PubMed Health⌕ Search

Biomedical subjects

Y Zuo

Publications and source records attributed to Y Zuo.

At least 19 recordsLinked to original sources

Anaerobic bio-hydrogen production using pre-heated river sediments as seed sludge.

Anaerobic bio-hydrogen production is the focus in the field of bio-energy resources. In this paper, a series of batch experiments were conducted to investigate the effects of several factors on anaerobic bio-hydrogen producing process carried out by pre-heated river sediments. The results showed that several factors such as substrate and its concentration, temperature and the initial pH value could affect the anaerobic bio-hydrogen production in different levels. At 35 degrees C and the initial pH of 6.5, using glucose of 20,000 mg COD/L as substrate, the highest hydrogen production of 323.8 ml-H2/g TVS in a 100 ml batch reactor was reached, the specific hydrogen production rate was 37.7 ml-H2/g TVS h, and the hydrogen content was 51.2%. Thereafter using the same pre-heated river sediments as seed sludge, continuous anaerobic bio-hydrogen production was achieved successfully in a lab-scale CSTR with gas-separator. At the organic loading rate of 36 kg COD/m3 d, the highest hydrogen production was 6.3-6.7 l-H2/l-reactor d, the specific hydrogen production was 1.3-1.4 mol-H2/mol-glucose, and the hydrogen content in the gas was 52.3%. The effluent of the bio-reactor contained some small molecular organics, mainly including ethanol, acetate, butyrate and their molar proportion is 1:1:0.6.

Acetates↗

Out of the Smokescreen: does an anti-smoking advertisement affect young women's perception of smoking in movies and their intention to smoke?

OBJECTIVE: To evaluate the effect of an anti-smoking advertisement on young women's perceptions of smoking in movies and their intention to smoke. SUBJECTS/ SETTING: 2038 females aged 12-17 years attending cinemas in New South Wales, Australia. DESIGN/ INTERVENTION: Quasi-experimental study of patrons, who were surveyed after having viewed a movie at their local cinema. The control group was surveyed during week 1 and the intervention group, during week 2. Before seeing the movie in week 2, a 30 second anti-smoking advertisement was shown, which featured a well known female actor drawing attention to the prevalence of smoking in movies. OUTCOMES: Attitude of current smokers and non-smokers to smoking in the movies; intention of current smokers and non-smokers to be smoking in 12 months time. RESULTS: Among non-smokers, 48.2% of the intervention subjects thought that the smoking in the movie they viewed was "not OK" compared with 28.3% of the control subjects (p < 0.0001). However, there was no difference among smokers in the intervention (26.4%) and control (16.9%) groups (p = 0.28). A higher percentage of current smokers in the intervention group indicated they were unlikely to smoke in 12 months time (47.8%) than smokers in the control condition (31.9%) (p = 0.03). For non-smokers, there was no difference in smoking intentions between conditions, with 95% saying they would be unlikely to be smoking in 12 months time. CONCLUSIONS: This "real world" study suggests that placing an anti-smoking advertisement before movies containing smoking scenes can help to "immunise" young women against the influences of film stars smoking.

Adolescent↗

Separation and determination of flavonoids and other phenolic compounds in cranberry juice by high-performance liquid chromatography.

A HPLC method was developed for the separation and determination of flavonoid and phenolic antioxidants in cranberry juices. Free flavonoid and phenolic compounds were fractionated into neutral and acidic groups by means of a solid-phase extraction method, followed by subsequent HPLC separations. Combined flavonoids and phenolics were hydrolyzed by acid before HPLC analysis. This developed method provides a fast and high resolution of individual flavonoid and phenolic compounds. In cranberry fruit, flavonoids and phenolic acids exist predominantly in combined forms, such as glycosides and esters. A total of 400 mg of total flavonoids and phenolic compounds/l of sample was found in a freshly squeezed cranberry juice, which was distributed as about 44% of phenolic acids and 56% of flavonoids. Benzoic acid was the major phenolic compound. Major flavonoids in the freshly squeezed cranberry juice were quercetin and myricetin.

Chromatography, High Pressure Liquid↗

Exoribonuclease superfamilies: structural analysis and phylogenetic distribution.

