Biomedical subjects

Y Su

Publications and source records attributed to Y Su.

At least 37 records · Page 2Linked to original sources

PubMed2001

Growth of infants during the first 18 months of life in urban and rural areas of southern China.

OBJECTIVE: Observe the growth pattern of infants from birth to 18 months. METHODOLOGY: A prospective study was conducted from 1994 to 1996 in urban and township-rural areas of Guangdong Province, southern China, recruiting 568 and 257 newborn infants, respectively. Anthropometric data was collected at birth, 1.5, 4, 5, 6, 8, 10, 12, 15, and 18 months. RESULTS: The urban infants at birth had Z-scores of weight for age (WAZ), height for age (HAZ) and weight for height (WHZ) below the National Center for Health Statistics (NCHS) median (P < 0.01). However, from 1.5 to 4 months, the WAZ and WHZ scores were above (P < 0.01), but by 7 months fell and remained at - 0.7 to - 0.8 SD below the NCHS median (P < 0.01). HAZ scores improved after birth, were at the NCHS median to 8 months (P = NS), and then decreased to 0.2-0.4 SD below the NCHS median (P < 0.01). Compared with the urban infants, the township-rural infants were lighter and shorter throughout the first 18 months of life, and from 8 months of age, were - 1 SD or more below the NCHS median. CONCLUSIONS: Growth retardation was found in this sample of Chinese infants. The magnitude of growth retardation was greater for infants in the township-rural area compared with those in the urban area.

Age Distribution↗

PubMed2001

Carbon disulfide exposure assessment in a Chinese viscose filament plant.

UNLABELLED: Carbon disulfide is a well-known occupational hazard in the viscose industry, and studies have shown considerable health effects when workers are exposed to high concentrations of this reagent. At exposure levels below the TLV-TWA(31 mg/m3), findings remain contradictory, probably due to deficient exposure data. The present study tries to identify the occupational hazards and thoroughly assess the exposure levels in a Chinese viscose rayon plant. METHODS: An industrial hygienic field survey and a sampling campaign were carried out, including multi-gas monitoring, on-line measurements, and stationary assessment in the spinning hall as well as personal exposure sampling for spinners (by charcoal tube absorbing and GC-FPD analysis). All data was introduced into Foxpro database, and analyzed by Epi info (6.04) and SPSS. RESULTS: On-line measurement showed that the geometric mean (GM) of carbon disulfide exposure amounted to 12.73 mg/m3 in 'exposure' and 0.08 mg/m3 in 'non-exposure' worksites. These concentrations in the air were related to the subject's activities showing the highest levels when they had to open the shield windows of the spinning machines. Stationary exposure measurements of carbon disulfide in the spinning hall amounted to 23.29 mg/m3 GM (range 5.8-97.94 mg/m3). Personal exposure of spinners was about 17.3 mg/m3 GM. Comparing these methods, the personal exposure sampling could exactly express the exposure levels of the worker's contacting situation. The on-line measurement by multi-gas monitor might also be recommended to the factory as it has its own advantages of rapid and independent assessment, but it under-estimates the exposure level.

Air Pollution, Indoor↗

PubMed2001

Theaflavins in black tea and catechins in green tea are equally effective antioxidants.

Green tea catechins, including (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epigallocatechin gallate (EGCG), are oxidized and dimerized during the manufacture of black tea and oolong tea to form orange-red pigments, theaflavins (TF), a mixture of theaflavin (TF1), theaflavin-3-gallate (TF2A), theaflavin-3'-gallate (TF2B) and theaflavin-3,3'-digallate (TF3). The present study was designed to compare the antioxidant activities of individual TF with that of each catechin using human LDL oxidation as a model. All catechins and TF tested inhibited Cu(+2)-mediated LDL oxidation. Analysis of the thiobarbituric acid-reactive substances (TBARS) and conjugated dienes produced during LDL oxidation revealed that the antioxidant activity was in the order: TF3 > ECG > EGCG > or = TF2B > or = TF2A > TF1 > or = EC > EGC. Four TF derivatives also demonstrated a dose-dependent antioxidant activity in Cu(+2)-mediated LDL oxidation at concentrations of 5-40 micromol/L. These results demonstrate that the TF present in black tea possess at least the same antioxidant potency as catechins present in green tea, and that the conversion of catechins to TF during fermentation in making black tea does not alter significantly their free radical-scavenging activity.

