Biomedical subjects

Y Zou

Publications and source records attributed to Y Zou.

At least 55 records · Page 3Linked to original sources

PubMed2001

Growth hormone signalling and apoptosis in neonatal rat cardiomyocytes.

Growth hormone (GH) has been reported to be useful to treat heart failure. To elucidate whether GH has direct beneficial effects on the heart, we examined effects of GH on oxidative stress-induced apoptosis in cardiac myocytes. TUNEL staining and DNA ladder analysis revealed that hydrogen peroxide (H2O2)-induced apoptosis of cardiomyocytes was significantly suppressed by the pretreatment with GH. GH strongly activated extracellular signal-regulated kinases (ERKs) in cardiac myocytes and the cardioprotective effect of GH was abolished by inhibition of ERKs. Overexpression of dominant negative mutant Ras suppressed GH-stimulated ERK activation. Overexpression of Csk that inactivates Src family tyrosine kinases also inhibited ERK activation evoked by GH. A broad-spectrum inhibitor of protein tyrosine kinases (PTKs), genistein, strongly suppressed GH-induced ERK activation and the cardioprotective effect of GH against apoptotic cell death. GH induced tyrosine phosphorylation of EGF receptor and JAK2 in cardiac myocytes, and an EGF receptor inhibitor tyrphostin AG1478 and a JAK2 inhibitor tyrphostin B42 completely inhibited GH-induced ERK activation. Tyrphostin B42 also suppressed the phosphorylation of EGF receptor stimulated by GH. These findings suggest that GH has a direct protective effect on cardiac myocytes against apoptosis and that the effect of GH is attributed at least in part to the activation of ERKs through Ras and PTKs including JAK2, Src, and EGF receptor tyrosine kinase.

Animals↗

PubMed2001

HER-2/neu induces p53 ubiquitination via Akt-mediated MDM2 phosphorylation.

HER-2/neu amplification or overexpression can make cancer cells resistant to apoptosis and promotes their growth. p53 is crucial in regulating cell growth and apoptosis, and is often mutated or deleted in many types of tumour. Moreover, many tumours with a wild-type gene for p53 do not have normal p53 function, suggesting that some oncogenic signals suppress the function of p53. In this study, we show that HER-2/neu-mediated resistance to DNA-damaging agents requires the activation of Akt, which enhances MDM2-mediated ubiquitination and degradation of p53. Akt physically associates with MDM2 and phosphorylates it at Ser166 and Ser186. Phosphorylation of MDM2 enhances its nuclear localization and its interaction with p300, and inhibits its interaction with p19ARF, thus increasing p53 degradation. Our study indicates that blocking the Akt pathway mediated by HER-2/neu would increase the cytotoxic effect of DNA-damaging drugs in tumour cells with wild-type p53.

3T3 Cells↗

PubMed2001

A virtual instrument for acquisition and analysis of the phonocardiogram and its internet-based application.

The objective of this study is to develop a phonocardiogram (PCG) acquisition and analysis instrument using virtual instrumentation technology and investigate its Internet-based application. The PCG instrument was developed using a Pentium 200 computer, a data acquisition board, and a two-channel custom designed bio-signal preamplifier. LabVIEW was used to create the instrument's front panels. Spectral and joint time-frequency analyses were implemented into the instrument. This instrument can be used to display the PCG and to analyze the individual heart sound and murmur for the detection of heart valve diseases. Using a test-bed, the PCG data acquisition and analysis were performed remotely over the Internet. Through the main PCG panel, an operator can control the acquisition and analysis of PCG signals. In the remote test, real-time transmission of the PCG signal over the Internet was possible. Remote operators were able to view smoothly scrolling PCG waveforms and could control all the acquisition parameters and perform spectral and time-frequency analyses on the acquired heart sound. This study demonstrated that a LabVIEW-based medical virtual instrument provides a low-cost and flexible solution for data acquisition and analysis of PCG. It also showed that the current Internet supports the transmission of real-time PCG signals. Compared with other telemedicine systems, this application transfers not only the medical data, but also the virtual instrument and its signal processing capability through the Internet.

Heart Valve Diseases↗

PubMed2001

Telomerase and cancer.

Telomerase, a eukaryotic ribonucleoprotein (RNP) complex, contains both an essential RNA and a protein reverse transcriptase subunit. By reverse transcription, the telomerase RNP maintains telomere length stability in almost all cancer cells. Over the past few years there has been significant progress in identifying the components of the telomerase holoenzyme complex and the proteins that associate with telomeres, in order to elucidate mechanisms of telomere length regulation. This review covers recent advances in the field including the use of telomerase in cancer diagnostics and an overview of anti-telomerase cancer therapeutic approaches.

