Biomedical subjects

Z Gao

Publications and source records attributed to Z Gao.

At least 37 records · Page 2Linked to original sources

PubMed2001

A study on the prevention and treatment of myopia with nacre on chicks.

The contents of mineral elements and amino acids in the hydrolysate of the traditional Chinese mineral medicine nacre have been determined. It has long since been proved by the practice of doctors of traditional Chinese medicine that pearl can be used to treat eye diseases. Based on such an understanding, a study is made of the influence of the said medicine on the incidence of myopia. First a form-sense-deprived model (FDM) for chicks is developed and the effect of the said medicine on the elongation of axis oculi is determined with an Abbe's comparator and an A-mode ultrasound instrument. The activity of superoxide dismutase (SOD), nitric oxide synthetase (NOS), and the content of nitric oxide (NO) in the retino-pigmental epithelium choroid homogenate are also analysed. The role of the said traditional Chinese mineral medicine in preventing and treating myopia is explained with respect to the above findings. The results obtained will provide a basis for using nacre, a traditional Chinese mineral medicine, to prevent and treat myopia.

Amino Acids↗

PubMed2001

Human CD34+ cell preparations contain over 100-fold greater NOD/SCID mouse engrafting capacity than do CD34- cell preparations.

OBJECTIVE: The CD34 cell surface marker is used widely for stem/progenitor cell isolation. Since several recent studies reported that CD34(-) cells also have in vivo engrafting capacity, we quantitatively compared the engraftment potential of CD34(+) vs CD34(-) cell preparations from normal human placental/umbilical cord blood (CB), bone marrow (BM), and mobilized peripheral blood (PBSC) specimens, using the nonobese diabetic/severe combined immunodeficient (NOD/SCID) mouse model. METHODS: CD34(+) and CD34(-) cell preparations were purified by four different approaches in 14 individual experiments involving 293 transplanted NOD/SCID mice. In most experiments, CD34(+) cells were depleted twice (CD34(=)) in order to obtain efficient depletion of CD34(+) cells from the CD34(-) cell preparations. RESULTS: Dose-dependent levels of human hematopoietic cells were observed after transplantation of CD34(+) cell preparations. To rigorously assess the complementary CD34(-) cell preparations, cell doses 10- to 1000-fold higher than the minimum dose of the CD34(+) cell preparations necessary for engraftment were transplanted. Nevertheless, of 125 NOD/SCID mice transplanted with CD34(-) cell preparations purified from the same starting cells, only six mice had detectable human hematopoiesis, by flow cytometric or PCR assay. CONCLUSIONS: CD34(-) cells provide only a minor contribution to hematopoietic engraftment in this in vivo model system, as compared to CD34(+) cells from the same samples of noncultured human cells. Hematopoiesis derived from actual CD34(-) cells is difficult to distinguish from that due to CD34(+) cells potentially contaminating the preparations.

Animals↗

PubMed2001

Influence of bromide on electrochemistry of photosynthetic reaction center films on gold electrodes.

A strong influence of bromide ion was found on voltammetry of layered films of photosynthetic reaction center (RC) protein and polyions on gold electrodes. Similar, but not identical, cyclic voltammetry peaks were observed for polyion films on gold with and without RC when the buffer solutions contained bromide ion. CVs of RC films were quite different in the absence of bromide. These new findings suggest that previously published results were biased by significant background peaks involving bromide ion adsorption/desorption.

Bromides↗

PubMed2001

Uncertainty in sample mass for small numbers of particles from granular materials.

The standard deviation of sample mass was quantitatively related to the number of particles in the sample, individual particle masses and the fractions of the numbers of different types of particles in the mixture. The theory was verified by sampling of cereal grain mixtures with a spinning riffler and Monte Carlo computer simulation. The theory is applicable to random sampling of well-mixed populations containing two or more types of particles.