Exoribonucleases play an important role in all aspects of RNA metabolism. Biochemical and genetic analyses in recent years have identified many new RNases and it is now clear that a single cell can contain multiple enzymes of this class. Here, we analyze the structure and phylogenetic distribution of the known exoribonucleases. Based on extensive sequence analysis and on their catalytic properties, all of the exoribonucleases and their homologs have been grouped into six superfamilies and various subfamilies. We identify common motifs that can be used to characterize newly-discovered exoribonucleases, and based on these motifs we correct some previously misassigned proteins. This analysis may serve as a useful first step for developing a nomenclature for this group of enzymes.

Amino Acid Sequence↗

[Expression of c-jun, c-fos and MDM2 mRNA in cultured kerotinocytes through transfecting HPV16].

OBJECTIVE: To study the expression of c-jun, c-fos and MDM2 mRNA in cultured kerotinocytes through transfecting HPV16. METHODS: Keratinocytes were cultured in serum-free medium, and secondary cultures continued in a suitable time. Plasmid pSV(2)-neo/HPV16 was transfected into cultured kerotinocytes using FuGENE(TM)6. Reverse-transcriptase polymerase chain reaction (RT-PCR) was used to detect c-jun, c-fos and MDM2 mRNA in keratinocytes of normal and transfected keratinocytes. RESULTS: After transfection, the morphology and structure of the keratinocytes were changed. The cells became larger and their nuclei became looser. There were particles in the cytoplasm. The expression of HPV16 mRNA was detected in the keratinocytes after transfecting pSV(2)-neo/HPV16 and the product was 110 bp fragment. The DNA fragment (7.9 kb) of HPV16 was also detected. In the transfected keratinocytes, the exprssions of c-jun, c-fos and MDM2 mRNA were detected and the products were 196 bp, 332 bp and 548 bp fragments, respectively. However, the above-mentioned expressions those were not detected in normal keratinocytes. CONCLUSION: HPV leads to cell proliferation by expressing c-jun, c-fos and MDM2.

Cells, Cultured↗

Modulation of neuronal nicotinic acetylcholine receptors by halothane in rat cortical neurons.

Inhalational general anesthetics have recently been shown to inhibit neuronal nicotinic acetylcholine (ACh) receptors (nnAChRs) expressed in Xenopus laevis oocytes and in molluscan neurons. However, drug actions on these systems are not necessarily the same as those seen on native mammalian neurons. Thus, we analyzed the detailed mechanisms of action of halothane on nnAChRs using rat cortical neurons in long-term primary culture. Currents induced by applications of ACh via a U-tube system were recorded by the whole-cell, patch-clamp technique. ACh evoked two types of currents, alpha-bungarotoxin-sensitive, fast desensitizing (alpha 7-type) currents and alpha-bungarotoxin-insensitive, slowly desensitizing (alpha 4 beta 2-type) currents. Halothane suppressed alpha 4 beta 2-type currents more than alpha 7-type currents with IC(50) values of 105 and 552 microM, respectively. Halothane shifted the ACh dose-response curve for the alpha 4 beta 2-type currents in the direction of lower ACh concentrations and slowed its apparent rate of desensitization. The rate of recovery after washout from halothane block was much faster than the rate of recovery from ACh desensitization. Thus, the halothane block was not caused by receptor desensitization. Chlorisondamine, an irreversible open channel blocker for nnAChRs, caused a time-dependent block that was attenuated by halothane. These results could be accounted for by kinetic simulation based on a model in which halothane causes flickering block of open channels, as seen in muscle nAChRs. Halothane block of nnAChRs is deemed to play an important role in anesthesia via a direct action on the receptor and an indirect action to suppress transmitter release.

Acetylcholine↗

The frequency of common skin conditions in preschool-age children in Australia: atopic dermatitis.

