Biomedical subjects

Y Xiao

Publications and source records attributed to Y Xiao.

At least 163 records · Page 9Linked to original sources

PubMed1999

Information acquisition from audio-video-data sources: an experimental study on remote diagnosis. The LOTAS Group.

OBJECTIVE: To determine what information sources are used during a remote diagnosis task. MATERIALS AND METHODS: Experienced trauma care providers viewed segments of videotaped initial trauma patient resuscitation and airway management. Experiment 1 collected responses from anesthesiologists to probing questions during and after the presentation of recorded video materials. Experiment 2 collected the responses from three types of care providers (anesthesiologists, nurses, and surgeons). Written and verbal responses were scored according to detection of critical events in video materials and categorized according to their content. Experiment 3 collected visual scanning data using an eyetracker during the viewing of recorded video materials from the three types of care providers. Eye-gaze data were analyzed in terms of focus on various parts of the videotaped materials. RESULTS: Care providers were found to be unable to detect several critical events. The three groups of subjects studied (anesthesiologists, nurses, and surgeons) focused on different aspects of videotaped materials. CONCLUSION: When the remote events and activities are multidisciplinary and rapidly changing, experts linked with audio-video-data connections may encounter difficulties in comprehending remote activities, and their information usage may be biased. Special training is needed for the remote decision-maker to appreciate tasks outside his or her speciality and beyond the boundaries of traditional divisions of labor.

Anesthesiology↗

PubMed1999

Activities of eighteen antimicrobial regimens against Mycobacterium avium infection in beige mice.

The therapeutic effect of 18 anti-Mycobacterium avium regimens was examined in beige mice after 91 days of infection. Treatments included monotherapy with clarithromycin (CLA), ethambutol (EMB), amikacin (AMI), rifabutin (RFB), ciprofloxacin (CIP), clofazimine (CLO), and combinations of CLA, CLA-EMB, or CLA-AMI with one of the other drugs. After monotherapy, only AMI and CLA displayed bacteriostatic and/or moderate bactericidal effects in spleens and lungs, while CIP and RFB were totally inactive and CLO and EMB showed intermediate effects against the isolate tested. Resistant mutants were isolated in spleens of mice treated with EMB, CIP, RFB, and CLO-Among two-drug combinations, CLA-RFB, CLA-CIP, and CLA-CLO were significantly more active than RFB, CIP, CLO, respectively, but not more active than CLA alone, in both organs; CLA-AMI and CLA-EMB were bactericidal in spleens and lungs, respectively. Although activity of CLA-EMB was significantly potentiated by RFB and CLO in spleens and lungs, that of CLA-AMI was significantly increased by RFB and CLO only in lungs. The most active regimen in spleens and lungs on day 91 was the combination of all three, namely CLA-AMI-EMB, which reduced the CFU numbers of 2.7 and 7.5 log10, in comparison with day 1 and day 91 counts in untreated control mice, respectively.

Amikacin↗

PubMed1999

Segregation and convergence of functionally defined V2 thin stripe and interstripe compartment projections to area V4 of macaques.

The organization of projections from V2 thin stripes and interstripes to V4 was investigated using a combination of physiological and anatomical techniques. The compartments of V2 were first characterized, in vivo, using optical recording of intrinsic signals. Multiple anterograde tracers were then injected into different V2 compartments. The distribution of labeled axons was analyzed in tangential or horizontal sections including V4. A small iontophoretic injection, either in a thin stripe or an interstripe, labeled a large primary and several secondary foci in V4. The primary foci from the thin stripe and interstripe were spatially segregated by a gap of approximately 1 mm. Furthermore, less dense regions within the primary foci were often 'filled-in' by secondary foci from the opposite V2 compartment. When two injections were made both at interstripes, their projections to V4 were almost entirely overlapping. These anatomical patterns indicate that segregation and convergence of intercortical pathways are both important features of V4 organization. Furthermore, the size of cortical modules increases considerably from the blobs of V1, through the stripes of V2, to the afferent domains of V4.

