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Biomedical subjects

Z Yu

Publications and source records attributed to Z Yu.

At least 55 records · Page 3Linked to original sources
PubMed2001

Radiobiological effects of a low-energy ion beam on wheat.

The radiobiological effects of a low-energy nitrogen ion (N+) beam on wheat were studied, particularly with regard to the induction of chromosome aberrations. The results demonstrated that the three test varieties showed different sensitivities to ion implantation, and a higher dose of ion implantation had a marked effect on the germination and survival rate of the seeds exposed. The germination rate and survival rate curve basically followed a similar trend in the same variety. Cytological analysis indicated that ion beams were effective in producing chromosome aberrations. The frequencies of mitotic or meiotic cells with chromosome aberrations increased linearly with increasing doses. The aberration types included, for example, acentric fragments, chromosome deletions, lagging chromosomes, chromosome bridges and micronuclei. In the root tip cells, aberrations chiefly consisted of acentric fragments and deletions. Chromosome bridges and lagging chromosomes were the main aberration phenomena observed in the pollen mother cells. The highest frequencies of root tip cells and pollen mother cells with chromosome aberrations were 15.2% and 39.8%, respectively. Changes in morphology and mutant were also observed in the plants derived from exposed seeds.

Chromosome Aberrations↗
PubMed2001

Bioaugmentation with resin-acid-degrading bacteria enhances resin acid removal in sequencing batch reactors treating pulp mill effluents.

Resin acids are the major toxicants in pulp and paper mill effluents (PPMEs), and they form pitch interfering with papermaking. Efficient and reliable resin acid removal is critically important to prevent toxicity discharge and ensure proper functioning of paper machines. Two resin-acid-degrading bacteria, Pseudomonas abietaniphila BKME-9 and Zoogloea resiniphila DhA-35, were tested in laboratory sequencing batch reactors (SBRs) for their ability to enhance resin acid removal by biomass from a full-scale biotreatment system treating PPMEs. Both bacteria enhanced resin acid removal but not removal of total organic carbon (TOC) by either pH-shocked or starved activated sludge. These two bacteria also increased resin acid removal when the sludge was given high concentration (200 microM) of resin acid. A most-probable-number polymerase chain reaction (MPN-PCR) assay showed that these two bacteria were initially not detectable (detection limit: 10(2) bacterial cells/ml) in the sludge community and were persistent after inoculation. Both bacteria did not substantially change the indigenous microbial community composition, as assayed by ribosomal intergenic spacer analysis (RISA). Our results suggest that it is feasible and potentially useful to enhance resin acid removal by bioaugmentation using resin-acid-degrading bacteria such as BKME-9 and DhA-35.

Abietanes↗
PubMed2001

A comparison of whole wheat, refined wheat and wheat bran as inhibitors of heterocyclic amines in the Salmonella mutagenicity assay and in the rat colonic aberrant crypt focus assay.

Refined wheat, unrefined whole wheat, and wheat bran were studied for their ability to protect against heterocyclic amines (HCAs) in vitro and in vivo. Wheat bran, which binds HCAs in vitro, as well as refined wheat and unrefined whole wheat, inhibited the mutagenic activities of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) when they were co-incubated and the supernatant (minus grain) was added to the Salmonella assay. The water-soluble fraction alone from refined and unrefined wheat, but not bran, also inhibited against these mutagens in vitro. In vivo, AIN-93G diets containing refined wheat or unrefined wheat were examined for their ability to inhibit IQ-induced colonic aberrant crypt foci (ACF) in the Fischer 344 rat. A slight increase in the number of AC/ACF (aberrant crypts/ACF) was seen after 16 weeks in rats treated post-initiation with refined wheat (P < 0.05), and fewer foci with two or three aberrant crypts (ACF-2) were found in rats given unrefined whole wheat post-initiation compared with animals treated with the same diet during the initiation phase (P < 0.05). There was no significant difference in the profile of IQ urinary metabolites or excretion of promutagens 0-48 h after carcinogen dosing, and grains had no effect on hepatic cytochrome P4501A1 (CYP1A1), CYP1A2, aryl sulfotransferase or N-acetyltransferase activities; however, a slightly higher UDP-glucuronosyl transferase activity was observed in rats fed unrefined wheat compared with refined wheat diets (P < 0.05). Thus, despite their antimutagenic activities in vitro, only marginal effects were seen with refined and unrefined wheat in vivo with respect to hepatic enzyme activities, carcinogen metabolism and IQ-induced ACF in the rat colon.

