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Biomedical subjects

Y Yang

Publications and source records attributed to Y Yang.

At least 1,243 records · Page 69Linked to original sources
PubMed1994

[Bacteriological detection of anterior chamber aspirate after extracapsular cataract extraction with intraocular lens implantation].

We cultured the anterior chamber aspirates of 83 patients with extracapsular cataract extraction and IOL implantation. Of the 83 cases, 5 (6.1%) had positive aspirates including 3 cases of staphylococcus epidermidis and 2 cases of staphylococcus aureus. No eye in our study developed bacterial endophthalmitis. Our study suggests that the anterior chamber of human eyes is capable of clearing a low inoculum of bacteria after cataract surgery without the development of bacterial endophthalmitis.

Aged↗
PubMed1994

[Immunohistochemical study on diamine oxidase in mammary cancer and adenosis].

In recent years, an obvious increase of diamine oxidase (DAO) in both blood and tumor tissues has been reported In this assay we observed an increased content and distribution of DAO in mammary cancer and adenosis by immunohistochemistry. The results show that: 1. DAO staining was strongly positive in mammary cancer and the brownish granules were spread over the cytoplasm; 2. In the adenosis of mammary gland, DAO was positive or weakly positive, but those hyperplastic ducts in it appeared to be strongly positive and the brownish granules distributed spotted; 3. The normal mammary tissue presented weak positive or negative DAO reaction. These observations indicated that the malignant tumor and hyperplastic changes of mammary gland induce increase of DAO in the cells, and the higher the DAO content, the greater the possibility of malignant changes.

Adenocarcinoma↗
PubMed1994

Expression of HLA class II-associated peptide transporter and proteasome genes in human placentas and trophoblast cell lines.

Expression of HLA class I antigens is closely controlled in the placental trophoblast cells, which interface directly with maternal cells during pregnancy. In this study, the possibility that peptide transporter (TAP-1, TAP-2) or proteasome (LMP7) genes might be involved in regulating antigen expression in these or other cells that comprise placentas was investigated. Analysis by Northern blot hybridization showed that transcripts from all three genes were present in samples of first trimester and term placental RNA. TAP-1 and TAP-2 messages were consistently more abundant in early than in late gestation placentas, whereas the reverse was observed for LMP7 mRNA. Futher experiments were done on two trophoblast cell lines. One line, Jar, is negative for HLA class I, and the second, JEG-3, expresses HLA-G as well as other HLA class I genes. Both Jar and JEG-3 cells contained TAP-1, TAP-2 and LMP7 mRNA. With the exception of LMP7 in JEG-3 cells, message from all three genes was increased by treating the trophoblast cells with interferon-gamma. While no evidence was collected to support the postulate that the HLA class I negative status of some trophoblast cell subpopulations could be related to absent or dysfunctional TAP-1, TAP-2 or LMP7 mRNA, the data are consistent with the postulate that placental cell expression of HLA class I antigens could be influenced by the availability of peptide transporters and proteasome components.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

The three-dimensional NMR solution structure of alpha-cobratoxin at pH 7.5 and conformational differences with the NMR solution structure at pH 3.2.

The 3D solution structure of alpha-cobratoxin, a neurotoxin purified from the Naja naja siamensis snake venom, has been determined by Nuclear Magnetic Resonance spectroscopy, in conjunction with distance geometry and restrained molecular dynamics, at pH 7.5. A total of 490 distance restraints were obtained from NOE intensities and 25 phi dihedral angle restraints deduced from J-coupling data. The generated structures are well defined with root mean square deviations from a geometrical mean structure of 0.107 +/- 0.036 nm for the backbone atoms and 0.128 +/- 0.073 nm for the side-chain atoms (considering residues 1 to 66 minus 26 to 35). A comparison between the generated structures at pH 7.5 and the mean NMR solution structure at pH 3.2 revealed that the 3D structure of alpha-cobratoxin is more compact at neutral pH. This major difference is mainly due to the pH-dependent conformational variations of three residues His18, Thr44 and Thr59.

Amino Acid Sequence↗
PubMed1994

[Effects of high iodine and high fluorine on children's intelligence and the metabolism of iodine and fluorine].

An investigation on children's intelligence and the metabolism of iodine and fluorine in high iodine and fluorine regions was carried out. The results were as follows. In high iodine and high fluorine areas, the thyroid enlargement prevalence rate among inhabitants and that among children were 3.8% and 29.8%, respectively. The dental fluorosis prevalence rate among inhabitants and that among children was 35.48% and 72.9%, respectively. The pupils' average intelligence quotient (IQ) was 76.67 +/- 7.75, slightly lower than the control point, but that of low intelligent pupils was 16.7%. The urinary iodine and urinary fluoride were 816.25 +/- 1.80 micrograms/L and 2.08 +/- 1.03 mg/L, respectively, markedly higher than the control point. The thyroid iodine-131 (131I) uptake rate was markedly lower than the control point. The values at 3 h and 24 h were 9.36 +/- 1.55% and 9.26 +/- 4.63%, respectively. The serum TSH was obviously higher than the control point. These results indicate that high iodine and high fluorine exert severe damage to human body.

