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Y P Zhu

Publications and source records attributed to Y P Zhu.

At least 19 recordsLinked to original sources
PubMed2004

Assessment of genetic, antigenic and pathotypic criteria for the characterization of IBDV strains.

The aim of this work was the selection and comparison of representative infectious bursal disease virus (IBDV) strains. Nine strains of IBDV, isolated at different times and from different geographic regions of Europe and China, were characterized. Batches of all strains were prepared following standardized protocols and checked for the absence of contaminating viruses. Criteria used for their characterization were: (i) the nucleotide sequence of the VP2 variable region, (ii) binding to a panel of neutralizing monoclonal antibodies in antigen capture enzyme-linked immunosorbent assays, and (iii) virulence in specific pathogen free chickens after infection with a standardized number of median embryo infective doses. Based on the first two criteria, two of nine strains were classified as classical virulent (cv) IBDV (F52/70, Cu-1wt), and five as very virulent (vv) IBDV (849VB, 96108, HK46, GX, Harbin). Remarkably, although a clear-cut difference was demonstrable between European cvIBDV (F52/70 and Cu-1wt) and vvIBDV (849VB and 96108) strains, there was a continuum in the pathogenicity of Chinese vvIBDVs. Our results indicate the probable existence of differences in virulence within IBDV lineages determined on the basis of antigenic typing using monoclonal antibodies and the alignment of the VP2 sequences. This indicates limitations in the analysis of IBDV pathotypes based on the VP2 variable region and emphasizes that these criteria may not be sufficient for the classification of IBDV strains.

Amino Acid Sequence↗
PubMed1998

Self-organizing tree-growing network for the classification of protein sequences.

The self-organizing tree algorithm (SOTA) was recently introduced to construct phylogenetic trees from biological sequences, based on the principles of Kohonen's self-organizing maps and on Fritzke's growing cell structures. SOTA is designed in such a way that the generation of new nodes can be stopped when the sequences assigned to a node are already above a certain similarity threshold. In this way a phylogenetic tree resolved at a high taxonomic level can be obtained. This capability is especially useful to classify sets of diversified sequences. SOTA was originally designed to analyze pre-aligned sequences. It is now adapted to be able to analyze patterns associated to the frequency of residues along a sequence, such as protein dipeptide composition and other n-gram compositions. In this work we show that the algorithm applied to these data is able to not only successfully construct phylogenetic trees of protein families, such as cytochrome c, triosephophate isomerase, and hemoglobin alpha chains, but also classify very diversified sequence data sets, such as a mixture of interleukins and their receptors.

Algorithms↗
PubMed1998

Acute hepatitis in a patient using a Chinese herbal tea--a case report.

A case is presented of reversible acute hepatitis in a patient using a Chinese herbal tea. Upon identification of the tea mixture Aristolochia species, including A. debilis, which contains the highly toxic aristolochic acid, could be identified. We conclude that the acute hepatitis as described in this patient is most likely to be caused by (one of) the active ingredients of the Chinese herbal tea. Furthermore, this case illustrates that so-called natural products can cause unexpected severe adverse reactions.

Acute Disease↗
PubMed1998

Ocular contact time of a carbomer gel (GelTears) in humans.

BACKGROUND/AIMS: Carbomers are widely used in products for the treatment of dry eye; however, the polymer gel thins on addition of probes (for example, fluorescein salt) confounding the comparison of products by objective clinical tests such as spectrophotofluorimetry or scintigraphy. A novel method of radiolabelling carbomer gels, with minimum change to their rheology, has permitted the non-invasive evaluation of precorneal residence of the gel in volunteers using gamma scintigraphy. The technique was used to evaluate the precorneal clearance of the liquid phase and of a suspended particulate in GelTears. METHODS: Low sodium technetium-99m labelled diethylenetriaminepentacetic acid (99mTc-DTPA) was used to label carbomer 940 gel, either adsorbed onto sterile charcoal to model an entrapped drug, or added directly to the gel to a final activity of 1 MBq per 25 microliters dose. The clearance of the labelled gels was then compared with 99mTc-DTPA labelled saline in 12 volunteers. RESULTS: The addition of the low sodium radiopharmaceutical produced insignificant rheological changes in the gel compared with conventional 99mTc-DTPA labelling. The residence times on the eye of the gel formulations were significantly greater than that of the saline control. At 8 minutes postdosing, the label levels retained (mean (SD)) on the ocular surface were: saline, 7% (7%); 99mTc-DTPA gel, 42% (27%); and 99mTc-carbon gel, 42% (20%) of administered dose. There was no difference observed in the precorneal distribution between 99mTc-DTPA solution and particulate markers. CONCLUSIONS: These data demonstrate that carbomer based gels significantly extend contact of solutes or suspended solids with the corneal surface. The method of labelling does not significantly change the initial viscosity and is superior to previous methods which have used sodium salts (for example, sodium fluorescein) and therefore underestimate contact time.