Antioxidants↗

PubMed2001

Cell cycle regulation of cyclin-dependent kinases in tobacco cultivar Bright Yellow-2 cells.

Plants possess two major classes of cyclin-dependent kinases (CDK) with cyclin-binding motifs PSTAIRE (CDK-a) and PPTA/TLRE (CDK-b). Tobacco (Nicotiana tabacum L. cv Bright Yellow-2) cells are the most highly synchronizable plant culture, but no detailed analysis of CDK activities has been reported in this system. Here we describe isolation of new PPTALRE CDKs (Nicta;CdkB1) from Bright Yellow-2 cells and present detailed analysis of the mRNA, protein and kinase activity levels of CdkB1, and the PSTAIRE CDKA during the growth and cell cycles. CdkA and CdkB1 transcripts are more abundant in exponential than in stationary phase cells, but the two genes show strikingly different regulation during the cell cycle. CdkA mRNA and protein accumulate during G1 in cells re-entering the cell cycle, and immunoprecipitated histone H1 kinase activity increases at the G1/S boundary. Aphidicolin synchronized cells show the highest CDKA-associated histone H1 kinase activity during S-G2 phases, although CdkA mRNA and protein levels are not significantly regulated. In contrast, CdkB1 transcripts are present at very low levels until S phase and CDKB1 protein and kinase activity is almost undetectable in G1. CdkB1 mRNA accumulates through S until M phase and its associated kinase activity peaks at the G2/M boundary, confirming that transcription of PPTALRE CDKs is cell cycle regulated. We suggest that CDKA kinase activity likely plays roles at the G1/S phase boundary, during S phase, and at the G2/M phase transition, and that CDKB1 kinase activity is present only at G2/M.

CDC2 Protein Kinase↗

PubMed2001

Culture, change, and prediction.

Five studies studies that Chinese and Americans perceive change differently. Chinese anticipated more changes from an initial state than Americans did. When events were changing in a particular direction. Chinese were more likely than Americans to predict change in the direction of change. Moreover, for patterns with changing slopes, Chinese predicted greater change in the way slopes changed, in comparison to Americans. In addition, people who predicted change were perceived as wise by Chinese more than by Americans. Implications for social attribution, tolerance for contradiction, persistence on tasks, and the illusion of control are discussed.

Adaptation, Psychological↗

PubMed2001

Lack of protective effect by intermittent hypoxia on MPTP-induced neurotoxicity in mice.

In the study we report here, several lines of evidence support the preventive action of intermittent hypoxia against oxidative injuries in CNS. Our in vitro data showed that autooxidation and iron-induced lipid peroxidation were attenuated in cortical homogenates of intermittent hypoxia-treated animals. Furthermore, our preliminary study found that iron induced oxidative injuries were abolished in rat brain after intermittent hypoxic treatment (paper submitted). Several antioxidative defensive systems improve in response to intermittent hypoxia. Since attenuation of autooxidation and iron-induced lipid peroxidation were observed in cortical homogenates of intermittent hypoxia-treated mice, the lack of prevention by intermittent hypoxia of MPTP-induced neurotoxicity may be due to the MPTP action that is not oxidative related. Together with our previous studies, in which several antioxidants were shown to successfully prevent oxidative injuries, our data here suggest that intermittent hypoxia may offer a potential treatment for preventing CNS degenerative diseases.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

PubMed2001

[Repetitious sorption of phenol to organobentonites from water].

The properties and mechanisms for repetitious sorption of phenol to organobentonites from water were studied. Results showed that organobentonites could be used to sorb phenol from water many times with high removal rates. The sorption capacities of three single-cation organobentonites were 120 CTMAB-bentonites > 120 CPC-bentonites > 120 DTMAB-bentonites, when the original concentration of phenol was 1000 mg/L. The sorption mechanisms changed from adsorption to partition in the process of repetitious sorption. Sorption of phenol to CPC-bentonites could bring synergic sorption. The distribution coefficience (Kp) were related to the quantities of phenol on CPC-bentonites, while the distribution coefficience of phenol on CTMAB-bentonites and DTMAB-bentonite were constant.