Adolescent↗
PubMed1994

[Clinicopathological observations on 28 cases of cutaneous leishmaniasis in Karamay area].

Clinicopathological observations on 28 cases of cutaneous leishmaniasis with dermal lesions for 1-48 months were carried out. The cutaneous lesions detected in the patients might be categorized into four types. 1. Papular eruption or plaque. It was predominated by inflammatory reaction, including numerous leishmanias and macrophages and other inflammatory cells infiltrating in cutaneous tissue. 2. Soft node or abscess. It was composed of necrotic tissues, many degenerated and dead leishmanias as well as disintegrated inflammatory cells in the focal site. 3. Ulceration. It contained necrotic cutaneous tissue, a considerable number of dead leishmanias and granuloma formation. 4. Hard nodule. Tissue proliferation and healing were distinct, which was indicated by the increase of fibroblasts and fibrous tissue formation, round cells infiltration as well as the foreign body giant cell appearance; besides, a few leishmanias existed; occasionally, scar formation was visible in the superficial and deep layers of the derma. The paper presented for the first time the histopathological changes of cutaneous leishmaniasis in China. And, the description of cutaneous lesions will be of significance in the differential diagnosis between cutaneous leishmaniasis and post kala-azar dermal leishmaniasis.

Diagnosis, Differential↗
PubMed1994

The study of health effects of vinyl chloride air pollution on population.

A series of indicators, including serum lysozyme activity, G-banding chromosome aberration (G-banding CA) analysis, sister chromatid exchanges (SCEs), chromosome aberration (CA), T-lymphocyte transformation rate (TcTR), gamma-GT, GPT and AKP, were employed in the present survey among occupationally vinyl chloride (VC) exposed workers and inhabitants living in VC polluted area in a polyvinyl chloride (PVC) factory. The results showed that the serum lysozyme (S-LZM) activities in Group 3 (adult inhabitants exposed to 0.20 mg/m3 VC for at least 8 years), Group 2 (workers exposed to 4.1 mg/m3 for at least 7 years occupationally), Group 1 (workers exposed to 25.7 mg/m3 for at least 2 years) were significantly higher than control. G-banding CA analysis showed that the total chromosome breakage rates in both Groups 1 and 2 were higher, but no difference existed between Group 3 and control. Only Group 1 was observed having higher SCEs, CA level and lower TcTR than control. AKP levels in Groups 1 and 2 were higher than control, but no gamm-GT and GPT differences were found among groups. The study also suggests that G-banding CA analysis is more sensitive than CA and SCEs.

Adolescent↗
PubMed1994

An application of Expert Network to clinical classification and MEDLINE indexing.

An effective and efficient learning method, Expert Network (ExpNet), is introduced in this paper. ExpNet predicts the related categories of an arbitrary text based on a search of its nearest neighbors in a set of training texts, and a reasoning from the expert-assigned categories of these neighbors. Evaluations in patient-record text classification and MEDLINE document indexing show a performance of ExpNet in recall and precision comparable to the Linear Least Squares Fit (LLSF) mapping method, and significantly better than other methods tested. We also observed that ExpNet is much more efficient than LLSF in computation. The total training and testing time on the patient-record text collection (6134 texts) was 4 minutes for ExpNet versus 96 minutes for LLSF; on the MEDLINE document collection (2344 documents), the total time was 15 minutes for ExpNet versus 4.6 hours for LLSF. It is evident in this study that human knowledge of text categorization can be statistically learned without expensive computation, and that ExpNet is such a solution.

Abstracting and Indexing↗
PubMed1994

An evaluation of computer assisted clinical classification algorithms.

The Mayo Clinic has a long tradition of indexing patient records in high resolution and volume. Several algorithms have been developed which promise to help human coders in the classification process. We evaluate variations on code browsers and free text indexing systems with respect to their speed and error rates in our production environment. The more sophisticated indexing systems save measurable time in the coding process, but suffer from incompleteness which requires a back-up system or human verification. Expert Network does the best job of rank ordering clinical text, potentially enabling the creation of thresholds for the pass through of computer coded data without human review.