Animals↗

PubMed2001

Local gene transfer of tissue inhibitor of metalloproteinase-2 influences vein graft remodeling in a mouse model.

Recently, we established a new mouse model of vein graft arteriosclerosis by grafting vena cava to carotid arteries. In many respects, the morphological features of this murine vascular graft model resemble those of human venous bypass graft disease. Using this model, we studied the effects of local gene transfer of tissue inhibitor of metalloproteinase-2 (TIMP-2) on vein graft remodeling. Mouse isogeneic vessels of the vena caval veins were grafted end to end into carotid arteries, then enveloped with the replication-defective recombinant adenoviruses overexpressing human TIMP-2 (RAdTIMP-2) or beta-galactosidase (RAdLacZ) at 1x10(10) plaque-forming units/mL in a total volume of 50 microL, and incubated at room temperature for 20 minutes. In the untreated group, vessel wall thickening was observed as early as 1 week after surgery and progressed to 4- to 10-fold the original thickness in grafted veins at 4 and 8 weeks, respectively. RAdLacZ vector treatment significantly enhanced neointimal lesions at 8 weeks, which was completely blocked by RAdTIMP-2 gene overexpression. Interestingly, RAdTIMP-2 gene transfer resulted in a reduction in vessel diameter of grafted veins compared with ungrafted veins (819+/-96 versus 624+/-67 microm, respectively; P<0.05). Maximal beta-galactosidase activity was found at 2 weeks and was detectable until 4 weeks after gene transfer. Double immunofluorescence studies demonstrated that cells overexpressing TIMP-2 were mostly localized in the adventitia and were MAC-1-positive monocytes/macrophages but not smooth muscle cells. Furthermore, the activity of matrix metalloproteinases was markedly decreased in the vessel walls treated with RAdTIMP-2 compared with that in the untreated control group and the RAdLacZ-treated group. Thus, this mouse model has been proven to be useful in gene transfer studies. Our findings demonstrate that local TIMP-2 gene transfer significantly reduces vein graft diameter, ie, remodeling to an artery-like vessel via inhibition of matrix metalloproteinase activity.

Adenoviridae↗

PubMed2001

Headless flies generated by developmental pathway interference.

Ectopic expression of transcription factors in eye-antennal discs of Drosophila strongly interferes with their developmental program. Early ectopic expression in embryonic discs interferes with the developmental pathway primed by Eyeless and generates headless flies, which suggests that Eyeless is necessary for initiating cell proliferation and development of both the eye and antennal disc. Interference occurs through a block in the cell cycle that for some ectopic transcription factors is overcome by D-CycE or D-Myc. Late ectopic expression in cone cell precursors interferes with their differentiation. We propose that this developmental pathway interference is a general surveillance mechanism that eliminates most aberrations in the genetic program during development and evolution, and thus seriously restricts the pathways that evolution may take.

Animals↗

PubMed2001

Effectiveness of water soluble poly(L-glutamic acid)-camptothecin conjugate against resistant human lung cancer xenografted in nude mice.

A camptothecin (CPT) formulation that can be easily administered, is less toxic, and has greater antitumor effect is needed. In this study, a water-soluble CPT derivative was obtained by direct coupling of CPT to poly(L-glutamic acid) (PG) through the C20(S)-hydroxyl group. CPT was released from the resulting conjugate, PG-CPT, in phosphate-buffered saline with a zero-order kinetics in the initial 50 days. The release rates were 0.623% per day, 1.081% per day, and 1.396% per day at pH 5.3, 7.4, and 9.0, respectively. In vitro, PG-CPT was less potent in inhibiting cell growth than was free CPT in all human tumor cell lines tested. However, PG-CPT showed better antitumor activity and tolerability than did CPT in vivo. When H322 human lung tumor cells were inoculated subcutaneously in nude mice, PG-CPT delayed the growth of these well-established tumors with an absolute growth delay of 32 days when given as 4 doses with 4-day intervals between injections at an equivalent CPT dose of 40 mg/kg. When H322 cells were inoculated intratracheally in nude mice, 5 doses of intravenous injection of PG-CPT at an equivalent CPT dose of 10 mg/kg on days 4, 8, 12, 16, and 20 after inoculation significantly prolonged the median survival of treated mice, averaging 1.8-fold that of untreated mice (p=0.01). Increasing the dose of PG-CPT to an equivalent CPT dose of 40 mg/kg per injection administered in 4 doses on days 4, 8, 12, and 16 prolonged the median survival of treated mice by 4-fold (p=0.0008). Significantly, mice with intratracheally inoculated H322 tumors were resistant to both CPT and cisplatin treatments. These studies demonstrated that PG may be used as an effective solubilizing carrier for CPT and that PG-CPT may have potential application in the treatment of lung cancer.