Animals↗

PubMed1999

Catalytic roles of yeast GSK3beta/shaggy homolog Rim11p in meiotic activation.

In Saccharomyces cerevisiae, many meiotic genes are activated by a heteromeric transcription factor composed of Ime1p and Ume6p. Ime1p-Ume6p complex formation depends upon the protein kinase Rim11p, which interacts with and phosphorylates both Ime1p and Ume6p in vitro. Rim11p may promote complex formation through its phosphorylation of Ime1p and Ume6p or simply through its interaction with both proteins. Here, we characterize mutant Ime1p derivatives that interact with Rim11p but are not phosphorylated in vitro. These mutant proteins are also defective in interaction with Ume6p. These results argue that Ime1p must be phosphorylated to interact with Ume6p. Our genetic observations suggest that Ime1p tyrosine residues are among the Rim11p phosphoacceptors, and we find that Ime1p reacts with an anti-phosphotyrosine antibody. Ime1p and Rim11p have been thought to act only through Ume6p, but we find that Ime1p and Rim11p promote meiosis at a very low level in the absence of Ume6p. A nonphosphorylatable mutant Ime1p derivative promotes sporulation through this Ume6p-independent pathway, as does a mutant Rim11p derivative that fails to interact with Ime1p. Therefore, Ime1p and Rim11p have two genetically separable functions in the sporulation program. However, catalytic activity of Rim11p is required for sporulation in the presence or absence of Ume6p.

Base Sequence↗

PubMed1999

Dual-colour FISH analysis to characterize a marker chromosome in cytochrome P450 2B1 recombinant V79 Chinese hamster cells.

Recombinant V79 Chinese hamster cell lines have been constructed for the expression of useful functions, e.g. cytochromes P450, in order to study metabolism-dependent toxicity. Recombinant cell lines are derived as single clones upon gene transfer and selection from the parental V79 cell line. It is of fundamental importance for a reliable application of the recombinant cell lines to show that the original biological characteristics of the parental line are maintained. As part of these efforts, fluorescence in situ hybridization with Chinese hamster chromosome-specific DNA libraries was performed in order to identify the origin of the chromosomes from which a marker chromosome present in the recombinant cell line V79MZr2B1 was derived, which could not be identified by standard cytogenetic techniques.

Animals↗

PubMed1999

Analysis of bleomycin-induced chromosomal aberrations in Chinese hamster primary embryonic cells by FISH using arm-specific painting probes.

Chinese hamster primary embryonic cells (at G1 phase) were treated with 1.0 or 3.0 microg/ml bleomycin and chromosomal aberrations in first division metaphases were analysed by fluorescence in situ hybridization (FISH) using arm-specific painting probes for chromosomes 3, 4, 8 and 9. We observed that bleomycin induced all classes of chromosome-type aberrations very efficiently. The interesting findings were: (i) the frequency of induced interstitial translocations (i.e. insertions) was approximately equal to that of reciprocal translocations; (ii) the frequency of induced pericentric inversions was higher than that of centric rings. In our earlier studies, we found that X-rays induced a low frequency of interstitial translocations in comparison with reciprocal translocations and equal frequencies of centric rings and pericentric inversions. These data suggest that bleomycin differs from X-rays with respect to the induction of some specific types of aberrations. The results of a chi2 test examining the hypothesis that formed aberrations among the chromosomes or chromosome arms are randomly distributed on the basis of their relative lengths revealed a differential involvement of these chromosomes in the aberrations following exposure to bleomycin. In general, chromosome 8 was found to be more involved in induced aberrations than expected, chromosome 4 was randomly involved, whereas chromosomes 3 and 9 were less involved. This study demonstrates the utility of arm-specific painting probes for efficient detection of a large variety of chromosomal aberrations induced by bleomycin.

