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Biomedical subjects

B M Wang

Publications and source records attributed to B M Wang.

At least 37 records · Page 2Linked to original sources
PubMed1989

Characteristic of marrow culture and clinical relevance in leukemia with 8/21 translocation.

Karyotypes and in vitro cultures of bone marrow cells from eleven patients with acute myelogenous leukemia M2 type were performed. 8/21 translocation was found in 5 patients. In all of them the cultures in vitro shared one characteristic, i.e., clusters were small and less in number. These patients could relatively easily obtain complete remission. The similarity of CFU-GM in patients with t (8; 21) may be another important biological phenotype.

Adolescent↗
PubMed1989

Studies on CFU-mix of 47 patients with leukemia and myelodysplastic syndrome.

By limiting dilution assay, CFU-Mix of 47 cases of untreated leukemia, myelodysplastic syndrome and 30 cases of normal adults were studied. It is suggested that most cases of acute nonlymphocytic leukemia, like chronic myelogenous leukemia (CML) and myelodysplastic syndrome should have defect in pluripotent hemopoietic stem cell. The CFU-Mix of acute myelogenous leukemia (AML) and CML were obviously lower than that of normal adults (p less than 0.001). By light microscopy, scanning and transmission electron microscopy, it was confirmed that the CFU-Mix colonies, of leukemic patients were chiefly composed of leukemic cells. Their incorporating rate of 3H-TdR was high in the early stage of culture, but that of 55 + 59Fe was low in the whole course. This phenomenon was quite different from that of the normal adults in that the CFU-Mix of the patients showed distinctive proliferation and differentiation into the leukemic progenitor cells.

Adolescent↗
PubMed1989

[Flow cytometric analysis of the effect of activated macrophages on alveolar cell carcinoma of lung in vitro].

Evidences have shown that activated macrophages were cytotoxic to tumor cells but the mechanism of this killing effect is not well understood. Flow cytometry was used to study the effect of activated macrophages on cell proliferation cycle of alveolar cell carcinoma of lung (A 549). Among 74 C57BL/6J mice, 30 as experimental group were given corynebacterium parvum 0.5 ml (1 mg)/mouse intraperitoneally, and 44 as control group were given normal saline 0.5 ml/mouse instead. Peritoneal macrophages of both groups were co-cultured with A 549 in the ratio of 10:1 and 20:1 for 24 and 48 hrs respectively. Specimens were assayed with LXJ-Laser flow cytometer and relative % of tumor cells in G1/O, S and G2 + M phased were calculated by morphometry using Baisech's mathematical model and Zeiss OPTON Video plan. Results indicated that in the experimental group with E/T 20:1, co-cultured for 24 hrs., the % of tumor cells in S phase was markedly decreased (28.44%) and those in G1/0 phase was increased (60.18%) (P less than 0.01); while those of the control group were 40.41% and 49.99% respectively. Changes present in S and G1/0 phase tumor cells of the experimental group indicate that activated macrophages may block tumor cells from the G1/0 to S phase and thus affect their proliferation.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1989

[Studies on CFU-Mix in 54 cases of leukemia and myelodysplastic syndrome].

By use of limiting dilution assay, it is confirmed that most of acute nonlymphocytic leukemia, such as chronic myelogenous leukemia and myelodysplastic syndrome, had defect in the stage of pluripotent hemopoietic stem cell. With light microscopy, scanning and transmission electron microscopy, colonies which originated from leukemic progenitor cells (L-CFU) were ascertained. The incorporated rates of 3H-TdR and 55 + 59Fe showed that proliferative manner of LCFU was apparently different from that of normal adults.

Adolescent↗
PubMed1987

High frequency generalized transduction by miniMu plasmid phage.

Deletion derivatives of phage Mu which replicate as multicopy plasmids, and also transpose and package like Mu, have been developed for the in vivo cloning of bacterial genes. We show here that these miniMu plasmid phage are also efficient at generalized transduction and that both in vivo cloning and generalized transduction of a given gene can be accomplished in a single experiment.

