Biomedical subjects

S P Zhu

Publications and source records attributed to S P Zhu.

At least 19 recordsLinked to original sources

PubMed2002

Harmonic modulation instability and spatiotemporal chaos.

It is shown from the conserved Zakharov equations that many solitary patterns are formed from the modulational instability of unstable harmonic modes that are excited by a perturbative wave number. Pattern selection in our case is discussed. It is found that the evolution of solitary patterns may appear in three states: spatiotemporal coherence, chaos in time but the partial coherence in space, and spatiotemporal chaos. The spatially partial coherent state is essentially due to ion-acoustic wave emission, while spatiotemporal chaos characterized by its incoherent patterns in both space and time is caused by collision and fusion among patterns in stochastic motion. So energy carried by patterns in the system is redistributed.

Journal Article↗

PubMed2001

Three-dimensional optical trajectory tracing and energy deposition of a laser beam in a laser-driven fusion.

A convenient method of three-dimensional ray tracing is suggested in the geometrical optical approximation, in which the laser ray propagation is completely based on the concept of optical trajectory tracing rather than depending upon the effective force and propagation time. This tracing has two obvious advantages that the direct application of Snell's law can be avoided when a ray crosses a different density zone and that to any desired accuracy it takes much less computation time than existing tracing. For Gaussian light beam propagation, in a spherically symmetric plasma atmosphere, the results emphasize that the deposition uniformity is strongly dependent not only on the wavelength of the laser but also on the temperature of the plasma.

Journal Article↗

PubMed1998

Quercetin down-regulated bcl-2 gene expression in human leukemia HL-60 cells.

AIM: To study the effect of quercetin (Que) on bcl-2 gene expression in human leukemia HL-60 cells. METHODS: Immunohistochemical analysis and RNA Dot blot hybridization were used to identify the expression of bcl-2 genes. RESULTS: The expression of bcl-2 protein was 94% in control HL-60 cells, which became 45%-84% when they were cultured with Que 15-60 mumol.L-1 for 48 h. The expression of bcl-2 mRNA in HL-60 cells was obviously decreased in treatment with Que 15-60 mumol.L-1. CONCLUSION: The apoptotic action of Que in HL-60 cells was associated with the down-regulation of the apoptosis-suppressing gene bcl-2.

Antineoplastic Agents, Phytogenic↗

PubMed1997

Quercetin induced apoptosis in human leukemia HL-60 cells.

AIM: To examine whether quercetin (Que) might induce apoptosis in human leukemia HL-60 cells. METHODS: DNA fragmentation was visualized by agarose gel electrophoresis. Inhibition of proliferation was measured with a colorimetric MTT-assay. The DNA degradation was determined using flow cytometry, and the microscopic changes were observed by an electron microscope. RESULTS: Que 15-120 mumol.L-1 elicited typical apoptosis morphological changes including condensed chromatin, nuclear fragmentation, and reduction in volume. DNA fragmentation and DNA degradation in a concentration-dependent manner in HL-60 cells. Que inhibited HL-60 cell proliferation. The values of IC50 and 95% confidence limits were 43 (30-61) mumol.L-1 after 48-h treatment with Que. CONCLUSION: Que induced apoptosis in HL-60 cells.

Antineoplastic Agents, Phytogenic↗

PubMed1994

[An epidemiologic survey of blindness and low vision in persons over 45 years old in Doumen County].

An epidemiologic survey of blindness and low vision in persons over 45 years old in Doumen County, Guangdong Province was carried out in 1991. The sample size was 932 subjects. We found that the impairment of vision < 0.3 accounted for 10.94%. The prevalences of bilateral blindness and low vision were 1.61% and 3.22%, respectively. Both the prevalences of blindness and low vision were increased with age. The leading cause of blindness was cataract (45.20%) and the second, corneal opacity (16.70%).

Aged↗

PubMed1994

[Studies on reproductive toxicity induced by enriched uranium].

Reproductive toxicity induced by body contamination with enriched uranium (235UO2F2) in different levels was studied. Results showed abnormalities dominated with bicaps and non-hock sperms could be induced by 235UO2F2. Chromosome aberration in spermatogonia induced by 235UO2F2 was dominated with chromosome breakage, and caused chromosome fragment, translocation, polyvalent in primary spermatocyte and DNA strand breakage in sperm. The quantity of sperm DNA strand breakage increased with the raise of intake of 235UO2F2. It was noted that enriched uranium could damage genetic materials in rats and cause dominant lethality and skeletal abnormalities in fetal rats. Incidence (B) of the induced skeletal abnormalities correlated positively to the injected dose (I) of 235UO2F2 into their testes with a regression equation of B = 28.84 + 0.86I.

