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Biomedical subjects

Q Yu

Publications and source records attributed to Q Yu.

At least 181 records · Page 10Linked to original sources
PubMed1997

Comparing estimates of the effects of air pollution on human mortality obtained using different regression methodologies.

Studies using regression techniques report their results using a variety of statistics. Evaluation of the consistency of findings, such as in a metaanalysis, requires calculating the statistical estimates of the effect reported in each study in a comparable manner. In this paper, we consider multiple linear regression, multiple Poisson regression, and logistic regression estimates. We present results that are needed to calculate, on a common basis, the slope of the regression function at a specified value, the elasticity function of the regression function at a specified value, the relative risk at a specified value, and the odds ratio at a specified value. We apply these results to studies of the association of daily mortality in an area to the daily air pollution level of ozone and PM10. We calculate the estimated slope of the number of deaths per billion population associated with an increase of 1 ppb of ozone level in studies of daily mortality in three urban areas. These studies, in Los Angeles, New York, and St. Louis, produced very comparable results on a common basis, especially when compared to the coefficients as reported. We also calculated the estimated elasticity function of the daily mortality and daily PM10 level for eight areas and found that the elasticities varied within a factor of roughly two, much less than the variability in the coefficients as reported.

Air Pollutants↗
PubMed1997

[Dissociation and morphological observation of hair cells from chick basila papilla].

Hair cells were dissociated from basila papilla of 7 to 10 week post-hatched chicks (n = 15) by collagenase digestion followed by trituration. Morphological measurements of 215 viable hair cells from 5 chicks were performed. The average dimensions of the cells were: length 20.22 +/- 3.32 microns, width 9.93 +/- 2.01 microns of tall hair cells (n = 164); length 10.97 +/- 2.29 microns, width 14.8 +/- 2.29 microns of short hair cells (n = 30); length = width = 11.93 +/- 1.74 microns of intermediate hair cells (n = 21). Using fluorescein diacetate and propidium iodide, viability of isolated hair cells from another 5 chicks was determined. With excitatory light, fluorescence of viable cells were bright green in 3 hours, while the fluorescence of live cells were attenuated to such an extent that light green shadows were showed up to 5 hours after chicks were decapitated. The results suggested that the criterion of morphological observation and dying of cells should be combined to determine viability of isolated hair cells.

Animals↗
PubMed1997

[Effect of fermented morel liquid on immunity function in mice].

The experiments studied the effect of fermented morel liquid on immunity function in mice [correction of rats]. The results showed that fermented morel liquid could greatly enhance the non-specific immunity (macrophage's phagocytosis), specific immunity (delayed-type hypersensitivity), humoral immunity (the amount of hemolysin) and the weights of thymus. The author concluded that the fermented morel liquid could effectively regulate the immunity function in mice [correction of rats].

Adjuvants, Immunologic↗
PubMed1997

[Evaluation on the method to test the sex-improve function and its key points].

The mating-test with normal mouse is one of the methods built to test wheather the type of sexual function improvement food could improve the sexual function. Through controlling the influence factor of the experiment such as the most suitabke mating time, the weights of mating mice, the mating temperature and the mating cage, and through making the female mice in different sexual response circle to be in the same, we got quite good results. The authors' study affirms the availability and dependability of the sexual function experiment method set by the authors' intitute.

Animals↗
PubMed1997

[The development of a scale of life quality for diseases with visual impairment].

OBJECTIVE: To describe the development of a scale of life (QOL) quality which measures the quality of life of Chinese patients with visual impairment. METHODS: 20 items were chosen to form a scale. 57 cataractous patients with visual impairment and 60 glaucomatous patients with visual impairment and visual field loss at different levels simultaneously were measured by the scale to evaluate the validity, reliability and responsiveness of the scale. RESULTS: The scale consists of 20 items which cover four domains of QOL. The criterion related to the validity of the scale: r = 0.6865 (P = 0.000). The test-retest reliability of the scale: r = 0.8959 (P = 0.000). Coronback's alpha was 0.9358. The variance ratio (VR) of intra-individual variance to inter-individual variance was 0.0551 for overall scores. This correlation coefficient of split-half method was 0.9553. The responsiveness: t-test, t = 5.95 (P = 0.000). The effect size statistic was 1.533. CONCLUSION: The results also demonstrate that the scale has a satisfactory validity, reliability and responsiveness. It is suggested that the scale can be applied in clinical trails.

