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Biomedical subjects

W Yu

Publications and source records attributed to W Yu.

At least 55 records · Page 3Linked to original sources

Epidemiologic trends in the hospitalization of elderly Medicare patients for pneumonia, 1991-1998.

OBJECTIVES: This study determined hospitalization rates of elderly Americans for pneumonia from 1991 through 1998. METHODS: Epidemiologic data were described for 273,143 pneumonia hospitalizations. RESULTS: Annual hospitalizations for aspiration pneumonia increased by 93.5%. Pneumonia hospitalization rates increased steeply with age, especially among men. Black men were at highest risk for aspiration, unspecified, Klebsiella, "other gram-negative," and staphylococcal pneumonia; White men had the highest Haemophilus and pneumococcal pneumonia rates. Among women, Blacks predominated in aspiration and Klebsiella pneumonia; Whites had the highest Haemophilus and bronchopneumonia rates. CONCLUSIONS: An epidemic of hospitalization for aspiration pneumonia smoldered over 8 years. Significant disparities existed in hospitalization risks by race, sex, and principal diagnosis.

Black or African American↗

Variations in corticosterone feedback do not reveal differences in hpa activity after prenatal ethanol exposure.

BACKGROUND: Prenatal ethanol exposure results in hypothalamic-pituitary-adrenal (HPA) hyperresponsiveness to stressors in adult animals. Possible mechanisms mediating this alteration in HPA responsiveness include stress-associated changes in corticosterone (CORT) feedback signals, alterations in CORT signals under basal conditions, and CORT-independent mechanisms. METHODS: We examined the effects of adrenalectomy (ADX) and CORT replacement with a constant, low-level CORT signal via CORT/cholesterol pellets on HPA responses to restraint stress. Adult Sprague-Dawley rats from prenatal ethanol (E), pair-fed (PF), and ad libitum-fed control (C) groups underwent sham ADX (sham), ADX without CORT replacement, or ADX with CORT replacement. Animals were tested during the trough of the circadian rhythm. RESULTS: In the sham condition, E females showed increased adrenocorticotropin hormone (ACTH) and CORT responses to restraint stress compared with C females. Basal and stress-induced ACTH levels were significantly increased in ADX compared with sham animals across all prenatal groups. Constant CORT replacement reduced basal ACTH levels compared with levels in the ADX group, although levels were still increased compared with those observed in the sham group. CORT replacement was minimally effective at reducing ACTH levels during stress. CONCLUSIONS: Although the effects of ADX may have masked possible influences of circadian drive or prenatal group, these findings suggest that in the absence of a CORT feedback signal or in the presence of a constant, low-level CORT feedback signal, E, PF, and C animals do not differ in their abilities to regulate ACTH secretion during the trough of the circadian rhythm.

Adrenal Glands↗

[IFN-r/IL-4 expression in peripheral blood mononuclear cells of the patients with chronic severe hepatitis].

OBJECTIVE: To understand the expressions of interferon-r (INF-r) and interleukin-4 (IL-4) in peripheral blood mononuclear cells (PBMCs) of the patients with chronic severe hepatitis (CSH). METHODS: PBMCs from the patients with CSH were separated routinely and stimulated by PMA/Ionomycin/Monensin. The production of IFN-r/IL-4 by CD4+ T cells in PBMC was determined by fluorescence activated call sorting (FACS) analysis and fluorescence-quantitative PCR assay for quantification of HBV DNA. RESULTS: The percentage of IFN-gamma-producing T cells in CD4+ T cells was higher in patients with CSH (7.2%-26.3%) than in normal controls (2.2%-11.9%) (P<0.01). The percentage of Th1 cells increased significantly with the raise of hepatic inflammation activity. The percentage of IL-4-producing T cells in CD4+ T cells did not differ significantly between patients with CSH and normal controls. The quantification of HBV DNA decreased significantly with the increase of the percentage of IFN-gamma-producing T cells. CONCLUSIONS: Th1 cell is associated with hepatic inflammatory activity and IFN-gamma depresses HBV replication.

Adult↗

RRR-alpha-tocopheryl succinate induces MDA-MB-435 and MCF-7 human breast cancer cells to undergo differentiation.

