disease history of patients' family members were positively, significantly and independently related to KAB score. CONCLUSION: Health professionals' KAB score about stroke was low on average, health promotion is the access to improvement of health professionals' KAB level.

China↗
PubMed2001

[Glaucoma seton implantation surgery via different pathways for complicated glaucoma].

OBJECTIVE: To evaluate the effectiveness of glaucoma seton implantation surgeries via three different pathways for complicated glaucoma. METHODS: Ninety-nine cases (99 eyes) with complicated glaucoma having undergone glaucoma seton implantation surgeries were divided into three groups. Fifty-eight cases were included (58 eyes) in the group with anterior chamber implantation (AC group), 16 cases (16 eyes) were in the group with posterior chamber implantation (PC group) and 25 cases (25 eyes) were in the group with vitreous cavity implantation (VC group). RESULTS: The follow-up ranged from 6 to 34 months (mean 19.6 months). In the AC group, the postoperative intraocular pressure (IOP) of 40 cases (69.0%) was < 21 mm Hg (1 mm Hg = 0.133 kPa) without using any pressure-lowering agents. The postoperative IOP of 6 cases (10.3%) was < 21 mm Hg with pressure-lowering agents. Patients with IOP controlled < 21 mm Hg were altogether 46 cases (79.3%). The IOP of 11 cases (68.8%) in the PC group was controlled without agents and another 1 case (6.2%) was controlled with medications. Therefore, the total success rate was 75.0% (12 cases). The corresponding rates for the VC group were 10 cases (40.0%), 3 cases (12.0%) and 13 cases (52.0%) respectively. Statistical significant difference (chi 2 = 6.525, P = 0.038) was found in the success rates among these 3 groups. But if we excluded cases with neovascular glaucoma, no statistical difference (chi 2 = 4.231, P = 0.121) was found of the success rates among these 3 groups. CONCLUSION: No influence on surgical effectiveness was found among glaucoma seton implantation surgeries via different pathways for complicated glaucoma.

Adult↗
PubMed2001

[Vitreous surgery for proliferative maculopathy].

OBJECTIVE: To explore the indication of vitrectomy for the treatment of pre-macular proliferative disease, the surgical technique, results and the prevention and treatment of complications. METHODS: Forty-one eyes of 41 cases with different kinds of macular traction or macular pucker, including 12 cases of idiopathic epimacular membrane, 10 cases of macular hole complicated with epimacular membrane and 19 cases of macular pucker after reattachment surgery (no diabetic retinopathy or retinal detachment) were treated with vitreous surgery. The issue of this operation is to find out underlying fissures (an under-bridge) or weakly adherent sites between a membrane and the retina. Using flute-needle, intraocular pick, spade and vitreoretinal forceps, we can separate and peel the proliferative membrane and the posterior cortical vitreous from the retinal surface completely. RESULTS: In 41 cases, epimacular membrane was peeled successfully, and the normal anatomic structure of the macula was restored. Four cases had small amount of hemorrhage in the superficial layer of the retina in and after the operation, and all the other cases did not have any complications, such as retinal tear or detachment. Thirty-eight cases obtained higher visual acuity, and in 3 cases the visual acuity maintained at their pre-operative level. Metamorphopsia was significantly improved, even disappeared. The follow-up period was 3 months to 4 years. CONCLUSIONS: The therapeutic effects of vitreous surgery for treatment of various kinds of proliferative maculopathy are reliable. After the surgery, the visual acuity can be elevated, the symptoms can be ameliorated and the complications can be effectively controlled.

Adult↗
PubMed2001

[The combination of cyclosporin A and androgen in the treatment of chronic aplastic anemia].

OBJECTIVE: To explore the therapeutic effectiveness of combination of cyclosporin A (CsA) and androgen in the treatment of chronic aplastic anemia (CAA). METHOD: Androgen alone or combined with CsA for the treatment of CAA was compared by a randomized controlled clinical trial. RESULT: The efficacy of androgen combined with CsA (87.9%) was higher than that of androgen alone (57.1%). Therapeutic effectiveness of the combination treatment between the patients with positive and negative peripheral blood mononuclear cells (PBMNCs) inhibiting normal colony formation unit-granulocyte and macrophage (CFU-GM) test showed a significant difference (P < 0.005). CONCLUSION: Androgen combined with CsA had a much better efficacy than that of androgen alone in the treatment of CAA. The patients' PBMNCs inhibiting normal CFU-GM growth test can be used as an index of the treatment outcome. The side effects of the combination therapy are low and tolerable.

