Biomedical subjects

H Luo

Publications and source records attributed to H Luo.

At least 55 records · Page 3Linked to original sources

PubMed2001

The use of transducer-tipped ultrasound catheter for recanalization of thrombotic arterial occlusions.

Ultrasound energy is currently being used and intensively investigated for recanalization of thrombotically occluded arteries. The ultrasonic energy is mainly applied either by a transcutaneous approach or by a percutaneous approach through a catheter with an external ultrasound transducer. Catheter-delivered transducer-tipped ultrasound thrombolysis is a new and innovative method. In this article we summarize the current available data on the use of this new type of catheter and discuss future directions and clinical applications.

Animals↗

PubMed2001

Noninvasive transcutaneous low frequency ultrasound enhances thrombolysis in peripheral and coronary arteries.

Previous studies have shown that external ultrasound with low frequencies and high intensities can enhance thrombolytic drug-induced clot dissolution during in vitro experiments. In this series of studies, we evaluated the efficacy of peripheral and coronary thrombolysis in vivo in animals by using noninvasive transcutaneous ultrasound combined with thrombolytic drugs (streptokinase and tPA) and/or microbubbles agents (dodecafluoropentane [DDFP] and perfluorocarbon-exposed sonicated dextrose albumin [PESDA]). Thrombotic occlusions were induced in 74 rabbit iliofemoral arteries and 24 canine left anterior descending (LAD) coronary arteries in this in vivo study. By using the combination of transcutaneous ultrasound and streptokinase, the angiographic patency rate in rabbit iliofemoral arteries was higher (56%-100%) than with ultrasound (6%; P < or = 0.0036) and streptokinase alone (6%; P < or = 0.0012). Also, with transcutaneous ultrasound and microbubbles, the angiographic patency rates were 76%-100% as compared with ultrasound alone (0%, P < or = 0.0003) or microbubbles alone (9%, P < or = 0.0001). In the canine study of acute myocardial infarction, thrombolysis in myocardial infarction (TIMI) grade flow at 90 minutes in the tPA alone group was 0.92 +/- 1.4 as compared with 2.42 +/- 1.9 in the tPA plus transthoracic ultrasound group (P = 0.006). There was much improved reperfusion with tPA plus ultrasound as compared with tPA alone. In vivo animal studies demonstrate that noninvasive transcutaneous ultrasound can greatly enhance the effect of clot dissolution with thrombolytic drugs and/or microbubbles, and has the potential for clinical application as an adjunctive method to improve arterial thrombolysis.

Animals↗

PubMed2001

Identification and determination of oligomeric stilbenes in the roots of Caragana species by capillary electrophoresis.

A method based on capillary electrophoresis with electrochemical detection (CE-ED) was employed for the determination of one alkaloid (hypaphorine) and the four oligomeric stilbenes, pallidol, kobophenol A, miyabenol C and (+)-alpha-viniferin in the roots of Caragana species. The five analytes could be well separated within 12 min in a 40 cm length capillary at a separation voltage of 12 kV in a 100 mmol/L borate buffer (pH 10.0). The response was linear over about 3 orders of magnitude for all investigated analytes with detection limits (S/N = 3) ranging from 0.0385 to 0.111 mg/L. The five constituents presented in Caragana sinica can also be detected in the roots of other Caragana species, but their contents were quite different. It is demonstrated that CE-ED is a useful technique for the investigation of some electroactive constituents in plants.

China↗

PubMed2001

Aortic root dilatation in patients with emphysema.

BACKGROUND: Abdominal aortic aneurysms have been recognized to occur more frequently in patients with emphysema. However, the prevalence of aortic root dilatation in patients with emphysema and its relationship to risk factors for aortic enlargement have not been previously described. METHODS: We studied 47 patients, past smokers (aged 67 +/- 6 years, 18 women) with severe emphysema diagnosed by a pulmonary function test and an ultrafast computed tomographic scan. Two-dimensional echocardiography was used to measure the aortic root at the aortic annulus, sinus of Valsalva, sinotubular junction and proximal part of the ascending aorta. Measured mean values were compared with published normal values and age- and sex-matched patients without emphysema. The relationship between aortic root size and cardiac risk factors (hypertension, hypercholesterolemia, and diabetes) was also examined. RESULTS: In patients with emphysema the mean aortic root dimensions were significantly larger than normal values at each measured site (P <.0001) and those of patients without emphysema (P <.05 to.0001). A substantial percentage of patients with emphysema had larger sinus of Valsalva (43%) and proximal ascending aorta (59%) than the upper limit of normal. In the multivariable regression model, emphysema was a significant determinant of aortic root size at all measured sites and hypertension was associated with additional dilatation at the sinus of Valsalva, sinotubular junction, and proximal ascending aorta. CONCLUSIONS: (1) In patients with emphysema the aortic root dimension is significantly larger than in patients without emphysema. (2) Systemic hypertension is associated with additional enlargement of the proximal ascending aorta, the sinus of Valsalva, and the sinotubular junction.