Amines↗
PubMed2001

A 5-bp deletion in ELOVL4 is associated with two related forms of autosomal dominant macular dystrophy.

Stargardt-like macular dystrophy (STGD3, MIM 600110) and autosomal dominant macular dystrophy (adMD) are inherited forms of macular degeneration characterized by decreased visual acuity, macular atrophy and extensive fundus flecks. Genetic mapping data suggest that mutations in a single gene may be responsible for both conditions, already known to bear clinical resemblance. Here we limit the minimum genetic region for STGD3 and adMD to a 0.6-cM interval by recombination breakpoint mapping and identify a single 5-bp deletion within the protein-coding region of a new retinal photoreceptor-specific gene, ELOVL4, in all affected members of STGD3 and adMD families. Bioinformatic analysis of ELOVL4 revealed that it has homology to a group of yeast proteins that function in the biosynthesis of very long chain fatty acids. Our results are therefore the first to implicate the biosynthesis of fatty acids in the pathogenesis of inherited macular degeneration.

Amino Acid Sequence↗
PubMed2001

Rhinovirus elicits proasthmatic changes in airway responsiveness independently of viral infection.

BACKGROUND: Rhinovirus (RV), the principal pathogen responsible for the common cold, is importantly implicated in triggering attacks of asthma secondary to changes in airway responsiveness. OBJECTIVE: Because the airway histopathologic features of RV infection are relatively modest, we tested the hypothesis that RV can directly elicit proasthmatic-like changes in airway smooth muscle (ASM) responsiveness independently of actual viral infection and its associated cytopathic effects. METHODS: Isolated ASM tissues and cultured ASM cells were inoculated with either infectious or noninfectious (UV-irradiated) RV16 and RV2, the latter serotypes belonging to the "major" and "minor" groups of RV subtypes, respectively. ASM constrictor and relaxant responsiveness, G(i) protein expression, and proinflammatory cytokine release were subsequently compared under the different treatment conditions. RESULTS: In contrast to RV2, which had no effect, RV16 inoculation elicited enhanced ASM contractility and impaired relaxation to cholinergic and beta-adrenergic agonists, respectively, in association with increased ASM membrane G(i) protein expression and induced release of the proinflammatory cytokines IL-5 and IL-1beta. These proasthmatic-like effects were also observed in ASM exposed to UV-irradiated RV16, wherein viral replication was completely inhibited. In contrast, pretreatment of ASM with a neutralizing antibody directed against ICAM-1, the host receptor for the "major" group of RVs, completely abrogated the proasthmatic effects of RV16. CONCLUSIONS: The results demonstrate that (1) RV16 elicits proasthmatic changes in ASM responsiveness that can occur independently of actual viral infection of the ASM and (2) the effects of RV16 are attributed solely to binding of the virus to its host receptor (ICAM-1) on the ASM cell surface. Collectively, these findings support the notion that RV-induced exacerbation of wheezing in asthmatic individuals can occur even in the absence of any cytopathology associated with viral infection.

Animals↗
PubMed2001

Evaluation of the ELOVL4 gene in patients with age-related macular degeneration.

Stargardt-like macular degeneration (STGD(3)) and autosomal dominant macular degeneration (adMD) share phenotypic characters with atrophic age-related macular degeneration (AMD). Mutations in a photoreceptor cell-specific factor involved in the elongation of very long chain fatty acids (ELOVL(4)) were shown to be associated with STGD(3), adMD, and pattern dystrophy. We screened 778 patients with AMD and 551 age-matched controls to define the role of sequence variants in the ELOVL(4) gene in age-related macular degeneration. We detected three sequence variants in the non-coding region and eight variants in the coding region. No statistically significant association was observed between sequence variants in the ELOVL(4) gene and susceptibility to AMD. However, for the detection of modest effects of multiple alleles in a complex disease, the analysis of larger cohorts of patients may be required.