Animals↗

PubMed2001

[Calcineurin inhibitor attenuates the development and induces the regression of cardiac hypertrophy in rats with salt-sensitive hypertension].

BACKGROUND: It remains unclear how hemodynamic overload induces cardiac hypertrophy. Recently, activation of calcium-dependent phosphatase, calcineurin, has been elucidated to induce cardiac hypertrophy. In the present study, we examined the role of calcineurin in load-induced cardiac hypertrophy by using Dahl salt-sensitive (DS) rats, which develop both pressure and volume overload when fed a high salt diet. METHODS AND RESULTS: In the DS rat heart, the activity of calcineurin was increased and cardiac hypertrophy was induced by high salt diet. Treatment of DS rats with the calcineurin inhibitor FK506 (0.1 or 0.01 mg/kg every second day) from the age of 6 weeks to 12 weeks inhibited the activation of calcineurin in the heart in a dose-dependent manner and attenuated the development of load-induced cardiac hypertrophy and fibrosis without change of hemodynamic parameters. Additionally, treatment with 0.1 mg/kg every second day but not with 0.01 mg/kg every second day of FK506 from the age of 12 weeks to 16 weeks induced regression of cardiac hypertrophy in DS rats. Load-induced reprogramming of gene expression was also suppressed by the FK506 treatment. CONCLUSIONS: These results suggest that calcineurin is involved in the development of cardiac hypertrophy in rats with salt-sensitive hypertension and that inhibition of calcineurin could induce regression of cardiac hypertrophy.

Animals↗

PubMed2001

[Analysis on genetic polymorphism of 13 STR loci on chromosomes 11 and 19 in Chinese Hans].

OBJECTIVE: To analyze the genetic polymorphism of 8 STR loci on chromosome 11 and 5 STR loci on chromosome 19 in Chinese Hans. METHODS: Polymerase chain reaction-single strand length polymorphism(PCR-SSLP) was used to genotype 100 randomly selected individuals of the Han nationality at 8 STR loci(D11S1984, D11S1999, D11S1392, D11S1985, D11S2002, D11S1986, D11S4464 and D11S2359) on chromosome 11 and 5 STR loci(D19S247, D19S714, D19S433, D19S246, D19S254) on chromosome 19. RESULTS: Eight alleles and 26 genotypes, 9 alleles and 15 genotypes, 6 alleles and 16 genotypes, 12 alleles and 40 genotypes, 6 alleles and 19 genotypes, 12 alleles and 48 genotypes, 8 alleles and 20 genotypes, 7 alleles and 13 genotypes were observed at D11S1984, D11S1999, D11S1392, D11S1985, D11S2002, D11S1986, D11S4464 and D11S2359. The heterozygosities for the 8 STR loci were 87%, 68%, 73%, 92%, 71%, 86%, 75% and 71%, respectively. Ten alleles and 19 genotypes, 10 alleles and 26 genotypes, 10 alleles and 24 genotypes, 11 alleles and 29 genotypes, 8 alleles and 18 genotypes were observed at D19S247, D19S714, D19S433, D19S246, D19S254. The heterozygosities for the 5 STR loci were 63%, 82% 72%, 81% 74%, respectively. CONCLUSION: The distribution of allele frequencies of 8 STR loci on chromosome 11 and 5 STR loci on chromosome 19 was consistent with the Hardy-Weinberg equilibrium and the highly genetic polymorphism was observed in Chinese Han population.

China↗

PubMed2001

[Primary respiratory syncytial virus infection in mice].

OBJECTIVE: To establish a mice-model of primary respiratory syncytial virus infection. METHODS: Twelve Balb/c mice (8-12 w) were divided into two groups with three different titers of RSV infection in the experimental group. Mice were anaesthetized with pentobabitone(30 mg/kg) and infected by nasal drip of 0.1 ml of RSV which was harvested from HEP-2 cell culture. Three mice in the control group received sham infection with HEP-2 cell media. Five days later, lungs were removed in aseptic condition. Right lung was weighted and homoginized with MEM(1:10 ratio), then centrifuged at 4 degrees C, 2,000 r/min for 20 minutes. Supernatants were collected for virus isolation and plaque forming assay. Left lung was collected for histopathological and electromicroscopic examination. RESULTS: (1) RSV grew with a characteristic syncytial formation in HEP-2 cells, leading to the fusion of cells with round, elliptic, map or tree like shape. (2) Virus was isolated and detected in the lung tissue in experiment group. (3) There was a positive correlation between RSV titer added and that replicated in the lung. (4) After the eclipse phase, viral replication in the lung reached maximum within 4 and 6 days. The most apparent pathological change was found between day 5 and 8. Mononuclear cell infiltration was presented in the perivascular, peribronchial and in the alveoli spacers. (5) Huge viral replication with its fuzzy coat was detected inside the cytoplasm of the type II alveolar lining cell at high magnification. CONCLUSION: An animal model of RSV infection Balb/c mice was successfully established by nasal inoculation with respiratory syncytial virus.

