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Biomedical subjects

Y Li

Publications and source records attributed to Y Li.

At least 109 records · Page 6Linked to original sources
PubMed2006

Identification of Vibrio harveyi using PCR amplification of the toxR gene.

AIMS: The aim of this study was to develop an effective method for the identification of Vibrio harveyi based on using the toxR gene as a taxonomic marker. METHODS AND RESULTS: Primers for the toxR gene were designed for specificity to V. harveyi, and incorporated in a polymerase chain reaction (PCR). The results of the PCR, which took <5 h from DNA extraction to amplification, revealed positive amplification of the toxR gene fragment in 20 V. harveyi isolates including type strains, whereas DNA from 23 other Vibrionaceae type strains and 13 Vibrio parahaemolyticus strains were negative. The detection limit of the PCR was 4.0 x 10(3) cells ml(-1). In addition, the technique enabled the recognition of V. harveyi from diseased fish. CONCLUSIONS: The PCR was specific and sensitive, enabling the identification of V. harveyi within 5 h. SIGNIFICANCE AND IMPACT OF THE STUDY: The PCR allowed the rapid and sensitive detection of V. harveyi.

Animals↗
PubMed2006

Dispersion of exhaled droplet nuclei in a two-bed hospital ward with three different ventilation systems.

UNLABELLED: Effective ventilation in general hospital wards is important for controlling the airborne transmission of infectious respiratory diseases. Experiments have been carried out to increase our understanding of the interaction of the breathing flows of two individuals in a full-scale experimental hospital ward with three ventilation systems, i.e. mixing, downward and displacement ventilation. Two life-size breathing thermal manikins were used to simulate a source patient and a receiving patient. The exhalation jet from a bed-lying manikin was visualized using smoke. N2O was used as tracer gas to simulate the droplet nuclei exhaled by patients; and the spatial distribution of its concentrations was measured. Our experimental results show that for both mixing and downward ventilation, the exhaled jet penetrates a short distance and is diluted quickly by ventilation air. The exhaled droplet nuclei are well mixed in the ward. Bed distance does not affect the personal exposure of the receiving patient. For displacement ventilation, the exhaled jet can penetrate a long distance. A high concentration layer of exhaled droplet nuclei because of thermal stratification locking has also been observed with displacement ventilation. This work is useful for identifying an appropriate ventilation method that can remove droplet nuclei more effectively and minimize the risk of cross-infections in a hospital ward environment. PRACTICAL IMPLICATIONS: As one of the major potential sources for infectious droplet nuclei in a hospital environment, exhalation flows of an infected patient can interact with the respiratory activities of other close individuals and with the room ventilation systems. Our latest results provide information on the penetration of exhalation jets into the ambient environment in different ventilation systems. This work is useful in identifying an appropriate and effective ventilation method for removing droplet nuclei more effectively, and thus minimizing the risk of cross-infections in hospital wards with multiple beds.

Air Movements↗
PubMed2006

Skin phototyping in a Chinese female population: analysis of four hundred and four cases from four major cities of China.

BACKGROUND/PURPOSE: The sun-reactive skin types in 404 Chinese females living in different cities were investigated in this study. METHODS: A questionnaire was designed according to the original concept of skin types proposed by Fitzpatrick and the investigation was conducted in two ways: self-administered reporting and then a personal interview. Minimal erythema dose (MED) and minimal persistent pigmentation dose (MPPD) were also measured in part of the volunteers with a standard solar simulator. RESULTS: The results show that in the way of personal interview, the predominant skin type of the investigated group is type III (71.4%), and then type II (14.7%) and type IV (14.2%), while in the self-reporting manner, the result is as follows: type III, 74.3%, type II, 25.6% and type IV, 1%. There are no skin type I, V or VI in the studied group. MED and MPPD from the same population show some relevance to the skin types, e.g. with the change of skin type from Type II to IV, the mean value of MED increases gradually and the MPPD decreases slightly. CONCLUSIONS: From the study we concluded that the skin types of the investigated Chinese females are principally type III (more than 70%), and then type II and type IV. The different ways of answering the questionnaire did not affect the results remarkably. The measurements of photobiology parameters confirmed that there is a certain correlation between skin types and MED or MPPD determined in this group of volunteers.

