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Biomedical subjects

H Yin

Publications and source records attributed to H Yin.

At least 19 recordsLinked to original sources
PubMed2006

cDNA microarray analysis of gene expression in Brassica napus treated with oligochitosan elicitor.

An oilseed rape (Brassica napus H) cDNA microarray containing 8095 expressed sequence tags (ESTs) was used to analyze the B. napus gene expression changes elicited by oligochitosan. Transcript levels for 393 genes were altered twofold or more in oligochitosan-treated seedlings compared to control seedlings. Of the 393 genes, 257 were repressed and 136 were induced. Semi quantification RT-PCR of eight of these 393 genes confirmed the microarray results. These 393 genes were involved in different processes and had different functions including defense, primary metabolism, transcription, and signal transduction etc. Some of these genes were elicited by various pathogen-related or stress stimuli, and others were regulated by plant growth regulators like auxin and gibberellin. These manifested complicated interactions of oligochitosan and phytohormones. An important jasmonic acid (JA) synthase (2-oxophytodienoate-10,11-reductase) gene, a JA-mediated defense required kinase ATMPK4-homolog gene, an ethylene receptor gene, and two ethylene responsive element binding protein (EREBP) genes were induced by oligochitosan, suggesting that oligochitosan activated the plant self-defense through JA/ET signaling pathway.

Brassica napus↗
PubMed2006

Epidural cooling for selective brain hypothermia in porcine model.

BACKGROUND: Hypothermia has been shown to be neuroprotective in many animal models and several human trials of brain ischemic and trauma. However systemic hypothermia may result in fatal complications. This study was undertaken to test epidural cooling as a new method of inducing selective brain hypothermia. METHOD: Six adult swine (mean mass, 33.8+/-3.6 kg) were studied. Anesthesia was maintained with pentobarbital sodium (25 mg kg-1, i.v.) and pancuronium bromide (0.5 mg kg-1 h-1, i.v.). Five probes were placed in the rectum, deep brain, brain surface, epidural space, and room air for temperature monitoring respectively. Epidural cooling was performed using cold-saline (4 degrees C) perfusion into the epidural space through a flexible double-lumen catheter. The dripping speed of cold saline was controlled to maintain the target temperature. The changes of the epidural space pressure, complete blood counts, basic metabolic panels, tests for fibrinolysis and coagulation status were monitored to assess hypothermia-induced changes. FINDINGS: Following the epidural cooling perfused with cold-saline (4 degrees C) at mean dripping speed of 720 ml per hour, the local brain surface temperature could decrease rapidly to 17.3-21.6 degrees C within one minute, and deep brain temperature decreased to 27.2-29.7 degrees C within 5 minutes. The target temperatures were easily controlled by the dripping speed of cold saline (from mild to deep hypothermia). The rectal temperature was maintained at normal range within 6 perfusion hours. No arrhythmia was observed, and all hematological variables were within the normal range for swine. No increased intracranial pressure was induced by the cooling method. CONCLUSIONS: The data demonstrate that epidural space cooling was technically feasible and useful for selective brain hypothermia, and the target temperatures are easily controlled. The induction of hypothermia was rapid and maintained for a long period of time, whereas the body temperature was maintained within the normal range and without hemodynamic instability.

Animals↗
PubMed2006

Development of a recombinant indirect ELISA for the diagnosis of Theileria sp. (China) infection in small ruminants.