Animals↗

PubMed2001

Nationality differences in distributions of serum lipids, lipoproteins and apolipoproteins levels in Xinjiang China.

OBJECTIVE: To reveal the distribution characteristics of serum lipids, lipoproteins, and apolipoproteins levels in different nationalities. METHODS: Quantitative levels of those traits mentioned above were determined and body height (H), weight (W) and body mass index (BMI = W/H2) were assessed in 773 Kazaks (men 360 and women 413) and 911 Han nationality (men 466 and women 445) from the Xinjiang Autonomous Region of China. RESULTS: Kazaks men and women, respectively, had significantly higher serum levels of HDL-c and ApoA1 (all P < 0.001) and significantly lower serum levels of TG (men P < 0.01, women P < 0.001), Lp(a) (all P < 0.005), ApoB (men P < 0.005, women P < 0.001) and ApoB/A1 (men P < 0.01, women P < 0.001) than their Han nationality controls. The threshold points of ApoA1 (< 1.2 g/L) and ApoB (> 1.2 g/L) are higher in Hans than in Kazaks for ApoA1 (20.7 vs 9.8%) and ApoB (18.6 vs 14.3%); the serum levels of TG, HDL-c, Lp(a), ApoA1 and ApoB/A1 are all closely correlated with nationality (P < 0.001, P = 0.001, and P < 0.05, respectively). CONCLUSION: The results suggest that the nationality differences exist in serum levels of lipids, lipoproteins, and apolipoproteins, and Kazaks have a superior serum lipid pedigree to Hans. This differences may come from genetic differences, which affect the serum levels of lipids, lipoproteins, and apolipoproteins by controlling lipid metabolism patterns. Future study will be needed to dissect to the role of genetic factors on serum lipids.

Apolipoproteins↗

PubMed2001

[Causal factors of decline disease in exotic pine (Pinus taeda and P. elliottii) plantations].

Investigation on the cause of the decline of exotic pine plantations in Anhui Province was carried out from 1995 to 2000. The results showed that the cause might develop from the interaction of three or more sets of factors. The first group of factors called as predisposing factors were high and low temperature and rainfall, poor soil fertility, and excessive soil bulk density, soil moisture, and of stand density; the second group of factors called as inciting factors were insect defoliators, damaging diseases of needles, late spring frost, severe drought, and excessive resin-tapping, and the third group of factors called as contributing factors were several biotic agents such as shoot blight infected by Sphaeropsis sapinea, decay wood and root rot by fungi, and bark beetles and wood borers.

Causality↗

PubMed2001

[Relationship between decline disease of exotic pines(Pinus taeda and P. eliottii) and forest stand and environmental factors].

The relationship between decline disease of exotic pines(Pinus taeda and P. eliottii) plantations in Anhui Province and forest stand status and environmental factors was quantitatively analyzed. Among 18 variable factors from 4 types of factors(climate, soil, stand status, and other diseases and insect pests), 10 factors contributed greatly to the state of illness. These were tree age, stand density, resin-tapping, rainfall, temperature, clay soil, stone soil, soil depth, water-logging, and other diseases and insect pests. Of them soil depth and rainfall negatively, and others positively related with the severity of disease. Accordingly, a linear multiple regression model was derived, which might predict the developmental level of decline disease at any given conditions of exotic pine plantation. In addition, the spiral chart of decline disease was mapped based on the action size and time order of various nosogenetic factors during the incidence of decline disease, which was used to visually describe and quantitatively analyze the disease with complicated causes.

Causality↗

PubMed2001

[Comparison between one-site and two-site incision in phacotrabeculectomy].