Journal Article↗

PubMed2001

Uncertainty in analyte mass for samples containing small numbers of particles.

A sampling equation was derived that relates the standard deviation in analyte mass to the number of particles in the sample, the fractions of the different types of particles in the mixture and the masses and analyte concentrations of the individual particles. The equation, which is applicable to samples containing any number of particles, was verified by sampling and analysis of two cereal grain mixtures for manganese, potassium, chlorine and magnesium, and by Monte Carlo computer simulation. Comparison of the sampling precision of analyte mass with the analytical measurement precision was also studied, and it was shown that use of the equation allows the calculation of the minimum number of particles required to hold the sampling relative standard deviation to that of the analytical measurement.

Journal Article↗

PubMed2001

A novel method for beat-to-beat detection of ventricular late potentials.

A novel method for beat-to-beat detection of ventricular late potentials (VLP) from high-resolution electrocardiograms (ECGs) is presented. ECG signals from the X lead are first filtered using a bandpass filter, and then a time-sequence adaptive filter, to improve its signal-to-noise ratio. Eight features are extracted using wavelet transform, from the VLP time-frequency distribution of the filtered ECG signals, and used as inputs of specially designed artificial neural network for VLP recognition. The artificial neural network was trained and tested using clinical data, respectively. The results show that the presented method can detect beat-to-beat-based VLP with sensitivity of 80% and specificity of 77%, and the detection accuracy is 78%.

Action Potentials↗

PubMed2001

A3 adenosine receptor activation triggers phosphorylation of protein kinase B and protects rat basophilic leukemia 2H3 mast cells from apoptosis.

Adenosine accumulates to high levels in inflamed or ischemic tissues and activates A3 adenosine receptors (ARs) on mast cells to trigger degranulation. Here we show that stimulation of rat basophilic leukemia (RBL)-2H3 mast-like cells with the A3 AR agonists N6-(3-iodo)benzyl-5'-N-methylcarboxamidodoadenosine (IB-MECA; 10 nM) or inosine (10 microM) stimulates phosphorylation of protein kinase B (Akt). IB-MECA (1 microM) also causes a >50% reduction in apoptosis caused by exposure of RBL-2H3 cells to UV light. Akt phosphorylation is not stimulated by 100 nM N6-cyclopentyladenosine (A1-selective) or CGS21680 (A2A-selective) and is absent in cells pretreated with wortmannin or pertussis toxin. The KI values of the AR antagonists BW-1433 and 8-sulfophenyltheophylline (8-SPT) were determined in radioligand binding assays for all four subtypes of rat ARs: BW-1433 (A1, 5.8 +/- 1.0 nM; A2A, 240 +/- 37; A2B, 30 +/- 10; A3, 12,300 +/- 3, 700); 8-SPT (A1, 3.2 +/- 1.2 microM; A2A, 57 +/- 4; A2), 2.2 +/- 0.8; A3, >100). BW-1433 and the A3-selective antagonist MRS1523 (5 microM), but not 8-SPT (100 microM), block IB-MECA-induced protection from apoptosis, confirming the A3 AR as the mediator of the antiapoptotic response. The data suggest that adenosine and inosine activate Gi-coupled A3 ARs to protect mast cells from apoptosis by a pathway involving the betagamma subunits of Gi, phosphatidylinositol 3-kinase beta, and Akt. We speculate that activation of A3 ARs on mast cells or other cells that express A3 ARs (e.g., eosinophils) may facilitate their survival and accumulation in inflamed tissues.

Adenosine↗

PubMed2001

Up-regulation by IGF-I of proliferating cell nuclear antigen and Bcl-2 protein expression in human uterine leiomyoma cells.