Theileria sp. (China) causes severe limitations on the development of the livestock industry in the north-west of China. An enzyme-linked immunosorbent assay (ELISA) based on merozoite homogenate of the parasite for diagnosis of infection has been established; however, cross-reactivity with other small ruminant-infecting piroplasms could not be excluded. Thus, a prerequisite for epidemiological surveys and diagnosis was the establishment of a recombinant protein-based ELISA. To this end, serum from Theileria sp. (China)-infected sheep was used to screen a Theileria lestoquardi expression library, resulting in the identification of a specifically reacting clone with a high identity to the heat shock protein 70 (HSP70) of Theileria parva and Theileria annulata and thus named TlHSP70. An HSP70 homologue was also confirmed to be expressed by Theileria sp. (China) merozoites (TcHSP70). A part of the TlHSP70 protein, found to be conserved in TcHSP70, was recombinantly expressed and used to establish an ELISA. A total of 260 field serum samples tested resulted in a sensitivity and specificity of 94.3 and 89.5%, respectively, in comparison with the merozoite homogenate ELISA. The potentials of the application of the test in epidemiological surveys to map out the prevalence of the disease and for routine diagnostics are described.

Animals↗
PubMed2006

Cryopreservation of murine embryos, human spermatozoa and embryonic stem cells using a liquid nitrogen-free, controlled rate freezer.

A Stirling Cycle Cryocooler has been developed as an alternative to conventional liquid nitrogen controlled rate freezers. Unlike liquid nitrogen systems, the Stirling Cycle freezer does not pose a contamination risk, can be used in sterile conditions and has no need for a constant supply of cryogen. Three types of samples from two species (murine embryos, human spermatozoa and embryonic stem cells), each requiring different cooling protocols, were cryopreserved in the Stirling Cycle freezer. For comparison, cells were also frozen in a conventional liquid nitrogen controlled rate freezer. Upon thawing, the rates of survival of viable cells were generally greater than 50% for mouse embryos and human embryonic stem cells, based on morphology (mouse embryos) and staining and colony formation (human embryonic stem cells). Survival rates of human spermatozoa frozen in the Stirling Cycle freezer, based on motility and dead cell staining, were similar to those of samples frozen in a conventional controlled rate freezer using liquid nitrogen.

Animals↗
PubMed2006

The effects of substrate position on electroless polyol deposited nanostructured FeNi films.

The nanostructured FeNi thin films were deposited on a polycrystalline Cu substrate by reducing constituent metal salts in refluxing ethylene glycol. The effect of substrate position was investigated. During deposition, the substrate was subject to one of the following processes: (a) complete immersion in solution, (b) repeated immersion followed by suspension above solution (denoted as quenching), and (c) suspension above the solution. Compared to the conventional polyol synthesis of FeNi where Fe concentration could not exceed 30 at%, the quenching process dramatically increased Fe at% to above 40%. Complete suspension of substrate above the solution resulted in Fe-rich films where Fe at% >90%. The microhardness, adhesion, and magnetic properties of deposited films showed a strong dependence on the long-range and short-range order of the film, which, in turn, depended on the substrate position. Quenched films with ordered local Ni environment and higher crystallinity had the highest Vickers hardness, best adhesion to substrate, and largest saturation magnetization compared to those deposited on substrates placed in other positions. The oxidation of Fe occurring in the vapor deposition significantly affected the film properties.

Colloids↗
PubMed2005

The effects of particle size and surface coating on the cytotoxicity of nickel ferrite.

The safety and toxicity of nanoparticles are of growing concern despite their significant scientific interests and promising potentials in many applications. The properties of nanoparticles depend not only on the size but also the structure, microstructure and surface coating. These in turn are controlled by the synthesis and processing conditions. The dependence of cytotoxicity on particle size and on the presence of oleic acid as surfactant on nickel ferrite particles were investigated in vitro using the Neuro-2A cell line as a model. For nickel ferrite particles without oleic acid prepared by ball milling, cytotoxicity was independent of particle size within the given mass concentrations and surface areas accessible to the cells. For nickel ferrite particles coated with oleic acid prepared by the polyol method, the cytotoxicity significantly increased when one or two layers of oleic acid were deposited. Large particles (150+/-50 nm diameter) showed a higher cytotoxicity than smaller particles (10+/-3 nm diameter).

Animals↗
PubMed2005

Prevalence of and risk factors for non-compliance with glove utilization and hand hygiene among obstetrics and gynaecology workers in rural China.