Acrylic Resins↗
PubMed1996

Platelet activating factor and conception.

PURPOSE: This review provides evidence for the involvement of platelet activating factor (PAF) in the several facets of pregnancy establishment. METHODS: A comprehensive literature review and new data. RESULTS: PAF has a role in spermatozoal function, fertilization, embryo development, and implantation. CONCLUSIONS: PAF is intimately involved in conception.

Animals↗
PubMed1995

Traditional Chinese herbal medicine.

Herbal medicine, acupuncture and moxibustion, and massage are the three major constituent parts of traditional Chinese medicine. Although acupuncture is well known in many Western countries, Chinese herbal medicine, the most important part of traditional Chinese medicine, is less well known in the West. This article gives a brief introduction to the written history, theory, and teaching of Chinese herbal medicine in China. It also describes modern scientific research into and the quality control of Chinese herbal medicines in China. Some examples of how new drugs derived from Chinese herbs have been developed on the basis of traditional therapeutic experience are presented. Finally, the situation of Chinese herbal medicine in the West is discussed.

Aconitine↗
PubMed1995

Excess iodine induces the expression of thyroid solid cell nests in lymphocytic thyroiditis-prone BB/W rats.

Previous epidemiological studies have suggested that lymphocytic thyroiditis and/or an increased iodine intake may be risk factors for the development of thyroid cancer. We previously reported that excess iodine accelerated the development of thyroid lymphocytic infiltration (LI) in the autoimmune BB/W rat model. We also found that excess iodine increased thyroid cell proliferation in a disordered manner. The present study was designed to further explore these observations and to address the question as to whether excess iodine under certain conditions predisposes the thyroid gland to neoplasia. To test this hypothesis, the lymphocytic thyroiditis-prone BB/W rat was exposed to excess iodine in drinking water. Ten BB/W rats at 4 weeks of age were given iodine water (NaI 0.05%) for 10 weeks, whilst another 10 BB/W rats were given tap water and served as controls. Eighteen normal Wistar rats were also divided into excess iodine and control groups, served as a comparison to the BB/W rats. We found that an excess iodine intake accelerated the development of LI in the BB/W rat. Severe LI was usually accompanied by prominent thyroid cell proliferation, evident as numerous microfollicles and cell masses, not forming normal thyroid follicles. Numerous lymphocytes and plasma cells often encroached on these areas of increased cellular proliferation. The surprising feature, and a possible indicator of activated thyroid cell proliferation, was the high incidence of thyroid solid cell nest-like lesions (SCN) in the iodine treated BB/W rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Platelet activating factor treatment of spermatozoa enhances rabbit oocyte fertilization following subzonal sperm insertion.

PURPOSE: The objective of this study was to evaluate the effects of spermatozoal platelet activating factor (PAF) treatment on fertilization rates employing subzonal sperm insertion in the rabbit. STUDY DESIGN: Oocytes (n = 130) with distinct first polar bodies were injected with three to seven motile spermatozoa. Half (n = 65) of the oocytes were injected with PAF-treated sperm, whereas the other half (n = 65) served as controls and were injected with nontreated sperm. Fertilization rates were assessed by the formation of two pronuclei followed by cleavage to the two-cell stage. RESULTS: In the group of oocytes injected with PAF-treated sperm, we noted a significant (P < 0.001) improvement in fertilization rates, 61.5% (40/65), vs. control nontreated sperm, 20.0% (13/65). Subsequent cleavage to the two-cell stage was noted for 95% (38/40) in the treated vs 92.3% (12/13) in the nontreated fertilized zygotes. CONCLUSION: We conclude that PAF treatment of rabbit spermatozoa prior to subzonal insertion improves fertilization rates and may be of clinical significance in assisted reproductive programs.

