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Biomedical subjects

Z Yang

Publications and source records attributed to Z Yang.

At least 541 records · Page 30Linked to original sources
PubMed1998

[In vitro sensitivity of Plasmodium falciparum to chloroquine, piperaquine, pyronaridine and artesunate in Yuxi prefecture of Yunnan province].

AIM: To assess the sensitivity of Plasmodium falciparum to four antimalarials. METHODS: WHO standard in vitro microtest was used. RESULTS: The resistance rates of the malaria parasite to chloroquine, piperaquine pyronaridine and artesunate were 85.7%, 66.7%, 38.1% and 5.0%, respectively. CONCLUSION: Among the antimalarials tested in Yuxi Prefecture, Yunnan Province, high resistance of P. falciparum to chloroquine and piperaquine was found. The sensitivity of P. falciparum in part of the cases to pyronaridine decreased. However, most of the cases were relatively sensitive to artesunate.

Adolescent↗
PubMed1998

[Study on quality of China made NS3 antigen].

Using anti-HCV antibody screening assay to control the quality for blood is the main measure for preventing transmission of HCV in China. This study is to evaluate the quality of NS3 antigen because of their positive rate to anti NS3 antibody in HCV infected patients and to all kinds of anti-HCV antibody detecting kits, that need NS3 antigen. We collected four China genetically engineered NS3 antigens and other two NS3 antigens came from abroad. The first step is to confirm that the antibody reactivity with coated NS3 antigen is true. The second step is to compare the quality of China made NS3 antigens with NS3 antigens abroad. The results showed that coated NS3 antigen kits have high sensitivity in identifying the positivity of sera from second generation panel, among them that were RIBA-2 indeterminate or negative. Some negative or false positive results by coated Chinese NS3 antigens indicate that manufacturer should make more efforts to ensure the best condition terms for using these antigens.

Antigens, Viral↗
PubMed1998

[Approach to recognition of ECG P waves based on approximating functions].

A new method of recognizing ECG P waves based on approximating function is presented in this paper. The result of experiment demonstrates that the method based on the second order approximating functions to recognize P waves in useful and easy to do. The rate of correctness for recognizing P waves is higher than 99% according to MIT/BIH ECG Datebase.

Algorithms↗
PubMed1998

[Isolation and characterization of a insecticidal protein from Pseudomonas pseudoalcaligenes].

A insecticidal protein was purified by gel-filtration chromatography on Sephadex G-100 and anion-exchange chromatography on DEAE-Sephadex A-50 from the suspension of Pseudomonas pseudoalcaligenes culture. Certain biophysical and biochemical properties were also studied. The molecular weight of the subunit of the insecticidal protein is 25,100 and pI is 5.16. Amino acid composition analysis showed that it is an acidic protein.

Amino Acids↗
PubMed1998

[FT-IR study on the solid-state reaction of bilirubin on BaF2].

Bilirubinate complexes are the main component of pigment gallstones and the recent researches suggested that bilirubin free radical plays a role in some biological processes. In this paper the solid-state reaction of bilirubin on BaF2 was examined by FT-IR. The solid-state reaction was produced by grinding the crystalline bilirubin and single crystals BaF2 together in an agate mortar. From the results the free radical mechanism is suggested in the solid-state reaction of bilirubin on BaF2. The replacement of H on NH of pyrrole by Ba2+ was prior to that of H on COOH. The structure of the resultant complex from the solid-state reaction is different compared with that from the liquid-state reaction.

Barium Compounds↗
PubMed1998

[Determination of Sn/In in the ITO film by emission spectral method].

In the film sample analysis, the consstence within standard sample and analytical sample is discussed by emission spectral method. Using spark light source and moving electrode, the content of Sn/In in the ITO film is obtained by repeatedly exposing four samples. The accuracy and precision are satisfying.

English Abstract↗
PubMed1998

Overexpression of MDM2, p53, and NCAM proteins in human radiation-induced skin ulcers.

Using immunohistochemistry, we studied the overexpression of MDM2, p53, and NCAM proteins in human radiation-induced skin ulcers. We found that the positive rate of overexpression of MDM2, p53, and NCAM was 36%, 8%, and 32%, respectively. The overexpression of MDM2 protein was mainly observed in the nuclei of fibroblasts in the deeper part of the ulcer; that of p53 protein was in the nuclei of the epidermis and in the cytoplasm of fibroblasts and endothelial cells, whereas that of NCAM was located in the cytoplasm of squamous epithelial cells of the epidermis and in fibroblasts, fibrocytes, endothelial cells, and leiomyocytes in the media of arteriolar walls. The overexpression of MDM2, p53, and NCAM may be related to the poor healing of radiation-induced skin ulcers and the cancer transformation.