This study identified the prevalence of and risk factors for non-compliance with glove utilization and hand hygiene among rural obstetrics and gynaecology workers in two poor counties in Anhui, China. A cross-sectional survey was conducted using a self-administered anonymous semi-structured questionnaire. The study population included all health workers in the departments of obstetrics and gynaecology in township hospitals and county health facilities. Among the 137 participants, the rate of non-compliance with glove utilization was 61%, the rate of non-compliance with hand hygiene was 40%, and the rate of non-compliance with both was 67%. 'Unnecessary and inconvenient' accounted for 66% of the reasons for not always using gloves and 71% for not always washing hands. 'Short of gloves or water' accounted for 15% and 22% of reasons, respectively. Two variables were associated with non-compliance: county [odds ratio (OR)=11.56, P<0.001] and knowledge (OR=0.10, P=0.033). After removing county from the regression model, institutional level (OR=2.34, P=0.059), institutional support (OR=3.85, P=0.009) and knowledge (OR=0.05, P=0.007) were associated with non-compliance. The prevalence of non-compliance with glove utilization and hand hygiene was high. The risk factors for non-compliance were institutional level, institutional support and knowledge. These variables incorporated both subjective and objective reasons for non-compliance.

Adult↗
PubMed2005

A novel G protein-coupled receptor for gonadotropin-inhibitory hormone in the Japanese quail (Coturnix japonica): identification, expression and binding activity.

We recently identified a novel hypothalamic dodecapeptide inhibiting gonadotropin release in the Japanese quail (Coturnix japonica). This novel peptide was therefore named gonadotropin-inhibitory hormone (GnIH). The GnIH precursor encoded one GnIH and two GnIH-related peptides (GnIH-RP-1 and GnIH-RP-2) that shared the same C-terminal motif, Leu-Pro-Xaa-Arg-Phe-NH(2) (Xaa=Leu or Gln; LPXRF-amide peptides). Identification of the receptor for GnIH is crucial to elucidate the mode of action of GnIH. We therefore identified the receptor for GnIH in the quail diencephalon and characterized its expression and binding activity. We first cloned a cDNA encoding a putative GnIH receptor by a combination of 3' and 5' rapid amplification of cDNA ends (RACE) using PCR primers designed from the sequence for the receptor for rat RF-amide-related peptide (RFRP), an orthologous peptide of GnIH. Hydrophobic analysis revealed that the putative GnIH receptor possessed seven transmembrane domains, indicating a new member of the G protein-coupled receptor superfamily. The crude membrane fraction of COS-7 cells transfected with the putative GnIH receptor cDNA specifically bound to GnIH and GnIH-RPs in a concentration-dependent manner. Scatchard plot analysis of the binding showed that the identified GnIH receptor possessed a single class of high-affinity binding sites (K(d)=0.752 nM, B(max)=24.8 fmol/mg protein). Southern blotting analysis of reverse transcriptase-mediated PCR products revealed the expression of GnIH receptor mRNA in the pituitary gland and several brain regions including diencephalon in the quail. These results suggest that GnIH acts directly on the pituitary via GnIH receptor to inhibit gonadotropin release. GnIH may also act on the hypothalamus to inhibit gonadotropin-releasing hormone release.

Amino Acid Sequence↗
PubMed2004

Compression of frequency-modulated pulses using helically corrugated waveguides and its potential for generating multigigawatt rf radiation.

A new method to generate ultrahigh-power microwave pulses compatible with mildly relativistic electron sources is proposed. This method involves a novel microwave compressor in the form of a metal helically corrugated waveguide, which can enhance the power of frequency-modulated nanosecond pulses up to the multigigawatt level. The results of the proof-of-principle experiments at kilowatt power levels are in good agreement with theory.

Journal Article↗
PubMed2004

Spindles, mitochondria and redox potential in ageing oocytes.