Age Factors↗
PubMed2001

Effects of NF-kappaB1 (p50) targeted gene disruption on ionizing radiation-induced NF-kappaB activation and TNFalpha, IL-1alpha, IL-1beta and IL-6 mRNA expression in vivo.

PURPOSE: To investigate the role of the NF-kappaB1 (p50) gene in ionizing radiation (IR)-induced NF-kappaB activation and TNFalpha, IL-1alpha, IL-1beta and IL-6 mRNA expression in vivo. MATERIALS AND METHODS: NF-kappaB activation was analysed by the gel shift/supershift assay and the levels of TNFalpha, IL-1alpha, IL-1beta and IL-6 mRNA were measured using RNase protection assay (RPA). Various tissues from BALB/c, B6,129P-Nfkb1 (NF-kappaB1 or p50 gene knockout, p50(-/-)) and B6,129PF2 (wild-type, p50(+/+)) mice were analysed before or after exposure to a lethal dose (8.5 Gy) of total-body gamma-irradiation. RESULTS: Exposure of BALB/c mice to total-body IR selectively activated NF-kappaB in the spleen, mesenteric lymph nodes (LN) and bone marrow (BM). Gel supershift assay using polyclonal antibodies against NF-kappaB p50, p65 or c-Rel protein revealed that the NF-kappaB p50 subunit is a critical component of the NF-kappaB complexes activated by IR in vivo. Discretely augmented TNFalpha, IL-1alpha, IL-1beta and IL-6 mRNA expression was found in the spleen, LN and BM after BALB/c mice received IR. However, mice lacking the p50 gene (p50(-/-)) showed a significant reduction in IR-induced activation of NF-kappaB and increases in TNFalpha, IL-1alpha, IL-1beta and IL-6 mRNA expression, as compared with that of wild-type mice (p50(+/+)). CONCLUSIONS: The NF-kappaB p50 subunit is a critical component of the NF-kappaB complexes activated by IR and it plays an important role in mediating IR-induced TNFalpha, IL-1alpha, IL-1beta and IL-6 mRNA expression in vivo.

Animals↗
PubMed2001

Design and evaluation of a two-layer floating tablet for gastric retention using cisapride as a model drug.

A new kind of two-layer floating tablet for gastric retention (TFTGR) with cisapride as a model drug was developed. The in vitro drug release was determined, and the resultant buoyancy and the time-buoyancy curve were plotted. Because of the sodium bicarbonate added to the floating layer, when immersed in simulated gastric fluid (SGF) the tablet expands and rises to the surface, where the drug is gradually released. The in vitro drug release of this kind of two-layer dosage was controlled by the amount of hydroxypropylmethylcellulose (HPMC) in the drug-loading layer. Generally, the more HPMC, the slower the drug releases. Because cisapride has greater solubility in SGF than simulated intestinal fluid (SIF), its in vitro drug dissolution in SGF is faster than in SIF. One of the distinguishing characteristics of this kind of tablet is the separate regulation of buoyancy and drug release. The idea developed in this experiment can be used as a general modelfor the design of other tablets for gastric retention.

Body Fluids↗
PubMed2001

Reawakening the dragon: changing patterns of opiate use in Asia, with particular emphasis on China's Yunnan province.

Asian countries adjacent to the Golden Triangle and their neighbors have witnessed an evolution in "drug abuse" from traditional opium smoking to heroin eating, smoking, and finally heroin injection. A recent study of 630 heroin users was conducted in China's Yunnan Province, located close to the Golden Triangle. Data collected between August 1997 and February 1998 indicate injecting heroin users, in comparison to noninjectors, were more likely to have used drugs for a longer period of time, and to use drugs more frequently everyday. Other major differences existed between urban and rural subjects, especially highlighting differences between men and women. Women comprised a much higher proportion of urban subjects than rural subjects. Rural injectors were much more likely to be male, but urban injectors were almost evenly split between men and women. The emerging epidemic of heroin use in China and the continuing substance abuse problem in the United States provide an opportunity for collaborative research of mutual benefit.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Paraneoplastic optic neuropathy and cerebellar ataxia with small cell carcinoma of the lung.

