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Biomedical subjects

H Y Zhao

Publications and source records attributed to H Y Zhao.

At least 19 recordsLinked to original sources
PubMed2006

Six cases of ectopic ACTH syndrome caused by thymic carcinoid.

The ectopic ACTH syndrome (EAS) caused by thymic carcinoid is rare and its diagnosis remains a challenge to the endocrinologist. Here are six cases of EAS with a typical Cushing habitus accompanied by hyperpigmentation and hypokalemia. For all six patients, the high dose (8 mg) dexamethasone suppression test (HDDST) showed lack of suppression, computed tomography (CT) scanning documented anterior mediastinal masses, and the mediastenal tumors removed were confirmed as ACTH secreting thymic carcinoids by positive ACTH and NSE staining. Our data indicate that HDDST chest radiologic imaging and other laboratory examinations will greatly assist in diagnosing the thymic carcinoid-induced EAS at an earlier stage, which will significantly improve the long-term survival of the patient.

ACTH Syndrome, Ectopic↗
PubMed2004

Relationships between the changes of serum levels of OPG and RANKL with age, menopause, bone biochemical markers and bone mineral density in Chinese women aged 20-75.

The correlations between the serum levels of OPG, RANKL with age, menopause, bone markers, and bone mineral densities (BMDs) at the lumbar spine and proximal femur were studied in 504 pre- and postmenopausal Chinese women aged 20-75 years. We found that age was positively and negatively correlated with serum concentrations of OPG (r = 0.442, P < 0.001) and RANKL (r = -0.263, P < 0.001), respectively. Compared with premenopausal women, postmenopausal women showed higher serum OPG levels (107.6 +/- 3.0 vs 72.0 +/- 1.8 pg/ml, P < 0.001), lower serum RANKL concentrations (4.7 +/- 0.4 vs. 5.8 +/- 0.3 pg/ml, P < 0.001) and RANKL/OPG ratios (0.045 +/- 0. 004 vs. 0.099 +/- 0.008, P < 0.001). Neither serum levels of OPG nor RANKL or RANKL/OPG ratio correlated with BMDs after adjustment of age and menopause. They also showed no differences among normal, osteopenic and osteoporotic postmenopausal women. Serum levels of OPG were positively correlated with urinary excretion of NTx (r = 0.1453, P = 0.006). Serum levels of RANKL (r = -0.1928, P < 0.001) and RANKL/OPG ratio (r = -0.1303, P = 0.013) were inversely correlated with serum concentrations of OC. In multiple regression analysis, up to 20% variance (R(2) = 0.106-0.224) of the OPG-RANKL system in peripheral circulation can be explained by age, menopause and bone markers. These results suggest that although serum OPG and RANKL concentrations were unrelated with BMDs, the age- and menopause- dependent changes of serum OPG and RANKL might be a protective mechanism against the accelerated bone loss in postmenopausal women.

Adult↗
PubMed2002

Effect of electroporation and iontophoresis on skin permeation of Defibrase--a purified thrombin-like enzyme from the venom of Agkistrodon halys ussuriensis Emelianov.

The purpose of this study was to investigate electroporation and iontophoresis as a means for in vitro delivery of Defibrase--a thrombin-like enzyme (TLE) from Agkistrodon halys ussuriensis Emelianov snake venom--through human epidermis membrane (HEM). Electroporation was carried out using an exponential decay pulse generator (BioR-ad Genepulser, USA) for a period of 0.5 h, followed by a period of 5.5 h passive diffusion or iontophoresis. The results indicated that the combined use of electroporation and anodal iontophoresis in pH 6.4 permeation medium could effectively enhance the skin permeation of Defibrase, whose apparent permeability coefficient was 1.6 +/- 0.8 x 10(-4) cm.h-1. The delivery of Defibrase by the combined use of electroporation and anodal iontophoresis was more effective than by electroporation alone (P < 0.01) or by the combined use of electroporation and cathodal iontophoresis (P < 0.01). Moreover, when the pH of the permeation medium was raised from 6.4 to 7.4 the permeation of Defibrase caused by a combined use of electroporation and anodal iontophoresis showed a tendency to increase. These results implied that electroosmotic flow effect might be important for the iontophoretic (following electroporation) skin permeation of Defibrase.

Batroxobin↗
PubMed2001

Direct interaction of Arabidopsis cryptochromes with COP1 in light control development.