Animals↗

PubMed1999

Activation and Ca2+ permeation of stably transfected alpha3/beta4 neuronal nicotinic acetylcholine receptor.

The alpha3/beta4 rat neuronal nicotinic acetylcholine receptor, stably transfected in human embryonic kidney cells, was examined using the whole-cell-clamp technique and 2-dimensional confocal imaging. Application of agonists (nicotine, cytisine, epibatidine) activated a large (100-200 pA/pF) inwardly rectifying monovalent current, with little current at voltages between 0 and +40 mV. Rapid application of nicotine and cytisine indicated EC50 values of congruent with22 and congruent with64 microM, respectively, and suggested second order binding kinetics (Hill coefficient approximately 2). The time constant of desensitization (decay) of nicotine-activated current was concentration-dependent (typically approximately 10 s at 30 microM versus approximately 1.0 s at 100-1000 microM), but not voltage-dependent and was significantly smaller than the approximately 200 s reported for the alpha3/beta4 receptor expressed in Xenopus oocytes. Nicotine-activated current was rapidly and reversibly blocked by coapplication of mecamylamine and d-tubocurarine. At -80 mV holding potentials, the current was also suppressed by approximately 25% either upon complete removal or elevation of Ca2+ to 10 mM. Total replacement of Na+ by Ca2+ also completely blocked the current. On the other hand, evidence for permeation of Ca2+ was indicated by increased inward current at -40 mV upon elevation of Ca2+ from 2 to 10 mM, as well as a rise in the cytosolic Ca2+ proportional to the current carried by the receptor. These findings are consistent with the idea that Ca2+, in addition to its channel-permeating properties, may also regulate the receptor from an extracellular site. Our results suggest that the alpha3/beta4 neuronal nicotinic acetylcholine receptor, when stably expressed in human embryonic kidney 293 cells, has desensitization kinetics and Ca2+ regulatory mechanisms somewhat different from those described for the receptor expressed in Xenopus oocytes.

Animals↗

PubMed1999

Causes of childhood blindness in the People's Republic of China: results from 1131 blind school students in 18 provinces.

AIMS: To determine the anatomical site and underlying causes of blindness and severe visual impairment in children under 16 years of age in special education in the People's Republic of China with a view to determining potentially preventable and treatable causes. METHODS: A national study of children attending schools for the blind in China was conducted between April and June 1998 using the WHO Prevention of Blindness Programme (WHO/PBL) eye examination record for children with blindness and low vision. Eight Chinese ophthalmologists attended a training workshop before conducting the study. 36 blind schools in 18 provinces of China were included. RESULTS: 1245 children aged between 5 and 15 years were examined, of whom 1131 (91%) were blind or severely visually impaired (visual acuity less than 6/60 in the better eye). The commonest anatomical sites of visual loss were whole globe (mainly microphthalmos) 25.5% and retina (mainly dystrophies) 24.9%. Lens was the major site in 18. 8%, optic nerve in 13.6%, and glaucoma in 9%. Corneal scarring was not a major cause of visual loss. The aetiology was unknown in 52.9%, hereditary factors were responsible in 30.7%, and childhood causes in 14%. 15% of cases were considered potentially preventable and 22. 5% potentially treatable. CONCLUSION: The pattern of childhood blindness seen in this study is likely to reflect the improved health and socioeconomic status of China but may partly reflect bias in admission to, and location of, blind schools, with higher socioeconomic groups overrepresented. Nutritional and infective causes of blindness are uncommon, and hereditary and unknown factors are now the predominant causes.

Adolescent↗

PubMed1999

Human colon cancer cell proliferation mediated by the M3 muscarinic cholinergic receptor.