Studies of human oocytes obtained from women of advanced reproductive age revealed that spindles are frequently aberrant, with chromosomes sometimes failing to align properly at the equator during meiosis I and II. Chromosomal analyses of donated and spare human oocytes and cytogenetic and molecular studies on the origin of trisomies collectively suggest that errors in chromosome segregation during oogenesis increase with advancing maternal age and as the menopause approaches. Disturbances in the fidelity of chromosome segregation, especially at anaphase I, leading to aneuploidy are prime causes of reduced developmental competence of embryos in assisted reproduction, as well as being responsible for the genesis of genetic disease. This review provides an overview of spindle formation and chromosome behaviour in mammalian oocytes. Evidence of a link between abnormal mitochondrial function in oocytes and somatic follicular cells, and finally disturbances in chromosome cohesion and segregation, and cell cycle control in aged mammalian oocytes, are also discussed.

Aneuploidy↗
PubMed2004

A third species of Hypoderma (Diptera: Oestridae) affecting cattle and yaks in China: molecular and morphological evidence.

Cattle and yak hypodermosis in China is caused by Hypoderma bovis and H. lineatum, with a prevalence reaching up to 98-100% of the animals and maximum intensities exceeding 400 warbles for each animal. A third species, H. sinense, is also considered by Chinese researchers to affect livestock. The molecular characterization of the most variable region of the mitochondrial cytochrome oxidase I gene and of the ribosomal 28S gene has been performed for the third-stage larvae collected from cattle and yaks in China and identified (on the basis of the spinulation on the ventral side of the 10th segment) as H. bovis, H. lineatum, and H. sinense. Amplicons were digested with the HinfI and BfaI restriction enzymes, which provided diagnostic profiles to simultaneously differentiate the 3 Hypoderma species. Third-stage larvae of H. sinense were also examined by scanning electron microscopy, which revealed proper morphological characteristics different from those of H. bovis and H. lineatum. The molecular and morphological evidence herein reported support the existence of a third species of Hypoderma affecting cattle and yaks in China, and the results provide new tools for unequivocal identification of this species and present key components for the evaluation of its endogenous cycle and pathogenicity in animals and humans.

Animals↗
PubMed2003

Pharmacokinetics of ivermectin in the yak (Bos grunniens).

The yak (Bos grunniens) belongs to the cattle family Bovidae and lives in the mountains of China and adjacent areas. Due to the physiological adaptations of yak to its environment and the lack of data, the ivermectin pharmacokinetic was studied following a single subcutaneous dose at the recommended dose for cattle (0.2 mg kg(-1)). The observed peak plasma concentration (Cmax) was 48.93 ng ml(-1) and the time to reach Cmax (Tmax) was 0.73 day. These results show a faster rate of absorption than in cattle. The values for the absorption half-life (t(1/2a)), the distribution half-life (t(1/2alpha)) and the terminal half-life (t(1/2beta)) were 0.31, 0.74 and 4.82 days, respectively. The calculated area under the concentration-time curve (AUC) was 146.2 ng day ml(-1) and the mean residence time (MRT) was 3.57 days. The availability of ivermectin appears low in yaks in comparison to cattle but equivalent to that reported in horses and is likely to be due to physiological characteristics of this species.

Absorption↗
PubMed2002

Characterization of a polymorphic gene of T. lestoquardi and of a recently identified Theileria species pathogenic for small ruminants in China.

In the present study, we identified a gene from Theileria lestoquardi and from a recently described Theileria species which is highly pathogenic for small ruminants in China. Since the taxonomic position of the latter parasite is still not clear, we refer to it as Theileria (China) species. The gene described here comprises an open reading frame of about 948 bp which prospectively encodes a 35-kDa protein. Its sequence is most closely related to the polymorphic immunodominant membrane protein of T. parva (36% identity). A search for sequence patterns and motifs within the predicted amino acid sequence revealed that this gene possesses three membrane-spanning regions at its C-terminal part, suggesting that it is a membrane protein. Several allelic variants of this gene were found in each parasite species, demonstrating interspecies and intraspecies variation. The predicted amino acid sequence variants display a substantial size and sequence polymorphism in the central part of its presumed extracellular region, while the N-terminal and the transmembrane/intracellular regions are highly conserved.