Aged↗

PubMed2001

Efficiency, efficacy, and adverse effects of adenovirus vs. liposome-mediated gene therapy in cardiac allografts.

Virus- and nonvirus-mediated immunosuppressive cytokine gene therapy prolongs cardiac allograft survival in various nonfunctional heart transplant animal models, but its cardiac adverse effects have not been addressed. Recently, we developed a functional heterotopic heart transplant model in rabbits. For the first time, we were able to systematically compare the efficiency, efficacy, and adverse effects of optimized adenovirus- and liposome-mediated ex vivo interleukin (IL)-10 gene transfer in functional donor hearts. The efficiency of liposome-mediated gene transfer was greatly improved in physiologically functioning donor hearts and was only three- to fourfold lower than adenovirus-mediated gene transfer. The efficacy of liposome-mediated IL-10 gene transfer was much higher than that mediated by adenovirus. Significant negative inotropic and arrhythmogenic adverse effects on transplanted hearts were observed due to viral cytotoxicity and immunogenesis, which greatly abated the therapeutic efficacy of this first generation adenovirus-mediated gene therapy.

Adenoviridae↗

PubMed2001

Arterial thrombus dissolution in vivo using a transducer-tipped, high-frequency ultrasound catheter and local low-dose urokinase delivery.

PURPOSE: To examine the hypothesis that a transducer-tipped high-frequency ultrasound drug-delivery catheter may augment the thrombolytic effects of locally delivered low-dose urokinase and result in improved recanalization rates and reduced residual thrombotic burden. METHODS: Thrombi were induced in situ bilaterally in 5- to 6-cm-long segments of the superficial femoral arteries in 9 dogs by intraluminal thermal damage and injection of thrombin. A transducer-tipped high-frequency local drug-delivery catheter was applied at 1.1 MHz and 0.6 W for 60 minutes to one superficial femoral artery segment, and an identical catheter with an inactivated ultrasound transducer was used to treat the contralateral control segment. Urokinase (5000 IU/kg) was delivered bilaterally into the thrombi during the treatment interval. RESULTS: Angiography documented TIMI grade 2 or 3 flow in 9 (100%) segments in the ultrasound-treated group versus 6 (67%) of the controls (no ultrasound) (p = 0.058). Angiographically detected distal embolization was found in 2 ultrasound-treated segments compared with 5 controls (p = 0.02). Protruding or occlusive thrombi were seen angioscopically in 8 (89%) control segments but in only 1 (11%) of the ultrasound-treated arteries (p < 0.001). By histopathology, 7 (78%) segments in the control group had occlusive thrombi, whereas only 3 nonocclusive thrombi were found in the ultrasound-treatment group (p < 0.001). CONCLUSIONS: Catheter-delivered high-frequency ultrasound and local low-dose urokinase infusion is efficacious for the treatment of acute thrombotic occlusions as evaluated by angiography, angioscopy, and histopathology.

Animals↗

PubMed2001

Involvement of formate as an interspecies electron carrier in a syntrophic acetate-oxidizing anaerobic microorganism in coculture with methanogens.

To determine whether formate is involved in interspecies electron transfer between substrate-oxidizing bacteria and hydrogenotrophic microorganisms under anaerobic conditions, a syntrophic acetate-oxidizing bacterium Thermacetogenium phaeum strain PB was cocultured either with a formate /H2-utilizing methanogen strain TM (designated as PB/TM coculture), or an H2-utilizing methanogen strain deltaH (designated as PB/deltaH coculture). Acetate oxidation and subsequent methanogenesis in PB/TM coculture were found to be significantly faster than in PB/deltaH coculture. Formate dehydrogenase and hydrogenase were both detected in strains PB and TM. H2 partial pressures in the PB/TM coculture were kept lower (20 to 40 Pa) than those of the PB/deltaH coculture (40 to 60 Pa) during the exponential growth phase. Formate was also detected in both PB/TM and PB/deltaH cocultures, and the concentration of formate was maintained at a lower level in the PB/TM coculture (5 to 9 microM) than in the PB/deltaH coculture. Thermodynamic calculations revealed that the concentrations of both H2 and formate severely affect the syntrophic oxidation of acetate. These results strongly indicate that not only H2 but also formate may be involved in interspecies electron transfer.