Gene Expression↗
PubMed1998

Preventive effects of selenium-enriched spiruline (SESP) on radiation pneumonitis.

We studied the early effects of selenium-enriched spiruline (SESP) on radiation-induced pulmonary fibrosis using histopathology, cDNA-mRNA dot-blot hybridization, and a biochemical technique for quantifying the hydroxyproline content. We found marked lung injury in the irradiated group, whereas only slight hyperemia, hemorrhage, exudation, and thickness of the interalveolar wall in the lung in the selenium-treated group. The hydroxyproline (hyp) content in the lungs and the synthesis of type III collagen mRNA decreased in the SESP-treated group. Selenium-enriched spiruline may have a protective effect on the development of radiation pneumonitis.

Animals↗
PubMed1998

Binding of nonsteroidal antiinflammatory drugs to the alpha-subunit of the trifunctional protein of long chain fatty acid oxidation.

Nonsteroidal antiinflammatory drugs (NSAIDs) reduce the growth of colorectal carcinoma cell lines in vitro. The mechanism appears to be independent of cyclooxygenases, and the long chain fatty acid pathway has been suggested as an alternative inhibitory target. We now report that all NSAIDs tested bound to the alpha-subunit of the trifunctional protein of the long chain fatty acid oxidation pathway, as assessed by competition with 125I-[Nle15]-gastrin2,17 in a covalent cross-linking assay. Furthermore the NSAIDs diclofenac and ibuprofen inhibited the 3-hydroxyacyl-CoA dehydrogenase activity intrinsic to the alpha-subunit. The potencies of NSAIDs as inhibitors of human colon carcinoma cell proliferation correlated well with their affinities for the alpha-subunit. We conclude that inhibition of long chain fatty acid oxidation via binding of NSAIDs to the alpha-subunit of the trifunctional protein may contribute to the inhibitory effects of NSAIDs on colorectal carcinoma cell growth.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1998

Local interaction fields and adaptive regularizers for surface reconstruction and image relaxation.

A set of novel local interaction fields associated with input point data and adaptive regularizers are introduced for some problems in image processing and early-middle vision. The local interaction field is used to take the place of the delta-error term in conventional approaches. It consists of two parts; one is the usual error term, the other is a window function whose shape, size and orientation can be adapted to local structures in specific applications. Unlike the usual delta-error term, local interaction fields favour local flatness and thus impose smoothing implicitly. Several adaptive regularizers are introduced to keep discontinuities while smoothing. In finding solutions, even the simplest gradient descent algorithm is efficient in many examples. The results are stable under varying parameters and quite robust against noise.

Image Processing, Computer-Assisted↗
PubMed1997

Patterns of tuberculosis transmission in Central Los Angeles.

CONTEXT: Recent studies suggest that many tuberculosis cases in urban areas result from recent transmission. Delineation of the epidemiologic links between patients is important to optimize strategies to reduce tuberculosis transmission. OBJECTIVE: To identify epidemiologic links among recently infected urban patients with tuberculosis. DESIGN: Prospective evaluation of patients with tuberculosis. SETTING: Central Los Angeles, Calif. PATIENTS: A total of 162 patients who had culture-proven tuberculosis. INTERVENTIONS: Patients were prospectively interviewed to identify their contacts and whereabouts. The IS6110-based and pTBN12-based restriction fragment length polymorphism analyses were performed on Mycobacterium tuberculosis isolates. Patients whose isolates had identical or closely related restriction fragment length polymorphism patterns were considered a cluster. Unconditional logistic regression was used to identify independent predictors of clustering. MAIN OUTCOME MEASURES: Relationship of clinical and epidemiologic variables to clustering. RESULTS: A total of 96 (59%) of 162 patients were in 8 clusters. Only 2 of the 96 clustered patients named others in the cluster as contacts. The degree of homelessness was an independent predictor of clustering. Compared with nonclustered patients, patients in 6 clusters were significantly more likely to have spent time at 3 shelters and other locations when at least 1 patient in the cluster was contagious, and these locations were independent predictors of clustering. Among nonhomeless persons, clustered patients were significantly more likely than nonclustered patients to have used daytime services at 3 shelters. CONCLUSIONS: (1) Traditional contact investigation does not reliably identify patients infected with the same M tuberculosis strain, and (2) locations at which the homeless congregate are important sites of tuberculosis transmission for homeless and nonhomeless persons. Measures that reduce tuberculosis transmission should be based on locations rather than on personal contacts.