IGF-I has been reported to play a role in regulating proliferation of human leiomyoma cells. There is, however, little evidence to suggest that IGF-I inhibits apoptosis in the leiomyoma cells. The present study was conducted to elucidate whether IGF-I affects apoptosis and Bcl-2 protein expression, an apoptosis-inhibiting gene product, in cultured leiomyoma cells. In addition, we examined the effect of IGF-I on proliferating cell nuclear antigen (PCNA) expression in cultured leiomyoma cells. Isolated human leiomyoma cells were subcultured in phenol red-free DMEM supplemented with 10% FBS for 120 h and then stepped down to serum-free conditions for an additional 72 h in the absence or presence of graded concentrations of IGF-I (1.0, 10, and 100 ng/ml). The effects of IGF-I on Bcl-2 protein and PCNA expression in cultured leiomyoma cells were assessed by Western immunoblot analysis and immunocytochemical staining, whereas the effects of IGF-I on the cell viability and apoptosis of the cultured cells were determined by 3-(4,5-dimethylatriazol-2-yl)-2,5diphenyltetrasodium bromide (MTT) assay and terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling assay, respectively. Immunocytochemical staining demonstrated that IGF-I treatment resulted in the increase in PCNA labeling index in cultured leiomyoma cells in a dose-dependent manner. Immunoblot analysis of proteins extracted from the cultured leiomyoma cells revealed that the addition of IGF-I (10 and 100 ng/ml) significantly increased the expression of 35-kDa immunoreactive PCNA and 26-kDa Bcl-2 protein, compared with those in control cultures. Cell survival and proliferation of cultured leiomyoma cells, assessed by MTT assay, was significantly augmented by IGF-I treatment, compared with those of control cultures. Terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling assay showed that the apoptosis-positive rate of leiomyoma cells treated with IGF-I was significantly decreased, compared with that in control cultures. The present results suggest that IGF-I plays crucial roles in leiomyoma cell growth, not only in promoting the proliferative potential by up-regulation of PCNA expression but also in down-regulating apoptosis by up-regulation of Bcl-2 protein expression in leiomyoma cells.

Adult↗

PubMed2001

High levels of transgene expression following transduction of long-term NOD/SCID-repopulating human cells with a modified lentiviral vector.

Both oncoretroviral and lentiviral vectors have been shown to transduce CD34(+) human hematopoietic stem cells (HSC) capable of establishing human hematopoiesis in nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice that support partially human hematopoiesis. We and others have reported that murine stem cell virus (MSCV)-based oncoretroviral vectors efficiently transduced HSC that had been cultured ex vivo for 4-7 days with cytokines, resulting in transgene expression in lymphoid and myeloid progenies of SCID-engrafting cells 4-8 weeks post-transplantation. Although lentiviral vectors have been demonstrated to transduce HSC under minimal ex vivo culture conditions, concerns exist regarding the level of transgene expression mediated by these vectors. We therefore evaluated a novel hybrid lentiviral vector (GIN-MU3), in which the U3 region of the HIV-1 long terminal repeat was replaced by the MSCV U3 region (MU3). Human cord blood CD34(+) cells were transduced with vesicular stomatitis virus G envelope protein-pseudotyped lentiviruses during a 48-hour culture period. After a total of 4 days in culture, transduced cells were transplanted into NOD/SCID mice to examine gene transfer and expression in engrafting human cells. Fifteen weeks post-transplantation, 37% +/- 12% of engrafted human cells expressed the green fluorescence protein (GFP) gene introduced by the lentiviral vector. High levels of GFP expression were observed in lymphoid, myeloid and erythroid progenies, and in engrafted human cells that retained the CD34(+) phenotype 15 weeks post-transplantation. This study provides evidence that lentiviral vectors transduced both short-term and long-term engrafting human cells, and mediated persistent transgene expression at high levels in multiple lineages of hematopoietic cells.

Animals↗

PubMed2001

Keratinocyte growth factor expression in human gingival fibroblasts and stimulation of in vitro gene expression by retinoic acid.