Adsorption↗

PubMed2001

Retinoic acid regulated insulin-like growth factor gene expression in cord blood lymphocytes.

OBJECTIVE: To explore the immune promotion mechanism of retinoic acid (RA). METHODS: Reverse Transcription-Polymerase chain reaction (RT-PCR) was used to detect the gene expression of insulin like growth factor I (IGF-I) and IGF receptors (IGF-IR and IGF-IIR) in vitro, and their regulation by RA in human cord blood lymphocyte (CBL). RESULTS: Significant upregulation of IGF-I, IGF-IR and IGF-IIR mRNA was found at 6-24 hours in CBL incubated with physiologic concentrations of RA as compared to those without RA. CONCLUSION: The enhancement of IGF expression may be an important pathway for vitamin A to promote immune cellular functions.

Cells, Cultured↗

PubMed2001

[Studies on infiltration mechanism of adenoid cystic carcinoma: haptotaxis function assay of fibronectin].

OBJECTIVE: To investigate the invasion mechanism of adenoid cystic carcinoma (ACC) by ACC haptotaxis changes in fibronectin (FN). METHODS: Three strains of ACC cells were used. The haptotaxis changes in FN, and receptor changes in the cell membrane surface were determined. RESULTS: All three strains of ACC cells had remarkably greater migration ability than SCC cell. High level of alpha 2, alpha 3, alpha 6 and beta 1 receptor subunit types was found in the cell surface of ACC and SCC; and high level of alpha 5 in ACC3. High inhibition of haptotaxis reaction was found after blocked alpha 5 and beta 1 receptor subunit in ACC and a middle inhibition after blocked alpha 4. In SCC more strong inhibition was found after blocked alpha 1, alpha 4 and beta 1. CONCLUSIONS: This study indicates that ACC cells have greater invasion ability than SCC cells in FN and haptotaxis reaction of different receptor of tested cells in FN have some feature pattern.

Carcinoma, Adenoid Cystic↗

PubMed2001

[Studies on DNA amplification fingerprinting of cortex Magnoliae officinalis].

Total genomic DNA samples of Chinese traditional medicine(CTM) Cortex Magnoliae Officinalis ("Houpo"), its counterfeits and substitutes were amplified by DNA amplification fingerprinting(DAF). Their amplified DNA banding patterns were distinguished on PAGE. The results show that DAF can be used to identify CTM "Houpo", its counterfeits and substitutes, which is also quite valuable for correctly introducing original plant.

DNA Fingerprinting↗

PubMed2001

[An experimental study of the influence of burn on the expressions of IFN-gamma and IL-4 in T lymphocytes and on the expression of IL-12 in macrophages in mice].

OBJECTIVE: To investigate the influence of burn on the expressions of IFN-gamma and IL-4 in T lymphocytes and on the expression of IL-12 in macrophages in mice. METHODS: The mice inflicted by 12% TBSA burn on the back were employed as the model. The peritoneal macrophages (PMphis) were isolated and counted under light microscope (LM). The gene expression level of IL-12 P35 and P40 subunits was determined with RT-PCR. The ratio of spleen to body and splenic histology were also determined. Splenic T lymphocytes were isolated and the gene expression levels of IFN-gamma and IL-4 in the T lymphocytes were examined by RT-PCR. RESULTS: (1) PMphis decreased significantly on 3 postburn day (PBD) and recovered quickly thereafter. (2) The gene expressions of IL-12 P35 and P40 subunits in PMphis were enhanced obviously. (3) Splenic index increased evidently and the karyokinesis phase increased in splenic lymphocytes. (4) The expressions of IFN-gamma and IL-4 in splenic T lymphocytes increased postburn. CONCLUSION: The expressions of IFN-gamma and IL-4 in splenic T lymphocytes and the expressions of IL-12 in PMphis could be enhanced by burn injury.