Bilateral optic neuropathy and subacute cerebellar ataxia were manifestations of a paraneoplastic neurologic disorder in a woman found to have small cell carcinoma of the lung. Serologic tests revealed a neuronal autoantibody specific for CRMP-5, a 62-kd member of the collapsin response-mediating protein family. Unexplained optic neuropathy in the setting of subacute cerebellar ataxia should cause suspicion of a paraneoplastic disorder and prompt testing for this autoantibody, especially in patients at risk for lung carcinoma.

Aged↗
PubMed2001

Effects of the 20-kilodalton helper protein on Cry1Ac production and spore formation in Bacillus thuringiensis.

Bacillus thuringiensis produces large amounts of various pesticidal proteins during the stationary phase. In order to achieve a high yield and form crystals, some pesticidal proteins require the presence of other proteins. Helper protein P20 is required for efficient production of both the Cyt1A and Cry11A crystal proteins in B. thuringiensis subsp. israelensis. Although full-length Cry1 protoxins are usually independent in terms of expression and crystallization in B. thuringiensis, in this study P20 significantly enhanced production of Cry1Ac protoxin (133 kDa) in an acrystalliferous and plasmid-negative strain. In the presence of P20, the yield of Cry1Ac protoxin increased 2.5-fold, and on average the resulting crystals were 1.85 microm long and 0.85 microm wide, three times the size of the crystals formed in the control lacking P20. Correspondingly, the recombinant strain that coexpressed P20 and Cry1Ac exhibited higher toxicity against Heliothis armigera larvae than the control. Furthermore, serious degradation of Cry1Ac in vivo was observed, which has seldom been reported previously. Actually, most protein was completely degraded during synthesis, and after synthesis about one-third of the expressed protoxins were degraded further before crystallization. In this process, P20 protected only nascent Cry1Ac from degradation, indicating that it acted as a molecular chaperon. In addition, spores were smaller and rounder and had a thinner exosporium layer when they were produced in the presence of P20. In summary, Cry1Ac was severely degraded during synthesis; this degradation was effectively relieved by P20, which resulted in enhanced production. Our results indicated that P20 is an effective tool for optimizing protein production in vivo.

Animals↗
PubMed2001

Bacterial diversity and community structure in an aerated lagoon revealed by ribosomal intergenic spacer analyses and 16S ribosomal DNA sequencing.

We investigated the bacterial community structure in an aerated plug-flow lagoon treating pulp and paper mill effluent. For this investigation, we developed a composite method based on analyses of PCR amplicons containing the ribosomal intergenic spacer (RIS) and its flanking partial 16S rRNA gene. Community percent similarity was determined on the basis of RIS length polymorphism. A community succession was evident in the lagoon, indicated by a progressive community transition through seven sample locations. The most abrupt changes in community structure were associated with a temperature change from 39 to 35 degrees C and with increases in dissolved oxygen. The temporal differences in community structure, based on summer and winter samplings, were greater than the spatial differences during either season. Clone libraries of rDNA-RIS amplicons were constructed from each of three summer samples. Among 90 clones analyzed (30 clones from each sample), 56 phylotypes were distinguished by restriction fragment length polymorphism. Indices of phylotype richness, evenness, and diversity all increased in clone libraries from the beginning to the end of the lagoon. A representative clone of each phylotype was phylogenetically analyzed on the basis of its partial 16S rRNA gene sequence (ca. 450 bp). Phylogenetic analysis confirmed the increase in diversity and further indicated increasing richness of bacterial divisions. Pioneers in the community spatial succession appeared to include thermotolerant, microaerophilic methanol-oxidizing bacteria related to the genus Methylobacillus, as well as thermotolerant, microaerophilic nitrogen-fixing bacteria related to the genus Azospirillum.

Bacteria↗
PubMed2001

Targeted random mutagenesis to identify functionally important residues in the D2 protein of photosystem II in Synechocystis sp. strain PCC 6803.