Coliphages↗
PubMed1987

Cloning and characterization of the Escherichia coli K-12 alanine-valine transaminase (avtA) gene.

avtA, which encodes the alanine-valine transaminase, transaminase C, was cloned in vivo with high- and low-copy-number mini-Mu cloning vectors. The phenotype conferred by the cloned avtA+ gene usually depended upon the plasmid copy number; most high-copy-number avtA+ plasmids permitted isoleucine-requiring ilvE strains to grow in the absence of isoleucine (multicopy suppression), while low-copy-number avtA+ plasmids did not. avtA was mapped to a 1.25-kilobase segment by comparison of the restriction maps of 24 independent mini-Mu plasmids and then by gamma-delta (Tn1000) mutagenesis of a pBR322-avtA+ plasmid. The direction of transcription of avtA on the cloned fragment was determined with fusions to a promoterless lac gene.

Chromosome Mapping↗
PubMed1984

Interaction of calcium and neomycin with anionic phospholipid-lecithin liposomes. A differential scanning calorimetry study.

The interactions of calcium and neomycin with liposomes of various anionic phospholipids plus lecithin were studied by differential scanning calorimetry. Phosphatidylinositol bisphosphate differed from other acidic phospholipids in its interactions with both calcium and neomycin. Calcium, at concentrations as low as 1 mM, induced the appearance of a second transition peak in phosphatidylinositol bisphosphate-enriched liposomes only. Neomycin acted antagonistically and precluded this phase separation. In addition, neomycin lowered the phase transition temperature of phosphatidylinositol bisphosphate-lecithin liposomes while it raised the transition temperature of all other anionic phospholipid-lecithin liposomes tested. This fluidizing effect of neomycin and the antagonism to calcium may induce critical alterations of properties of biological membranes. The study supports and extends our previous findings and conclusions that phosphatidylinositol bisphosphate may play a crucial role in the expression of aminoglycoside toxicity.

Calcium↗
PubMed1984

Characterization of aminoglycoside-lipid interactions and development of a refined model for ototoxicity testing.

Aminoglycoside interactions with various phospholipids were measured in three model systems and compared with the ototoxicities of the drugs: (a) competition for [14C]neomycin binding; (b) competition for 45Ca2+ binding; and (c) effect on surface pressure of monomolecular lipid films. The efficacies of the antibiotics in displacing neomycin from phosphatidylserine, phosphatidylinositol or phosphatidylinositol bisphosphate were netilmicin greater than neomycin greater than or equal to gentamicin; the efficacies in displacing calcium from phosphatidylinositol, phosphatidylinositol phosphate or phosphatidylinositol bisphosphate were netilmicin greater than gentamicin greater than neomycin much greater than kanamycin greater than spectinomycin. Neither measure correlated well with the ototoxicities of the drugs which were quantitated at equimolar drug concentrations in cochlear perfusions: neomycin greater than gentamicin greater than or equal to tobramycin greater than netilmicin greater than or equal to amikacin. When monomolecular films of phosphatidylcholine with phosphatidylserine, cardiolipin, phosphatidylinositol, or phosphatidylinositol phosphate or bisphosphate were challenged with neomycin, the phosphatidylinositol bisphosphate film showed a unique dose-dependent increase in surface pressure while the others showed a decrease or no significant effect. The abilities of aminoglycosides to increase the surface pressure of a film of phosphatidylcholine:phosphatidylinositol bisphosphate (1:1 molar ratio) in the presence of 3 mM CaCl2 correlated well with their toxicities. Non-ototoxic cations increased the film pressure or left it unaffected. The results confirm the unique interactions between aminoglycosides and phosphatidylinositol bisphosphate as a possible basis of a mechanism of toxicity and development of a drug-screening system.

Aminoglycosides↗