BACKGROUND: Keratinocyte growth factor (KGF) is a stromally derived growth factor of the fibroblast growth factor (FGF) family with paracrine effects targeted to influence the growth and differentiation of epithelia. Regional and temporal changes in KGF expression play important roles in the development and maintenance of epithelial structures and in epithelial wound healing. Differing patterns of expression of KGF by fibroblasts in the gingival region could therefore be related to the observed regional variation in the differentiation and behavior of gingival epithelia. METHODS: The in vitro and in vivo patterns of expression of KGF mRNA in human gingival and periodontal fibroblasts were examined using reverse transcription polymerase chain reactions (RT-PCR) and in situ hybridization with digoxigenin-labeled riboprobes. The patterns observed for human gingiva were compared with those for human skin and for murine tissues. RESULTS: Gingival and periodontal fibroblasts showed expression of KGF transcripts in vitro, and the degree of expression was markedly influenced by the presence of retinoic acid, an agent known to influence patterns of epithelial differentiation. Sections of human and murine gingiva and skin showed regionally variable expression of transcripts with the cells expressing KGF in the subepithelial, rather than the deeper, connective tissues and periodontium. CONCLUSIONS: The results point to a role of KGF in the maintenance of normal growth and differentiation of gingival epithelia. A lack of KGF expression by periodontal fibroblasts in vivo is expected to hinder apical epithelial migration and thus stabilize the epithelial attachment. The effects of retinoic acid (RA) on KGF expression in vitro provide an indirect mechanism by which RA may regulate the growth and differentiation of gingival epithelia.

Animals↗

PubMed2001

[Pests on zingiberaceous plants and their control in south China].

The pests on the zingiberaceous plants and their occurrence and damage as well as control have been investigated in the ginger plantation of South China Botanical Garden recently. 12 insect pests and 1 mite pest are common. To control them effectively, such as selecting loose, fertile soil as planting field with proper shade, applying healthy and vigorous seeds, seedling and rhizomes for propagation, regulating plant density, sanitizing the field in time are mostly recommended. The application of chemical and biological pesticides and the protection on the beneficial organisms are also stressed.

China↗

PubMed2001

Novel short-acting A2A adenosine receptor agonists for coronary vasodilation: inverse relationship between affinity and duration of action of A2A agonists.

Several potent and selective A2A adenosine receptor agonists are currently available. These compounds have a high affinity for the A2A receptor and a long duration of action. However, in situations where a short duration of action is desired, currently available A2A receptor agonists are less than ideal. From a series of recently synthesized A2A receptor agonists, two agonists (CVT-3146 and CVT-3033) with low affinity were selected for further characterization as selective and short-acting coronary vasodilators. Both compounds were selective for the A2A adenosine receptor (AdoR) versus the A1, A2B, and A3AdoR in binding and functional studies. CVT-3146 and CVT-3033 appeared to be weak partial agonists to cause cAMP accumulation in PC12 cells, but were full and potent agonists to cause coronary vasodilation, a response that has a very large A2A receptor reserve. However, the durations of action of CVT-3146 and CVT-3033 were remarkably shorter than those of the high-affinity agonists CGS21680 or WRC0470, presumably due to the relative lower affinity of CVT-3146 and CVT-3033 for the A2A receptor. Indeed, an inverse relationship was found between the affinity of the various agonists for the A2A receptor and the duration of their actions. These data indicate that low-affinity agonists can produce a response that is of equivalent magnitude but more rapid in termination than that caused by a high-affinity agonist. Hence, the low-affinity A2A agonists CVT-3146 and CVT-3033 may prove to be superior to currently available high-affinity agonists as coronary vasodilators during myocardial imaging with radionuclide agents.

Adenosine↗

PubMed2001

[Accurate diagnosis of stages of hepatic fibrosis by measuring levels of serum hyaluronic acid, procollagen type III, and collagen type IV].