Arabidopsis seedling photomorphogenesis involves two antagonistically acting components, COP1 and HY5. COP1 specifically targets HY5 for degradation via the 26S proteasome in the dark through their direct physical interaction. Little is known regarding how light signals perceived by photoreceptors are transduced to regulate COP1. Arabidopsis has two related cryptochromes (cry1 and cry2) mediating various blue/ultraviolet-A light responses. Here we show that both photoactivated cryptochromes repress COP1 activity through a direct protein-protein contact and that this direct regulation is primarily responsible for the cryptochrome-mediated blue light regulation of seedling photomorphogenic development and genome expression profile.

Arabidopsis↗
PubMed2000

Transmission/disequilibrium tests for quantitative traits.

The transmission/disequilibrium test (TDT) is a powerful method of locating disease genes. The TDT was originally proposed for use in studies of qualitative traits in families with both parents available. Recently, the TDT has been extended to studies of qualitative traits in sibships without parents available and in families with one parent available. It has also been extended for use in studies of quantitative traits in families with both parents available and in sibships with multiple offspring. In this paper, we first propose a new class of TDT-type tests for linkage in the presence of linkage disequilibrium for use in studies of families with both parents available. The TDT of Spielman et al. (1993) for qualitative traits and the TDT of Rabinowitz (1997) for quantitative traits are special cases of the new tests. Second, we propose a new class of TDT-type tests for linkage for use in studies of families with one parent available. Third, we study the validity and the power of the tests using simulations. Finally, we propose a method of combining data from different types of families. The combined test is valuable and allows researchers full use of the available data in detecting linkage between a marker locus and an unobservable quantitative trait locus. An important feature of the tests proposed in this paper is that no assumptions on the distribution of the quantitative traits are needed.

Computer Simulation↗
PubMed1998

Treatment of carcinoma of the hard palate with gamma knife radiosurgery.

The Gamma Knife radiosurgical treatment of two patients suffering from carcinomas of the hard palate is reported. A 67-year-old woman was treated with partial resection of an adenocarcinoma of the hard palate two years previously. Computerized tomographic imaging showed the tumor had grown (T4N1M0). The second patient, a 58-year-old woman, had a cauliflower-like tumor of the hard palate (T2N0M0). Pathological diagnosis obtained by needle biopsy was squamous cell carcinoma. These two patients underwent radiosurgical treatment with the Gamma Knife. A surface dose of 20 Gy was administered at the 35% isodose curve. These two patients were followed up for 18 and 15 months, respectively. Encouraging results were obtained. Further research is needed in order to validate this new treatment of carcinomas of the hard palate.

Adenocarcinoma↗
PubMed1998

Hepatitis G virus infection in screened Chinese blood donors.

BACKGROUND AND OBJECTIVES: To determine the prevalence of the recently identified hepatitis G virus (HGV)/GBV-C in screened Chinese paid blood donors. MATERIALS AND METHODS: Two hundred and seventy-nine plasma samples were tested for HGV RNA by RT-PCR with nested primers from the 5'-noncoding region of GBV-C. All samples were obtained from plasma or blood bags that had been screened twice by routine selection tests (ALT, HBsAg, Anti-HCV, anti-HIV, and syphilis) and were available for clinical use. RESULTS: HGV RNA was detected in 2 (4%) of 50 paid plasma donors from the Beijing Red Cross Blood Center, 1 (2%) of 50 paid blood donors from Taiyuan, and 9 (5%) of 179 paid blood donors from Hebei, a total HGV detection rate of 4.3% (12/279). CONCLUSIONS: Our data suggest that HGV infection is relatively frequent even in screened donors, at least in paid screened donors, although larger-scale studies are required.

Blood Donors↗
PubMed1997

[Effects of Andrographis paniculata component on nitric oxide, endothelin and lipid peroxidation in experimental atherosclerotic rabbits].

OBJECTIVE: To observe the effects of Andrographis Paniculata component (API0134) on nitric oxide (NO), endothelin (ET), cyclic guanosine monophosphate (cGMP), lipid peroxide (LPO) and superoxide dismutase (SOD) in experimental atherosclerotic rabbit. METHODS: An atherosclerotic rabbit model was established by feeding high cholesterol diet supplemented by bovine serum albumin injection bolus. The rabbits were randomly divided into the control, model, and API0134 treated group. Blood samples were collected before 4 weeks and 8 weeks after relevent treatment. RESULTS: Before 4 and after 8 weeks API0134 administration, compared with model group, the NO, cGMP and activity of SOD increased (P < 0.01), while LPO and ET decreased (P < 0.01). CONCLUSIONS: API0134 possesses the effects of antioxidation, preserving endothelial function, and maintaining the balance of NO/ET.

Animals↗
PubMed1996

Susceptibility locus for inflammatory bowel disease on chromosome 16 has a role in Crohn's disease, but not in ulcerative colitis.