Cataract↗
PubMed1997

[CT examination and diagnosis of oral and maxillofacial tumors invading the pterygopalatine space].

CT findings in 33 cases (proven histopathologically) suffered from oral and maxillofacial tumors affecting the pterygopalatine space were retrospectively analyzed. The authors conclude that the main CT manifestations of this space involvement by tumors can be depicted as a soft tissue mass occupancy and the wall structures destruction. Tumors occurring in different locations of oral and maxillofacial areas have different features of CT appearances. In addition, the primary tumor of this space is probed from histogenesis and CT findings, and its diagnostic criteria are discussed. As a modality of imaging, CT has an important role for assessing the lesions of this fossa.

Adolescent↗
PubMed1997

[Resistant antibiotic analysis of methicillin-resistant staphylococcus].

Methicillin-resistant staphylococcus aureus is one of the important patholonic bacteria which cause nosocomial infection. In order to investigate the resistant antibiotic circumstances of this organism and hence provide foundations of prevention and treatment, we determined the resistant rates of 88 staphylococcus strains for methicillin and for other 14 kinds of commonly used antibiotics, and we determined the engendering beta-lactamase. The results showed that the isolation rate of methicillin-resistant staphylococcus aureus (MRSA) was 56%; the rate of methicillin-resistant staphylococcus coagulase-negative (MRSCoN) was 47.6%; the resistance rate and the multi-resistant rate of methicillin-resistant staphylococcus (MRS) for the 14 kinds of antibiotics were higher as compared with those of methicillin-sensitive (MSSA). Among all the tested strains, MRSA was the highest to engender beta-lactamase (92.9%); Methicillin-sensitive staphylococcus coagulase-negative (MSSCoN) was the lowest (39.4%). MRS was sensitive to vancomycin and furantoin. These suggest that when treating this bacterium, we should select these two antibiotics first.

Anti-Bacterial Agents↗
PubMed1997

[Early T cell development in gene-targeted mutant mice].

Early intrathymic T cell development is highly coordinated and controlled by the interaction of a variety of molecules. The development of gene targeting technology provided a valuable tool to study the function of these molecules in vivo. The analysis of TCR and CD3 gene targeted mice indicated that CD44-CD25+ is a control point in early T cell development. At this stage, the expression of pre-TCR complex (composed of pre-TCR alpha, TCR beta and CD3) and/or its combination with unknown ligand provide signals for further progression beyond the CD44-CD25+ stage. The deficiency of any component in pre-TCR complex would lead to the blockage of T cell development at early stages.

Animals↗
PubMed1997

[Vision change and quality of life in the patients with cataract].

PURPOSE: We tried to assess the relationship between quality of life and visual impairment and restoring of patients with cataract and explore the factors which affect quality of life of patients with cataract. METHODS: The 142 cases of cataract with different visual impairment and the 33 cases of cataract prior to surgery and at 3 months after cataract extraction and intraocular lens implantation were measured by the scale of quality of life for diseases with visual impairment. RESULTS: The scores of quality of life and their subscores were significantly associated with the visual acuity of patients with cataract. The scores of quality of life between preoperation and after surgery had significantly difference. The factors which affect quality of life of patients with cataract included visual impairment, age and occupations. CONCLUSION: Visual impairment that caused by cataract would cause decline in quality of life. Cataract surgery was effective in improving visual acuity and quality of life of the patients. Measuring quality of life would afford a new method for evaluating visual impairment of cataract.

Adolescent↗
PubMed1997

[Cost-effectiveness analysis of the screening strategies for primary angle closure glaucoma].