RRR-alpha-Tocopheryl succinate (vitamin E succinate, VES) is a potent antitumor agent, inducing DNA synthesis arrest, differentiation, and apoptosis. Because little is known about VES-induced differentiation, studies reported here characterize VES effects on the differentiation status of human breast cancer cell lines and investigate possible molecular mechanisms involved. VES-induced differentiation of human MCF-7 and MDA-MB-435 breast cancer cells was characterized by morphological changes, induction of lipid droplets, induction of beta-casein mRNA expression, and down-regulation of Her2/neu protein. In contrast, VES treatment of normal human mammary epithelial cells, MCF-10A cells, and T-47D cells did not induce differentiation. Studies addressing mechanisms showed that neither antibody neutralization of the transforming growth factor-beta signaling pathway nor expression of a dominant-negative mutant of c-Jun N-terminal kinase blocked the ability of VES to induce differentiation; however, treatment of cells with PD 98059, a chemical inhibitor of mitogen-activated protein kinase kinase (MEK1/2), blocked the ability of VES to induce differentiation.

Antibodies↗

Genetic analysis of wild-type hepatitis A virus strains.

OBJECTIVE: To clarify the distribution of hepatitis A virus (HAV) genotype in geographical regions of China. METHODS: Seventeen representative HAV strains were isolated from the stool or serum of hepatitis A patients in different geographical regions. Viral RNA was recovered from stool or serum by proteinase K digestion and phenol-chloroform extraction, followed by ethanol precipitation prior to reverse transcription and polymerase chain reaction (RT-PCR) amplification. The nucleotide sequences of VP1/2A junction region were tested by using a direct sequencing technique. RESULTS: A pairwise comparison of sequences within 168 bases at the VP1/2A junction revealed that all the sequences clustered within genotype I. About 53% of strains clustered in genotype I B, with less than 6% variability; while the others clustered in genotype I A, with less than 5.3% variability. Sequence homology between genotype I A and I B varied from 88.7% to 92.3%. CONCLUSION: Epidemic or sporadic HAV strains in China may belong to HAV genotype I A or I B. Epidemiologically related strains may be identical or closely related in sequence.

Genotype↗

[Studies on the manufacture and immunogenicity of purified rabies vaccines on humans Vero cell].

OBJECTIVE: Using Vero cell as basic cultural material to improve the quality of rabies vaccines and to produce rabies vaccines for humans. METHODS: CTN-1V10 strain were used for production. Vero cell of 150th generation were used for cultivation. Rotating cultivatal method with rotating bottle was used. Fluids with virus were collected at different time. Puritied rabies vaccine was produced on Vero cell after clarification, condensation, purification and extermination. A batch of vaccines made by this techniques were used for immunological observation. Sixty-three people were injected with this rabies vaccine according to the procedure of time of exposure. Thirty of them were injected with vaccines made in France (Verorab) while the others were injected with vaccines to be tested. Side effect and neutralizing antibody were recorded. RESULTS: The quality of this newly developed rabies vaccines has met the quality set by WHO. After all dosages of injection, the rates of positive antibody were both 100% in two groups. The neutralizing antibody among testing group was 11.94 IU/ml comparing with control as 11.69 IU/ml. CONCLUSION: Purified rabies vaccines on Vero cell for humans had reasonable manufacture technique and less little effect with good technological imnunogenicity.

Animals↗

[Analyses on the risk factors of Measles in Anhui province during 1998 and 1999].

OBJECTIVE: To evaluate the measures targeting measles control. METHODS: Measles cases were studied serologically under AFP surveillance system. RESULTS: The incidence was 1.36/100 000 in 1999. The incidence of children under 5 was 3.65/100 000, with 84.00% and 87.49% reduction, as compared with the incidence in 1991 and 1997 before intensified vaccination campaigns in children aged 1 - 6. The indicators of surveillance showed an improvement in 1999 than that in 1998. CONCLUSION: Training for health staff at county, township, vallage levels played an important role in improving the sensibility and timeliness of measles surveillance system. Routine immunization is a key element in curbing measles outbreaks and reducing measles incidence.

Adolescent↗

[Attitude to voluntary HIV testing and result disclosure among rural residents in China].

OBJECTIVE: To identify the determinants of individual acceptance of voluntary HIV testing and the scope of test results disclosure. METHODS: A cross-sectional study was performed to interview 1 057 subjects aged 15 - 49. RESULTS: Among 653 subjects who had heard of HIV/AIDS, 575 (88.1%) reported willingness to be tested for HIV infection. Of subjects who would accept the offer, 90.2% agreed to disclose testing results to their spouse, 77.1% to other family member, 54.8% to their friends and 50.8% to their neighbors. Logistic regression analysis indicated that the acceptability was associated with being a man, and having better knowledge in HIV/AIDS. CONCLUSIONS: The level of acceptability of voluntary HIV testing is high among people who know about HIV/AIDS. Given the large number of people in rural China who never heard of HIV/AIDS, it is important to carry out information-oriented education activities to increase AIDS awareness among rural residents.