Age Distribution↗
PubMed2006

The common -318C/T polymorphism in the promoter region of CTLA4 gene is associated with reduced risk of ophthalmopathy in Chinese Graves' patients.

Studies in the past have clearly established that CTLA4 is a susceptible gene for Graves' disease (GD). However, association studies between CTLA4 and the risk of developing Graves' ophthalmopathy (GO) in GD patients have shown conflicting results. In this study, associations of five CTLA4 single nucleotide polymorphisms (-1722A/G, -1661A/G, -318C/T, +49G/A, CT60) with GD risk and GO susceptibility in GD patients were investigated in a Chinese population. Our results showed that either +49A/G or CT60 polymorphism was associated with GD susceptibility in the Chinese population. Significant differences in the distribution of the genotypes or alleles evaluated between GD patients with and without clinically evident GO were only found for -318C/T polymorphism (P = 0.03). Multiple logistic regressions revealed that the -318T allele was negatively associated with GO under both additive and dominant genetic models (adjusted OR = 0.56, 95%CI 0.35-0.89, P = 0.014; adjusted OR = 0.51, 95%CI 0.30-0.84, P = 0.009, respectively). Stratification analysis according to gender demonstrated different scenarios concerning the role of the -318T allele in GO risk: a significant protective role for GO was only confirmed in male but not in female GD patients. Haplotype analyses showed that only the haplotypes containing the -318T allele played a protective role in GO. In conclusion, results from this study suggested that the -318T allele might play a protective role in GO susceptibility for GD patients at least in the Chinese population. However, extended analyses with larger sample size should be carried out in patients from different ethnic origins to further verify this association.

Adult↗
PubMed2006

Characterization of antibody responses elicited by human immunodeficiency virus type 1 primary isolate trimeric and monomeric envelope glycoproteins in selected adjuvants.

We previously reported that soluble, stable YU2 gp140 trimeric human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein immunogens could elicit improved breadth of neutralization against HIV-1 isolates compared to monomeric YU2 gp120 proteins. In this guinea pig immunization study, we sought to extend these data and determine if adjuvant could quantitatively or qualitatively alter the neutralizing response elicited by trimeric or monomeric immunogens. Consistent with our earlier studies, the YU2 gp140 immunogens elicited higher-titer neutralizing antibodies against homologous and heterologous isolates than those elicited by monomeric YU2 gp120. Additionally, the GlaxoSmithKline family of adjuvants AS01B, AS02A, and AS03 induced higher levels of neutralizing antibodies compared to emulsification of the same immunogens in Ribi adjuvant. Further analysis of vaccine sera indicated that homologous virus neutralization was not mediated by antibodies to the V3 loop, although V3 loop-directed neutralization could be detected for some heterologous isolates. In most gp120-inoculated animals, the homologous YU2 neutralization activity was inhibited by a peptide derived from the YU2 V1 loop, whereas the neutralizing activity elicited by YU2 gp140 trimers was much less sensitive to V1 peptide inhibition. Consistent with a less V1-focused antibody response, sera from the gp140-immunized animals more efficiently neutralized heterologous HIV-1 isolates, as determined by two distinct neutralization formats. Thus, there appear to be qualitative differences in the neutralizing antibody response elicited by YU2 gp140 compared to YU2 monomeric gp120. Further mapping analysis of more conserved regions of gp120/gp41 may be required to determine the neutralizing specificity elicited by the trimeric immunogens.

Adjuvants, Immunologic↗
PubMed2006

Human saliva proteome and transcriptome.

This paper tests the hypothesis that salivary proteins and their counterpart mRNAs co-exist in human whole saliva. Global profiling of human saliva proteomes and transcriptomes by mass spectrometry (MS) and expression microarray technologies, respectively, revealed many similarities between saliva proteins and mRNAs. Of the function-known proteins identified in saliva, from 61 to 70% were also found present as mRNA transcripts. For genes not detected at both protein and mRNA levels, we made further efforts to determine if the counterpart is present. Of 19 selected genes detected only at the protein level, the mRNAs of 13 (68%) genes were found in saliva by RT-PCR. In contrast, of many mRNAs detected only by microarrays, their protein products were found in saliva, as reported previously by other investigators. The saliva transcriptome may provide preliminary insights into the boundary of the saliva proteome.