Animals↗
PubMed1994

[Osteogenesis role played by dermal fibroblasts cultured in vitro].

Fibroblasts were harvested by in vitro culture of split-thickness skin of New-Zealand rabbit. Some opaque bone nodules were formed in the culture flasks when the fibroblasts underwent subculture for 8 days. Some of the nodules might enlarge, extend and form trabecula-like or flake-like structures, when the fibroblasts underwent subculture for 37 days. The above mentioned structures revealed golden-yellow fluorescence under the blue-violet light fluorescence microscope when the specimens were labeled with Tetracycline intravitally, denoting that they were newly formed bone tissues. In these structures, the calcium salt staining and collagen staining also showed positive reaction, fully reflecting the calcium and collagen composition. Osteogenesis caused by dermal fibroblast cultured in vitro was thus verified. There were evenly scattered oval spots in the osteogenic areas, after the specimens were treated with Alcina Blue-Sirius Red stain. Their diameter was about 10 microns, and they stained yellow color by Picric Acid. Therefore, these spots colored yellow with Picric Acid might be the dermal epithelia (and/or endothelia), which induced the fibroblasts to form the bone tissues.

Animals↗
PubMed1994

[Analgesic effect and no physical dependence of amygdalin].

Analgesic effect of amygdalin (AM) in mice was observed in hot plate and acetic acid-induced writhing tests. AM did not induce tolerance as morphine did, and did not cause morphine-characteristic tail-erecting response in mice. Mice given AM and then challenged with nalorphine showed no jumping response. AM could not substitute for morphine in morphine-addicted rats in relieving withdrawal syndrome. No antiinflammatory activity was found with AM.

Amygdalin↗
PubMed1993

Embryonic platelet activating factor production in the rabbit increases during the preimplantation phase.

OBJECTIVE: This study measured platelet activating factor (PAF) production by rabbit embryos in vitro and ascertained if there is increased PAF production associated with advancing embryonic development. STUDY DESIGN: Two-cell rabbit embryos were recovered from superovulated New Zealand White does and cultured in vitro for 96 hr. Every 24 hr embryos were scored for developmental stage and PAF activity from the corresponding culture medium was measured by platelet aggregation and organic phosphate analyses. RESULTS: PAF was detected in culture medium at all stages from two cells to blastocysts and rose significantly (P < 0.001) at each 24-hr interval, reaching maximal levels at the expanded blastocyst stage. CONCLUSION: Maximal PAF production by expanded blastocysts may be an embryonic paracrine signal that facilitates implantation.

Animals↗
PubMed1993

Effects of osteogenesis on dermal fibroblasts cultured in vitro.

Fibroblast were harvested from in vitro culture of split-thickness skin of New Zealand rabbit. Some opaque bone nodules were found in the culture flasks when the fibroblasts underwent subculture for 8 days. After a 37-day subculture of fibroblasts, some of the nodules might enlarge extend and form trabecular-like or flake-like structures. The above-mentioned structures revealed golden-yellow fluorescence under the blueviolet light fluorescence microscope when the specimens were labeled with tetracycline intravitally, denoting that they were newly formed bone tissues. Both calcium salt and collagen stainings for these structures showed positive reaction, fully reflecting the calcium and collagen composition. Osteogenesis caused by dermal fibroblast cultured in vitro was thus verified.

Animals↗
PubMed1992

The presence of platelet-activating factor binding sites in human myometrium and their role in uterine contraction.

It has recently been suggested that platelet-activating factor is involved in a number of processes associated with reproductive biology. We have demonstrated a critical role for this autacoid in the initiation and maintenance of parturition both in animals and man. In the present investigation, it has been demonstrated that platelet-activating factor affects contraction in strips of human myometrium at concentrations as low as 10(-10) mol/L. A platelet-activating factor receptor has been identified and characterized in human myometrium. Platelet-activating factor acts to cause an increase in intracellular Ca2+ concentration of isolated myometrial smooth muscle cells in culture and an increase in the phosphorylation of the 20 kd light chain of myosin in a concentration-dependent fashion. The presence of platelet-activating factor receptors in human myometrium, the observed increase in Ca2+ concentration and phosphorylation of myosin light chain in the presence of platelet-activating factor provide further support for the importance of this autacoid in the initiation of parturition.