We have demonstrated previously cell surface receptors for gastrointestinal peptides on 10 human colon cancer cell lines. Because most of the cells studied bind muscarinic cholinergic agonists, we undertook the determination of the cholinergic receptor subtype expressed by human colon cancer cells, as well as the biological function of these receptors, and more specifically, the effect on cell proliferation. We used radiolabeled ligand binding, PCR, calcium mobilization, and cellular proliferation studies. The present study demonstrates a muscarinic cholinergic receptor having two classes of binding site for carbamylcholine. Analysis demonstrated 2499+/-153 binding sites/cell, of which 75% had a high affinity for carbamylcholine (Kd 55 microM), and 25% had a low affinity (Kd 0.33 mM). N-Methylscopolamine, a receptor antagonist, recognized only one binding site having high affinity (Kd 0.20 nM). The number of muscarinic cholinergic binding sites/cell found on colon cancer cells is 50% of the number of receptors found on guinea pig chief cells in physiological conditions. Specific cholinergic receptor antagonists inhibit binding in the following order of potency: N-methylscopolamine > 4-DAMP >> pirenzipine > AF-DX116. This order of potency pharmacologically classifies the receptor as an M3 subtype. Receptor expression, studied by reverse transcription-PCR, correlates with the binding data. Specifically, cell lines that exhibit binding, abundantly expressed the M3 receptor subtype, whereas cell lines that do not exhibit binding for muscarinic cholinergic agonists did not abundantly express the M3 receptor. Agonist activation of the M3 receptor on these cells resulted in intracellular calcium mobilization. The dose-response curve of calcium mobilization suggests that there are spare receptors on these cells. Signal transduction can be inhibited by receptor antagonists in the same order of potency in which the binding is inhibited. Exogenous agonist added to the cells in culture induces significant cell proliferation. These results demonstrate a muscarinic cholinergic receptor of the M3 subtype on human colon cancer cells. This receptor induces intracellular calcium mobilization and mediates cell proliferation. The data suggest that there are spare receptors present, and that there may be enhanced intracellular signal activation in response to receptor binding.

Animals↗

PubMed1999

Expression of AP-1 transcription factors in rat hippocampus and cerebellum after trimethyltin neurotoxicity.

Neurotoxic insult causes neurons to degenerate due to necrosis or apoptosis. After this neurodegenerative phase, gene expression in surviving neurons is altered to undergo regeneration and repair to adapt to changes in the cellular environment. In this study, we examined the expression of four AP-1 transcription factors, Jun, JunB, JunD and FRA-2, and AP-1 DNA binding activity in the rat hippocampus to examine changes during the periods of degeneration and then of regeneration and repair after TMT-induced neurotoxicity. The expression of these factors in the cerebellum was examined as a control since this brain region is not grossly affected by TMT. AP-1 DNA binding slowly increased in both the cerebellum and hippocampus from one hour to eight days after TMT exposure. Levels of Jun in the hippocampus significantly increased at 12 hours after TMT while JunB and JunD expression did not change. On the other hand, FRA-2 was induced at 8 days in the hippocampus after TMT treatment and was expressed only in hippocampi containing neurodegeneration as gauged by elevated glial fibrillary acidic protein levels. FRA-2 immunoreactivity was detected in the AP-1 DNA binding complex only in hippocampal extracts from rats after eight days post-trimethyltin administration. Thus, FRA-2 is a component of the AP-1 DNA binding complex suggesting that it is involved in regulating genes during a later stage of TMT neurotoxicity.

Animals↗

PubMed1999

[Pharmacokinetics of pramiracetam in animals].

Pharmacokinetic rules of pramiracetam were studied here. After giving pramiracetam orally to dogs, we drew their blood at various times. The drug concentrations in blood plasma were detected by HPLC. 3p87 program was used to calculate the pharmacokinetic parameters. The time-concentration curve corresponded to one apartment model. T1/2 was about 2.3-3.9 hours in various doses. After pramiracetam was given to rats per os, high concentrations of pramiracetam were detected in the rats' tissues. The kidney had the highest concentration of pramiracetam; the liver had the next highest concentration, and then the intestine, lung, muscle, heart, gonad, spleen and sebum had the high concentration in order. The drug was also detected in the brain. 0.7% of the given dose was excreted in unchanged form in bile in 24 hours. 28.26% and 6.35% were excreted in urine and feces respectively in 72 hours. The plasma protein combining rate detected by the method of balance dialysis was 20.1-22.2%.