Adult↗
PubMed2006

Ammonia removal in the catalytic wet air oxygen process of landfill leachates with Co/Bi catalyst.

Oxidation of ammonia in landfill leachates in the catalytic wet air oxidation (CWAO) process was investigated with Co/Bi catalyst. The characterization of the Co/Bi catalyst was carried out by the X-ray diffraction technique. Studies of ammonia removal from the landfill leachates by CWAO showed that Co/Bi catalyst exhibited higher activities for both total organic carbon (TOC) and ammonia with removal levels of 99% for TOC and 98% for ammonia, respectively. Results also indicated that large amounts of ammonia were produced during the elimination of nitrogenous organic compounds in the CWAO process and the further oxidation of ammonia gave off essentially N2 under 240 degrees C. When the system temperature reached above 240 degrees C, ammonia oxidation rate was much higher with nitrate dominating in the effluent; a very small amount of nitrite was observed in the reaction process, it possibly acts as the intermediate of nitrate ion and molecular nitrogen formation, showing that the system temperature had significant effects on the ammonia oxidation and reaction selectivity towards the production of molecular nitrogen or nitrate.

Ammonia↗
PubMed2006

Hippocampal cerebrospinal fluid spaces on MR imaging: Relationship to aging and Alzheimer disease.

BACKGROUND AND PURPOSE: Perihippocampal fissures (PHFs) and hippocampal sulcus residual cavities (HSCs) are common findings in the MR imaging examination of the hippocampus in aging and Alzheimer disease (AD); however, little is known about how to distinguish them or their relative clinical relevance. We hypothesized that prominence of the HSC, unlike PHF, is not significantly influenced by the hippocampal atrophy related to aging or AD. METHODS: We studied and evaluated these hippocampal CSF spaces on MR imaging scans from 130 normal control (NC) subjects (20-90 years of age) and 27 AD patients. RESULTS: HSC is poorly correlated with age and is not related to the magnitude of hippocampal atrophy. There is no significant difference of HSCs between AD and age-matched NCs, but in the extremely high HSCs group (top 20%), 91% of cases are NC. PHFs, on the other hand, are strongly correlated with age and are valuable in the diagnosis of AD. Location and communication with ambient cistern is the key to distinguish HSC from PHF. CONCLUSION: Identifying hippocampal atrophy (enlarged PHF) may be particularly challenging in the presence of HSC. Distinguishing among the CSF spaces in hippocampus may help in the radiologic evaluation of hippocampal atrophy. Patients with extremely high HSCs (>8.4) can be excluded from AD risk with 93% specificity.

Adult↗
PubMed2006

Telomerase activity and the subunit of telomerase in hydatidiform mole and their relationship with the development of postmolar tumor.

OBJECTIVES: To investigate the pattern of telomerase activity and the subunit of telomerase in normal placentae and GTD, and to determine the prognostic significance of telomerase activity and the subunit of telomerase in GTD. METHODS: Telomerase activity human telomerase (hTERT) and human telomerase (hTR) expression were analyzed in the initial uterine evacuation specimen of 63 hydatidiform moles (HMs), 42 normal human placental tissues, 17 malignant gestational trophoblastic tumors, primary cultures of normal villi and JAR cell lines by use of the polymerase chain reaction-based telomeric repeat amplification protocol (TRAP) assay and reverse transcription-polymerase chain reaction (RT-PCR) methods. RESULTS: Telomerase activity was 100% in primary cultures of normal villi and JAR cell lines and in less than 60-day early placental villi, while only 9.1% in greater than 60-day placental villi, 27% in HMs and 58% in malignant trophoblastic tumors. High levels of hTR could be found in all groups. hTR expression was detected in all cases of < 60-day placental villi, in 72.7% > 60-day placental villi, in 87.3% in HMs and 100% in malignant trophoblastic tumors. Telomerase activity and hTERT expression had significant differences among the groups. Telomerase activity was associated with serum hCG levels but not related to other clinical risk factors. CONCLUSIONS: Telomerase activity may be correlated with the development of trophoblastic tumors, and hTERT may be a useful diagnostic marker for detecting the existence of malignant trophoblastic cells.