Adolescent↗
PubMed2001

[Comparative effects of carvedilol, losartan and their combination in preventing left ventricular remodeling after acute myocardial infarction in rats].

OBJECTIVE: To compare the effects of carvedilol, losartan and their combination in preventing from left ventricular remodeling (LVRM) after acute myocardial infarction(AMI) in rats. METHODS: Twenty-four hours after ligating left coronary artery, 100 surviving AMI female SD rats were randomly assigned to: (1) AMI control (n = 25), (2) carvedilol (1 mg x kg(-1) x d(-1)) (C1) (n = 25); (3) losartan (3 mg x kg(-1) x d(-1)) (L3)(n = 25); and (4) carvedilol (1 mg x kg(-1) x d(-1)) + losartan (3 mg x kg(-1) x d(-1)) (C1 + L3) (n = 25) groups. Sham-operated group (n = 17) were selected randomly as non-infarction control. After 4 weeks of therapy with the drugs by gastric gavage, hemodynamic studies were performed, then the rat hearts were fixed and pathologically analyzed. Exclusive of the rats with MI size < 35% or > 55%, complete data were obtained in 65 rats, which were comprised of AMI control (n = 13), C1 (n = 12), L3 (n = 13), C1 + L3 (n = 14) and sham-operated (n = 13) groups. RESULTS: There were no significant differences in MI size among the four AMI groups (45.8% - 46.7%, P > 0.05) . Compared with sham-operated group, Left ventricular (LV) end diastolic pressure (LVEDP), volume (LVV), weight (LVW), septal thickness (STh) and right ventricular weight (RVW) were all significantly increased (all P < 0.01 ) in AMI group, while the left ventricular pressure maximal rate of rise and fall (dp/dt) were significantly decreased (all P < 0.01). In comparison with AMI group, LVEDP, LVV, LVW, STh and RVW were all significantly decreased (all P < 0.01), while +/- dp/dt and +/- dp/dt/LVSP were significantly increased (P < 0.05 - 0.01) in all three therapy groups, with LVEDP decreasing more in the combination and L3 groups than in C1 group (P < 0.05 - 0.01) and STh decreasing more in the combination group than in C1 group (P < 0.01), but there were no significant differences in other variables among the three therapy groups. CONCLUSION: Carvedilol, losartan and their combination all can prevent from LVRM after AMI in rats, improve hemodynamics and LV function, with the combination superior.

Adrenergic beta-Antagonists↗
PubMed2000

Nanomechanics of individual carbon nanotubes from pyrolytically grown arrays.

The bending modulus of individual carbon nanotubes from aligned arrays grown by pyrolysis was measured by in situ electromechanical resonance in transmission electron microscopy (TEM). The bending modulus of nanotubes with point defects was approximately 30 GPa and that of nanotubes with volume defect was 2-3 GPa. The time-decay constant of nanotube resonance in a vacuum of 10(-4) Torr was approximately 85 micros. A femtogram nanobalance was demonstrated based on nanotube resonance; it has the potential for measuring the mass of chain-structured large molecules. The in situ TEM provides a powerful approach towards nanomechanics of fiberlike nanomaterials with well-characterized defect structures.

Journal Article↗
PubMed2000

Serological and histological findings in infection and transmission of GBV-C/HGV to macaques.