In the Western world, chronic inflammatory bowel disease (IBD) presents as two major clinical forms, Crohn's disease (CD) and ulcerative colitis (UC) [Targan, S.R. and Shanahan, F. (1994). In Retford, D.C (ed.), Inflammatory Bowel Disease: From Bench to Bedside. Williams and Wilkins, Baltimore]. Genetic epidemiological studies, the occurrence of rare syndromes associated with IBD, and animal models suggest that inherited factors play significant roles in the susceptibility to both forms of IBD [Yang, H.-Y. and Rotter, J.I. (1995) In Kirsner, J.B. and Shorter, R.G. (eds). Genetic Aspects of Idiopathic Inflammatory Bowel Disease. Williams and Wilkins, Baltimore, pp.301-331]. Recently, a genome-wide search on European families with multiple affected members with CD identified a putative susceptibility locus in the centromeric region of chromosome 16 [Hugot, J.-P. et al. (1996) Nature, 379, 821-823]. We have now tested this region in an independent set of US families, confirmed that this region is likely to contain a gene predisposing to CD, and further refined the chromosomal location of this gene. Most importantly with respect to this locus, our data also seem to indicate that there is heterogeneity both within the CD group, and between the CD and UC groups with respect to this locus. The susceptibility locus appears to be involved only in non-Jewish CD sibpairs and not in our Ashkenazi Jewish CD sibpairs. Additionally, we have tested sibpairs having either only UC or both UC and CD for involvement of this locus, and have found no evidence that this region predisposes to IBD in these patients.

Chromosome Mapping↗
PubMed1996

Effect of captopril on proliferation of aortic smooth muscle cells.

AIM: To study the effect of captopril (Cap) on proliferation of smooth muscle cells (SMC). METHODS: Proliferation of cultured porcine aortic SMC was promoted by hyperlipidemic sera (HLS). RESULTS: Cap (0.2 mg.L-1) remarkably reduced [3H]thymidine ([3H]TdR) incorporation, inhibited DNA synthesis and proliferation of SMC, and lessened morphological changes caused by HLS. After administration of Cap, malondialdehyde (MDA) content and plasminogen activator inhibitor (PAI) activity were reduced, 6-keto-PGF1 alpha and cAMP contents were obviously increased (P < 0.05-0.01). CONCLUSION: Cap inhibited the proliferation of SMC, associated with MDA, PAI, 6-keto-PGF1 alpha and cAMP.

6-Ketoprostaglandin F1 alpha↗
PubMed1995

Effect of radiofrequency catheter ablation on calcium channel of ventricular myocytes.

Using whole-cell patch-clamp technique, the effect of radiofrequency catheter ablation (RFCA) on calcium current (Ica) of guinea pig ventricular myocytes was examined. The radiofrequency energy delivered was 20 W x 10 s. RF-CA decreased Ica apparently with the affected area reaching up to 1.2 cm from the ablation focus. In the meanwhile, the pathological lesion size resulted from RFCA was merely 0.41 +/- 0.11 cm. These findings indicate that RFCA, apart from causing tissue necrosis by heat, can affect myocyte membrane currents in a large area. This may explain why RFCA has a very high success rate with a small pathological lesion.

Animals↗
PubMed1995

A comparative study of radiofrequency ablation in unipolar and bipolar fashion.

In this study we compared the effects of radiofrequency (RF) energy applied to the swine endocardium in a unipolar fashion and in a bipolar one with two different interelectrode distances (5 mm, 10 mm). RF energy (500 kHz) delivered to the swine endocardium was divided into eight categories: 100 J, 101-200 J, 201-300 J, 301-400 J, 401-500 J, 501-600 J, 601-1000 J, and > 1000 J. The results showed that when RF energy was applied in a bipolar fashion, the lesions involved the catheter/tissue interface and partly the interelectrode spacing, while in a unipolar fashion. They were found in the catheter/tissue interface only. At any energy level, there were no statistically significant differences in lesion depths among all the three fashions, and the lesion surface areas produced by the bipolar fashion (with 5 mm or 10 mm interelectrode spacing) were all greater than those by the unipolar fashion (P < 0.05). When the delivered energy was under 500 joules, a greater lesion surface area was found in 5 mm bipolar fashion than in 10mm bipolar fashion (P < 0.05), while energy exceeded 500 joules, the differences in the lesion surface areas were no longer significant between these two bipolar fashions.

Animals↗
PubMed1995

Experimental studies on preventive effects of API0134 on vessel reocclusion after thrombolysis.