OBJECTIVE: To study the accurate diagnosis of various stages of hepatic fibrosis by measuring serum hyaluronic acid (HA), procollagen type III (PC III), and collagen type IV (CIV). METHODS: The concentrations of serum HA, PC III, CIV in 253 patients with chronic liver disease were measured by radioimmunoassay. Liver biopsies were performed in all of the patients at the same time. According to the results of liver pathological diagnosis, we assessed the ability of serum HA, PC III and CIV to identify correctly patients with hepatic fibrosis (staging >or=S(2)) or cirrhosis (S(4)). RESULTS: The cutoff value of HA, PC III and C IV to identify correctly patients with hepatic fibrosis was 90 microg/L, 90 microg/L, 75 microg/L respectively. The sensitivity (Se) was 80.4%, 82%, 63.1%; the specificity (Spe) was 70.2%, 60.8%, 83.8%; the positive prediction value (PPV) was 86.7%, 83.5%, 90.4%; the negative prediction value (NPV) was 59.8%, 58.4%, 48.4%, respectively. The cutoff value to identify patients with cirrhosis was: HA 210 microg/L, Se 96.2%, Spe 85.3%, PPV 65.4%, NPV 98.8%; PC III 150 microg/L, Se 76.4%, Spe 68.7%, PPV 40.4%, NPV 91.3%; C IV 90 microg/L, Se 80%, Spe 75.8%, PPV 47.8%, NPV 93.2%, respectively. CONCLUSIONS: The determination of serum HA, PC III and C IV can make relatively accurate diagnosis to various stages of hepatic fibrosis. HA is the best for diagnosis of liver cirrhosis.

Biopsy↗

PubMed2001

[Observation on the effect of disinfection to HBsAg by electrolyzed oxidizing water].

OBJECTIVE: Observation on the effect of disinfection on gastroscope, contaminated by hepatitis B surface antigen (HBsAg) in the electrolyzed oxidizing water (EOW). METHODS: Contaminated gastric juice and serum was added to EOW for 1 minute. Positive control samples were treated with PBS instead of EOW in the same way. Gastroscopes used for hepatitis patients were immersed in the EOW for 1 minute after cleaning. Samples were collected before and after treatment. ELISA was used to test HBsAg. RESULTS: With mixed samples (average S/N = 42.16) of EOW, HBsAg became negative when diluted in 100 times. However, the HBsAg of positive control samples remained positive. After cleaning the gastroscope (average S/N = 5.99) immersed in EOW, HBsAg became negative. CONCLUSION: EOW was effective in destroying HBsAg which could be used for gastroscope disinfection.

Disinfection↗

PubMed2001

[Surgical treatment of congenital nuclear cataract].

OBJECTIVE: To study the characteristics of congenital nuclear cataract and evaluate the therapeutic effects of extracapsular cataract extraction (ECCE) with or without intraocular lens (IOL) implantation in different age groups. METHOD: ECCE with or without IOL implantation was performed on 76 eyes of 38 cases with congenital nuclear cataract in different age groups. Under operative microscope, the characteristics of the opacity of the posterior capsule were described. The visual acuity and possible complications were followed up for a mean period of 6 months. RESULTS: The opacity of the posterior capsule was progressively developing, its diameter was similar to that of the opaque nucleus. The difference of the post-operative corrected visual acuity in different age groups was significant (chi(2) = 27.84, P < 0.005). The rates of the secondary cataract were negatively correlated to the age groups (r = -0.969 2, P < 0.05). In 2 eyes, slight iris capture occurred in 3 - 12 year group. CONCLUSIONS: Congenital nuclear cataract can combine with posterior capsular cataract. The etiology remains to be studied. The therapeutic effects of the congenital nuclear cataract mainly depend on the time of operation. The early treatment of post-operative complications in children is of primary importance.

Adolescent↗

PubMed2001

[The influence of recombinant human growth hormone on the metabolism of glucose and protein in severely burned patients].

