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Biomedical subjects

L Z Yu

Publications and source records attributed to L Z Yu.

12 recordsLinked to original sources
PubMed2000

Solid-phase extraction of acidic herbicides.

A discussion of solid-phase extraction method development for acidic herbicides is presented that reviews sample matrix modification, extraction sorbent selection, derivatization procedures for gas chromatographic analysis, and clean-up procedures for high-performance liquid chromatographic analysis. Acidic herbicides are families of compounds that include derivatives of phenol (dinoseb, dinoterb and pentachlorophenol), benzoic acid (acifluorfen, chloramben, dicamba, 3,5-dichlorobenzoic acid and dacthal--a dibenzoic acid derivative), acetic acid [2,4-dichlorophenoxyacetic acid (2,4-D), 4-chloro-2-methylphenoxyacetic acid (MCPA) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T)], propanoic acid [dichlorprop, fluazifop, haloxyfop, 2-(4-chloro-2-methylphenoxy)propanoic acid (MCPP) and silvex], butanoic acid [4-(2,4-dichlorophenoxy)butanoic acid (2,4-DB) and 4-(4-chloro-2-methylphenoxy)butanoic acid (MCPB)], and other miscellaneous acids such as pyridinecarboxylic acid (picloram) and thiadiazine dioxide (bentazon).

Chromatography, Gas↗
PubMed1999

Chromosomal aberrations during progression of chronic myeloid leukemia identified by cytogenetic and molecular cytogenetic tools: implication of 1q12-21.

To study the genomic abnormality underlying the acute transformation of chronic myeloid leukemia (CML), 15 CML patients in blast crisis (BC), 3 in accelerated phase (AP), and 20 in chronic phase (CP) were analyzed by conventional cytogenetics, comparative genomic hybridization (CGH), and dual-color chromosomal painting. Philadelphia (Ph) chromosome was identified in every case studied. Only 5 among 20 CP patients had additional abnormalities while 13 of 18 patients with disease progression (BC + AP) showed extra numerical and/or structural chromosomal aberrations. Cytogenetically, the most common chromosome gains during BC and AP were double or triple Ph chromosomes (5 of 14 cases) and trisomy 8 (5 of 14 cases). Trisomies 7 and 17 (1 of 14 cases each) were also observed. CGH analysis detected genetic imbalances in eight cases. Gains of chromosome 20 (3 cases) and 17q (2 cases) were observed, respectively. The recurrent chromosome loss was the deletion of the short arm of chromosome 17, seen in one case with i(17)(q10) and one case with an unbalanced translocation (1;17). In one case, a very complex chromosomal rearrangement, del(3),del(6),der(6)t(17;3;6),der(17)t(6;17), was seen. A novel finding of this work is the involvement of chromosome 1(q12-21qter) in CML disease progression. Overrepresentation of 1(q12-21qter) region was detected by CGH in one case which had a derivative chromosome 17. This abnormal chromosome was later confirmed by fluorescence in situ hybridization (FISH) painting to be a fusion between chromosome 1 and 17 to form the der(17)t(1;17) (q12-21;p11). Two other cases showed the same region being involved in translocations, t(1;10)(q12-21;q26) and t(1;11)(q12-21;p15). It is possible that one or more genes residing on chromosome 1q12-21 may be important in the acute transformation of CML. In conclusion, we find that the combined use of CGH, chromosome painting, and classic cytogenetic analysis allows a better evaluation of the genomic aberration involved in CML blastic transformation, and offers new directions for its further molecular investigations.

Adult↗
PubMed1998

Targeted diagnosis of bladder and ureteral carcinoma using radiolabelled BDI-1.

The aim of this study is to investigate the possibility of radioimmunoimaging (RII) by radiolabelled anti-bladder carcinoma monoclonal antibody BDI-1 applied to diagnosis of bladder cancer and ureteral cancer. BDI-1 was labelled with 131I and 99mTc. The immunoreactivity, pharmacokinetics and biodistribution in mice were studied. RII was performed in 46 patients. The results showed that 131I, 99mTc-BDI-1 have satisfactory immunoreactivity and excellent tumor-locating properties. The blood clearance half-life T1/2alpha and T1/2beta were 35 h in the first phase and 151 h in the second phase, respectively. Thirty-nine patients were studied by an intravesical administration method; the sensitivity was 90.5%. Seven patients were studied by an intravenous administration method. The RII results of three cases with primary or recurrent bladder cancer and three cases with ureteral cancer were confirmed histologically. RII was negative in one patient with suspected lung metastasis that was shown on radiography. The investigation revealed that RII can be used as an auxiliary method for the detection of bladder cancer and may be valuable for the diagnosis of ureteral cancer.