Binding Sites↗
PubMed1991

Prolongation of parturition in the pregnant rat following treatment with a platelet activating factor receptor antagonist.

The presence of platelet activating factor (PAF) in amniotic fluid of women only in labor is indicative of a role for PAF in parturition. In addition, stimulated amnion membrane produces both PAF and prostaglandin E2, each of which is capable of inducing myometrial contraction. To evaluate the involvement of PAF in the process of parturition, we administered the PAF receptor antagonist, L-659,989, to 17-day timed pregnant rats and followed the events of labor and delivery. Administration by mouth with L-659,989 of three concentrations (1.6, 16, and 48 mg/kg/day) did not alter the gestational period; however, the duration of parturition was increased from 2-fold to 5-fold by such treatment. No toxicity of the analog was apparent; treated dams showed no signs of morbidity, and fetal mortality was not significantly altered by treatment with the antagonist. Based on these experiments, it is suggested that the PAF receptor antagonist interferes with the normal progression of events of parturition and that PAF is an integral mediator in initiating the myometrial contraction necessary for expulsion of the fetus.

Animals↗
PubMed1991

[Histochemical study on effect of radix Salviae miltiorrhizae on growth of isolated cells from embryonic chicken frontal bone cultured in vitro].

12-day embryonic chicken frontal bone digested with trypsin to prepare the suspension of isolated bone cells. 3 x 10(6) cells were harvested altogether. The cells were divided equally into five parts. Then the Eagle medium and 0.1%, 0.2%, 0.4% and 0.8% Radix Salviae Miltiorrhizae in Eagle medium were added respectively and cultured in 5% CO2 incubator. It was observed under the inverted microscope every day. At the 26th day of culture, the cells were studied. The specimens were stained with H. E., Alcian Blue-Sirius Red, Alizarin Red S staining and alkaline phosphatase-acid phosphatase reaction for comparison. It was found that the maturation of the osteoblast-like cells could be accelerated by Radix Salviae Miltiorrhizae. Secretion of the collagenous substance, positive alkaline phosphatase reaction and deposition of mineral on the collagenous substance, forming bone nodules were found to be enhanced. But unduly high concentration of Radix Salviae Miltiorrhizae could lead to inhibition of osteoblast-like cell growth. The optimal concentration of Radix Salviae Miltiorrhizae was 0.2% in culture medium.

Animals↗
PubMed1989

Growth-inhibition effects of oleic acid, linoleic acid, and their methyl esters on transplanted tumors in mice.

We investigated the effects of oleic acid and linoleic acid on transplanted Ehrlich ascites carcinoma and Ehrlich solid carcinoma in ACR mice. Both acids significantly prolonged the life spans of Ehrlich ascites carcinoma-bearing mice and inhibited the growth of Ehrlich solid carcinoma in mice compared with the findings in untreated control mice. Methyl esters of these acids also prolonged the survival of Ehrlich ascites carcinoma-bearing mice, but they were less effective in lengthening the survival of mice given transplants of Ehrlich ascites carcinoma. In addition, gas-chromatography analysis of tumor cell lipids showed that appreciable changes occurred in the fatty acid composition of the tumor cell grown in mice treated with oleic acid or linoleic acid. Linoleic acid caused more pronounced alterations in fatty acid composition of tumor cell lipids than did oleic acid, a feature that parallels the intensity of the cytotoxicity potential of the two free fatty acids. These results suggest that (a) the free carboxyl group of free fatty acids plays a role in killing tumor cells and (b) the modification of the fatty acid composition of tumor cells also correlates with the antitumor effects of oleic and linoleic acids. In addition, these results indicate that free fatty acids may be of tumor-oriented distribution; as a consequence, free fatty acids selectively inhibit the growth of tumor cells.

Animals↗