Journal Article↗

PubMed2001

Inhibitory effect and mechanism of acarbose combined with gymnemic acid on maltose absorption in rat intestine.

AIM: To compare the combinative and individual effect of acarbose and gymnemic acid (GA) on maltose absorption and hydrolysis in small intestine to determine whether nutrient control in diabetic care can be improved by combination of them. METHODS: The absorption and hydrolysis of maltose were studied by cyclic perfusion of intestinal loops in situ and motility of the intestine was recorded with the intestinal ring in vitro using Wistar rats. RESULTS: The total inhibitory rate of maltose absorption was improved by the combination of GA (0.1g/L-1.0 g/L) and acarbose (0.1 mmol/L-2.0 mmol/L) throughout their effective duration (P <0.05, U test of Mann-Whitney), although the improvement only could be seen at a low dosage during the first hour. With the combination, inhibitory duration of acarbose on maltose absorption was prolonged to 3h and the inhibitory effect onset of GA was fastened to 15 min. GA suppressed the intestinal mobility with a good correlation (r = 0.98) to the inhibitory effect of GA on maltose absorption and the inhibitory effect of 2 mmol/L (high dose) acarbose on maltose hydrolysis was dual modulated by 1g/L GA in vivo indicating that the combined effects involved the functional alteration of intestinal barriers. CONCLUSION: There are augmented effects of acarbose and GA,which involve pre-cellular and paracellular barriers. Diabetic care can be improved by employing the combination.

Acarbose↗

PubMed2001

Inhibitory effect of voglibose and gymnemic acid on maltose absorption in vivo.

AIM: To determine whether diabetic care can be improved by combination of voglibose and gymnemic acid (GA), we compared the combinative and individual effects of voglibose and GA on maltose absorption in small intestine. METHODS: The small intestine 30 cm long from 2 cm caudal ward Treitz's ligament of Wistar rat was used as an in situ loop, which was randomly perfused in recircular mode with maltose (10mmol/L) with or without different dosages of voglibose and/or GA for an hour. To compare the time course, perfusion of 10 mmol/L maltose was repeated four times. Each time continued for 1 hour and separated by 30 minutes rinse. In the first time, lower dosages of GA (0.5g/L) and/or voglibose (2 micromol/L) were contained except control. RESULTS: Absorptive rate of maltose was the lowest in combinative group (P<0.05, ANOVA), for example, the inhibition rate was about 37% during the first hour when 0.5 g/L-GA and 2 micromol/L voglibose with 10 mmol/L maltose were perfused in the loop. The onset time was shortened to 30 minutes and the effective duration was prolonged to 4 hours with the combination; therefore the total amount of maltose absorption during the effective duration was inhibited more significantly than that in the individual administration (P < 0.05, U test of Mann Whitney). The effect of GA on absorptive barriers of the intestine played an important role in the combinative effects. CONCLUSION: There are augmented effects of voglibose and GA. The management of diabetes mellitus can be improved by employing the combination.

Animals↗

PubMed2001

Hepatocellular carcinoma and aflatoxin exposure in Zhuqing Village, Fusui County, People's Republic of China.

Hepatocellular carcinoma (HCC) is a common cause of cancer morbidity and mortality in Asia and Africa. Epidemiological studies have found that dietary exposure to aflatoxin B1 (AFB1) and chronic infection with hepatitis B virus are two major risk factors for HCC. We have collated the incidence and mortality data of malignant tumors from 1973 to 1999 in Zhuqing Village, Fusui County, an area with very high HCC rates, and found that this cancer accounted for 64% of the total cancer incidence. Dietary intake of AFB1 was monitored for 1 week in a study group consisting of 15 males and 14 females from different households in this village. Four of 29 participants (13.8%) and 3 of 15 (20%) male participants were hepatitis B virus surface antigen positive. AFB1 was detectable in 76.7% (23 of 30) of ground corn samples (range, 0.4-128.1 ppb), 66.7% (20 of 30) of cooking peanut oil samples (range, 0.1-52.5 ppb), and 23.3% (7 of 30) of rice samples (range, 0.3-2.0 ppb) collected from each household. Mean levels of serum AFB1-albumin adducts in this group were 1.24 +/- 0.31 pmol/mg of albumin at the beginning of the study and 1.21 +/- 0.19 pmol/mg of albumin at the end of the period. Urinary AFB1 metabolites were detectable in 88.9% (24 of 27) samples (range, 0.9-3569.7 ng/24-h urine). These data provide the exposure and disease risk information for establishing intervention studies to diminish the impact of aflatoxin exposure in this high-risk population.