Cell Line↗
PubMed2006

Stimulative activity of Drynaria fortunei (Kunze) J. Sm. extracts and two of its flavonoids on the proliferation of osteoblastic like cells.

The osteoblastic activity of extracts of Drynaria fortunei (Kunze) J. Sm. rhizome was assayed in the UMR106 cell line cultured in vitro. An ethanol extract and its fractions were added to the cell culture at different concentrations. Osteoblastic proliferation stimulating activity was determined using the MTT method. The ethanol extract, and its ethyl acetate and n-butanol fractions exhibited stimulating activity. Two active constituents were isolated from n-butanol fraction by bioassay-directed isolation, and identified as naringin and neoeriocitrin. The latter is reported for the first time from this herbal medicine.

Cell Line↗
PubMed2005

Dynamic changes in orbitofrontal neuronal activity in rats during opiate administration and withdrawal.

The orbitofrontal cortex is involved in the reinforcing effects of drugs of abuse. However, how the dynamic activity in OFC changes during opiate administration and withdrawal period has not been investigated. We first tested the effects of opiates and drug craving with the conditioned place preference paradigm, using manganese-enhanced magnetic resonance imaging and traditional electroencephalograph recording techniques in rats. T1-weighted 2D MRI (4.7 T) was used after unilateral injection of MnCl(2) (200 nL, 80 mM) into the right orbitofrontal cortex. The manganese-enhanced magnetic resonance imaging data suggested that the OFC activity decreased during the opiate administration period but recovered increasingly during the withdrawal period. Also, we found decreases and increases in gamma-band (20-100 Hz) activity during the opiate administration and withdrawal period, respectively. Our results showed that orbitofrontal cortex activity decreased during morphine administration and then went up progressively over several days during withdrawal. The time course of the recovery of orbitofrontal activity from inhibition during the withdrawal period may be related to the experience of drug craving.

Animals↗
PubMed2005

Intracarotid transplantation of bone marrow stromal cells increases axon-myelin remodeling after stroke.

The present study investigates the induction of axon and myelin remodeling as a possible mechanism by which treatment of stroke with bone marrow stromal cells improves neurological functional recovery. Adult male Wistar rats were subjected to 2 h of middle cerebral artery occlusion, followed by an injection of 2 x 10(6) rat bone marrow stromal cells or phosphate-buffered saline into the internal carotid artery 24 h later. Animals were killed at 28 days after stroke. Functional tests, histo- and immunohistochemical staining were performed. Significant functional recovery was found after bone marrow stromal cell administration in all the three tests performed (modified neurological severity score, adhesive-removal and corner tests). Bone marrow stromal cell treatment markedly increased vessel sprouting, synaptophysin expression and NG2 positive cell numbers and density in the cortical peri-infarct area. In bone marrow stromal cell-treated rats, the number of Ki-67 positive proliferating cells and oligodendrocyte precursor cells in the corpus callosum increased significantly in concert with the enhancement of the areas of the corpus callosum in both hemispheres. These results suggest that bone marrow stromal cells facilitate axonal sprouting and remyelination in the cortical ischemic boundary zone and corpus callosum, which may underlie neurological functional improvement caused by bone marrow stromal cell treatment.

Animals↗
PubMed2005

Persistent sodium currents and repetitive firing in motoneurons of the sacrocaudal spinal cord of adult rats.