To identify important residues in the D2 protein of photosystem II (PSII) in the cyanobacterium Synechocystis sp. strain PCC 6803, we randomly mutagenized a region of psbDI (coding for a 96-residue-long C-terminal part of D2) with sodium bisulfite. Mutagenized plasmids were introduced into a Synechocystis sp. strain PCC 6803 mutant that lacks both psbD genes, and mutants with impaired PSII function were selected. Nine D2 residues were identified that are important for PSII stability and/or function, as their mutation led to impairment of photoautotrophic growth. Five of these residues are likely to be involved in the formation of the Q(A)-binding niche; these are Ala249, Ser254, Gly258, Ala260, and His268. Three others (Gly278, Ser283, and Gly288) are in transmembrane alpha-helix E, and their alteration leads to destabilization of PSII but not to major functional alterations of the remaining centers, indicating that they are unlikely to interact directly with cofactors. In the C-terminal lumenal tail of D2, only one residue (Arg294) was identified as functionally important for PSII. However, from the number of mutants generated it is likely that most or all of the 70 residues that are susceptible to bisulfite mutagenesis have been altered at least once. The fact that mutations in most of these residues have not been picked up by our screening method suggests that these mutations led to a normal photoautotrophic phenotype. A novel method of intragenic complementation in Synechocystis sp. strain PCC 6803 was developed to facilitate genetic analysis of psbDI mutants containing several amino acid changes in the targeted domain. Recombination between genome copies in the same cell appears to be much more prevalent in Synechocystis sp. strain PCC 6803 than was generally assumed.

Amino Acid Sequence↗
PubMed2001

DNA-based and culture-based characterization of a hydrocarbon-degrading consortium enriched from Arctic soil.

A hydrocarbon-degrading consortium was enriched from fuel-contaminated soil from the northeastern tip of Ellesmere Island (82 degrees 30'N, 62 degrees 19'W). The enrichment culture was grown on Jet A-1 fuel at 7 degrees C. Bacterial 16S RNA gene (rDNA) fragments were amplified by polymerase chain reaction (PCR) from members of the above consortium and cloned into a plasmid vector. Partial sequences (approximately 500 bp) were determined for 29 randomly selected rDNA clones. The majority of sequences were most similar to the corresponding rDNA sequences of Rhodococcus erythropolis (15 sequences), Sphingomonas spp. (six sequences), and Pseudomonas synxantha (four sequences). Amplified ribosomal DNA restriction analysis confirmed that a larger set of 50 clones had frequencies of the three phylotypes similar to those above. Phylotype-specific PCR assays were developed and validated for the above three phylotypes. The consortium was plated and grown on Jet A-1 fuel vapors, and randomly selected isolated colonies were screened with the above PCR assays. Of 17 colonies, six matched the Rhodococcus phylotype, and three matched the Pseudomonas phylotype. A representative strain of each phylotype was physiologically characterized. Both isolates grew on alkanes at low temperature and had general characteristics consistent with their respective phylotypes. During growth of the consortium, the three phylotype populations were monitored by a most probable number PCR assay. All three phylotypes were detected, but their relative abundance was not consistent with that of the phylotypes in the clone library. The relative abundance of all three phylotypes changed substantially during long-term incubation of the consortium. The DNA-based approach used identified phylotypes consistently present in the consortium, but it failed to predict the relative abundance of their populations.

Arctic Regions↗
PubMed2001

Clinical trial of arotinolol in the treatment of hypertension: dippers vs. non-dippers.