OBJECTIVE: To determine the prevalence and severity of atopic dermatitis in a stratified cross-section of preschool-age children examined throughout Victoria, Australia. DESIGN: A cross-sectional skin survey using a selected cluster sample of the various centers throughout Victoria. SETTING: The study population included Victorian children attending child-care centers, preschools, and Maternal and Child Health Centres, with the reference population being Australian children aged 5 years and younger. PARTICIPANTS: Of 1634 potential participants, 1116 children (68.3%) were examined. INTERVENTION: A dermatologist performed a total skin examination, including head and neck, limbs, and trunk, on all children. The diaper area was examined in children younger than 12 months. MAIN OUTCOME MEASURE: All parents were administered a questionnaire to elicit demographic information, history of skin conditions, and family history of skin problems or related diseases. The examiner recorded the presence, site, and severity of atopic dermatitis for calculation of age- and sex-specific prevalence rates. RESULTS: The age- and sex-adjusted point prevalence was 30.8% (95% confidence interval [CI], 28.0%-33.5%). Most children (63.7%) were classified as having minimal or mild disease. Only 5.8% of children with atopic dermatitis did not have face or flexural involvement. Of the 237 children with atopic dermatitis and information available, 209 used 1 or more products to treat their condition. CONCLUSIONS: Atopic dermatitis is common, decreasing in prevalence after the first 3 years of life. Most children have mild disease requiring little if any treatment, and much could be prevented with simple measures. Educational programs directed at those caring for preschool-age children that provide information on simple preventive measures, where practical, and sources of advice for treatment, if necessary, could substantially reduce the morbidity of this condition in predisposed children.

Child Day Care Centers↗

Dual action of n-alcohols on neuronal nicotinic acetylcholine receptors.

Alcohol is known to modulate the activity of a variety of neuroreceptors and ion channels. Recently, neuronal nicotinic acetylcholine receptors (nnAChRs) have become a specific focus of study because not only are they potently modulated by alcohol but also they regulate the release of various transmitters, including gamma-aminobutyric acid (GABA) and dopamine, which play an important role in the behavioral effects of ethanol. Whereas the potency of normal alcohols (n-alcohols) to potentiate GABA(A) receptors and to inhibit N-methyl-D-aspartate receptors increases with carbon chain length, we have found that n-alcohols, depending on the carbon chain length, exert a dual action, potentiation and inhibition, on nnAChRs in primary cultured rat cortical neurons. The mechanism of dual action of n-alcohols on nnAChRs was further analyzed using human embryonic kidney cells expressing the alpha 4 beta 2 subunits. Shorter chain alcohols from methanol to n-propanol potentiated acetylcholine (ACh)-induced currents, whereas longer chain alcohols from n-pentanol to n-dodecanol inhibited the currents. n-Butanol either potentiated or inhibited the currents depending on the concentrations of ACh and butanol. The parameters for both potentiation (log EC(200)) and inhibition (log IC(50)) were linearly related to carbon number, albeit with different slopes. The slope for potentiation was -0.299, indicating a change in free energy change (Delta Delta G) of 405 cal/mol/methylene group, whereas the slope for inhibition was -0.584, indicating a Delta Delta G of 792 cal/mol. These results suggest that potentiating and inhibitory actions are exerted through two different binding sites. Ethanol decreased the potency of n-octanol to inhibit ACh currents, possibly resulting from an allosteric mechanism.

1-Octanol↗

[A study on bacterial contamination of dental handpieces].

OBJECTIVE: The aim of this study is to evaluate the effects of different factors, including concentration of the bacterial suspension, number of stops set on handpieces, and different disinfectants, on bacterial contamination of handpieces and their clinical significance. METHODS: Bacterial contamination of 20 handpieces were analyzed in different concentration of bacterial suspension, number of stops set on handpieces and after using different out surface disinfectants. RESULTS: Statistical increment (P < 0.05) of handpieces inside contamination was observed relevant to increment of the bacterial suspension concentration. No statistical relevance was seen between handpiece inside contamination and the number of stops set on handpieces(P > 0.05). Disinfection with different disinfectants significantly decreased out surface contamination(P < 0.05), but no statistical change of bacteria (P > 0.05) was observed inside handpieces. CONCLUSION: As the concentration of bacterial suspension is the key factor affecting the inside contamination of handpieces, oral cavity cleanness is essential before dental therapy. The surface disinfection of handpieces is necessary after dental therapy, but cannot prevent cross-contamination between patients.