24 model rabbits with femoral arterial thrombosis were divided into two groups: the treatment group consisting of 12 rabbits which received API0134, and the control group composed of another 12 rabbits. 2 hours after recanalization by urokinase thrombolysis, reocclusion occurred only in 1/12 vessel (8%) with incomplete occlusion in the treated group, but in 8/12 (67%) with complete occlusion in the control group as assessed by angiograsphy. Pathological examination of specimen taken 24 hours after thrombolysis showed that 6/12 (50%) of the treated group gave the evidence of thrombus occlusion, and milder intimal injury and less adhered blood cells than in the control group, 83% of which had thrombus occlusion. In comparision with the control group, the function of platelet in the treated group demonstrated lower platelet aggregation rate (PAgR) and plasma thromboxane A2 (TXA2) level, higher prostacyclin (PGI2) and plasminogen activator (PA) activity as well as lower plasminogen activator inhibitor (PAI) activity. From the above it may be concluded that the preventive effect of API0134 on reocclusion might be due to inhibition of platelets aggregation and promotion of fibrinolysis.

6-Ketoprostaglandin F1 alpha↗
PubMed1995

An experimental study of the mechanism of andrographis paniculata nees (APN) in alleviating the Ca(2+)-overloading in the process of myocardial ischemic reperfusion.

The aim of this experiment is to study the mechanism of APN in alleviating the Ca(2+)-overloading in dog model during the process of ischemic reperfusion. In comparison with the sustained ischemic group, the parameters in the ischemic reperfusion group demonstrated: Ca(2+) of ischemic region of myocardial cell increased (P < 0.05), Na+ increased remarkably (P < 0.01), the activity of Ca(2+)-ATPase dropped remarkably (P < 0.01), and MDA increased significantly (P < 0.01). Whereas in the group pretreated with APN, the Ca(2+) in the relevant area reduced (P < 0.05), Na+ decreased significantly (P < 0.01), the activity of Ca(2+)-ATPase and Na+-K+ ATPase increased remarkably (P < 0.01), and MDA decreased significantly (P < 0.01). These findings indicate tha APN may improve the activity of sarcolemma ATPase in alleviating the Ca(2+) and Na+ -overloading by decreasing the harmful effect of oxygen free radicals.

Animals↗
PubMed1995

Effect of captopril on antithrombus function of endothelium.

The experimental models of cultured porcine aortic endothelial cells (EC) in vitro were established. 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), thromboxane B2(TXB2)content, plasminogen activator (PA), plasminogen activator inhibitor (PAI) activity in cultured medium and cyclic adenosine monophosphate (cAMP) level in EC were measured with radioimmunoassay (RIA), chromogenic substrates methods, in order to assess the effect and mechanism of captopril (CP) on antithrombus function of EC. The results showed that after administration of CP, the contents of 6-keto-PGF1 alpha and cAMP and PA activity were significantly higher, PAI activity were remarkably lower than those of control group. These effects were dose-dependent. Our finding indicated that CP might act as a prospective drug for antithrombosis through promoting anticoagulation and fibrinolysis function and increasing antithrombus action of EC.

6-Ketoprostaglandin F1 alpha↗
PubMed1994

Effects of amrinone on cardiac contraction and relaxation in isolated, perfused rat heart.

The effects of amrinone on cardiac contraction and relaxation were assessed in isolated, perfused rat hearts. It was found that the left ventricular developed pressure (LVDP), dp/dtmax and -da/dtmax did not significantly increase, and the time constant (tau) did not markedly shorten with perfusion of low concentration (1 nmol/L, 100 nmol/L) of amrinone. The perfusion with higher concentration (1000 nmol/L) of amrinone reduced LVDP (P < 0.01), dp/dtmax (P < 0.01), -dp/dtmax (P < 0.01), and prolonged tau (P < 0.05) significantly. It was assumed that amrinone has no direct positive inotropic effect, and can not improve cardiac relaxation. On the contrary, the cardiac contraction and relaxation will be inhibited at higher concentration of amrinone.

Amrinone↗
PubMed1994

The effect of andrographis paniculata nees (APN) in alleviating the myocardial ischemic reperfusion injury.

In experimental dogs, the effect of APN in alleviating the ischemia-reperfusion injury was prominent. Compared with the sustained ischemia group, superoxide dismutase (SOD) in the ischemic region of myocardial tissue in the ischemia-reperfusion group was significantly decreased and malondialdehyde (MDA) markedly increased: Ca2+ in myocardial cells was increased; and ultrastructural changes of myocardial tissues were severe. In the APN-pretreated ischemia-reperfusion group, on the contrary, all the above parameters showed reversely, i.e., SOD increased, MDA and intracellular Ca2+ decreased, the ultrastructure changes were less distorted.

Animals↗