OBJECTIVE: To compare the effect of one-site and two-site incision in phacotrabeculectomy in terms of intraocular pressure control. METHODS: Forty-five cases (47 eyes) of phacotrabeculectomy were retrospectively reviewed. The nuclei of all the cases were not harder than Grade III. One-site approach was performed on 29 eyes, and two-site approach, on 18 eyes. The effects of intraocular pressure control were compared between the two groups. RESULTS: Follow-up was 13-30 months (mean 18.9 months). The postoperative intraocular pressure in the one-site group was (16.81 +/- 4.56) mm Hg (1 mm Hg = 0.133 kPa), (15.32 +/- 6.67) mm Hg lower than that before surgery. And the postoperative intraocular pressure in the two-site group was (17.63 +/- 4.60) mm Hg, (16.42 +/- 6.98) mm Hg lower than that before surgery. There was no significant difference between the two groups relative to the effect of intraocular pressure control (t = 1.44, P > 0.05). CONCLUSION: Phacotrabeculectomy, either with one-site approach or with two-site approach, can provide good intraocular pressure control. The effects are similar between the two approaches in soft cataract patients.

Adult↗

PubMed2001

[Telomerase activity of common malignant tumors].

OBJECTIVE: To study the usefulness of detection of telomerase activity in the diagnosis of malignant tumors. METHODS: Modified telomeric repeat amplification protocol (TRAP) was employed to examine telomerase activity in 283 malignant tumor tissues, 42 adjacent tissues and 61 benign tumor tissues. RESULTS: Of the 283 malignant tumors and 42 adjacent tissues, telomerase was positive in 264 (93.3%) and 11 (26.1%), respectively. Only 4 of the 62 (6.6%) benign tumors were telomerase positive. CONCLUSION: Telomerase activity may be used as tumor marker in the diagnosis of malignant tumors.

Biomarkers, Tumor↗

PubMed2001

[The development of clinical application of the rejuvenator and a study of its mechanism for the treatment of functional erectile dysfunction].

In this paper, we describe the development and clinical application of the Rejuvenator and report the result of our study on its mechanism for the treatment of functional erectile dysfunction (FED). The Rejuvenator, which can be used both at home and in hospitals to treat patients with FED, was developed on the basis of our clinical practice in the light of the modern theory of traditional Chinese medicine and by integrating multiple techniques of engineering science. It works by means of the paraoral use of the special herbal medicine, electro-magnetic effects, thermal moxibustion and drug-ingression. 2250 patients with FED received the treatment. Using combined electro-neurophysiological techniques, pulsed ultrasound Doppler and microcomputer image-scanning, we further studied the mechanism of the Rejuvenator for the treatment of FED. The total effective rate was 92%. The clinical data and result of study indicate that the Rejuvenator for the patients with functional erectile dysfunction is a safe, effective and scientific new method.

Adult↗

PubMed2001

[A clinical study on black diaphragm posterior chamber intraocular lens implantation].

OBJECTIVE: To discuss the effect of black-diaphragm intraocular lens implantation in the management of cataract or aphakia with aniridia. METHODS: Thirty-three cases (34 eyes) of black-diaphragm posterior chamber intraocular lens implantation were retrospectively analyzed, among which 18 eyes had undergone primary intraocular lens implantation and 16 secondary intraocular lens implantation. RESULTS: After 1-52 months of follow-up, postoperative corrected visual acuities were greater-than-or-equal 1.0 in 17 eyes, 0.5-0.9 in 11 eyes and 0.1 -0.4 in 6 eyes. The complications included intraoperative ciliary body bleeding in 2 eyes and retinal detachment in one eye. CONCLUSION: Black-diaphragm intraocular lens implantation is effective in the management of cataract or aphakia with aniridia.

Adolescent↗

PubMed2001

[Determination of roxithromycin in serum by high-performance liquid chromatography with ultraviolet detection].

OBJECTIVE: To make better the RP-HPLC method for the determination of roxithromycin(RM) in human serum. METHODS: RM and clarithromycin (internal standard) were extracted from alkalinized serum sample (500 microliters) with methylene chloride. After evaporation of the organic layer, the residue was dissolved in 100 microliters of acetonitrile-ammonium phosphate (1:1, pH 6.0) and washed with n-hexane, then 20 microliters was injected onto a column (5 microns, 15 cm x 4.6 mm) of Penomenex luna C18. The mobile phase was acetonitrile-0.05 mol/L phosphoric acid (39:19:42, adjusted to pH 7.2 with ammonia water) pumped at 1.2 ml/min through the column. The variable wavelength UV detector operated at 0.01 aufs and the wavelength was set at 210 nm. RESULTS: The retention times for RM and clarithromycin were 4.4 min and 5.0 min, respectively. Standard curve was linear in the concentration range of 0.25 to 32 mg/L. The detection limit in serum was 0.06 mg/L; the average method recovery 97.4%; the inter-day RSD less than 3.0%. CONCLUSION: This method was found to be simple, rapid, sensitive and accurate for determination of RM in human serum.

Chromatography, High Pressure Liquid↗