Adult↗

Angular distributions of fast electrons, ions, and Bremsstrahlung x/gamma-rays in intense laser interaction with solid targets.

We study the angular distributions of fast electrons, ions, and bremsstrahlung x/ gamma-rays generated during the interaction of an ultrashort intense laser pulse with solid targets. A relation is found on the angular directions for fast electrons and ions as a function of the particle's kinetic energy, experienced Coulomb potential changes, and the incident angle of the laser pulse. It is valid independent of the acceleration mechanisms and the polarization of the laser pulse, as confirmed by particle-in-cell simulations. The angular distribution of bremsstrahlung x/gamma-rays is presented to show explicitly its correlation with the corresponding angular distributions of electrons.

Journal Article↗

Decrease of neuronal nitric oxide synthase in the cerebellum of aged rats.

Nitric oxide (NO) is produced as an important neurotransmitter in the central nervous system (CNS) to participate in some pathophysiological pathways. In the present study, change of neuronal nitric oxide synthase (nNOS) was examined in isolated cerebellum of Wistar rats aged from 2 to 24 months. Northern blot showed a lower mRNA level of nNOS in rats aged 6, 12 and 24 months than that in rats aged 2 months. Western blot analysis also indicated that the expression of nNOS protein was lower in rats aged 6, 12 and 24 months than that of 2 months rats. However, the activity of nNOS determined by conversion of [(3)H] L-arginine to [(3)H] L-citrulline was decreased significantly in rats aged 24 months only. These results indicate the decrease of NOS expression in cerebellum of aged rat that seems helpful to explain the causes of malfunction in CNS of aged mammalian.

Aging↗

cDNA cloning of a novel bHLH-PAS transcription factor superfamily gene, BMAL2: its mRNA expression, subcellular distribution, and chromosomal localization.

We isolated a human cDNA encoding a novel member of the bHLH-PAS transcription factor superfamily, BMAL2, which is highly similar to, but distinct from, BMAL1. The composite cDNA covered a 1720-bp sequence consisting of a putative 1653-bp open reading frame encoding a polypeptide of 551 amino acids. The deduced BMAL2 product contains a bHLH-PAS domain in its N-terminal region and a variable C-terminus. The overall identity of BMAL2 polypeptide to that of human BMAL1 is 49%. RNA analysis revealed that expression of BMAL2 transcripts was restricted to the fetal brain and to the adult liver in human, while human BMAL1 mRNA was expressed in the brain and skeletal muscle. The chromosomal localization of the human BMAL2 gene was determined by fluorescent in situ hybridization to be localized on chromosome 12 at region p12.2-p11.2. These results suggest that BMAL2 may play different roles from BMAL1 in the embryonic brain and in adult mammals.

Adult↗

Depletion of a microtubule-associated motor protein induces the loss of dendritic identity.

Dendrites are short stout tapering processes that are rich in ribosomes and Golgi elements, whereas axons are long thin processes of uniform diameter that are deficient in these organelles. It has been hypothesized that the unique morphological and compositional features of axons and dendrites result from their distinct patterns of microtubule polarity orientation. The microtubules within axons are uniformly oriented with their plus ends distal to the cell body, whereas microtubules within dendrites are nonuniformly oriented. The minus-end-distal microtubules are thought to arise via their specific transport into dendrites by the motor protein known as CHO1/MKLP1. According to this model, CHO1/MKLP1 transports microtubules with their minus ends leading into dendrites by generating forces against the plus-end-distal microtubules, thus creating drag on the plus-end-distal microtubules. Here we show that depletion of CHO1/MKLP1 from cultured neurons causes a rapid redistribution of microtubules within dendrites such that minus-end-distal microtubules are chased back to the cell body while plus-end-distal microtubules are redistributed forward. The dendrite grows significantly longer and thinner, loses its taper, and acquires a progressively more axon-like organelle composition. These results suggest that the forces generated by CHO1/MKLP1 are necessary for maintaining the minus-end-distal microtubules in the dendrite, for antagonizing the anterograde transport of the plus-end-distal microtubules, and for sustaining a pattern of microtubule organization necessary for the maintenance of dendritic morphology and composition. Thus, we would conclude that dendritic identity is dependent on forces generated by CHO1/MKLP1.