PURPOSE: To evaluate varlous primary angle clouse glaucoma(PACG)screening strategies by cost effectiveness analysis for choosing the best screening strategy. METHODS: We designed a model of the process of PACG screening, diagnosis, treatment, and estimated variable parameters of this model through literatures reviewed and the results of our study. Then four screening strategiers which are oblique flashlight test, measurement of axial anterior chamber depth (AACD), examination of peripheral anterior chamber depth (PACD), and combination of oblique flashlight test with examination of PACD in series were calculated by computer to obtain the costs for various screening strategies and the quality ajusted life years (QALYs) saved. We performed sensitivity analysis to determine how the variation in the parameter assumptions would affect the calculated cost effectiveness of the various screening strategies. Based on the principle of cost effectiveness, the screening strategy of more cost effective would be chosen. RESULTS: The results showed that no matter what age group, the screening strategy of oblique flashlight test and measuring PACD combined in series is the lowest cost per QALY gained than other strategies. This screening strategy is optimum, next is oblique flashlight test Screening method. We found that screening strategies not only gains QALY, but also is cost saving as well in the range 40-< 70 years old. sensitivity analysis result showed that optimum strategy is still the combined serial strategy, in addition to the capable closure angle ratio of a population with a 10% up and down, the oblique flashlight test became an optimum strategy and the combined serial method became next in > or = 70 years old group. CONCLUSION: The results showed that the oblique flashlight test and measurement of PACD combined in series is an optimum screening strategy. This research suggests that using adequate screening strategy should not only increase the QALYs, but also save the cost for the government and the patients themselves.

Anterior Chamber↗
PubMed1997

[Effect of heat, noise and their combination on plasma and myocardial angiotensin II in rats].

Effects of heat (40 degrees C, relative humidity 82%), noise (115dB) and the combination of heat and noise on angiotensin (A II) content in plasma and myocardia was observed in rats. The results showed: (1) plasma A II in control group, heat group, noise group and combined group were 358.72 +/- 35.78, 624.08 +/- 36.32, 783.27 +/- 34.32 and 619.65 +/- 37.72 pg/ml respectively. The A II content in heat group, noise group and combined group are significantly higher than that of the control group (P<0.01). The increase in noise group was significant as compared with those in the heat group and combined group (P<0.05). (2) The myocardia A II in control group, heat group, noise group and combined group were 594.78 +/- 82.46, 935.10 +/- 15l.51, 326.22 +/- 28.45, and 438.37 +/- 58.63 pg/mg W.W respectively. The myocardial A II content in heat group was significantly higher (P<0.01), but that in noise group than the control was significantly lower(P<0.O5).

Angiotensin II↗
PubMed1997

The selective recognition of antibody IgY for digestive system cancers.

Biological methods for cancer therapies are very important. A small and efficient target carrier is the key component for anti-cancer drugs. In our laboratory, the antibody IgY was extracted from egg yolk of a SPF hen. The SPF hen was immunized with an antigene of P110 protein which was purified from human stomach cancer MGC-803 cells. Results indicated that the antibody IgY can specifically recognize gastrointestinal system cancers. It may become an important carrier for antitumorigenic drugs.

Adenocarcinoma↗
PubMed1997

Computer analysis of human depth EEG in different sleep stages.

This study compares delta (< 4 Hz), theta (4-8 Hz), alpha (8-12 Hz) and beta (12-20 Hz) band EEG signals during wakefulness, rapid-eye-movement (REM) sleep, and stage 1 and stage 2 non-REM sleep recorded from both surface and depth electrodes in patients with drug-resistant partial seizures. Computer analysis utilizing Fast Fourier Transforms (FFT) was performed with the Neurovision software developed for this purpose. Mean amplitudes were calculated for each of the frequency bands. Preliminary analysis was performed with emphasis on the presence and characteristics of theta activity in the hippocampus of the brain. Results demonstrate theta wave activity in the hippocampus with an increase of theta activity in REM sleep as compared to non-REM sleep (stages 1 and 2).

Adult↗
PubMed1996

A new alternatively spliced exon between v9 and v10 provides a molecular basis for synthesis of soluble CD44.