Aged↗
PubMed1996

Construction and expression of single-chain Fv antibody against human bladder carcinoma.

We designed two sets of oligonucleotide primers to amplify the immunoglobulin heavy- and light-chain variable-region genes from genomic DNA by polymerase chain reaction (PCR). The genomic DNA was extracted from hybridoma BDI-1 cells, which secreted a monoclonal antibody (mAb) against human bladder carcinoma. The primers contained special restriction sites that allowed the variable-region genes to be easily cloned for sequencing and expression. The recombinants were sequenced by Sanger's method. It was proved that the full lengths of the VH and VK genes were 366 and 324 bp, respectively. Compared with other published sequences, the VH gene was a member of mouse heavy-chain VH subgroup II and originated from the rearrangement of VH, Dsp2.2 and JH4. The VK gene was VK subgroup IV and from VK and JK4. The VH and VK genes was inserted expression vector pWAI80. By inducement, the ScFv antibodies were expressed and secreted from Escherichia coli. Binding activities against the bladder carcinoma cells were detected. We suggest that ScFv antibody recognized the antigen specifically.

Amino Acid Sequence↗
PubMed1994

Radioimmunoimaging diagnosis of human bladder carcinoma.

The monoclonal antibody (BDI-1) against human bladder carcinoma has been shown to have selective reactivity for bladder cancer. A total of 19 bladder cancer patients were studied by radioimmunoimaging (RII) and a clear immunoscintigraphy was observed in all. Blood samples collected at 1, 2, 3, days after instillation were shown to be almost free from radioactivity. It is suggested that BDI-1, as a target carrier, might also be for instillation target treatment of superficial bladder cancer.

Animals↗
PubMed1990

Application of target-specific drug immunoconjugates to experimental bone marrow replacement therapy in mice.

Immunoconjugates whose cytotoxic component consists of a phytopeptide are often used as purging agents in bone marrow replacement therapy. Less popular are drug immunoconjugates containing a small molecular weight cytotoxic drug attached to the target-specific conjugand via an appropriate spacer molecule. High target specificity, resistance of the drug to intralysosomal proteases and, once cleaved from the spacer, ready exist of the drug from the lysosome are among the advantages drug immunoconjugates hold over phytotoxin immunoconjugates. The cytotoxic drug daunomycin attached via an acid-sensitive spacer to monoclonal antibody of appropriate specificity was shown to purge murine bone marrow of contaminating tumor cells without affecting its hematopoietic potential. Lethally irradiated mice reconstituted with syngeneic bone marrow from which contaminating lymphoma cells had been removed survived indefinitely. Furthermore, lymphoma-bearing mice, provided they were sufficiently irradiated to eliminate tumor cells in situ, were successfully reconstituted with fully allogeneic bone marrow from which potentially graft-versus-host-reactive T-cells had been purged.

Animals↗
PubMed1989

Smelting, underground mining, smoking, and lung cancer: a case-control study in a tin mine area.

An increased risk of lung cancer in the Dachang tin mine of Guangxi has been reported. To investigate the factors contributing to the excessive risk of lung cancer, we conducted a matched case-control study in the mine area and analyzed the effects of multiple factors, such as living and housing conditions, occupational exposure, and smoking, with the methods of conditional logistic regression. The case series consisted of 69 patients with primary bronchial cancer, 55 of whom had died. The control series consisted of 138 individuals, 55 of whom were decreased. The results showed that the factors contributing to the excessive risk of lung cancer in the mine area related mainly to occupational exposure. The significant risk factors were time of exposure to smelting, time of exposure to underground mining, and age at which underground mining was begun. In study model II where living controls were used, daily consumption of cigarettes was an additional risk factor. Furthermore, there was a synergistic action among these factors. The relation of the risk factors to lung cancer is discussed.

Case-Control Studies↗
PubMed1982

U.V.-enhanced reactivation of capsid protein synthesis and infectious centre formation in mouse cells infected with U.V.-irradiated Minute-Virus-of-Mice.

The effect of U.V.-irradiation of mouse A9 cells on their ability to replicate unirradiated and U.V.-irradiated Minute-Virus-of-Mice was studied. The survival of two viral functions was measured in primary infected cells: the synthesis of viral structural proteins, as detected in situ using an immunoenzymatic assay, and the production of infectious centres, as detected by plaque formation onto appropriate indicator cells. Cell irradiation prior to infection enhanced virus survival over that in control cells (U.V.-enhanced reactivation phenomenon). The magnitude of this effect was similar for both viral functions, suggesting that the step(s) of the virus cycle sensitive to the reactivation process precede(s) the release of the primary burst and secondary infection.

Animals↗