Adult↗

PubMed2001

[Apoptosis in pressure overload-induced heart hypertrophy].

Pressure overload can result in heart hypertrophy, and induce apoptosis, but the phenomenon of apoptosis during the forepart of cardiomyocyte hypertrophy remains unclear. The aim of this study was to inquire into the process of cardiomyocyte apoptosis during the forepart of cardiomyocyte hypertrophy. We constructed the hypertrophy model by transverse aortic constriction of male SD rat. The apoptosis ratio was detected by TUNEL method and FCM. The result demonstrated that hypertrophy indexes increased with the time of constriction, reached the highest level at day 7, maintained that level, and then decreased at day 91. The apoptosis ratio of cardiomyocyte at day 4 was higher than that at day 0 detected by FCM method, and the ratio at day 7 was markedly lower than that at day 4. After day 28, the apoptosis ratio of cardiomyocyte went up again with the time of constriction after surgery. TUNEL method revealed that positive nuclei were observed in cardiomyocytes exclusively in the left ventricle; the apoptosis ratio increased when constriction continued. TUNEL method confirmed the result of FCM. These data indicate that cardiac hypertrophy is initiated by apoptosis of cardiomyocyte, these two factors(hypertrophy and apoptosis) maintain the balance between growth and death during the early short period of aortic constriction, and when aortic constriction goes on they are involved in the pathogenesis of heart remodeling.

Adaptation, Physiological↗

PubMed2001

[Therapeutic potential of recombinant adenovirus expressing p53 in hepatocellular carcinoma cell lines].

OBJECTIVE: To investigate the effects of the recombinant adenoviral vector Ad-p53 on the biological behavior of hepatocellular carcinoma (HCC) cells in vitro and in vivo. METHODS: With recombinant adenoviral vector expressing WT-p53 (Ad-p53), p53 gene was transfected into the HCC cell line, PLC/PRF/5. The cytotoxicities of Ad-p53 to cells were measured by MTT assay. Cell growth properties and cell cycle patterns were assessed with flow cytometry. The animal model was developed by injecting HCC cells into the dorsum of nude mice. Ad-p53 was injected intratumorally. The animals were killed, and then excised tumors were weighed and analyzed for p53 and p21 protein expression using western blot assay. RESULTS: The introduction of exogenous wild-type p53 resulted in the inhibition of cell growth, high G2/M ratio and cell apoptosis, and low S ratio in PLC/PRF/5. The expression of both p53 and p21 proteins was upregulated in the cells. CONCLUSIONS: Replication-deficient adenoviral vector expressing WT-p53 may be useful for gene therapy of HCC.

Adenoviridae↗

PubMed2001

[Resources of medicinal plants from genus Dioscorea in Guizhou province].

OBJECTIVE: To gain a clear idea on the species and distribution of medicinal plants from Dioscorea in Guizhou province. METHOD: By consulting related specimens and date and carrying out identification study. RESULT: There are 17 species (including varieties) of medicinal plants from Dioscorea in Guizhou province. The distribution, growing environment and medicinal effect of these species have been clarified, and an identification index has been established. CONCLUSION: A scientific basis can be provided by this study for exploiting the medicinal plants from Dioscorea resources in Guizhou province.

China↗

PubMed2001

[Alveolar macrophage and airway inflammation in patients with chronic obstructive pulmonary disease].

OBJECTIVE: To investigate the effects of alveolar macrophage(AM) on airway inflammation of chronic obstructive pulmonary disease(COPD). METHODS: Broncho alveolar fluid(BALF) and bronchial mucosa biopsies were performed as usual. The levels of macrophage inflammatory-1 alpha (MIP-1 alpha), gelatinase B (MMP-9), interleukin(IL)-8 in BALF and the culture supernatants of AMs were measured with ELISA. The levels of endothelin (ET) were measured with radioimmunoassay method. The AMs expressing lymphocytic functional associated antigen-1 (LFA-1) in BALF, the AMs in mucosa and the thickness of mucosa were measured with immunocytochemistry and immunohistochemistry technique. RESULTS: The levels of MIP-1 alpha, MMP-9, IL-8 and ET in the culture supernatants of AMs in patients with COPD were (1 446.9 +/- 126.7) microg/L, (16.98 +/- 5.15) microg /L, (43.98 +/- 5.54) ng/L, (168.10 +/- 21.22) microg/L respectively; while those were (1 123.5 +/- 90.6) microg/L, (5.24 +/- 0.93) microg/L, (25.99 +/- 6.05) ng/L, (124.68 +/- 9.96) microg/L in a control group. The number of macrophages in mucosa in patients with COPD was (1.71 +/- 0.48) cells/Hp, while that was (0.59 +/- 0.18) cells/Hp in the control group (0.63 +/- 0.25) x 10(4). Statistical significance was found between the two groups. The number of AMs and polymorphonuclear leucocyte in BALF were inversely correlated with forced expiratory volume in one second as percentage of predicted value(FEV(1)% Pre) (r = -0.511, P < 0.01; r = -0.562, P < 0.01). The levels of MMP-9 and ET in the culture supernatants of AMs were inversely correlated with FEV(1)% Pre(r = -0.678, P < 0.01; r = -0.871, P < 0.01). Both the level of MIP-1 alpha and the positive number of AM expressing LFA-1 in BALF were positively correlated with the number of AMs in BALF(r = 0.572, P < 0.01; r = 0.625, P < 0.01). CONCLUSION: AM may be involved in the process of airway inflammation and subsequent airway obstruction.