Abstracting and Indexing↗
PubMed1994

[In vitro sensitivity of Plasmodium falciparum to mefloquine, quinine, amodiaquine, chloroquine, pyronaridine and sulfadoxine/pyrimethamine in south Yunnan].

The sensitivity of P. falciparum to mefloquine, quinine, amodiaquine, chloroquine, pyronaridine, and sulfadoxine/pyrimethamine (MEF, QNN, AMO, CHL, PYR, S/P) was tested using in vitro microtest in south Yunnan Province in 1992. The ID50 were 46, 480, 52, 150, 15 and 2 x 10(4)/25 x 10(2) nmol/L, respectively; ID95 were 160, 1,536, 292, 680, 60 and 24 x 10(5)/3 x 10(5) nmol/L, respectively. All the isolates (30) were sensitive to MEF and QNN; 100% (30/30) and 96.7% (29/30) isolates were found to be resistant to AMO and CHL, the cross-resistance rate was 100% to the two drugs. One of 5 isolates exhibited resistance to PYR. The results suggest that the P. falciparum was susceptible to MEF and QNN, but was resistant to AMO, CHL and S/P. CHL-resistant P. falciparum showed a marked cross-resistance to AMO, but not to MEF, QNN, and S/P; AMO-resistant P. falciparum exhibited cross-resistance to CHL, but not to MEF, QNN, and S/P.

Amodiaquine↗
PubMed1994

Ethnic differences in disposition of antipyrine and acetaminophen between Tibetan and Han healthy volunteers.

The differences in disposition of antipyrine and acetaminophen between Tibetan and Han healthy volunteers were studied in a randomized crossover design. The half-life of antipyrine was found to be 18.8 +/- 4.89 h in 16 Han and 15.0 +/- 3.02 h in 17 Tibetan (P < 0.05) and the clearance was 1.35 +/- 0.37 L.h-1 in Han and 1.71 +/- 0.44 L.h-1 in Tibetan (P < 0.05). The half-life of acetaminophen was 3.1 +/- 0.86 h in Han and 3.2 +/- 1.12 h in Tibetan (P > 0.05). The experimental results indicate that the disposition of antipyrine between Tibetan and Han healthy volunteers significantly differed, the clearance of antipyrine in Tibetan increased by 20%, but the disposition of acetaminophen between the two ethnic groups showed no difference.

Acetaminophen↗
PubMed1994

Inhibition of mitochondrial superoxide generation in rat alveolar macrophages by 12-O-tetradecanoylphorbol-13-acetate: potential role of protein kinase C.

We have observed that lucigenin-derived chemiluminescence (CL) measures superoxide anion (O2-) production from two major cellular compartments in rat alveolar macrophages (AMs): extracellular O2- produced by NADPH oxidase; and intracellular O2- produced by the reduction of molecular oxygen by the mitochondrial electron transport chain. Although the treatment of AMs with 30 ng/mL 12-O-tetradecanoyl phorbol-13-acetate (TPA) increases the production of O2- by NADPH oxidase, the net result of TPA addition monitors is a decrease in lucigenin-derived CL resulting from inhibition of mitochondrial-derived O2- production. Since protein kinase C (PKC) has been shown to be the cellular receptor through which TPA mediates its effects, it was postulated that activation of PKC inhibits mitochondrial-derived O2- production as measured by lucigenin-derived CL. Studies performed with 50 microM H-7 (a PKC inhibitor) support this hypothesis by blocking the inhibition of mitochondrial-derived CL by TPA, while HA-1004, a negative control for H-7, had no effect on the system. These results suggest that mitochondrial respiration may be modulated by the actions of PKC. Moreover, this observation suggests a novel mechanism whereby chemicals which activate PKC may affect cellular function through modulation of mitochondrial activity.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1994

[Effects of compatible using of fructurs Evodiae on the main chemical components of rhizoma Coptidis].

The results of experimental studies on the compatible using of Fructus Evodiae with Rhizoma Coptidis show that in the decoction of the two drugs there is an additive property for the chemical constituents and no new chemical substances were found. But the decocting rate of berberine, the main constituent of Rhizoma Coptidis, decreases by 37.0% after decocting with Fructus Evodiae.

Berberine↗
PubMed1994

Image analysis for the study of radionuclide distribution in tissue sections.