To compare the effects of an alpha, beta blocker, arotinolol, in the treatment of essential hypertension between patients with a dipper and those with a non-dipper profile by means of 24-h ambulatory blood pressure monitoring (ABPM), a multicenter single blind parallel trial was carried out in five clinical centers. After a one-week single blind placebo run-in period, the patients underwent ABPM if their clinic diastolic blood pressure (DBP) ranged from 90-109 mmHg and their clinic systolic blood pressure (SBP) was <180 mmHg. They were divided into two groups according to the absence (non-dipper group, 24 cases) or presence (dipper group, 23 cases) of nocturnal BP reduction > or =10% of daytime BP. ABPM was measured again at the end of the active treatment phase. All patients were given Arotinolol 10-20 mg twice daily for 4 weeks. Twenty four-hour systolic and diastolic average BPs (MSBP, MDBP), 24-h systolic and diastolic blood pressure load (LS BP, LDBP), daytime systolic and diastolic average BPs (dMSBP, dMDBP), daytime systolic and diastolic blood pressure load (dLSBP, dLDBP), nighttime systolic and diastolic average BPs (nMSBP, nMDBP) and nighttime systolic and diastolic blood pressure load (nLSBP, nLDBP) were calculated. Arotinolol was effective in 78.2% of dippers and 54.2% of non-dippers, but the difference in effectiveness between these groups was not statistically significant. After treatment, SBP and DBP-including 24-h, daytime and nighttime systolic and diastolic BPs- were significantly reduced in both groups. During the daytime period, the systolic and diastolic blood pressures were significantly reduced in both dippers and non-dippers, while nighttime systolic and diastolic blood pressures were significantly reduced only in the non-dipper group. No significant changes were found in the dipper group over this period. In conclusion, Arotinolol, which can be dosed twice daily, is an effective antihypertensive agent which effectively lowers blood pressure during the day while reducing nighttime blood pressure more in non-dippers than in dippers, without excessive lowering blood pressure in the latter.

Adrenergic beta-Antagonists↗
PubMed2001

CRMP-5 neuronal autoantibody: marker of lung cancer and thymoma-related autoimmunity.

We have defined a new paraneoplastic immunoglobulin G (IgG) autoantibody specific for CRMP-5, a previously unknown 62-kd neuronal cytoplasmic protein of the collapsin response-mediator family. CRMP-5 is in adult central and peripheral neurons, including synapses, and in small-cell lung carcinomas. Since 1993, our Clinical Neuroimmunology Laboratory has detected CRMP-5-IgG in 121 patients among approximately 68,000 whose sera were submitted for standardized immunofluorescence screening because a subacute neurological presentation was suspected to be paraneoplastic. This makes CRMP-5 autoantibody as frequent as PCA-1 (anti-Yo) autoantibody, second only to ANNA-1 (anti-Hu). Clinical information, obtained for 116 patients, revealed multifocal neurological signs. Most remarkable were the high frequencies of chorea (11%) and cranial neuropathy (17%, including 10% loss of olfaction/taste, 7% optic neuropathy). Other common signs were peripheral neuropathy (47%), autonomic neuropathy (31%), cerebellar ataxia (26%), subacute dementia (25%), and neuromuscular junction disorders (12%). Spinal fluid was inflammatory in 86%, and CRMP-5-IgG in 37% equaled or significantly exceeded serum titers. Lung carcinoma (mostly limited small-cell) was found in 77% of patients; thymoma was in 6%. Half of those remaining had miscellaneous neoplasms; all but two were smokers. Serum IgG in all cases bound to recombinant CRMP-5 (predominantly N-terminal epitopes), but not to human CRMP-2 or CRMP-3.

Amino Acid Sequence↗
PubMed2001

The principle and technique of using Chinese drugs in the treatment of hypertension.

Differential use of Chinese and western drugs, and combination of traditional theory of materia medica with the results of modern pharmacological research can be regarded as a general principle in the treatment of a disease, while combination of lowering blood pressure with preventing and treating complications is a specific method in the treatment of hypertension. As to the use of drugs based on differentiation of diseases and/or symptoms, drugs which have the action of relieving symptoms but also reducing blood pressure should be used as the first choice. For those drugs which have the action of relieving symptoms but can not lower blood pressure should not be used or should be used as less as possible. Drugs with action of raising blood pressure are contraindicated. When patients have the symptoms of hyperactivity of yang resulting from yin deficiency, Huang Bo ([symbol: see text] Cortex Phellodendri) and Zhi Mu ([symbol: see text] Rhizoma Anemarrhenae) are used together to enhance the effects of both nourishing yin to reduce pathogenic fire, and reducing blood pressure. This practice conforms to the TCM theory and also to the modern pharmacological research.

Diagnosis, Differential↗