Cross Infection↗

A tetravalent single-chain antibody-streptavidin fusion protein for pretargeted lymphoma therapy.

Single-chain Fv antibody fragments from the CD20-specific murine monoclonal antibody B9E9 were genetically engineered as streptavidin fusions [single-chain Fv-streptavidin (scFvSA) fusion protein] for use in pretargeted radioimmunotherapy. The scFvSA constructs were expressed as soluble, tetrameric species in the periplasm of Escherichia coli. Expression levels were affected by the order of the variable regions and the length and composition of the single-chain Fv linker. The best expressor was obtained with the variable regions in the heavy chain-light chain configuration separated by a 25-mer Gly4Ser linker. This construct produced 250-300 mg of soluble, tetrameric fusion protein per liter of fermentor culture. The fusion protein (Mr 173,600) was purified from crude lysates by iminobiotin affinity chromatography with an overall yield of about 50% and was analyzed for functionality both in vitro and in vivo. Immunoreactivity of the scFvSA fusion protein and its nanomolar affinity to CD20-positive Ramos cells were comparable with the B9E9 monoclonal antibody. The fusion protein had a biotin dissociation rate identical to recombinant streptavidin and bound an average of 3.6 biotins/molecule of a possible 4 biotins/molecule. Labeled fusion protein cleared from the blood of BALB/c mice with a P half-life of about 16 h. In nude mice bearing Ramos xenografts, the fusion protein demonstrated sufficient tumor localization of functional streptavidin to enable efficient, tumor-specific targeting of a subsequently administered radionuclide-chelate/biotin molecule. These results suggest that large quantities of functional scFvSA can be produced for clinical testing as a therapy for non-Hodgkin's lymphoma.

Amino Acid Sequence↗

[Identification of cry-type genes of 31 Bacillus thuringiensis isolates and analysis of their expression product].

In this study, cry-type gene of 31 isolates of Bt had been identified using PCR-RFLP identification system, and SDS-PAGE analysis and bioassay had been performed. 25 strains containing cry1 type gene express 130-150 kD protein and 16 of them contain cry1I gene, which codes 80 kD protein and is larvicidal to both lepidopteran and coleopteran species. 15 strains contain both cry1 and cry2 type gene; 10 strains contain unknown cry-type gene; 6 strains don't contain seven identified cry-type gene. Result of bioassay shows that the strains containing both cry1 and cry2 gene have high toxicity to lepidopteran order, 7 of them are strongly insecticidal to Pristiphora beijingensis and Lymantria dispar larvae; the strains containing cry1Ab + 1Ac + 2A or cry1Aa + 1Ac + 2A have high activity to Heliothis armigera; no cry gene, no activity. It is indicated that identification of cry-type gene and its analysis of SDS-PAGE protein can predict insecticidal activity of Bt isolates, and it is no pertinency between cry-type gene and serotype of Bt strain.

Animals↗

The DNase activity of RNase T and its application to DNA cloning.

RNase T is one of eight distinct 3'-->5' exoribonucleases present in Escherichia coli. The enzyme plays an important role in stable RNA metabolism, including tRNA end turnover and 3' maturation of most stable RNAs because it is the only RNase that can efficiently remove residues near a double-stranded (ds) stem. In the course of study of its specificity and mechanism, we found that RNase T also has single-strand-specific DNase activity. Purified RNase T degrades both single-stranded (ss)RNA and ssDNA in a non-processive manner. However, in contrast to its action on RNA, RNase T binds ssDNA much more tightly and shows less sequence specificity. As with RNA, DNA secondary structure strongly affects its degradation by RNase T. Thus, RNase T action on a dsDNA with a single-stranded 3'-extension efficiently generates blunt-ended DNA. This property of RNase T suggested that it might be a useful enzyme for blunt-ended DNA cloning. We show here that RNase T provides much higher cloning efficiency than the currently used mung bean nuclease.

Cloning, Molecular↗

The frequency of common nonmalignant skin conditions in adults in central Victoria, Australia.