UNLABELLED: Tissue section autoradiographs are often prepared to review the precise spatial locations of a radiolabeled molecule relative to cells, such as in the study of radiolabeled antibody distribution. The objective of this work was to develop and evaluate a method to automatically detect both grains and cell nuclei from stained tissue autoradiographs using a microscope and an image analyzer. METHOD: Using a sequence of morphological image operations, the densely stained regions of the section, representing the cell nuclei are identified first, and then subtracted from the original image. This enables the identification of autoradiographic grains under conditions of variable contrast, by separation of the grains overlapping the cell nuclei from the extracellular spaces, permitting a more accurate and robust automatic segmentation routine. RESULTS: The accuracy of the method to detect grains has been evaluated at different threshold levels. The highest accuracy obtained was approximately 90%. The accuracy in the detection of cell nuclei was histology-dependent. As examples, we have estimated accuracies of approximately: 86%, 81% and 77% for kidney, EL-4 lymphoma and pneumonocyte sections, respectively. CONCLUSION: This method was tested using specimens designed to study radiolabeled antibody distribution, but it should be applicable with comparable accuracy to other radiolabeled compounds for which quantitative information on the heterogeneity of distribution is required.

Animals↗
PubMed1994

[Risk factors of prostate cancer--a matched case-control study].

A 1:2 matched case-control study was used to determine the risk factors of prostate cancer. Twenty-seven cases of prostate cancer were matched with an equal number of other malignant tumor cases (non-urological tumor) and other urological cases (non-malignant tumor). Both study and control groups were the same in age, sex, race, and day of admission. All of these patients were treated in the First Affiliated Hospital of West China University of Medical Sciences. The questionnaire was used to survey the both groups of patients. Such data as diet, lifestyle, marital status and past history of other prostate diseases were obtained. Single factor analysis and multiple conditional logistic regression analysis were used to estimate the relative risk (RR), 95% confidence interval (95% CI) and P values. Statistical analysis was performed using the Egret, Epilog soft ware. The results were as follows: 1. Increasing dietary vitamin A was associated with a significant decrease in the risk of prostate cancer (RR = 0.948, 95% CI = 0.9309-0.9947, P = 0.029). This factor also showed dose response gradients. The relative risk was decreasing with exposure dose increasing. 2. The positive previous prostate history, such as prostatitis and benign prostate hyperplasia, increased the risk of prostate cancer (RR = 6.385, 95% CI = 1.046-38.97, P = 0.045). 3. Another finding in the widower, divorce and remarried men (RR = 4.312, 95% CI = 1.367-13.6, P = 0.013). And 4. There was no relationship between the risk of prostate cancer and dietary fat intake, vasectomy, socioeconomic status, familial malignant tumor history, smoking and alcohol consumption.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1994

[Experimental study of antiinfection effect of topical "moist ointment" in burn wound infection].

A controversy on the therapeutic effect of topical "moist ointment" in burns has been noticed recently. An experimental study is designed for the evaluation of its antibacterial and antiinfection effect. A 20% fullthickness burn wound is produced on SD rat back, and they are seeded with 10(9) CFU of Pseudomonas aeruginosa ATCC-27853. "Moist ointment", cream base, 1% silver sulfadiazine (Ag-SD) cream or 1.2% silver norfloxacin (Ag-FLX) cream is topically applied to the burn wounds at various time interval of 10 min, 8h, 24h, and 48h, after the inoculation of Pseudomonas aeruginosa. Topical therapy lasted for 48h, with dressing change once a day but twice a day for "moist ointment" therapy only. Bacterial counts of subeschar tissue and heart blood culture, and histopathologic study of the wounds are made as laboratory criteria. A modified agar well diffusion (AWD) test is performed as a bacterial inhibitory study using Pseudomonas aeruginosa ATCC-27853, E. coli ATCC-25922, or Staphylococcus aureus ATCC-25923. Results of the study show that Ag-FLX cream has a strong antibacterial effect and Ag-SD cream a moderate effect. However, "moist ointment" and cream base do not show antibacterial effect. Bacterial counts of subeschar tissue and histopathologic study of the infected burn wounds show that more than 70% of the animals in the "moist ointment" group have invasive wound infection, and the incidence of septicemia with Pseudomonas aeruginosa is 50% as determined by blood cultures. The above mentioned results indicate that "moist ointment" has no antibacterial and anti-infection effect.

Administration, Topical↗
PubMed1993

Hypoxic forebrain cholinergic neuron injury: role of glucose, excitatory amino acid receptors and nitric oxide.

Glucose depletion increased sensitivity to hypoxic insult in basal forebrain forebrain cultures in a dose-dependent manner as indicated by reduction of choline acetyltransferase (ChAT) activity, increased lactate dehydrogenase (LDH) release and disrupted morphology. The glutamate receptor antagonists 2-amino-5-phosphonovaleric acid (APV) and 6-cyano-2,3-nitroquinoxoline (CNQX) limited the degree of injury in combination and individually. The nitric oxide synthase (NOS) inhibitor N-nitro-L-arginine (NNLA) also either completely protected against mild injury or attenuated severe injury.

2-Amino-5-phosphonovalerate↗