Months after sacral spinal transection in rats (chronic spinal rats), motoneurons below the injury exhibit large, low-threshold persistent inward currents (PICs), composed of persistent sodium currents (Na PICs) and persistent calcium currents (Ca PICs). Here, we studied whether motoneurons of normal adult rats also exhibited Na and Ca PICs when the spinal cord was acutely transected at the sacral level (acute spinal rats) and examined the role of the Na PIC in firing behavior. Intracellular recordings were obtained from motoneurons of acute and chronic spinal rats while the whole sacrocaudal spinal cord was maintained in vitro. Compared with chronic spinal rats, motoneurons of acute spinal rats were more difficult to activate because the input resistance was 22% lower and resting membrane potential was hyperpolarized 4.1 mV further below firing threshold (-50.9 +/- 6.2 mV). In acute spinal rats, during a slow voltage ramp, a PIC was activated subthreshold to the spike (at -57.2 +/- 5.0 mV) and reached a peak current of 1.11 +/- 1.21 nA. This PIC was less than one-half the size of that in chronic spinal rats (2.79 +/- 0.94 nA) and usually was not large enough to produce bistable behavior (plateau potentials and self-sustained firing not present), unlike in chronic spinal rats. The PIC was composed of two components: a TTX-sensitive Na PIC (0.44 +/- 0.36 nA) and a nimodipine-sensitive Ca PIC (0.78 +/- 0.82 nA). Both were smaller than in chronic spinal rats (but with similar Na/Ca ratio). The presence of the Na PIC was critical for normal repetitive firing, because no detectable Na PIC was found in the few motoneurons that could not fire repetitively during a slow ramp current injection and motoneurons that had large Na PICs more readily produced repetitive firing and had lower minimum firing rates compared with neurons with small Na PICs. Furthermore, when the Na PIC was selectively blocked with riluzole, steady repetitive firing was eliminated, even though transient firing could be evoked on a rapid current step and the spike itself was unaffected. In summary, only small Ca and Na PICs occur in acute spinal motoneurons, but the Na PIC is essential for steady repetitive firing. We discuss how availability of monoamines may explain the variability in Na PICs and firing in the normal and spinal animals.

Animals↗
PubMed2005

Door-opening motion can potentially lead to a transient breakdown in negative-pressure isolation conditions: the importance of vorticity and buoyancy airflows.

A patient with severe chickenpox was admitted to a negative-pressure isolation room. He remained sedated, intubated and mechanically ventilated throughout his admission. He was managed only by nurses immune to chickenpox. A non-immune male nurse occasionally handed equipment through the doorway, without entering the room. Ten days later, he also developed chickenpox. Sequencing of viruses from the patient and nurse showed the same rare genotype, indicating nosocomial transmission. An experimental model demonstrated that, despite negative pressure, opening the door could have resulted in transport of infectious air out of the isolation room, leading to a breakdown in isolation conditions.

Air Pressure↗
PubMed2005

Ginkgo biloba for acute ischaemic stroke.

BACKGROUND: Ginkgo biloba extract is widely used in the treatment of acute ischaemic stroke in China. We aimed to assess the evidence from randomised controlled trials and quasi-randomised controlled trials on the use of Ginkgo biloba extract in acute ischaemic stroke. OBJECTIVES: The primary objective was to determine whether Ginkgo biloba extract improves functional outcome without causing undue harm in patients with acute ischaemic stroke. Secondary objectives were to assess the effect of Ginkgo biloba extract on neurological impairment and quality of life. SEARCH STRATEGY: We searched the Cochrane Stroke Group Trials Register (last searched October 2004), the Trials Register of the Cochrane Complementary Medicine Field (last searched October 2004) and the Chinese Stroke Trials Register (last searched June 2004). In addition, we searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 3, 2004), MEDLINE (1966 to August 2004), EMBASE (1980 to June 2004), AMED (1985 to May 2002) and the China Biological Medicine Database (CBM-disc, 1979 to August 2004). We searched relevant clinical trials and research registers and contacted pharmaceutical companies and researchers in an effort to identify further published and unpublished studies. SELECTION CRITERIA: Randomised controlled trials or quasi-randomised controlled clinical trials comparing Ginkgo biloba extract with placebo or open control (no placebo) in patients with acute ischaemic stroke. DATA COLLECTION AND ANALYSIS: Two reviewers independently selected trials for inclusion, assessed trial quality and extracted the data. MAIN RESULTS: Fourteen trials were identified, of which 10 trials (792 patients) were included. Four trials are awaiting assessment. In the 10 included trials follow up was performed at 14 to 35 days after stroke. In all studies neurological outcome was assessed but none of them reported on disability (activities of daily living function) or quality of life. Only three trials reported adverse events. In nine trials, all of them assessed to be of inferior quality, significant improvement in neurological deficit at the end of the treatment was used as the outcome measure. When analysing these trials together, Ginkgo biloba extract was associated with a significant increase in the number of improved patients (Peto odds ratio (OR) 2.66; 95% confidence interval (CI) 1.79 to 3.94). One placebo-controlled trial, assessed to be of good quality, reported neurological outcome as a continuous variable. It failed to show an improvement of neurological deficit at the end of treatment (weighted mean difference (fixed) 0.81; 95% CI -8.9 to 10.52). No deaths or major adverse events were reported during the follow-up period. AUTHORS' CONCLUSIONS: There was no convincing evidence from trials of sufficient methodological quality to support the routine use of Ginkgo biloba extract to promote recovery after stroke. High-quality and large-scale randomised controlled trials are needed to test its efficacy.