Animals↗

PubMed1999

Angiotensin I-converting enzyme gene polymorphism in Chinese patients with obstructive sleep apnea syndrome.

OBJECTIVE: To investigate the relationship of an insertion/deletion (I/D) polymorphism of the angiotension-converting enzyme (ACE) gene to obstructive sleep apnea syndrome (OSAS) patients and the control subjects. METHODS: Genomic DNA was extracted from blood samples and amplified by polymerase chain reaction (PCR). PCR primers flanked the polymorphic region in intro 16 of the ACE gene. RESULTS: OSAS patients had significantly higher frequencies of I/I genotype and insertion allele of the ACE gene as compared with the control subjects in Chinese population. The OSAS patients with I/I genotype had significantly longer apnea time, lower minimum SaO2 and greater AHI than the OSAS patients with I/D genotype. CONCLUSION: These results indicate that the I/I genotype and I allele are a risk factor for OSAS in Chinese.

Adult↗

PubMed1999

[Polymorphism of angiotensin-converting enzyme gene and susceptibility to asthma with familial aggregation].

OBJECTIVE: Angiotensin-converting enzyme (ACE) plays a key role in the metabolism of angiotensin II (AT II) and inactivation of bradykinins and tachykinins, which are potent bronchial constrictors and mediators of inflammation asthma, and ACE is heavily expressed in the lungs. An insertion-deletion (D/I) polymorphism of ACE gene has been shown to be associated with levels of ACE. Whether or not the polymorphism of ACE gene is associated with asthma and bronchial responsiveness was investigated. METHODS: A case-control study was carried out in 50 asthmatics, 7 families with at least 2 asthmatic individuals, and 50 healthy subjects. The insertion/deletion (I/D) polymorphism of ACE gene was amplified by polymerase chain reaction (PCR). Methacholine broncho(Mch)-provocation and pulmonary function tests were performed in all asthmatics. RESULTS: There was an higher gene frequency of DD genotype of ACE gene in asthmatic subjects and families individuals compared with healthy subjects (46% vs 16%, P < 0.05; Odd ratio 4.98). Accordingly, the mean values of FEV1% and FEV1/FVC were higher in asthmatics carrying non-DD alleles than patients with DD genotype (74% vs 57%, P < 0.05; 79% vs 69%, P < 0.05, respectively). CONCLUSIONS: The results suggested that DD allele of ACE genotype was significantly involved in genetic susceptibility to asthma. DD genotype of ACE might be a risk factor for the degree of airway obstruction.

Adolescent↗

PubMed1999

[Extensive HLA class II studies in Chinese narcoleptic patients].

OBJECTIVE: Narcolepsy is a debilitating, lifelong sleep disorder. Its familial occurrence suggests that genetic factors may be of importance in the etiology. Narcolepsy is a very rare disease among Chinese, thus it was of interest to study the association of narcolepsy with the HLA system in Chinese narcoleptic patients. METHODS: To explore the role of HLA-DRB genes in the development of narcolepsy, we studied 10 narcoleptic patients and 50 race matched controls in whom HLA-DR typing was performed by the method of DNA amplification with sequence-specific primers (PCR-SSP). RESULTS: All narcoleptic patients were found to be of DRB1 * 1501 and DRB5 * 0101 genotype. CONCLUSION: These results indicate that HLA-DRB1 * 1501 is a better primary candidate susceptibility gene for narcolepsy in Chinese.

Adult↗

PubMed1999

[Analysis of bone mineral density and relevant factors in 781 healthy people aged 15 to 50].