Animals↗

PubMed2001

[The changes of serum levels of interleukin-6 and interleukin-8 in pregnant women with systemic lupus erythematosus].

OBJECTIVE: To assess the changes of serum levels of interleukin-6(IL-6) and interleukin-8 (IL-8) in pregnant women with stationary phase systemic lupus erythematosus (SLE). METHODS: Enzyme-linked immunosorbent assay (ELISA) was used to measure serum IL-6 and IL-8 from 14 pregnant women with stationary phase SLE (SLE group), 12 normal pregnant women (normal pregnant group) and 12 normal non-pregnant women (group normal non-pregnant). The later two groups are set as controls. RESULTS: The IL-6, IL-8 levels in group SLE patients are (20.31 +/- 5.70) ng/L and (48.80 +/- 9.17) ng/L, significantly higher than those in normal pregnant group [IL-6, IL-8 levels are (8.40 +/- 2.49) ng/L and (21.15 +/- 5.21) ng/L, respectively, P < 0.01)] and normal non-pregnant group [IL-6, IL-8 levels are (6.14 +/- 0.86) ng/L and (17.71 +/- 4.43) ng/L, respectively, P < 0.01]. However, there's no significant difference between the normal pregnant group and normal non-pregnant group (P > 0.05). CONCLUSION: Serum levels of IL-6, IL-8 may be helpful to monitor the progress of SLE during pregnancy.

Adult↗

PubMed2001

[Clindamycin soluble suppository-production and its efficacy in treating bacterial vaginosis].

OBJECTIVE: To make the soluble suppository of clindamycin which is an effective drug for treatment of Bacterial vaginosis and to treat patients in clinical trials. METHODS: Outpatients who had vaginal infections from Sept. 1998 to Jan. 1999 were investigated. The diagnoses of bacterial vaginosis were made according to Amsel's criteria and 80 patients were included in this study. They were divided into two groups to be treated respectively by metronidanole suppository and clindamycin suppository which were made by our hospital pharmacy. RESULTS: The cure rate of metronidanole was 87.5% and that of clindamycin 90.3%; No significant difference was noted between the two groups(P > 0.05). The new clindamycin suppository was not irritant and it was easy to dissolve in vagina. There was no discontinued treatment because of side-effect. CONCLUSION: The clindamycin suppository does not irritate the mucosa of vagina, it is an efficacious remedy for bacterial vaginosis.

Administration, Intravaginal↗

PubMed2000

Patterns of histone acetylation suggest dual pathways for gene activation by a bifunctional locus control region.

The five genes of the human growth hormone (hGH) cluster are expressed in either the pituitary or placenta. Activation of the cluster is dependent on a locus control region (LCR) comprising pituitary- specific (HSI,II, -15 kb), placenta-specific (HSIV, -30 kb) and shared (HSIII, -28 kb; HSV, -32 kb) DNase I hypersensitive sites. Gene activation in the pituitary is paralleled by acetylation of a 32 kb chromatin domain 5' to the cluster centered at HSI,II. In the present study we observed that acetylation of this region in placental chromatin was discretely limited to shared HSIII and HSV. Transgenic studies revealed placenta-specific activation of linked genes by a determinant (P-element) located 2 kb 5' to each of the four placentally expressed genes. A localized peak of histone acetylation was observed at these P-elements in placenta but not pituitary. These data support a model for bifunctional action of the hGH LCR in which separate positive determinants, HSI,II and the P-elements, activate their respective target genes by tissue-specific recruitment of distinctly regulated histone acetyl transferase activities.

Acetylation↗

PubMed2000

Low-temperature structure of indium quantum chains on silicon

The array of quasi-one-dimensional indium chains in the Si(111)- (4x1)-In surface reconstruction exhibits a phase transition to a low-temperature (8x2) phase. It has been suggested that this phase transition is related to a charge density wave (CDW) formation. The x-ray diffraction results presented here demonstrate that at 20 K the CDW has not yet condensed into a superstructure even though good transverse coupling was established. This indicates that CDW formation cannot be the driving force for the phase transition. Furthermore we elucidate the subtle highly anisotropic interchain correlations and reveal the detailed atomic structure of the low-temperature (8x2) phase.