Ginkgo biloba↗
PubMed2005

A model of polyelectrolyte conductance in moist solvents as a basis of water sensors.

The conductance of interpenetrated polymer networks (IPNs) containing quaternary amino groups was studied in cyclohexane, toluene, ethyl ether, ethyl acetate, and tetrahydrofurane as a function of water content by electrochemical impedance spectroscopy. IPNs were then used as sensitive materials to detect water traces in organic solvents with promising results for the construction of a moisture sensor. The detection onset for water concentration increased with the dielectric constant of the solvent. Different IPN-based sensors in the same solvent showed a detection limit at lower water concentration if their characteristic plot [conductance/relative humidity (RH%) in air] was shifted toward lower RH%. This suggests that the composition of this class of polymers can be tuned to achieve the best performance for each solvent.

Journal Article↗
PubMed2005

Bone marrow stromal cells increase astrocyte survival via upregulation of phosphoinositide 3-kinase/threonine protein kinase and mitogen-activated protein kinase kinase/extracellular signal-regulated kinase pathways and stimulate astrocyte trophic factor gene expression after anaerobic insult.

Transplantation of bone marrow stromal cells improves animal neurological functional recovery after stroke. Astrocytes are known to provide structural, trophic and metabolic support for neurons. Thus astrocytes are critical for neural survival during post-ischemia. However, information on the effects of bone marrow stromal cells on astrocytic survival post-ischemia is unavailable. We investigated the influence of rat bone marrow stromal cells on rat astrocytic apoptosis and survival post-ischemia employing an anaerobic chamber. Our data indicate that rat bone marrow stromal cells reduce cell death and apoptosis, and increase the DNA proliferation rate in astrocytes post-ischemia. Mitogen-activated protein kinase kinase/extracellular signal regulated kinase and phosphoinositide 3-kinase/threonine protein kinase pathways are involved in cell survival. Western blot showed that rat bone marrow stromal cells activate these two pathways in astrocytes post-ischemia, and upregulate total extracellular signal regulated kinase 1/2 and threonine protein kinase. Since astrocytes produce various neurotrophic factors, we performed reverse transcription polymerase chain reaction to investigate rat bone marrow stromal cells' effect on astrocyte growth factor gene expression post-ischemia. We observed that brain-derived neurotrophic factor, vascular endothelial growth factor and basic fibroblast growth factor gene expression was enhanced by rat bone marrow stromal cell coculture. These data suggest that bone marrow stromal cells increase astrocytic survival post-ischemic injury. This protective function might involve the activation of mitogen-activated protein kinase kinase/extracellular signal-regulated kinase and phosphoinositide 3-kinase/threonine protein kinase pathways. Upregulation of brain-derived neurotrophic factor, vascular endothelial growth factor and basic fibroblast growth factor may also contribute to astrocyte survival.

Anaerobiosis↗