Adult↗

PubMed2001

[Purification of conjugated bilirubin from human urine].

OBJECTIVES: To develop a simple, practical method with fine yield and purity for separating conjugated bilirubin(Bc) from a sustainable and facile material in order that it could serve as a calibrator for total and direct bilirubin determination. METHODS: Isolating Bc from urine of patients with obstructive jaundice by CHCl3: CH3CH2OH(1:1, V/V) followed by CNBr activated Sepharose 4B-HAS affinity chromatography, we analyzed the products by the use of Doumas J-G diazo method and HPLC, respectively. RESULTS: Determined by J-G diazo method, the crude product extracted by CHCl3: CH3CH2OH(1:1, V/V) yields 90.2 +/- 5.4%(n = 3) of urine Bc, the ratio of Bc to total dry weight being 67.9 +/- 6.4%(n = 3). The final product purified by affinity chromatography with the ratio of separation of 1.5, 1.737 and analyzed by HPLC has the yield of 46.9% and purity of 94.7%(BDG of 76.2%, BMG of 18.5%). CONCLUSION: The above data demonstrate that urine conjugated bilirubin can be successfully purified by CHCl3: CH3CH2OH extraction followed by Sephrose-HSA affinity chromatography with sufficient purity and output.

Bilirubin↗

PubMed2001

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

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

Birth Weight↗

PubMed2001

[Purification and characterization of 2-carbonyl reductase from marine bacteria Bacillus sp].

ANADPH-dependent 2-Oxoaldehyde reductase was isolated and purified from a marine bacteria Bacillus sp. The purification procedure involved ammonium sulfate fractionation and Q Sepharose FF, Hydroxyapatite, Sephadex G-100 column chromatographies. The specific activity of the purified enzyme was increased by 141.1 folds over crude extract and the recovery yield was 11.4%. 2-Oxoaldehyde compounds were found to be speciall good substrates. The optimum pH of the enzyme activity was 6.2-6.6. The Km coefficient for 3-deoxyglucosone was 2.5 mmol/L. The molecular weight of the enzyme was estimated to be 33 kD The enzyme activity is stable below 30 degrees C and pH 5.0-8.0. EDTA, beta-mercaptoethanol and dithiothreitol enhanced the enzyme activity. On the other hand, the enzyme activity was partially lost by idoacetic acid or N-ethylmaleimide.

Alcohol Oxidoreductases↗

PubMed2001

[Clinical observation on sensorineural hearing loss secondary to secretory otitis media].

OBJECTIVE: To study whether secretory otitis media causes sensorineural deafness or not, especially in stubborn cases. METHODS: The 0.5 kHz, 1 kHz, 2 kHz, 4 kHz BC stimuli were administered to 164 patients with secretory otitis media, and their BC loss calculated. As a control, BC threshold was also recorded in the contralateral ear of 66 unilaterally deaf patients. RESULTS: BC threshold was raised in 94 out of 164 patients (57.3%). There was no statistically significant difference between bilaterally and unilaterally deaf groups. All patients had similar BC hearing loss in the same frequency, but had different BC hearing loss in different frequencies and the most serious loss was in 4 kHz. CONCLUSION: The rate of sensorineural deafness caused by secretory otitis media is higher than expected. Frequency and intensity of hearing loss between unilaterally and bilaterally deaf patients with secretory otitis media were no different. All ears had different hearing loss in different frequencies, but the most serious hearing loss was in high frequency and it had the tendency to spread to the speech frequency.

Adolescent↗