OBJECTIVE: To investigate the influence of recombinant human growth hormone (rhGH) on the metabolism of glucose and protein in severely burned patients. METHODS: The serum levels of total protein and albumin and the incidence of hyperglycemia in 24 cases of severely burned patients treated by rhGH were determined and compared with those in patients without rhGH treatment (control group). RESULTS: The serum levels of total protein (TP) and albumin in burned patients after being treated by rhGH were much higher than those before treatment and those in control group. The blood level of glucose increased within 2 weeks, especially 1 week postburn. The incidences of hyperglycemia were 52.38%, 50.24% and 20% on 0 similar 3, 4 similar 7 and 8 similar 14 postburn days (PBDs), respectively. And the incidences of hyperglycemia were 100%, 50% and 0% when the administration of rhGH started within 1, 2 and after 2 weeks respectively. CONCLUSION: The systemic protein synthesis in severely burned patients could be accelerated by the use of rhGH. But early administration of rhGH in burned patients could affect blood sugar level obviously. And the optimal time to give rhGH is 2 weeks after burn injury.

Adult↗

PubMed2001

[Vasonatrin peptide attenuates hypoxia-induced increase in [Ca(2+)] (i) of culured rat cardiac fibroblasts].

The purpose of this work was to test the hypothesis that vasonatrin peptide (VNP) can attenuate the growth-promoting effect by hypoxia in cardiac fibroblasts of cultured neonatal rats. Cultured fibroblasts were divided into four groups: control group, hypoxia group, VNP group and VNP+hypoxia group. The growth of cardiac fibroblasts was observed using MTT method and the incorporation of (3)H-TdR, and the effect of VNP on the intracellular level of Ca(2+) was measured by means of interactive laser cytometry. It was found that hypoxia (2% - 3%) increased significantly the MTT optical density (OD) of cardiac fibroblasts (P<0.05 vs control group), but the increase was greatly attenuated in the VNP (10(- 6)mol/L) group and also the incorporation of (3)H-TdR in cardiac fibroblasts (P<0.05 vs hypoxia group). VNP (10(- 6)mol/L) also decreased the intracellular level of Ca(2+) which was increased by hypoxia (P<0.05) as compared with control and hypoxia group. These findings demonstrate that VNP can attenuate the hypoxia-induced growth-promoting effect in cardiac fibroblasts, which may be associated with the elevation of intracellular Ca(2+).

Animals↗

PubMed2001

[Effect of total flavones of Hippophae rhamnoides L. on sympathetic activity in hypertension].

OBJECTIVE: To investigate the effect of total flavones of hippophae rhamnoides L (TFH) on sympathetic nerve activity of essential hypertensive patients and to determine whether TFH possesses inhibitory effect on sympathetic activity after supine isometric exercise. METHODS: Heart rate, blood pressure and plasma catecholamines of the patients were measured before and after treatment. 88 patients were randomly divided into TFH group (n = 35), calcium antagonist nifedipine (n = 33) and verapamil ER (n = 20) group. RESULTS: It was shown after 8 weeks of treatment that TFH did not alter the rest heart rate and plasma catecholamine concentration in the patients (P > 0.05). In contrast, nifedipine produced an increase of noradrenaline and adrenaline level(P < 0.01). Isometric exercise may significantly increase the heart rate, blood pressure and plasma catecholamine concentration in hypertensive patients. In TFH group, exercise did not increase the heart rate, blood pressure and plasma catecholamine concentration after treatment. In nifedipine group, however, the same isometric exercise significantly increased the heart rate, blood pressure and noradrenaline concentration after treatment (P < 0.01). In verapamil group, the plasma catecholamine concentration did not change after treatment, but it was significantly increased after isometric exercise. CONCLUSIONS: The results suggest that TFH does not alter the sympathetic activity in treatment of hypertension and the inhibitory effect of TFH on sympathetic activity after supine isometric exercise may provide clinical benefits.

Aged↗