Journal Article↗

PubMed2000

Mortality rates among carriers of ataxia-telangiectasia mutant alleles.

BACKGROUND: Mutations at the ataxia-telangiectasia locus cause a distinctive autosomal recessive syndrome in homozygotes and predispose heterozygotes to cancer and ischemic heart disease. OBJECTIVE: To examine mortality rates among persons carrying a mutated ataxia-telangiectasia gene. DESIGN: Retrospective cohort study. SETTING: The United States and Canada. PARTICIPANTS: 405 grandparents of patients with ataxia-telangiectasia. MEASUREMENTS: Ages at death and risk for death (from all causes, cancer, ischemic heart disease, and other causes) among carriers and noncarriers of ataxia-telangiectasia mutations. RESULTS: Compared with noncarriers, carriers of a mutated ataxia-telangiectasia allele had a significantly increased risk for death at 20 through 79 years of age (relative risk, 1.9 [95% CI, 1.3 to 2.8]) (P < 0.001). On average, carriers died 7 to 8 years earlier than noncarriers. Cancer caused most of the excess deaths, and ischemic heart disease caused the remainder. Among carriers, relative risk for death from cancer and ischemic heart disease before 80 years of age was 2.6 (CI, 1.4 to 4.7; P = 0.002) and 2.0 (CI, 1.0 to 4.0; P = 0.062), respectively. Compared with noncarriers, carriers who died of cancer were a mean of 4 years younger (P > 0.2) and carriers who died of ischemic heart disease were a mean of 11 years younger (P = 0.006). CONCLUSION: Carriers of mutations at the ataxia-telangiectasia locus, who make up 1.4% to 2% of the general population, have a higher mortality rate and an earlier age at death from cancer and ischemic heart disease than noncarriers.

Adult↗

PubMed2000

Development and evaluation of a glow discharge microwave-induced-plasma tandem source for time-of-flight mass spectrometry.

In this work, a new glow discharge, microwave-induced-plasma (GDMIP), tandem ion source was developed, characterized, and used in conjunction with time-of-flight mass spectrometry. This tandem source was designed to be simple and compact The GD and the MIP unit are independent and demountable, providing flexibility in tuning and operating. The microwave plasma can be formed with very low power (a few watts) and overlapped with the glow discharge. The discharge current increased with the addition of microwave discharge when the GD was operated in constant-voltage mode, and the amplitude of the current increase was found to be related to microwave power, discharge pressure, and sampling distance. With the addition of microwave discharge, significant signal enhancement was achieved under a discharge pressure of 2.0 Torr and a discharge voltage of 500 V with 2.0-mm sampling distance. Enhanced factors of analyte signals ranging from approximately 1 to nearly 10 could be obtained with MIP boosting, while no significant change in noise level was observed. This new tandem source provides improved performance in direct solid sample analysis.

Journal Article↗

PubMed2000

Helium plasma source time-of-flight mass spectrometry: off-cone sampling for elemental analysis

In this paper, an atmospheric pressure, helium microwave-induced plasma (MIP) ion source coupled with an orthogonal acceleration time-of-flight mass spectrometer (TOFMS) is explored for elemental analysis. Studies of the relationship between ion signals and sampling distance of the MS reveal that background signals can be suppressed dramatically without sacrificing the signal intensities of analytes when the microwave plasma plume is off the tip of the sampler orifice. This "off-cone" ion sampling mode provides a technique to obtain nearly "clean" background spectra and, thus, eliminates the spectral interference from entrainment air and the working-gas species, making it possible to sensitively determine isotopes that suffered from spectral interference in ICPMS and MIPMS (such as 40Ca, 52Cr, 55Mn, and 56Fe). On the other hand, since the high-temperature plasma is kept away from the sampler aperture, off-cone sampling places little demand on the cooling device and the lifetime of the sampler plate can be extended. The instrumental system can provide a fairly good mass resolution of 1100 (fwhm). The detection limits (3sigma) in the tens of picograms per milliliter level for the elements studied can be achieved with a digital oscilloscope. These detection limits can be easily improved with an advanced detection system, which is currently available in commercial markets.

Journal Article↗