Seven healthy macaques were inoculated with the GBV-C/HGV-RNA serum from a non-A-E hepatitis patient. The serology and pathology of the liver in the animals were observed. The results indicated that all inoculated animals were infected with a GBV-C/HGV-RNA viremia and had mildly abnormal alanine transaminase levels during the infectious period. The histology, immuno-histochemistry, and in situ hybridization in the liver tissues of the inoculated animals also showed that there was a very mild hepatitis with the positive antigenic expression and the genome of GBV-C/HGV-NS5 in hepatocytes. The pathological changes in the infected animals appeared to become normal whether or not GBV-C/HGV-RNA viremia persisted. There is a possibility that the mild virulence of the GBV-C/HGV to the host became harmless with time after inoculation. Infection and the transmission of the GBV-C/HGV virus in the macaques provides an appropriate animal model and new information about GBV-C/HGV infection in both humans and animals. It is possible that this virus is a mild and self-limited pathogenic agent to the hepatic cells of primates.

Alanine Transaminase↗
PubMed2000

Evaluation of electron beam tomographic coronary arteriography with three-dimensional reconstruction in healthy subjects.

In this study, the authors evaluated the performance characteristics of contrast-enhanced electron-beam tomography (EBT) with three-dimensional reconstruction in defining the coronary artery lumen in healthy subjects. Thirty patients with normal coronary angiograms by selective coronary arteriography (SCA) underwent contrast-enhanced EBT examination. Measured parameters included degree of luminal enhancement, intravascular contrast-to-noise ratio (CNR), and diameter and length of visualized lumen. Ventricular cavity, aortic blood pool, and coronary artery attenuation were found to be significantly different before and after intravenous injection of contrast material (p < 0.001). CNR decreased from proximal to distal segments within each vessel (p < 0.001), with a peak of 11.2 +/- 2.3 occurring in the proximal left anterior descending coronary artery (LAD) to a low of 4.8 +/- 2.0 in the distal left circumflex (LCX). Luminal diameters visualized by EBT had no significant difference with that of SCA (p > 0.05). Therefore, EBT angiography with three-dimensional reconstruction allows for noninvasive coronary arteriography revealing long segments of the major coronary arteries in normal subjects.

Adult↗
PubMed2000

Detection and analysis of intracoronary artery stent after PTCA using contrast-enhanced three-dimensional electron beam tomography.

We evaluated several three-dimensional methods of contrast-enhanced electron beam tomography (EBT) for evaluation of intracoronary stent characteristics after percutaneous transluminal coronary angioplasty (PTCA). Twenty-six patients who had undergone PTCA and stenting (31 stents) were investigated by using contrast-enhanced, electrocardiographically (ECG) triggered EBT scanning. EBT results were compared with conventional selective coronary arteriography (SCA). Overall, 27 intracoronary stents had been identified on EBT images (87.1%), while 4 stents could not be evaluated because of impaired image quality. EBT correctly identified the only case in which there was a residual stenosis at the distal portion of the stent. As compared with SCA results, EBT showed an over-estimation of intracoronary stent diameter (p < 0.001) and accurate measurement on the visualized length of the stents (p > 0.05). Fifty Hu, 100 Hu and 150 Hu were used as the observed window levels on three-dimensional (3-D) images; the accuracy for stent assessment increased with ascending window levels. EBT can reliably characterize coronary artery stents and may become a useful non-invasiveive method for patency evaluation of stented coronary segments after PTCA.

Adult↗
PubMed2000

[The application of polymerase chain reaction-single strain conformation polymorphism in the pedigree analysis of familial hypercholerolemia patients].

OBJECTIVE: To discuss the value of polymerase chain reaction-single strand conformation polymorphism(PCR-SSCP) in the pedigree analysis of familial hypercholesterolemia(FH) patients. METHODS: For 4 patients with FH detected by PCR-SSCP and DNA sequence analysis (1 homozygote has point mutation in exon 7, 1 heterozygote in exon 14, and 2 heterozygotes in 3' part of exon 4 ), members of each pedigree, altogether 23 individuals, were analysed using PCR-SSCP. RESULTS: Every member of the 4 pedigrees was examined genetically. Besides the 4 probands, another 1 homozygote and 8 heterozygotes were found. CONCLUSION: The PCR-SSCP method can be used in the pedigree analysis of FH probands. The early diagnosis of siblings and relatives can help to provide genetic consultation and direction so as to pay attention to development of hypercholesterolemia.