The numerous isoforms of murine CD44 contain a common peptide region that is encoded by exons 1-5, 16-18, and 20 and variant regions derived from exons 6-15, usually referred to as v1-v10. We have obtained evidence for expression of an additional exon between v9 (or exon 14) and the exon previously termed v10 (or exon 15). Thus, we now number the variant exons as follows: v1-v9 (exons 6-14), v10 (exon 15), and v11 (exon 16); the remaining 3'-exons become exons 17-21 (newly numbered exons are underlined). The new exon, now termed exon v10, contains 93 base pairs and can be internally spliced; the 5'-region is termed v10a, and the 3'-region, v10b. Stop codons are positioned in v10a such that translated protein would be truncated prior to the transmembrane domain and secreted as a soluble protein. We have also found that the previously described v9 exon (now termed v9a), which is 90 base pairs in length, is actually the 5'-region of a longer exon of 142 base pairs (the 3'-region is termed v9b) and thus arises by internal splicing of the longer exon. Using reverse transcription-polymerase chain reaction, four different cDNAs for CD44 isoforms that use different combinations of the new exonic sequences have been found. The mRNAs containing the new exonic sequences are restricted in their expression; to date, we have demonstrated their presence in murine G8 myoblasts in culture and in embryonic muscle and cartilage tissues in vivo. Of these new isoforms, the predominant, full-length amplified product is encoded by exons 1-5, exon 13 (v8), the 5'-part of exon 14 (v9a), exon 15 (v10), exon 16 (v11), exons 17-19, and exon 21. When COS-7 cells were transfected with v10-containing cDNA constructs, the cells secreted low molecular weight soluble CD44 into their medium. Thus, the stop codons within the new exon v10 provide a molecular basis for de novo synthesis of soluble CD44 isoforms.

Alternative Splicing↗
PubMed1996

Conservation of a hairpin ribozyme sequence in HIV-1 is required for efficient viral replication.

We have previously described a hairpin ribozyme that targets a highly conserved sequence in the U5 region of HIV-1. To determine if escape mutations would compromise virus replication, we introduced critical mutations into the ribozyme target site of an infectious molecular clone of HIV-1MN. HIV-1 MNA has a substitution of A for G immediately 3' to the cleavage site and HIV-1 MNGC has two substitutions in the flanking sequences that are complementary to the ribozyme. In vitro studies confirmed that neither the MNA-nor the MNGC-mutated target sequence was cleaved by the ribozyme, and furthermore, the MNGC-mutated target sequence failed to bind the ribozyme. Compensatory GC substitutions in the substrate recognition domain of the ribozyme resulted in a switch of binding and cleavage specificity. Replication of both the MNA and MNGC mutant viruses was initially two to three logs lower than that of wild-type virus, but after 3 weeks, virus production rose sharply in both cultures. Nucleotide sequence of RT-PCR-amplified viral sequences obtained from virus produced at later time points revealed complete reversion of MNA or partial reversion of MNGC to wild-type genotypes. No additional mutations within the ribozyme target sequence were observed. These results indicate that mutations in this conserved ribozyme target sequence led to significant attenuation of HIV-1MN.

Animals↗
PubMed1996

Expression of multiple CD44 isoforms in the apical ectodermal ridge of the embryonic mouse limb.

Previous immunohistochemical studies have shown that CD44 is highly enriched within the apical ectodermal ridge of the developing limb (Wheatley et al. [1993] Development 119: 295-306), but the particular isoforms of CD44 were not identified. We show here that CD44s (standard or "hemopoietic" isoform) and several CD44 variants, especially V3-V10, V4-V10, and V6-V10, are concentrated in the apical ectodermal ridge in the early mouse limb. Since CD44s is a major cell surface receptor for hyaluronan, we compared its localization with that of hyaluronan. In the early limb bud, hyaluronan is distributed throughout the mesoderm but is absent from all regions of the ectoderm. Hyaluronan is especially enriched in the basement membrane separating ectoderm and mesoderm, except beneath the apical ectodermal ridge where it is absent. Since CD44s is a known endocytic receptor for hyaluronan, its presence in ridge ectoderm could lead to degradation of hyaluronan destined for the neighboring region of basement membrane, thus facilitating interaction of the ridge with underlying mesoderm. The CD44 (V3-V10) isoform found in the ridge is expressed elsewhere as a proteoglycan with heparan sulfate chains that bind fibroblast growth factors. Since fibroblast growth factors are present in the ridge and are essential for limb morphogenesis, CD44 (V3-V10) is likely to act as a cofactor or modulator in the growth-promoting action or maintenance of the ridge.

Animals↗