Amino Acid Sequence↗
PubMed2002

Development of an enzyme-linked immunosorbent assay for the diagnosis of Theileria sp. infection in sheep.

A rapid, sensitive and specific diagnostic method, an enzyme-linked immunosorbent assay (ELISA), was developed for the diagnosis of Theileria sp. infection in sheep; and optimal conditions were established, such as antigen concentration, serum dilution, coating time, Tween-20 concentration and conjugate. The results were analyzed by measuring the coefficient of variation (CV). Three sera titers (high, middle, low) were analyzed over the measurement range, resulting in a CV of around 10%, whereas a 30% variation is the maximum acceptable. The cut-off value was determined by the mean of a negative control plus three standard deviations. Cross-reaction was found only with Babesia ovis. However, this result may be questionable, because it cannot be excluded that these sheep were already infected with both Theileria sp. and B. ovis. The ELISA described in the present study proved to be a useful tool for studying the epidemiology of Theileria sp.

Animals↗
PubMed2002

Transmission of Babesia sp to sheep with field-collected Haemaphysalis qinghaiensis.

Haemaphysalis qinghaiensis ticks collected in the Gannan Tibet Autonomous Region were infested onto a sheep from a Babesia-free area. A strain of small Babesia (1.8-2.1 microm in length) was isolated from the sheep. Most of the Babesia in erythrocytes were round, oval, single pyriform, double pyriform, budding or elongated in form. Measurements were made of 100 single sides of the double-pyriform Babesia and compared with those for B. motasi and B. ovis from Holland, using Student's t-test. The Gannan small Babesia was similar to the B. ovis from Holland, but differed significantly from the Dutch B. motasi.

Animals↗
PubMed2002

A field test on the treatment of ovine theileriosis with an injection of Kangjiaoming.

A compound effective for the treatment of ovine theileriosis was selected and a slow-release preparation (named Kangjiaoming) was prepared. A total of 1,172 sheep and goats in Zhangjiachuan, Lintan and Yuzhong Counties, Gansu Province, where small ruminants are seriously affected by theileriosis, were injected with this preparation at a dosage of 5 mg/kg body weight. The infection rate of the control group in each of the above-mentioned counties was 98.5%, 85% and 80%, respectively. None of the treated animals became sick due to theileriosis. This drug proved to be useful for the treatment of carrier cases, although its effect was apparently slower than in acute theileriosis. The effect of the preparation on some weak animals was not satisfactory.

Animals↗
PubMed2002

Peptoid inhibition of trypanothione reductase as a potential antitrypanosomal and antileishmanial drug lead.

One route to the design of lead compounds for rational drug design approaches to developing drugs against trypanosomiasis, Chagas' disease and leishmaniasis is to develop novel inhibitors of the parasite-specific enzyme trypanothione reductase. A lead inhibitor based on a peptoid structure was designed in the present study based on the known strong competitive inhibition of trypanothione reductase by N-benzoyl-Leu-Arg-Arg-beta-naphthylamide and N-benzyloxycarbonyl-Ala-Arg-Arg-4-methoxy- beta-naphthylamide. In the target peptoid the arginyl residues were replaced by alkylimidazolium units and the benzyloxycarbonyl group by the benzylaminocarbonyl function. The peptoid was synthesised using t-butoxycarbonyl protection chemistry and couplings were activated by 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate. The resulting peptoid was shown to be a competitive inhibitor of recombinant trypanothione reductase from Trypanosoma cruzi with a K(i) value of 179 microM and with only weak inhibition of human erythrocyte glutathione reductase (the inhibition of glutathione reductase was at least 291-fold weaker than of trypanothione reductase).

Animals↗