Adolescent↗
PubMed2000

Platelet-derived growth factor and basic fibroblast growth factor immunolocalized in proliferative retinal diseases.

OBJECTIVE: To study the role of platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF) in the development of proliferative vitreoretinopathy (PVR). METHODS: Immunohistochemical localization was performed on frozen sections of the epiretinal or subretinal membranes from 21 PVR patients using! monoclonal antibodies against PDGF and bFGF and the streptavidin peroxidase system. RESULTS: PDGF was expressed in 15 of 21 specimens (71.4%), and bFGF was expressed in 14 specimens (66.7%). Different cell density was seen in different types of epiretinal membranes. The cell density of vascular membranes induced by PDR and Eales disease was the highest (> or = 61 cells/field, x 1000); nonvascular membranes induced by PVR or traumatic PVR had moderate cell density (31-60 cells/field); and the macular membrane had the lowest cell density (< or = 30 cells/field). CONCLUSION: The presents of PDGF and bFGF in PVR tissues suggest that PDGF and bFGF may play an important role in the development of PVR.

Epiretinal Membrane↗
PubMed2000

Aristolochic acid I-induced apoptosis in LLC-PK1 cells and amelioration of the apoptotic damage by calcium antagonist.

OBJECTIVE: To examine the effect of different concentrations of aristolochic acid I (AAI) in inducing apoptosis of cultured porcine renal cell line LLC-PK1 and to investigate the relationship between intracellular free calcium concentration ([Ca++]i) and LLC-PK1 apoptosis induced by AAI and the influence of a calcium antagonist, lacidipine on apoptosis and [Ca++]i. METHODS: LLC-PK1 cells were treated in different groups: a. the normal group without treatment; b. the group with AAl alone (0.01 g.L-1, 0.02 g.L-1, 0.04 g.L-1, 0.08 g.L-1); c. the group with lacidipine alone (10 ng.L-1, 10(2) ng.L-1, 10(3) ng.L-1); d. the group with AAI (0.04 g.L-1) plus lacidipine (10 ng.L-1, 10(2) ng.L-1, 10(3) ng.L-1). Light microscopy, agarose gel electrophoresis, Annexin-V-Flous apoptosis detection kit and flow cytometry using propidium iodide staining to identify or quantify the apoptosis of LLC-PK1 cells. Mean [Ca++]i was measured by laser confocus microscopy using Fluo-3/AM staining. RESULTS: A series of morphologic changes that were characteristic of apoptosis, Annexin-V-Flous staining positive apoptotic cells and "DNA ladder" were identified in AAI (0.02 g.L-1-0.08 g.L-1) treated LLC-PK1 cells. Quantitative analysis of apoptotic cells showed that the percentage of apoptotic cells in AAI (0.02 g.L-1, 0.04 g.L-1 or 0.08 g.L-1) group was significantly higher than that in normal group (5.3%, 48.5%, 78.7% vs 2.6%, P < 0.001). Mean [Ca++]i was significantly higher in cells treated with AAI (0.04 g.L-1) than that in normal cells (58.01 +/- 18.89 vs 22.66 +/- 4.78, P < 0.001). In group treated with AAI plus lacidipine (102 ng.L-1, 103 ng.L-1), mean [Ca++]i was significantly lower than that treated with AAI alone (35.47 +/- 12.85, 28.55 +/- 10.16 vs 58.01 +/- 18.89, P < 0.001). And the percentage of apoptotic cells in group treated with AAI plus lacidipine (10(2) ng.L-1, 10(3) ng.L-1) was also significantly lower than that treated with AAI alone (19.0%, 27.8% vs 34.7%, P < 0.001). CONCLUSIONS: High concentrations of AAI may induce apoptosis of LLC-PK1 cells. The mean [Ca++]i in AAI-treated LLC-PK1 cells was increased significantly, suggesting that the increase of [Ca++]i may be related to apoptosis in LLC-PK1 cells. Lacidipine may decrease the raised mean [Ca++]i levels caused by AAI and the percentage of apoptotic cells, and lacidipine may ameliorate AAI-induced apoptotic damage by inhibiting the increase of [Ca++]i in LLC-PK1 cells.

Animals↗