Animals↗

PubMed1994

[An epidemiologic survey on lens opacities in Doumen County].

Age-related lens opacity is the main cause of vision disability in elderly all over the world. A longitudinal study was designed to investigate the prevalence of lens opacity. 1,817 eyes of 932 adults over 45 year-old were sampled randomly. The lens opacities were graded according to a standardized photo of the Lens Opacities Classification System II (LOCS-II). The prevalence of lens opacities in nuclear color, nuclear opacity, cortical opacity and subcapsular opacity was 16.1%, 28.6%, 30.3% and 8.7% respectively. The frequency of all four types of opacities increased with age. The prevalence of lens opacities in four types were higher in female than that in male. The color of nuclear was related to the degree of myopia, the deeper the higher. These results are important information in eye care project.

Age Factors↗

PubMed1990

Detection of DNA damage in spermiogenic stages of mice treated with enriched uranyl fluoride by alkaline elution.

DNA breakage in spermiogenic stages of mice treated with enriched uranyl fluoride (UO2F2) was studied using an alkaline elution technique. Mature spermatozoa were sampled from the animal's vas and eluted with a buffer (PH 12.2) at 3-day intervals over a 33-day period after i.p. injection of 2 mg UO2F2/kg and always at 36 days after thymidine labeling in the testes. Elution of sperm DNA from treated animals varied with spermiogenic stages. At 12 days after exposure the amount of the elution of sperm DNA was found highest and increased with the increasing UO2F2 dose up to 6 mg/kg.

Animals↗

PubMed1990

Induction of chromosomal aberrations in male mouse germ cells by uranyl fluoride containing enriched uranium.

Cytogenetic damage induced by a wide range of concentrations of uranyl fluoride injected into mouse testes was evaluated by determining the frequencies of chromosomal aberrations in spermatogonia and primary spermatocytes. Breaks, gaps and polyploids were observed in spermatogonia. The frequencies of the significant type of aberration, breaks, were induced according to the injected doses of uranyl fluoride. Primary spermatocytes were examined for fragments, univalents and multivalents. The multivalents observed in this study resulted either from chromatid interchanges or from reciprocal translocations. The reciprocal translocations were induced in spermatogonia and recorded in primary spermatocytes. For primary spermatocytes the incidence of aberrant cells largely depended on the administered dose. Sampling time after treatment could affect the frequencies of chromosomal aberrations in male mouse germ cells.

Animals↗

PubMed1989

[Selective accumulation of 147Pm in organism on induction of micronucleus and SCE of bone marrow cells as well as the mutagenic effect on fetal liver and spleen].

Study of accumulation peculiarity of 147Pm showed that iv. different doses of 147Pm were the same selectively localized in skeleton. Retention of 147Pm in skeleton was elevated when the radioactive doses of 147Pm were increased. At the same time absorption dose of 147Pm radiation was also raised. The ability of 147Pm to induce sister chromatid exchanges (SCEs) has been investigated by IdU labelling methods. A statistically significant elevation of SCEs was observed after 147Pm intake. The number of SCEs per cell in bone marrow cells was always higher in mice when the animals were maintained on the doses of 37 Bq/g. We observed the injurious effects of 147Pm, using micronucleus rates in bone marrow cells as indicator. The results showed that the lower limit of injected activity effecting marked rise of rates was 185 Bq/g A peak rate of 1.34% was reached at 24 here after intake of 147Pm 1.85 x 10(5) Bq/g. Our study is also to ascertain the correlation between maternal deposition, perinatal uptake of 147Pm and their chromosome aberrations of maternal and fetal liver cells. Results indicated that 147Pm was predominantly deposited in maternal liver. Deposition of 147Pm in maternal spleen was about one quarter of that in the maternal liver. In view of the placental barrier uptake of 147Pm by fetal liver or spleen was definitely depressed. Studies indicated that maternal contamination of 147Pm could induce chromosome aberrations in fetal liver and spleen cells. Among the type of aberrations induced by 147Pm, chromatid breakage were predominant.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1988