Animals↗

Identification of novel purine and pyrimidine cyclin-dependent kinase inhibitors with distinct molecular interactions and tumor cell growth inhibition profiles.

Substituted guanines and pyrimidines were tested as inhibitors of cyclin B1/CDK1 and cyclin A3/CDK2 and soaked into crystals of monomeric CDK2. O6-Cyclohexylmethylguanine (NU2058) was a competitive inhibitor of CDK1 and CDK2 with respect to ATP (Ki values: CDK1, 5 +/- 1 microM; CDK2, 12 +/- 3 microM) and formed a triplet of hydrogen bonds (i.e., NH-9 to Glu 81, N-3 to Leu 83, and 2-NH2 to Leu 83). The triplet of hydrogen bonding and CDK inhibition was reproduced by 2,6-diamino-4-cyclohexylmethyloxy-5-nitrosopyrimidine (NU6027, Ki values: CDK1, 2.5 +/- 0.4 microM; CDK2, 1.3 +/- 0.2 microM). Against human tumor cells, NU2058 and NU6027 were growth inhibitory in vitro (mean GI50 values of 13 +/- 7 microM and 10 +/- 6 microM, respectively), with a pattern of sensitivity distinct from flavopiridol and olomoucine. These CDK inhibition and chemosensitivity data indicate that the distinct mode of binding of NU2058 and NU6027 has direct consequences for enzyme and cell growth inhibition.

Antineoplastic Agents↗

Electron acceleration by a short relativistic laser pulse at the front of solid targets.

Acceleration of electrons in a low-density plasma in front of a solid target by a propagating short ultraintense laser pulse is studied. When the laser is reflected at the target surface the accelerated electrons, with energy scaling as the laser intensity, continue to move forward inertially and thus escape from the pulse. Electrons accelerated backwards by the reflected light can attain even higher energies due to their longer acceleration length and their high initial momentum from a relativistic return current.

Journal Article↗

Two-photon microscopy of aorta fibers shows proteolysis induced by LDL hydroperoxides.

Oxidatively modified LDL mimics several aspects of atherogenesis. In this disease, degradation of the matrix proteins' network also occurs. By a new morphological ex vivo approach, not requiring sample processing, we explored the relationship between the degradation of matrix protein and oxidatively modified LDL. Two-photon excitation fluorescence microscopy images of fresh cross-section rings of rat aorta, acquired while the sample was maintained in a glucose- and oxygen-supplemented buffer, showed straight, parallel, thick, long extracellular matrix proteins. Traditional microscopic examination, requiring sample fixation and staining, shows smaller and curved fibers. Instead, we observed curved and broken fibers after a 30-min incubation of aorta with either LDL containing lipid hydroperoxides, or tert-butyl-hydroperoxide. The adhesion of LDL to the endothelium and its internalization was directly visualized by using a lipid fluorophore. The damage to aorta matrix proteins induced by LDL and tert-butyl-hydroperoxide was fully prevented by antioxidants, such as ascorbate or Trolox C, or inhibitors of proteases. The image spectroscopy of the fibers' autofluorescence (polarization and lifetime) revealed an increased mobility of the fluorescent cross-link in fibers. Damaged matrix proteins were also imaged in aorta samples from apolipoprotein E knock-out mice. Our ex vivo images directly visualized the activation of a fast redox-sensitive proteolytic process in the arterial wall triggered by lipid hydroperoxides in LDL.

Animals↗

Immunogenicity of porcine transmissible gastroenteritis virus spike protein expressed in plants.

Transgenic plants expressing recombinant proteins from pathogenic microorganisms provide an inexpensive edible vaccine for induction of local immunity. Three transgenic plant lines were generated expressing the spike (S) protein of transmissible gastroenteritis virus (TGEV), a protein crucial for establishing mucosal immunity. All three of them were driven by a strong plant promoter. One construct contained the 3.7 kb 5' end of the native S gene sequence. In the second construct part of the S gene, from nucleotide 49 to 1785, was modified for optimal plant recognition and was fused to a plant signal peptide coding sequence. The third construct contained the D epitope-coding region of the S gene, from nucleotide 1201 to 1591, which was fused to the alfalfa beta-amylase gene. The S gene products were detected by enzyme-linked immunosorbent assay (ELISA) and Western blotting. Antigens from all three transgenic plant lines induced TGEV-specific immune responses in pigs as determined by virus neutralization and ELISA, and the resultant antibody titers for all three constructs were similar.

Animals↗