BACKGROUND: Nonmalignant skin conditions are believed to be common in adults, although there are very few community-based studies to determine their exact frequency. OBJECTIVE: To record the prevalence of common, nonmalignant skin conditions in adults in central Victoria, Australia. METHODS: A total of 1457 respondents from a random selection of adults aged 20 years and over from Maryborough, central Victoria, were given a total body examination by a dermatologist or dermatology trainee. People with any nail or skin signs suggestive of tinea had scrapings taken for fungal culture. RESULTS: The age- and sex-adjusted prevalence of warts was 7.1% (95% confidence interval (CI), 5.8-8.4%), acne 12.8% (95% CI, 11.0-14.5%), atopic dermatitis 6.9% (95% CI, 5.6-8.3%), seborrheic dermatitis 9. 7% (95% CI, 8.2-11.2%), asteatotic dermatitis 8.6% (95% CI, 7.1-10. 0%), psoriasis 6.6% (95% CI, 5.7-7.9%), culture-positive tinea 12% (95% CI, 10.3-13.6%), seborrheic keratoses 58.2% (95% CI, 55.6-60. 7%), and Campbell de Morgan spots (cherry angiomas) 54.4% (95% CI, 51.9-57.0%). There was variation in the prevalence of many of these conditions with age. CONCLUSIONS: This study demonstrates that nonmalignant skin conditions are common in adults in Australia. Their diagnosis and management represent a considerable burden not only to those suffering from the conditions, but also to the health system which provides for their care.

Acne Vulgaris↗

Identification of a receptor-binding pocket on the envelope protein of friend murine leukemia virus.

Based on previous structural and functional studies, a potential receptor-binding site composed of residues that form a pocket at one end of the two long antiparallel helices in the receptor-binding domain of Friend 57 murine leukemia virus envelope protein (RBD) has been proposed. To test this hypothesis, directed substitutions for residues in the pocket were introduced and consequences for infection and for receptor binding were measured. Receptor binding was measured initially by a sensitive assay based on coexpression of receptor and RBD in Xenopus oocytes, and the findings were confirmed by using purified proteins. Three residues that are critical for both binding and infection (S84, D86, and W102), with side chains that extend into the pocket, were identified. Moreover, when mCAT-1 was overexpressed, the infectivity of Fr57-MLV carrying pocket substitutions was partially restored. Substitutions for 18 adjacent residues and 11 other previously unexamined surface-exposed residues outside of the RBD pocket had no detectable effect on function. Taken together, these findings support a model in which the RBD pocket interacts directly with mCAT-1 (likely residues, Y235 and E237) and multiple receptor-envelope complexes are required to form the fusion pore.

3T3 Cells↗

Flagellar duplication and migration during the Trichomonas vaginalis cell cycle.

Trichomonas vaginalis is a flagellated protozoan, a representative of 1 of the earliest known eukaryotic lineages. Trichomonas vaginalis lacks centrioles but possesses basal bodies. We report here the cell cycle-dependent flagellar dynamics of T. vaginalis. By immunofluorescence, we found that T. vaginalis flagella duplicated during S-phase, segregated toward the nuclear poles, and then emanated from the spindle poles at mitosis. This behavior strongly parallels that of centrioles and other spindle pole-associated structures variously termed centrosomes, spindle pole bodies, or microtubule organizing centers. These observations support the hypothesis that flagellar forces may have provided motile forces for spindle pole alignment in an ancestral eukaryote.

Animals↗

Prenatal alcohol use and offspring size at 10 years of age.

The Maternal Health Practices and Child Development Project is a longitudinal study of the effects of prenatal exposure to alcohol and other substances. Women were selected from a prenatal clinic and interviewed at the 4th and 7th months of pregnancy. Their offspring were examined at delivery, at 8 and 18 months, and at 3, 6, and 10 years. This report examined 610 offspring, at age 10, who were exposed prenatally to alcohol. Most alcohol use in this low-income cohort was light to moderate, although the entire spectrum of alcohol use is represented. The weight, length, head circumference, and skinfold thickness of the offspring were measured. At each assessment phase, we found a significant association between size and prenatal exposure to alcohol. At age 10, the children who were prenatally exposed to alcohol continued to be significantly smaller in weight, height, head circumference, and skinfold thickness. These results indicate that prenatal alcohol exposure has a long-term impact on offspring growth.

Alcohol Drinking↗