OBJECTIVE: To determine further the age to form peak bone mass (PBM) and the factor influencing it and bone mineral density (BMD) and to find an effective way to prevent from osteoporosis in the elderly. METHODS: BMD was measured in 781 people aged 15 to 50 years and relevant factors in lifestyle were investigated. Multivariate regression was used to analyze the relationship between BMD and lifestyles and to identify both risk and benefit factors for osteoporosis. RESULTS: For every ten-kilogram increase in body weight, BMD at varied sites increased by an amount of 0.028 - 0.056 g/cm(2) for males and 0.050 - 0.086 g/cm(2) for females, respectively. During their adolescence for males, for every increase of one grade in physical exercise, BMD at varied sites increased by an amount of 0.034 - 0.078 g/cm(2) in males and BMD at lumbar vertebra in males aged 15 - 24 correlated negatively with their total amount of alcohol drinking, and that at lumbar vertebra and of the whole body increased by about 0.035 g/cm(2) in females, which correlated negatively with their total amount of cigarette smoking. Female BMD at lumbar vertebra correlated reversely with their age of menarche and correlated positively with their average time of breast feeding. CONCLUSION: Increase in physical exercise during puberty could increase PBM for the adolescents and keeping adequate body weight and reducing cigarette smoking and alcohol drinking would benefit for the prevention from age-related osteoporosis.

Absorptiometry, Photon↗

PubMed1999

[Effect of nitric oxide on HSV-1 infection of HeLa cells and Vero-E6 cells].

The effects of nitric oxide(NO) on HSV-1 infection of HeLa cell line and Vero-E6 cell line were investigated in this study. The titers of HSV-1 in supernatants from infected culture of Vero-E6 cells were decreased by a NO donor, sodium nitroprusside(SNP), in a dose-dependent manner, while the control compound potassium ferricyanide (KFC) had no effect. However, SNP had no effect on that of HeLa cells. The results reaffirm the antiviral effect of NO and suggest that the susceptibility of different cell lines to the effect of NO might be varied.

Animals↗

PubMed1999

[Follow-up study of human herpesvirus 6 and human cytomegalovirus infection in organ transplantation recipients].

OBJECTIVE: To trace the study of the prevalence and adverse factors of human herpesvirus 6(HHV-6) and human cytomegalovirus(HCMV) infection in organ transplantation recipients. METHOD: Blood and urine specimens were detected by virus isolation, polymerase chain reaction(PCR), and indirect immunofluorescent assay. RESULT: HCMV and HHV-6 isolation rate were 25.8% and 32.3%, respectively. Anti-HCMV IgM and anti-HHV-6 IgM positive rates before operation were 0% and 3.2%, their positive rates after operation were 19.4% and 25.8%, respectively. HCMV-DNA and HHV-6-DNA positive rates before operation were 35.5% and 45.2%; their positive rates after operation were 45.2% and 61.3%, and kept the high positive rates for a long period. The patients who died within 3 months were all complicated by HCMV and/or HHV-6 productive infection. The productive infection rates of HCMV and HHV-6 were 25.8% and 32.2%, respectively. CONCLUSION: The majority of HCMV and HHV-6 infection are reactivation. Productive infection attack at 2 weeks after operation, reaches the peak at 3-4 weeks after operation, and attacks at anytime within 3 months. HCMV and/or HHV-6 productive infection are fatal to recipients.

Cytomegalovirus Infections↗

PubMed1999

[Examination of human herpesvirus-6 antibody in blood patients serum].

To know the infection state of human herpesvirus-6(HHV-6) in leukemia, lymphoma, myeloproliferative disorder syndrome, and multiple myeloma, indirect fluoroimmunoassay was taken to examine the rate of HHV-6's antibody. The results were that: the patient's rate of HHV-6 antibody was 75.6% (149/197), the blood donor's rate was 45.6% (115/252), there was a significant difference between them (P < 0.01). The results show that the examined patients are infected by HHV-6, which has a good relationship with leukemia, lymphoma, myeloproliferative disorder syndrome, and multiple myeloma.

Adolescent↗