Adolescent↗
PubMed1997

Identification, partial characterization, and genetic mapping of kinesin-like protein genes in mouse.

Microtubule-dependent motors of the kinesin superfamily have undergone structural and functional diversification during evolution and play crucial roles in cell division and intracellular transport. Degenerate oligonucleotides homologous to highly conserved regions of sequence within the motor domain were used in a polymerase chain reaction to isolate five new members (KIF3C, KIFC2, KIFC3, KIFC4, and KIF22) of the kinesin superfamily from a mouse brain cDNA library. Northern analysis showed that KIF3C and KIFC2 are expressed mainly in neural tissues, that KIFC4 and KIF22 are expressed primarily in proliferative tissues and cell lines, and that KIFC3 is apparently ubiquitous. To elucidate the organization of genes encoding kinesin-like motors in the mouse genome and to explore the potential associations of these genes with classical mouse mutations or human genetic diseases, these new genes as well as genes encoding the previously reported KIF3A and KIF3B motors were mapped to mouse chromosomes by using an interspecific backcross panel of DNAs from The Jackson Laboratory. The data indicate that the gene KIFC4 is present in three copies in the mouse genome on chromosomes 13 (KIFC4A), 10 (KIFC4B), and 17 (KIFC4C). The gene KIF22 is present in two copies on chromosomes 7 (KIF22A) and 1 (KIF22B). The genes KIF3A, KIF3B, KIF3C, KIFC2, and KIFC3 are each single loci and map to chromosomes 11, 2, 12, 15, and 8, respectively.

Amino Acid Sequence↗
PubMed1997

Urinary microalbumin and retinol-binding protein assay for verifying children's nephron development and maturation.

In order to further understanding of the development and maturation of the renal tubular reabsorption and glomerular permeability functions for the determination of the clinical pathological manifestation and treatment processing of renal diseases, random urine samples were collected from healthy subjects aged from birth to 60 years. All the samples were stored frozen at -70 degrees C for 4 months. The concentrations of the retinol-binding protein (RBP) and microalbumin (MALB) in urine were measured by enzyme-linked immunosorbent assay and at 492 nm with the microplate reader as a valuable marker of renal tubular and glomerular development and maturation The concentrations of RBP and MALB in urine gradually decrease with age. The level of RBP in urine is higher in children before 3 years than after 3 years (P < 0.01). The levels of MALB in urine is higher in children before 1 year of age than after 1 year (P < 0.01). Our results suggest that the development and maturation of the glomerular permeability functions and the renal tubular reabsorption are gradual and continuous processes from birth to adolescence but the key stage of their maturation may be at about 1 year and 3 years respectively: and that the rate of the tubular development may be slower than that of the glomerular development. Our results also extend existing data for normal ranges of RBP and MALB in urine from neonates to adults.

Adolescent↗
PubMed1997

Synthesis of epothilones A and B in solid and solution phase.

Epothilones A and B, two compounds that have been recently isolated from myxobacterium Sorangium cellulosum strain 90, have generated intense interest among chemists, biologists and clinicians owing to the structural complexity, unusual mechanism of interaction with microtubules and anticancer potential of these molecules. Like taxol, they exhibit cytotoxicity against tumour cells by inducing microtubule assembly and stabilization, even in taxol-resistant cell lines. Following the structural elucidation of these molecules by X-ray crystallography in 1996, several syntheses of epothilones A and B have been reported, indicative of the potential importance of these molecules in the cancer field. Here we report the first solid-phase synthesis of epothilone A, the total synthesis of epothilone B, and the generation of a small epothilone library. The solid-phase synthesis applied here to epothilone A could open up new possibilities in natural-product synthesis and, together with solution-phase synthesis of other epothilones, paves the way for the generation of large combinatorial libraries of these important molecules for biological screening.

Antineoplastic Agents↗
PubMed1997

Cellular expression of antiapoptotic BCL-2 oncoprotein in newly diagnosed childhood acute lymphoblastic leukemia: a Children's Cancer Group Study.

We found a marked variation in BCL-2 oncoprotein expression levels of primary leukemic cells from 338 children with newly diagnosed acute lymphoblastic leukemia (ALL). None of the high-risk features predictive of poor treatment outcome in childhood ALL, such as older age, high white blood cell (WBC) count, organomegaly, T-lineage immunophenotype, ability of leukemic cells to cause overt leukemia in severe combined immunodeficient (SCID) mice, presence of MLL-AF4, and BCR-ABL fusion transcripts were associated with high levels of BCL-2 expression. Overall, high BCL-2 levels were not associated with slow early response, failure to achieve complete remission, or poor event-free survival. High BCL-2 levels in primary leukemic cells predicted slow early response only in T-lineage ALL patients, which comprised approximately 15% of the total patient population. Even for this small subset of patients, the level of BCL-2 expression did not have a significant impact on the short-term event-free survival.

Adolescent↗
PubMed1997

An unexpected localization of basonuclin in the centrosome, mitochondria, and acrosome of developing spermatids.

Basonuclin is a zinc finger protein that was thought to be restricted to keratinocytes of stratified squamous epithelia. In epidermis, basonuclin is associated with the nuclei of mitotically active basal cells but not in terminally differentiating keratinocytes. We report here the isolation of a novel form of basonuclin, which we show is also expressed in stratified epithelia. Most unexpectedly, we find both forms in testis, where a surprising localization pattern was uncovered. While basonuclin RNA expression occurs in mitotically active germ cells, protein was not detected until the meiotic stage, where basonuclin localized to the appendage of the distal centriole of spermatocytes and spermatids. Near the end of spermiogenesis, basonuclin also accumulated in the acrosome and mitochondrial sheath surrounding the flagellum. Intriguingly, a perfect six-amino acid residue mitochondrial targeting sequence (Komiya, T., N. Hachiya, M. Sakaguchi, T. Omura, and K. Mihara. 1994. J. Biol. Chem. 269:30893-30897; Shore, G.C., H.M. McBride, D.G. Millar, N.A. Steenaart, and M. Nguyen. 1995. Eur. J. Biochem. 227: 9-18; McBride, H.M., I.S. Goping, and G.C. Shore. 1996. J. Cell. Biol. 134:307-313) is present in basonuclin 1a but not in the 1b form. Moreover, three distinct affinity-purified peptide antibodies gave this unusual pattern of basonuclin antibody staining, which was confirmed by cell fractionation studies. Our findings suggest a unique role for basonuclin in centrosomes within the developing spermatid, and a role for one of the protein forms in germ cell mitochondrial function. Its localization with the acrosome suggests that it may also perform a special function during or shortly after fertilization.

Acrosome↗
PubMed1997

The characterization, molecular cloning, and expression of a novel hematopoietic cell antigen from CD34+ human bone marrow cells.

The adhesion molecule BEN/SC1/DM-GRASP (BEN) is a marker in the developing chicken nervous system that is also expressed on the surface of embryonic and adult hematopoietic cells such as immature thymocytes, myeloid progenitors, and erythroid progenitors. F84.1 and KG-CAM, two monoclonal antibodies to rat neuronal glycoproteins with similarity to BEN, cross-react with an antigen on rat hematopoietic progenitors, but F84.1 only also recognizes human blood cell progenitors. We have defined the antigen recognized by F84.1 as the hematopoietic cell antigen (HCA). HCA expression was detected on 40% to 70% of CD34+ fetal and adult bone marrow cells and mobilized peripheral blood cells. Precursor cell activity for long-term in vitro bone marrow cell culture was confined to the subset of CD34+ cells that coexpress HCA. HCA is expressed by the most primitive subsets of CD34+ cells, including all rhodamine 123(lo), Thy-1+, and CD38(-/lo) CD34+ adult bone marrow cells. HCA was also detected on myeloid progenitors but not on early B-cell progenitors. We also describe here the cloning and characterization of cDNAs encoding two variants of the human HCA antigen (huHCA-1 and huHCA-2) and of a cDNA clone encoding rat HCA (raHCA). The deduced amino acid sequences of huHCA and raHCA are homologous to that of chicken BEN. Recombinant proteins produced from either human or rat HCA cDNAs were recognized by F84.1, whereas rat HCA but not human HCA was recognized by antirat KG-CAM. Expression of either form of huHCA in CHO cells conferred homophilic adhesion that could be competed with soluble recombinant huHCA-Fc. The molecular cloning of HCA and the availability of recombinant HCA should permit further evaluation of its role in human and rodent hematopoiesis.

Adult↗